| Age | Commit message (Collapse) | Author |
|---|
|
commit cc1582c231ea041fbc68861dfaf957eaf902b829 upstream.
When doing sampling, for example:
perf record -e cycles:u ...
On workloads that do a lot of kernel entry/exits we see kernel
samples, even though :u is specified. This is due to skid existing.
This might be a security issue because it can leak kernel addresses even
though kernel sampling support is disabled.
The patch drops the kernel samples if exclude_kernel is specified.
For example, test on Haswell desktop:
perf record -e cycles:u <mgen>
perf report --stdio
Before patch applied:
99.77% mgen mgen [.] buf_read
0.20% mgen mgen [.] rand_buf_init
0.01% mgen [kernel.vmlinux] [k] apic_timer_interrupt
0.00% mgen mgen [.] last_free_elem
0.00% mgen libc-2.23.so [.] __random_r
0.00% mgen libc-2.23.so [.] _int_malloc
0.00% mgen mgen [.] rand_array_init
0.00% mgen [kernel.vmlinux] [k] page_fault
0.00% mgen libc-2.23.so [.] __random
0.00% mgen libc-2.23.so [.] __strcasestr
0.00% mgen ld-2.23.so [.] strcmp
0.00% mgen ld-2.23.so [.] _dl_start
0.00% mgen libc-2.23.so [.] sched_setaffinity@@GLIBC_2.3.4
0.00% mgen ld-2.23.so [.] _start
We can see kernel symbols apic_timer_interrupt and page_fault.
After patch applied:
99.79% mgen mgen [.] buf_read
0.19% mgen mgen [.] rand_buf_init
0.00% mgen libc-2.23.so [.] __random_r
0.00% mgen mgen [.] rand_array_init
0.00% mgen mgen [.] last_free_elem
0.00% mgen libc-2.23.so [.] vfprintf
0.00% mgen libc-2.23.so [.] rand
0.00% mgen libc-2.23.so [.] __random
0.00% mgen libc-2.23.so [.] _int_malloc
0.00% mgen libc-2.23.so [.] _IO_doallocbuf
0.00% mgen ld-2.23.so [.] do_lookup_x
0.00% mgen ld-2.23.so [.] open_verify.constprop.7
0.00% mgen ld-2.23.so [.] _dl_important_hwcaps
0.00% mgen libc-2.23.so [.] sched_setaffinity@@GLIBC_2.3.4
0.00% mgen ld-2.23.so [.] _start
There are only userspace symbols.
Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: acme@kernel.org
Cc: jolsa@kernel.org
Cc: kan.liang@intel.com
Cc: mark.rutland@arm.com
Cc: will.deacon@arm.com
Cc: yao.jin@intel.com
Link: http://lkml.kernel.org/r/1495706947-3744-1-git-send-email-yao.jin@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 41c25707d21716826e3c1f60967f5550610ec1c9 upstream.
In most cases, a cgroup controller don't care about the liftimes of
cgroups. For the controller, a css becomes online when ->css_online()
is called on it and offline when ->css_offline() is called.
However, cpuset is special in that the user interface it exposes cares
whether certain cgroups exist or not. Combined with the RCU delay
between cgroup removal and css offlining, this can lead to user
visible behavior oddities where operations which should succeed after
cgroup removals fail for some time period. The effects of cgroup
removals are delayed when seen from userland.
This patch adds css_is_dying() which tests whether offline is pending
and updates is_cpuset_online() so that the function returns false also
while offline is pending. This gets rid of the userland visible
delays.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Link: http://lkml.kernel.org/r/327ca1f5-7957-fbb9-9e5f-9ba149d40ba2@oracle.com
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
bits to 64 bits on 64-bit platforms
commit 5ea30e4e58040cfd6434c2f33dc3ea76e2c15b05 upstream.
The stack canary is an 'unsigned long' and should be fully initialized to
random data rather than only 32 bits of random data.
Signed-off-by: Daniel Micay <danielmicay@gmail.com>
Acked-by: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Rik van Riel <riel@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Arjan van Ven <arjan@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: kernel-hardening@lists.openwall.com
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/20170504133209.3053-1-danielmicay@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit c70d9d809fdeecedb96972457ee45c49a232d97f upstream.
When I introduced ptracer_cred I failed to consider the weirdness of
fork where the task_struct copies the old value by default. This
winds up leaving ptracer_cred set even when a process forks and
the child process does not wind up being ptraced.
Because ptracer_cred is not set on non-ptraced processes whose
parents were ptraced this has broken the ability of the enlightenment
window manager to start setuid children.
Fix this by properly initializing ptracer_cred in ptrace_init_task
This must be done with a little bit of care to preserve the current value
of ptracer_cred when ptrace carries through fork. Re-reading the
ptracer_cred from the ptracing process at this point is inconsistent
with how PT_PTRACE_CAP has been maintained all of these years.
Tested-by: Takashi Iwai <tiwai@suse.de>
Fixes: 64b875f7ac8a ("ptrace: Capture the ptracer's creds not PT_PTRACE_CAP")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 30e7d894c1478c88d50ce94ddcdbd7f9763d9cdd upstream.
Enabling the tracer selftest triggers occasionally the warning in
text_poke(), which warns when the to be modified page is not marked
reserved.
The reason is that the tracer selftest installs kprobes on functions marked
__init for testing. These probes are removed after the tests, but that
removal schedules the delayed kprobes_optimizer work, which will do the
actual text poke. If the work is executed after the init text is freed,
then the warning triggers. The bug can be reproduced reliably when the work
delay is increased.
Flush the optimizer work and wait for the optimizing/unoptimizing lists to
become empty before returning from the kprobes tracer selftest. That
ensures that all operations which were queued due to the probes removal
have completed.
Link: http://lkml.kernel.org/r/20170516094802.76a468bb@gandalf.local.home
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Fixes: 6274de498 ("kprobes: Support delayed unoptimizing")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 2c4569ca26986d18243f282dd727da27e9adae4c upstream.
irq_set_chained_handler_and_data() sets up the chained interrupt and then
stores the handler data.
That's racy against an immediate interrupt which gets handled before the
store of the handler data happened. The handler will dereference a NULL
pointer and crash.
Cure it by storing handler data before installing the chained handler.
Reported-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 094f469172e00d6ab0a3130b0e01c83b3cf3a98d upstream.
Cgroup created inside throttled group must inherit current throttle_count.
Broken throttle_count allows to nominate throttled entries as a next buddy,
later this leads to null pointer dereference in pick_next_task_fair().
This patch initialize cfs_rq->throttle_count at first enqueue: laziness
allows to skip locking all rq at group creation. Lazy approach also allows
to skip full sub-tree scan at throttling hierarchy (not in this patch).
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: bsegall@google.com
Link: http://lkml.kernel.org/r/146608182119.21870.8439834428248129633.stgit@buzz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Ben Pineau <benjamin.pineau@mirakl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 754bd598be9bbc953bc709a9e8ed7f3188bfb9d7 upstream.
Hierarchy could be already throttled at this point. Throttled next
buddy could trigger a NULL pointer dereference in pick_next_task_fair().
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ben Segall <bsegall@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/146608183552.21905.15924473394414832071.stgit@buzz
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Ben Pineau <benjamin.pineau@mirakl.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 3fd37226216620c1a468afa999739d5016fbc349 upstream.
Imagine we have a pid namespace and a task from its parent's pid_ns,
which made setns() to the pid namespace. The task is doing fork(),
while the pid namespace's child reaper is dying. We have the race
between them:
Task from parent pid_ns Child reaper
copy_process() ..
alloc_pid() ..
.. zap_pid_ns_processes()
.. disable_pid_allocation()
.. read_lock(&tasklist_lock)
.. iterate over pids in pid_ns
.. kill tasks linked to pids
.. read_unlock(&tasklist_lock)
write_lock_irq(&tasklist_lock); ..
attach_pid(p, PIDTYPE_PID); ..
.. ..
So, just created task p won't receive SIGKILL signal,
and the pid namespace will be in contradictory state.
Only manual kill will help there, but does the userspace
care about this? I suppose, the most users just inject
a task into a pid namespace and wait a SIGCHLD from it.
The patch fixes the problem. It simply checks for
(pid_ns->nr_hashed & PIDNS_HASH_ADDING) in copy_process().
We do it under the tasklist_lock, and can't skip
PIDNS_HASH_ADDING as noted by Oleg:
"zap_pid_ns_processes() does disable_pid_allocation()
and then takes tasklist_lock to kill the whole namespace.
Given that copy_process() checks PIDNS_HASH_ADDING
under write_lock(tasklist) they can't race;
if copy_process() takes this lock first, the new child will
be killed, otherwise copy_process() can't miss
the change in ->nr_hashed."
If allocation is disabled, we just return -ENOMEM
like it's made for such cases in alloc_pid().
v2: Do not move disable_pid_allocation(), do not
introduce a new variable in copy_process() and simplify
the patch as suggested by Oleg Nesterov.
Account the problem with double irq enabling
found by Eric W. Biederman.
Fixes: c876ad768215 ("pidns: Stop pid allocation when init dies")
Signed-off-by: Kirill Tkhai <ktkhai@virtuozzo.com>
CC: Andrew Morton <akpm@linux-foundation.org>
CC: Ingo Molnar <mingo@kernel.org>
CC: Peter Zijlstra <peterz@infradead.org>
CC: Oleg Nesterov <oleg@redhat.com>
CC: Mike Rapoport <rppt@linux.vnet.ibm.com>
CC: Michal Hocko <mhocko@suse.com>
CC: Andy Lutomirski <luto@kernel.org>
CC: "Eric W. Biederman" <ebiederm@xmission.com>
CC: Andrei Vagin <avagin@openvz.org>
CC: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Serge Hallyn <serge@hallyn.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit b9a985db98961ae1ba0be169f19df1c567e4ffe0 upstream.
The code can potentially sleep for an indefinite amount of time in
zap_pid_ns_processes triggering the hung task timeout, and increasing
the system average. This is undesirable. Sleep with a task state of
TASK_INTERRUPTIBLE instead of TASK_UNINTERRUPTIBLE to remove these
undesirable side effects.
Apparently under heavy load this has been allowing Chrome to trigger
the hung time task timeout error and cause ChromeOS to reboot.
Reported-by: Vovo Yang <vovoy@google.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Fixes: 6347e9009104 ("pidns: guarantee that the pidns init will be the last pidns process reaped")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 07a77929ba672d93642a56dc2255dd21e6e2290b upstream.
The author meant to free the variable that was just allocated, instead
of the one that failed to be allocated, but made a simple typo. This
patch rectifies that.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 321027c1fe77f892f4ea07846aeae08cefbbb290 upstream.
Di Shen reported a race between two concurrent sys_perf_event_open()
calls where both try and move the same pre-existing software group
into a hardware context.
The problem is exactly that described in commit:
f63a8daa5812 ("perf: Fix event->ctx locking")
... where, while we wait for a ctx->mutex acquisition, the event->ctx
relation can have changed under us.
That very same commit failed to recognise sys_perf_event_context() as an
external access vector to the events and thereby didn't apply the
established locking rules correctly.
So while one sys_perf_event_open() call is stuck waiting on
mutex_lock_double(), the other (which owns said locks) moves the group
about. So by the time the former sys_perf_event_open() acquires the
locks, the context we've acquired is stale (and possibly dead).
Apply the established locking rules as per perf_event_ctx_lock_nested()
to the mutex_lock_double() for the 'move_group' case. This obviously means
we need to validate state after we acquire the locks.
Reported-by: Di Shen (Keen Lab)
Tested-by: John Dias <joaodias@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Min Chong <mchong@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Fixes: f63a8daa5812 ("perf: Fix event->ctx locking")
Link: http://lkml.kernel.org/r/20170106131444.GZ3174@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 4.4:
- Test perf_event::group_flags instead of group_caps
- Adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit d29216842a85c7970c536108e093963f02714498 upstream.
CAI Qian <caiqian@redhat.com> pointed out that the semantics
of shared subtrees make it possible to create an exponentially
increasing number of mounts in a mount namespace.
mkdir /tmp/1 /tmp/2
mount --make-rshared /
for i in $(seq 1 20) ; do mount --bind /tmp/1 /tmp/2 ; done
Will create create 2^20 or 1048576 mounts, which is a practical problem
as some people have managed to hit this by accident.
As such CVE-2016-6213 was assigned.
Ian Kent <raven@themaw.net> described the situation for autofs users
as follows:
> The number of mounts for direct mount maps is usually not very large because of
> the way they are implemented, large direct mount maps can have performance
> problems. There can be anywhere from a few (likely case a few hundred) to less
> than 10000, plus mounts that have been triggered and not yet expired.
>
> Indirect mounts have one autofs mount at the root plus the number of mounts that
> have been triggered and not yet expired.
>
> The number of autofs indirect map entries can range from a few to the common
> case of several thousand and in rare cases up to between 30000 and 50000. I've
> not heard of people with maps larger than 50000 entries.
>
> The larger the number of map entries the greater the possibility for a large
> number of active mounts so it's not hard to expect cases of a 1000 or somewhat
> more active mounts.
So I am setting the default number of mounts allowed per mount
namespace at 100,000. This is more than enough for any use case I
know of, but small enough to quickly stop an exponential increase
in mounts. Which should be perfect to catch misconfigurations and
malfunctioning programs.
For anyone who needs a higher limit this can be changed by writing
to the new /proc/sys/fs/mount-max sysctl.
Tested-by: CAI Qian <caiqian@redhat.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
[bwh: Backported to 4.4: adjust context]
Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 78f7a45dac2a2d2002f98a3a95f7979867868d73 upstream.
I noticed that reading the snapshot file when it is empty no longer gives a
status. It suppose to show the status of the snapshot buffer as well as how
to allocate and use it. For example:
># cat snapshot
# tracer: nop
#
#
# * Snapshot is allocated *
#
# Snapshot commands:
# echo 0 > snapshot : Clears and frees snapshot buffer
# echo 1 > snapshot : Allocates snapshot buffer, if not already allocated.
# Takes a snapshot of the main buffer.
# echo 2 > snapshot : Clears snapshot buffer (but does not allocate or free)
# (Doesn't have to be '2' works with any number that
# is not a '0' or '1')
But instead it just showed an empty buffer:
># cat snapshot
# tracer: nop
#
# entries-in-buffer/entries-written: 0/0 #P:4
#
# _-----=> irqs-off
# / _----=> need-resched
# | / _---=> hardirq/softirq
# || / _--=> preempt-depth
# ||| / delay
# TASK-PID CPU# |||| TIMESTAMP FUNCTION
# | | | |||| | |
What happened was that it was using the ring_buffer_iter_empty() function to
see if it was empty, and if it was, it showed the status. But that function
was returning false when it was empty. The reason was that the iter header
page was on the reader page, and the reader page was empty, but so was the
buffer itself. The check only tested to see if the iter was on the commit
page, but the commit page was no longer pointing to the reader page, but as
all pages were empty, the buffer is also.
Fixes: 651e22f2701b ("ring-buffer: Always reset iterator to reader page")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit df62db5be2e5f070ecd1a5ece5945b590ee112e0 upstream.
Currently the snapshot trigger enables the probe and then allocates the
snapshot. If the probe triggers before the allocation, it could cause the
snapshot to fail and turn tracing off. It's best to allocate the snapshot
buffer first, and then enable the trigger. If something goes wrong in the
enabling of the trigger, the snapshot buffer is still allocated, but it can
also be freed by the user by writting zero into the snapshot buffer file.
Also add a check of the return status of alloc_snapshot().
Fixes: 77fd5c15e3 ("tracing: Add snapshot trigger to function probes")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 82cc4fc2e70ec5baeff8f776f2773abc8b2cc0ae upstream.
When two function probes are added to set_ftrace_filter, and then one of
them is removed, the update to the function locations is not performed, and
the record keeping of the function states are corrupted, and causes an
ftrace_bug() to occur.
This is easily reproducable by adding two probes, removing one, and then
adding it back again.
# cd /sys/kernel/debug/tracing
# echo schedule:traceoff > set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
# echo \!do_IRQ:traceoff > /debug/tracing/set_ftrace_filter
# echo do_IRQ:traceoff > set_ftrace_filter
Causes:
------------[ cut here ]------------
WARNING: CPU: 2 PID: 1098 at kernel/trace/ftrace.c:2369 ftrace_get_addr_curr+0x143/0x220
Modules linked in: [...]
CPU: 2 PID: 1098 Comm: bash Not tainted 4.10.0-test+ #405
Hardware name: Hewlett-Packard HP Compaq Pro 6300 SFF/339A, BIOS K01 v02.05 05/07/2012
Call Trace:
dump_stack+0x68/0x9f
__warn+0x111/0x130
? trace_irq_work_interrupt+0xa0/0xa0
warn_slowpath_null+0x1d/0x20
ftrace_get_addr_curr+0x143/0x220
? __fentry__+0x10/0x10
ftrace_replace_code+0xe3/0x4f0
? ftrace_int3_handler+0x90/0x90
? printk+0x99/0xb5
? 0xffffffff81000000
ftrace_modify_all_code+0x97/0x110
arch_ftrace_update_code+0x10/0x20
ftrace_run_update_code+0x1c/0x60
ftrace_run_modify_code.isra.48.constprop.62+0x8e/0xd0
register_ftrace_function_probe+0x4b6/0x590
? ftrace_startup+0x310/0x310
? debug_lockdep_rcu_enabled.part.4+0x1a/0x30
? update_stack_state+0x88/0x110
? ftrace_regex_write.isra.43.part.44+0x1d3/0x320
? preempt_count_sub+0x18/0xd0
? mutex_lock_nested+0x104/0x800
? ftrace_regex_write.isra.43.part.44+0x1d3/0x320
? __unwind_start+0x1c0/0x1c0
? _mutex_lock_nest_lock+0x800/0x800
ftrace_trace_probe_callback.isra.3+0xc0/0x130
? func_set_flag+0xe0/0xe0
? __lock_acquire+0x642/0x1790
? __might_fault+0x1e/0x20
? trace_get_user+0x398/0x470
? strcmp+0x35/0x60
ftrace_trace_onoff_callback+0x48/0x70
ftrace_regex_write.isra.43.part.44+0x251/0x320
? match_records+0x420/0x420
ftrace_filter_write+0x2b/0x30
__vfs_write+0xd7/0x330
? do_loop_readv_writev+0x120/0x120
? locks_remove_posix+0x90/0x2f0
? do_lock_file_wait+0x160/0x160
? __lock_is_held+0x93/0x100
? rcu_read_lock_sched_held+0x5c/0xb0
? preempt_count_sub+0x18/0xd0
? __sb_start_write+0x10a/0x230
? vfs_write+0x222/0x240
vfs_write+0xef/0x240
SyS_write+0xab/0x130
? SyS_read+0x130/0x130
? trace_hardirqs_on_caller+0x182/0x280
? trace_hardirqs_on_thunk+0x1a/0x1c
entry_SYSCALL_64_fastpath+0x18/0xad
RIP: 0033:0x7fe61c157c30
RSP: 002b:00007ffe87890258 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: ffffffff8114a410 RCX: 00007fe61c157c30
RDX: 0000000000000010 RSI: 000055814798f5e0 RDI: 0000000000000001
RBP: ffff8800c9027f98 R08: 00007fe61c422740 R09: 00007fe61ca53700
R10: 0000000000000073 R11: 0000000000000246 R12: 0000558147a36400
R13: 00007ffe8788f160 R14: 0000000000000024 R15: 00007ffe8788f15c
? trace_hardirqs_off_caller+0xc0/0x110
---[ end trace 99fa09b3d9869c2c ]---
Bad trampoline accounting at: ffffffff81cc3b00 (do_IRQ+0x0/0x150)
Fixes: 59df055f1991 ("ftrace: trace different functions with a different tracer")
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
non-root cgroups
commit 77f88796cee819b9c4562b0b6b44691b3b7755b1 upstream.
Creation of a kthread goes through a couple interlocked stages between
the kthread itself and its creator. Once the new kthread starts
running, it initializes itself and wakes up the creator. The creator
then can further configure the kthread and then let it start doing its
job by waking it up.
In this configuration-by-creator stage, the creator is the only one
that can wake it up but the kthread is visible to userland. When
altering the kthread's attributes from userland is allowed, this is
fine; however, for cases where CPU affinity is critical,
kthread_bind() is used to first disable affinity changes from userland
and then set the affinity. This also prevents the kthread from being
migrated into non-root cgroups as that can affect the CPU affinity and
many other things.
Unfortunately, the cgroup side of protection is racy. While the
PF_NO_SETAFFINITY flag prevents further migrations, userland can win
the race before the creator sets the flag with kthread_bind() and put
the kthread in a non-root cgroup, which can lead to all sorts of
problems including incorrect CPU affinity and starvation.
This bug got triggered by userland which periodically tries to migrate
all processes in the root cpuset cgroup to a non-root one. Per-cpu
workqueue workers got caught while being created and ended up with
incorrected CPU affinity breaking concurrency management and sometimes
stalling workqueue execution.
This patch adds task->no_cgroup_migration which disallows the task to
be migrated by userland. kthreadd starts with the flag set making
every child kthread start in the root cgroup with migration
disallowed. The flag is cleared after the kthread finishes
initialization by which time PF_NO_SETAFFINITY is set if the kthread
should stay in the root cgroup.
It'd be better to wait for the initialization instead of failing but I
couldn't think of a way of implementing that without adding either a
new PF flag, or sleeping and retrying from waiting side. Even if
userland depends on changing cgroup membership of a kthread, it either
has to be synchronized with kthread_create() or periodically repeat,
so it's unlikely that this would break anything.
v2: Switch to a simpler implementation using a new task_struct bit
field suggested by Oleg.
Signed-off-by: Tejun Heo <tj@kernel.org>
Suggested-by: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Reported-and-debugged-by: Chris Mason <clm@fb.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 62277de758b155dc04b78f195a1cb5208c37b2df upstream.
In case of error, the function kthread_run() returns ERR_PTR()
and never returns NULL. The NULL test in the return value check
should be replaced with IS_ERR().
Link: http://lkml.kernel.org/r/1466184839-14927-1-git-send-email-weiyj_lk@163.com
Fixes: 6c43e554a ("ring-buffer: Add ring buffer startup selftest")
Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 5402e97af667e35e54177af8f6575518bf251d51 upstream.
In PT_SEIZED + LISTEN mode STOP/CONT signals cause a wakeup against
__TASK_TRACED. If this races with the ptrace_unfreeze_traced at the end
of a PTRACE_LISTEN, this can wake the task /after/ the check against
__TASK_TRACED, but before the reset of state to TASK_TRACED. This
causes it to instead clobber TASK_WAKING, allowing a subsequent wakeup
against TRACED while the task is still on the rq wake_list, corrupting
it.
Oleg said:
"The kernel can crash or this can lead to other hard-to-debug problems.
In short, "task->state = TASK_TRACED" in ptrace_unfreeze_traced()
assumes that nobody else can wake it up, but PTRACE_LISTEN breaks the
contract. Obviusly it is very wrong to manipulate task->state if this
task is already running, or WAKING, or it sleeps again"
[akpm@linux-foundation.org: coding-style fixes]
Fixes: 9899d11f ("ptrace: ensure arch_ptrace/ptrace_request can never race with SIGKILL")
Link: http://lkml.kernel.org/r/xm26y3vfhmkp.fsf_-_@bsegall-linux.mtv.corp.google.com
Signed-off-by: Ben Segall <bsegall@google.com>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit de5540d088fe97ad583cc7d396586437b32149a5 upstream.
Under extremely heavy uses of padata, crashes occur, and with list
debugging turned on, this happens instead:
[87487.298728] WARNING: CPU: 1 PID: 882 at lib/list_debug.c:33
__list_add+0xae/0x130
[87487.301868] list_add corruption. prev->next should be next
(ffffb17abfc043d0), but was ffff8dba70872c80. (prev=ffff8dba70872b00).
[87487.339011] [<ffffffff9a53d075>] dump_stack+0x68/0xa3
[87487.342198] [<ffffffff99e119a1>] ? console_unlock+0x281/0x6d0
[87487.345364] [<ffffffff99d6b91f>] __warn+0xff/0x140
[87487.348513] [<ffffffff99d6b9aa>] warn_slowpath_fmt+0x4a/0x50
[87487.351659] [<ffffffff9a58b5de>] __list_add+0xae/0x130
[87487.354772] [<ffffffff9add5094>] ? _raw_spin_lock+0x64/0x70
[87487.357915] [<ffffffff99eefd66>] padata_reorder+0x1e6/0x420
[87487.361084] [<ffffffff99ef0055>] padata_do_serial+0xa5/0x120
padata_reorder calls list_add_tail with the list to which its adding
locked, which seems correct:
spin_lock(&squeue->serial.lock);
list_add_tail(&padata->list, &squeue->serial.list);
spin_unlock(&squeue->serial.lock);
This therefore leaves only place where such inconsistency could occur:
if padata->list is added at the same time on two different threads.
This pdata pointer comes from the function call to
padata_get_next(pd), which has in it the following block:
next_queue = per_cpu_ptr(pd->pqueue, cpu);
padata = NULL;
reorder = &next_queue->reorder;
if (!list_empty(&reorder->list)) {
padata = list_entry(reorder->list.next,
struct padata_priv, list);
spin_lock(&reorder->lock);
list_del_init(&padata->list);
atomic_dec(&pd->reorder_objects);
spin_unlock(&reorder->lock);
pd->processed++;
goto out;
}
out:
return padata;
I strongly suspect that the problem here is that two threads can race
on reorder list. Even though the deletion is locked, call to
list_entry is not locked, which means it's feasible that two threads
pick up the same padata object and subsequently call list_add_tail on
them at the same time. The fix is thus be hoist that lock outside of
that block.
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Acked-by: Steffen Klassert <steffen.klassert@secunet.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 619bd4a71874a8fd78eb6ccf9f272c5e98bcc7b7 upstream.
Since the change in commit:
fd7a4bed1835 ("sched, rt: Convert switched_{from, to}_rt() / prio_changed_rt() to balance callbacks")
... we don't reschedule a task under certain circumstances:
Lets say task-A, SCHED_OTHER, is running on CPU0 (and it may run only on
CPU0) and holds a PI lock. This task is removed from the CPU because it
used up its time slice and another SCHED_OTHER task is running. Task-B on
CPU1 runs at RT priority and asks for the lock owned by task-A. This
results in a priority boost for task-A. Task-B goes to sleep until the
lock has been made available. Task-A is already runnable (but not active),
so it receives no wake up.
The reality now is that task-A gets on the CPU once the scheduler decides
to remove the current task despite the fact that a high priority task is
enqueued and waiting. This may take a long time.
The desired behaviour is that CPU0 immediately reschedules after the
priority boost which made task-A the task with the lowest priority.
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: fd7a4bed1835 ("sched, rt: Convert switched_{from, to}_rt() prio_changed_rt() to balance callbacks")
Link: http://lkml.kernel.org/r/20170124144006.29821-1-bigeasy@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit e7cc4865f0f31698ef2f7aac01a50e78968985b7 upstream.
While hunting for clues to a use-after-free, Oleg spotted that
perf_event_init_context() can loose an error value with the result
that fork() can succeed even though we did not fully inherit the perf
event context.
Spotted-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: oleg@redhat.com
Fixes: 889ff0150661 ("perf/core: Split context's event group list into pinned and non-pinned lists")
Link: http://lkml.kernel.org/r/20170316125823.190342547@infradead.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 725fc629ff2545b061407305ae51016c9f928fce upstream.
Linux preallocates the task structs of the idle tasks for all possible
CPUs. This currently means they all end up on node 0. This also
implies that the cache line of MWAIT, which is around the flags field in
the task struct, are all located in node 0.
We see a noticeable performance improvement on Knights Landing CPUs when
the cache lines used for MWAIT are located in the local nodes of the
CPUs using them. I would expect this to give a (likely slight)
improvement on other systems too.
The patch implements placing the idle task in the node of its CPUs, by
passing the right target node to copy_process()
[akpm@linux-foundation.org: use NUMA_NO_NODE, not a bare -1]
Link: http://lkml.kernel.org/r/1463492694-15833-1-git-send-email-andi@firstfloor.org
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 9bbb25afeb182502ca4f2c4f3f88af0681b34cae upstream.
Thomas spotted that fixup_pi_state_owner() can return errors and we
fail to unlock the rt_mutex in that case.
Reported-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: dvhart@infradead.org
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170304093558.867401760@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit c236c8e95a3d395b0494e7108f0d41cf36ec107c upstream.
While working on the futex code, I stumbled over this potential
use-after-free scenario. Dmitry triggered it later with syzkaller.
pi_mutex is a pointer into pi_state, which we drop the reference on in
unqueue_me_pi(). So any access to that pointer after that is bad.
Since other sites already do rt_mutex_unlock() with hb->lock held, see
for example futex_lock_pi(), simply move the unlock before
unqueue_me_pi().
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Darren Hart <dvhart@linux.intel.com>
Cc: juri.lelli@arm.com
Cc: bigeasy@linutronix.de
Cc: xlpang@redhat.com
Cc: rostedt@goodmis.org
Cc: mathieu.desnoyers@efficios.com
Cc: jdesfossez@efficios.com
Cc: dvhart@infradead.org
Cc: bristot@redhat.com
Link: http://lkml.kernel.org/r/20170304093558.801744246@infradead.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 907565337ebf998a68cb5c5b2174ce5e5da065eb upstream.
Userspace applications should be allowed to expect the membarrier system
call with MEMBARRIER_CMD_SHARED command to issue memory barriers on
nohz_full CPUs, but synchronize_sched() does not take those into
account.
Given that we do not want unrelated processes to be able to affect
real-time sensitive nohz_full CPUs, simply return ENOSYS when membarrier
is invoked on a kernel with enabled nohz_full CPUs.
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
CC: Josh Triplett <josh@joshtriplett.org>
CC: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Rik van Riel <riel@redhat.com>
Acked-by: Lai Jiangshan <jiangshanlai@gmail.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit fc98c3c8c9dcafd67adcce69e6ce3191d5306c9c upstream.
Use rcuidle console tracepoint because, apparently, it may be issued
from an idle CPU:
hw-breakpoint: Failed to enable monitor mode on CPU 0.
hw-breakpoint: CPU 0 failed to disable vector catch
===============================
[ ERR: suspicious RCU usage. ]
4.10.0-rc8-next-20170215+ #119 Not tainted
-------------------------------
./include/trace/events/printk.h:32 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
RCU used illegally from idle CPU!
rcu_scheduler_active = 2, debug_locks = 0
RCU used illegally from extended quiescent state!
2 locks held by swapper/0/0:
#0: (cpu_pm_notifier_lock){......}, at: [<c0237e2c>] cpu_pm_exit+0x10/0x54
#1: (console_lock){+.+.+.}, at: [<c01ab350>] vprintk_emit+0x264/0x474
stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.10.0-rc8-next-20170215+ #119
Hardware name: Generic OMAP4 (Flattened Device Tree)
console_unlock
vprintk_emit
vprintk_default
printk
reset_ctrl_regs
dbg_cpu_pm_notify
notifier_call_chain
cpu_pm_exit
omap_enter_idle_coupled
cpuidle_enter_state
cpuidle_enter_state_coupled
do_idle
cpu_startup_entry
start_kernel
This RCU warning, however, is suppressed by lockdep_off() in printk().
lockdep_off() increments the ->lockdep_recursion counter and thus
disables RCU_LOCKDEP_WARN() and debug_lockdep_rcu_enabled(), which want
lockdep to be enabled "current->lockdep_recursion == 0".
Link: http://lkml.kernel.org/r/20170217015932.11898-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Reported-by: Tony Lindgren <tony@atomide.com>
Tested-by: Tony Lindgren <tony@atomide.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Petr Mladek <pmladek@suse.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Russell King <rmk@armlinux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 25f71d1c3e98ef0e52371746220d66458eac75bc upstream.
The UEVENT user mode helper is enabled before the initcalls are executed
and is available when the root filesystem has been mounted.
The user mode helper is triggered by device init calls and the executable
might use the futex syscall.
futex_init() is marked __initcall which maps to device_initcall, but there
is no guarantee that futex_init() is invoked _before_ the first device init
call which triggers the UEVENT user mode helper.
If the user mode helper uses the futex syscall before futex_init() then the
syscall crashes with a NULL pointer dereference because the futex subsystem
has not been initialized yet.
Move futex_init() to core_initcall so futexes are initialized before the
root filesystem is mounted and the usermode helper becomes available.
[ tglx: Rewrote changelog ]
Signed-off-by: Yang Yang <yang.yang29@zte.com.cn>
Cc: jiang.biao2@zte.com.cn
Cc: jiang.zhengxiong@zte.com.cn
Cc: zhong.weidong@zte.com.cn
Cc: deng.huali@zte.com.cn
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1483085875-6130-1-git-send-email-yang.yang29@zte.com.cn
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 0b3589be9b98994ce3d5aeca52445d1f5627c4ba upstream.
Andres reported that MMAP2 records for anonymous memory always have
their protection field 0.
Turns out, someone daft put the prot/flags generation code in the file
branch, leaving them unset for anonymous memory.
Reported-by: Andres Freund <andres@anarazel.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Don Zickus <dzickus@redhat.com
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@gmail.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: acme@kernel.org
Cc: anton@ozlabs.org
Cc: namhyung@kernel.org
Fixes: f972eb63b100 ("perf: Pass protection and flags bits through mmap2 interface")
Link: http://lkml.kernel.org/r/20170126221508.GF6536@twins.programming.kicks-ass.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ff9f8a7cf935468a94d9927c68b00daae701667e upstream.
We perform the conversion between kernel jiffies and ms only when
exporting kernel value to user space.
We need to do the opposite operation when value is written by user.
Only matters when HZ != 1000
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit b6416e61012429e0277bd15a229222fd17afc1c1 upstream.
Modules that use static_key_deferred need a way to synchronize with
any delayed work that is still pending when the module is unloaded.
Introduce static_key_deferred_flush() which flushes any pending
jump label updates.
Signed-off-by: David Matlack <dmatlack@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit f931ab479dd24cf7a2c6e2df19778406892591fb upstream.
Both arch_add_memory() and arch_remove_memory() expect a single threaded
context.
For example, arch/x86/mm/init_64.c::kernel_physical_mapping_init() does
not hold any locks over this check and branch:
if (pgd_val(*pgd)) {
pud = (pud_t *)pgd_page_vaddr(*pgd);
paddr_last = phys_pud_init(pud, __pa(vaddr),
__pa(vaddr_end),
page_size_mask);
continue;
}
pud = alloc_low_page();
paddr_last = phys_pud_init(pud, __pa(vaddr), __pa(vaddr_end),
page_size_mask);
The result is that two threads calling devm_memremap_pages()
simultaneously can end up colliding on pgd initialization. This leads
to crash signatures like the following where the loser of the race
initializes the wrong pgd entry:
BUG: unable to handle kernel paging request at ffff888ebfff0000
IP: memcpy_erms+0x6/0x10
PGD 2f8e8fc067 PUD 0 /* <---- Invalid PUD */
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
CPU: 54 PID: 3818 Comm: systemd-udevd Not tainted 4.6.7+ #13
task: ffff882fac290040 ti: ffff882f887a4000 task.ti: ffff882f887a4000
RIP: memcpy_erms+0x6/0x10
[..]
Call Trace:
? pmem_do_bvec+0x205/0x370 [nd_pmem]
? blk_queue_enter+0x3a/0x280
pmem_rw_page+0x38/0x80 [nd_pmem]
bdev_read_page+0x84/0xb0
Hold the standard memory hotplug mutex over calls to
arch_{add,remove}_memory().
Fixes: 41e94a851304 ("add devm_memremap_pages")
Link: http://lkml.kernel.org/r/148357647831.9498.12606007370121652979.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit c1a9eeb938b5433947e5ea22f89baff3182e7075 upstream.
When a disfunctional timer, e.g. dummy timer, is installed, the tick core
tries to setup the broadcast timer.
If no broadcast device is installed, the kernel crashes with a NULL pointer
dereference in tick_broadcast_setup_oneshot() because the function has no
sanity check.
Reported-by: Mason <slash.tmp@free.fr>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Anna-Maria Gleixner <anna-maria@linutronix.de>
Cc: Richard Cochran <rcochran@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>,
Cc: Sebastian Frias <sf84@laposte.net>
Cc: Thibaud Cornic <thibaud_cornic@sigmadesigns.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Link: http://lkml.kernel.org/r/1147ef90-7877-e4d2-bb2b-5c4fa8d3144b@free.fr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
[resolves a messed up backport, so no matching upstream commit]
The backport of upstream commit 777c6e0daebb ("hotplug: Make
register and unregister notifier API symmetric") to linux-4.4.y
introduced a harmless warning in 'allnoconfig' builds as spotted by
kernelci.org:
kernel/cpu.c:226:13: warning: 'cpu_notify_nofail' defined but not used [-Wunused-function]
So far, this is the only stable tree that is affected, as linux-4.6 and
higher contain commit 984581728eb4 ("cpu/hotplug: Split out cpu down functions")
that makes the function used in all configurations, while older longterm
releases so far don't seem to have a backport of 777c6e0daebb.
The fix for the warning is trivial: move the unused function back
into the #ifdef section where it was before.
Link: https://kernelci.org/build/id/586fcacb59b514049ef6c3aa/logs/
Fixes: 1c0f4e0ebb79 ("hotplug: Make register and unregister notifier API symmetric") in v4.4.y
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 794de08a16cf1fc1bf785dc48f66d36218cf6d88 upstream.
Both the wakeup and irqsoff tracers can use the function graph tracer when
the display-graph option is set. The problem is that they ignore the notrace
file, and record the entry of functions that would be ignored by the
function_graph tracer. This causes the trace->depth to be recorded into the
ring buffer. The set_graph_notrace uses a trick by adding a large negative
number to the trace->depth when a graph function is to be ignored.
On trace output, the graph function uses the depth to record a stack of
functions. But since the depth is negative, it accesses the array with a
negative number and causes an out of bounds access that can cause a kernel
oops or corrupt data.
Have the print functions handle cases where a tracer still records functions
even when they are in set_graph_notrace.
Also add warnings if the depth is below zero before accessing the array.
Note, the function graph logic will still prevent the return of these
functions from being recorded, which means that they will be left hanging
without a return. For example:
# echo '*spin*' > set_graph_notrace
# echo 1 > options/display-graph
# echo wakeup > current_tracer
# cat trace
[...]
_raw_spin_lock() {
preempt_count_add() {
do_raw_spin_lock() {
update_rq_clock();
Where it should look like:
_raw_spin_lock() {
preempt_count_add();
do_raw_spin_lock();
}
update_rq_clock();
Cc: Namhyung Kim <namhyung.kim@lge.com>
Fixes: 29ad23b00474 ("ftrace: Add set_graph_notrace filter")
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 9c1645727b8fa90d07256fdfcc45bf831242a3ab upstream.
The clocksource delta to nanoseconds conversion is using signed math, but
the delta is unsigned. This makes the conversion space smaller than
necessary and in case of a multiplication overflow the conversion can
become negative. The conversion is done with scaled math:
s64 nsec_delta = ((s64)clkdelta * clk->mult) >> clk->shift;
Shifting a signed integer right obvioulsy preserves the sign, which has
interesting consequences:
- Time jumps backwards
- __iter_div_u64_rem() which is used in one of the calling code pathes
will take forever to piecewise calculate the seconds/nanoseconds part.
This has been reported by several people with different scenarios:
David observed that when stopping a VM with a debugger:
"It was essentially the stopped by debugger case. I forget exactly why,
but the guest was being explicitly stopped from outside, it wasn't just
scheduling lag. I think it was something in the vicinity of 10 minutes
stopped."
When lifting the stop the machine went dead.
The stopped by debugger case is not really interesting, but nevertheless it
would be a good thing not to die completely.
But this was also observed on a live system by Liav:
"When the OS is too overloaded, delta will get a high enough value for the
msb of the sum delta * tkr->mult + tkr->xtime_nsec to be set, and so
after the shift the nsec variable will gain a value similar to
0xffffffffff000000."
Unfortunately this has been reintroduced recently with commit 6bd58f09e1d8
("time: Add cycles to nanoseconds translation"). It had been fixed a year
ago already in commit 35a4933a8959 ("time: Avoid signed overflow in
timekeeping_get_ns()").
Though it's not surprising that the issue has been reintroduced because the
function itself and the whole call chain uses s64 for the result and the
propagation of it. The change in this recent commit is subtle:
s64 nsec;
- nsec = (d * m + n) >> s:
+ nsec = d * m + n;
+ nsec >>= s;
d being type of cycle_t adds another level of obfuscation.
This wouldn't have happened if the previous change to unsigned computation
would have made the 'nsec' variable u64 right away and a follow up patch
had cleaned up the whole call chain.
There have been patches submitted which basically did a revert of the above
patch leaving everything else unchanged as signed. Back to square one. This
spawned a admittedly pointless discussion about potential users which rely
on the unsigned behaviour until someone pointed out that it had been fixed
before. The changelogs of said patches added further confusion as they made
finally false claims about the consequences for eventual users which expect
signed results.
Despite delta being cycle_t, aka. u64, it's very well possible to hand in
a signed negative value and the signed computation will happily return the
correct result. But nobody actually sat down and analyzed the code which
was added as user after the propably unintended signed conversion.
Though in sensitive code like this it's better to analyze it proper and
make sure that nothing relies on this than hunting the subtle wreckage half
a year later. After analyzing all call chains it stands that no caller can
hand in a negative value (which actually would work due to the s64 cast)
and rely on the signed math to do the right thing.
Change the conversion function to unsigned math. The conversion of all call
chains is done in a follow up patch.
This solves the starvation issue, which was caused by the negative result,
but it does not solve the underlying problem. It merily procrastinates
it. When the timekeeper update is deferred long enough that the unsigned
multiplication overflows, then time going backwards is observable again.
It does neither solve the issue of clocksources with a small counter width
which will wrap around possibly several times and cause random time stamps
to be generated. But those are usually not found on systems used for
virtualization, so this is likely a non issue.
I took the liberty to claim authorship for this simply because
analyzing all callsites and writing the changelog took substantially
more time than just making the simple s/s64/u64/ change and ignore the
rest.
Fixes: 6bd58f09e1d8 ("time: Add cycles to nanoseconds translation")
Reported-by: David Gibson <david@gibson.dropbear.id.au>
Reported-by: Liav Rehana <liavr@mellanox.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Parit Bhargava <prarit@redhat.com>
Cc: Laurent Vivier <lvivier@redhat.com>
Cc: "Christopher S. Hall" <christopher.s.hall@intel.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Link: http://lkml.kernel.org/r/20161208204228.688545601@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 2d13bb6494c807bcf3f78af0e96c0b8615a94385 upstream.
We've got a delay loop waiting for secondary CPUs. That loop uses
loops_per_jiffy. However, loops_per_jiffy doesn't actually mean how
many tight loops make up a jiffy on all architectures. It is quite
common to see things like this in the boot log:
Calibrating delay loop (skipped), value calculated using timer
frequency.. 48.00 BogoMIPS (lpj=24000)
In my case I was seeing lots of cases where other CPUs timed out
entering the debugger only to print their stack crawls shortly after the
kdb> prompt was written.
Elsewhere in kgdb we already use udelay(), so that should be safe enough
to use to implement our timeout. We'll delay 1 ms for 1000 times, which
should give us a full second of delay (just like the old code wanted)
but allow us to notice that we're done every 1 ms.
[akpm@linux-foundation.org: simplifications, per Daniel]
Link: http://lkml.kernel.org/r/1477091361-2039-1-git-send-email-dianders@chromium.org
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Brian Norris <briannorris@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 4d1f0fb096aedea7bb5489af93498a82e467c480 upstream.
NMI handler doesn't call set_irq_regs(), it's set only by normal IRQ.
Thus get_irq_regs() returns NULL or stale registers snapshot with IP/SP
pointing to the code interrupted by IRQ which was interrupted by NMI.
NULL isn't a problem: in this case watchdog calls dump_stack() and
prints full stack trace including NMI. But if we're stuck in IRQ
handler then NMI watchlog will print stack trace without IRQ part at
all.
This patch uses registers snapshot passed into NMI handler as arguments:
these registers point exactly to the instruction interrupted by NMI.
Fixes: 55537871ef66 ("kernel/watchdog.c: perform all-CPU backtrace in case of hard lockup")
Link: http://lkml.kernel.org/r/146771764784.86724.6006627197118544150.stgit@buzz
Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Ulrich Obergfell <uobergfe@redhat.com>
Cc: Aaron Tomlin <atomlin@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit f84df2a6f268de584a201e8911384a2d244876e3 upstream.
When the user namespace support was merged the need to prevent
ptrace from revealing the contents of an unreadable executable
was overlooked.
Correct this oversight by ensuring that the executed file
or files are in mm->user_ns, by adjusting mm->user_ns.
Use the new function privileged_wrt_inode_uidgid to see if
the executable is a member of the user namespace, and as such
if having CAP_SYS_PTRACE in the user namespace should allow
tracing the executable. If not update mm->user_ns to
the parent user namespace until an appropriate parent is found.
Reported-by: Jann Horn <jann@thejh.net>
Fixes: 9e4a36ece652 ("userns: Fail exec for suid and sgid binaries with ids outside our user namespace.")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 64b875f7ac8a5d60a4e191479299e931ee949b67 upstream.
When the flag PT_PTRACE_CAP was added the PTRACE_TRACEME path was
overlooked. This can result in incorrect behavior when an application
like strace traces an exec of a setuid executable.
Further PT_PTRACE_CAP does not have enough information for making good
security decisions as it does not report which user namespace the
capability is in. This has already allowed one mistake through
insufficient granulariy.
I found this issue when I was testing another corner case of exec and
discovered that I could not get strace to set PT_PTRACE_CAP even when
running strace as root with a full set of caps.
This change fixes the above issue with strace allowing stracing as
root a setuid executable without disabling setuid. More fundamentaly
this change allows what is allowable at all times, by using the correct
information in it's decision.
Fixes: 4214e42f96d4 ("v2.4.9.11 -> v2.4.9.12")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit bfedb589252c01fa505ac9f6f2a3d5d68d707ef4 upstream.
During exec dumpable is cleared if the file that is being executed is
not readable by the user executing the file. A bug in
ptrace_may_access allows reading the file if the executable happens to
enter into a subordinate user namespace (aka clone(CLONE_NEWUSER),
unshare(CLONE_NEWUSER), or setns(fd, CLONE_NEWUSER).
This problem is fixed with only necessary userspace breakage by adding
a user namespace owner to mm_struct, captured at the time of exec, so
it is clear in which user namespace CAP_SYS_PTRACE must be present in
to be able to safely give read permission to the executable.
The function ptrace_may_access is modified to verify that the ptracer
has CAP_SYS_ADMIN in task->mm->user_ns instead of task->cred->user_ns.
This ensures that if the task changes it's cred into a subordinate
user namespace it does not become ptraceable.
The function ptrace_attach is modified to only set PT_PTRACE_CAP when
CAP_SYS_PTRACE is held over task->mm->user_ns. The intent of
PT_PTRACE_CAP is to be a flag to note that whatever permission changes
the task might go through the tracer has sufficient permissions for
it not to be an issue. task->cred->user_ns is always the same
as or descendent of mm->user_ns. Which guarantees that having
CAP_SYS_PTRACE over mm->user_ns is the worst case for the tasks
credentials.
To prevent regressions mm->dumpable and mm->user_ns are not considered
when a task has no mm. As simply failing ptrace_may_attach causes
regressions in privileged applications attempting to read things
such as /proc/<pid>/stat
Acked-by: Kees Cook <keescook@chromium.org>
Tested-by: Cyrill Gorcunov <gorcunov@openvz.org>
Fixes: 8409cca70561 ("userns: allow ptrace from non-init user namespaces")
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 777c6e0daebb3fcefbbd6f620410a946b07ef6d0 upstream.
Yu Zhao has noticed that __unregister_cpu_notifier only unregisters its
notifiers when HOTPLUG_CPU=y while the registration might succeed even
when HOTPLUG_CPU=n if MODULE is enabled. This means that e.g. zswap
might keep a stale notifier on the list on the manual clean up during
the pool tear down and thus corrupt the list. Resulting in the following
[ 144.964346] BUG: unable to handle kernel paging request at ffff880658a2be78
[ 144.971337] IP: [<ffffffffa290b00b>] raw_notifier_chain_register+0x1b/0x40
<snipped>
[ 145.122628] Call Trace:
[ 145.125086] [<ffffffffa28e5cf8>] __register_cpu_notifier+0x18/0x20
[ 145.131350] [<ffffffffa2a5dd73>] zswap_pool_create+0x273/0x400
[ 145.137268] [<ffffffffa2a5e0fc>] __zswap_param_set+0x1fc/0x300
[ 145.143188] [<ffffffffa2944c1d>] ? trace_hardirqs_on+0xd/0x10
[ 145.149018] [<ffffffffa2908798>] ? kernel_param_lock+0x28/0x30
[ 145.154940] [<ffffffffa2a3e8cf>] ? __might_fault+0x4f/0xa0
[ 145.160511] [<ffffffffa2a5e237>] zswap_compressor_param_set+0x17/0x20
[ 145.167035] [<ffffffffa2908d3c>] param_attr_store+0x5c/0xb0
[ 145.172694] [<ffffffffa290848d>] module_attr_store+0x1d/0x30
[ 145.178443] [<ffffffffa2b2b41f>] sysfs_kf_write+0x4f/0x70
[ 145.183925] [<ffffffffa2b2a5b9>] kernfs_fop_write+0x149/0x180
[ 145.189761] [<ffffffffa2a99248>] __vfs_write+0x18/0x40
[ 145.194982] [<ffffffffa2a9a412>] vfs_write+0xb2/0x1a0
[ 145.200122] [<ffffffffa2a9a732>] SyS_write+0x52/0xa0
[ 145.205177] [<ffffffffa2ff4d97>] entry_SYSCALL_64_fastpath+0x12/0x17
This can be even triggered manually by changing
/sys/module/zswap/parameters/compressor multiple times.
Fix this issue by making unregister APIs symmetric to the register so
there are no surprises.
Fixes: 47e627bc8c9a ("[PATCH] hotplug: Allow modules to use the cpu hotplug notifiers even if !CONFIG_HOTPLUG_CPU")
Reported-and-tested-by: Yu Zhao <yuzhao@google.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Cc: linux-mm@kvack.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Dan Streetman <ddstreet@ieee.org>
Link: http://lkml.kernel.org/r/20161207135438.4310-1-mhocko@kernel.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 1be5d4fa0af34fb7bafa205aeb59f5c7cc7a089d upstream.
While debugging the rtmutex unlock vs. dequeue race Will suggested to use
READ_ONCE() in rt_mutex_owner() as it might race against the
cmpxchg_release() in unlock_rt_mutex_safe().
Will: "It's a minor thing which will most likely not matter in practice"
Careful search did not unearth an actual problem in todays code, but it's
better to be safe than surprised.
Suggested-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Daney <ddaney@caviumnetworks.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20161130210030.431379999@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit dbb26055defd03d59f678cb5f2c992abe05b064a upstream.
David reported a futex/rtmutex state corruption. It's caused by the
following problem:
CPU0 CPU1 CPU2
l->owner=T1
rt_mutex_lock(l)
lock(l->wait_lock)
l->owner = T1 | HAS_WAITERS;
enqueue(T2)
boost()
unlock(l->wait_lock)
schedule()
rt_mutex_lock(l)
lock(l->wait_lock)
l->owner = T1 | HAS_WAITERS;
enqueue(T3)
boost()
unlock(l->wait_lock)
schedule()
signal(->T2) signal(->T3)
lock(l->wait_lock)
dequeue(T2)
deboost()
unlock(l->wait_lock)
lock(l->wait_lock)
dequeue(T3)
===> wait list is now empty
deboost()
unlock(l->wait_lock)
lock(l->wait_lock)
fixup_rt_mutex_waiters()
if (wait_list_empty(l)) {
owner = l->owner & ~HAS_WAITERS;
l->owner = owner
==> l->owner = T1
}
lock(l->wait_lock)
rt_mutex_unlock(l) fixup_rt_mutex_waiters()
if (wait_list_empty(l)) {
owner = l->owner & ~HAS_WAITERS;
cmpxchg(l->owner, T1, NULL)
===> Success (l->owner = NULL)
l->owner = owner
==> l->owner = T1
}
That means the problem is caused by fixup_rt_mutex_waiters() which does the
RMW to clear the waiters bit unconditionally when there are no waiters in
the rtmutexes rbtree.
This can be fatal: A concurrent unlock can release the rtmutex in the
fastpath because the waiters bit is not set. If the cmpxchg() gets in the
middle of the RMW operation then the previous owner, which just unlocked
the rtmutex is set as the owner again when the write takes place after the
successfull cmpxchg().
The solution is rather trivial: verify that the owner member of the rtmutex
has the waiters bit set before clearing it. This does not require a
cmpxchg() or other atomic operations because the waiters bit can only be
set and cleared with the rtmutex wait_lock held. It's also safe against the
fast path unlock attempt. The unlock attempt via cmpxchg() will either see
the bit set and take the slowpath or see the bit cleared and release it
atomically in the fastpath.
It's remarkable that the test program provided by David triggers on ARM64
and MIPS64 really quick, but it refuses to reproduce on x86-64, while the
problem exists there as well. That refusal might explain that this got not
discovered earlier despite the bug existing from day one of the rtmutex
implementation more than 10 years ago.
Thanks to David for meticulously instrumenting the code and providing the
information which allowed to decode this subtle problem.
Reported-by: David Daney <ddaney@caviumnetworks.com>
Tested-by: David Daney <david.daney@cavium.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Siewior <bigeasy@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Fixes: 23f78d4a03c5 ("[PATCH] pi-futex: rt mutex core")
Link: http://lkml.kernel.org/r/20161130210030.351136722@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit bedc1969150d480c462cdac320fa944b694a7162 upstream.
Carrying out the following steps results in a softlockup in the
RCU callback-offload (rcuo) kthreads:
1. Connect to ixgbevf, and set the speed to 10Gb/s.
2. Use ifconfig to bring the nic up and down repeatedly.
[ 317.005148] IPv6: ADDRCONF(NETDEV_CHANGE): eth2: link becomes ready
[ 368.106005] BUG: soft lockup - CPU#1 stuck for 22s! [rcuos/1:15]
[ 368.106005] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[ 368.106005] task: ffff88057dd8a220 ti: ffff88057dd9c000 task.ti: ffff88057dd9c000
[ 368.106005] RIP: 0010:[<ffffffff81579e04>] [<ffffffff81579e04>] fib_table_lookup+0x14/0x390
[ 368.106005] RSP: 0018:ffff88061fc83ce8 EFLAGS: 00000286
[ 368.106005] RAX: 0000000000000001 RBX: 00000000020155c0 RCX: 0000000000000001
[ 368.106005] RDX: ffff88061fc83d50 RSI: ffff88061fc83d70 RDI: ffff880036d11a00
[ 368.106005] RBP: ffff88061fc83d08 R08: 0000000000000001 R09: 0000000000000000
[ 368.106005] R10: ffff880036d11a00 R11: ffffffff819e0900 R12: ffff88061fc83c58
[ 368.106005] R13: ffffffff816154dd R14: ffff88061fc83d08 R15: 00000000020155c0
[ 368.106005] FS: 0000000000000000(0000) GS:ffff88061fc80000(0000) knlGS:0000000000000000
[ 368.106005] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 368.106005] CR2: 00007f8c2aee9c40 CR3: 000000057b222000 CR4: 00000000000407e0
[ 368.106005] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[ 368.106005] DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
[ 368.106005] Stack:
[ 368.106005] 00000000010000c0 ffff88057b766000 ffff8802e380b000 ffff88057af03e00
[ 368.106005] ffff88061fc83dc0 ffffffff815349a6 ffff88061fc83d40 ffffffff814ee146
[ 368.106005] ffff8802e380af00 00000000e380af00 ffffffff819e0900 020155c0010000c0
[ 368.106005] Call Trace:
[ 368.106005] <IRQ>
[ 368.106005]
[ 368.106005] [<ffffffff815349a6>] ip_route_input_noref+0x516/0xbd0
[ 368.106005] [<ffffffff814ee146>] ? skb_release_data+0xd6/0x110
[ 368.106005] [<ffffffff814ee20a>] ? kfree_skb+0x3a/0xa0
[ 368.106005] [<ffffffff8153698f>] ip_rcv_finish+0x29f/0x350
[ 368.106005] [<ffffffff81537034>] ip_rcv+0x234/0x380
[ 368.106005] [<ffffffff814fd656>] __netif_receive_skb_core+0x676/0x870
[ 368.106005] [<ffffffff814fd868>] __netif_receive_skb+0x18/0x60
[ 368.106005] [<ffffffff814fe4de>] process_backlog+0xae/0x180
[ 368.106005] [<ffffffff814fdcb2>] net_rx_action+0x152/0x240
[ 368.106005] [<ffffffff81077b3f>] __do_softirq+0xef/0x280
[ 368.106005] [<ffffffff8161619c>] call_softirq+0x1c/0x30
[ 368.106005] <EOI>
[ 368.106005]
[ 368.106005] [<ffffffff81015d95>] do_softirq+0x65/0xa0
[ 368.106005] [<ffffffff81077174>] local_bh_enable+0x94/0xa0
[ 368.106005] [<ffffffff81114922>] rcu_nocb_kthread+0x232/0x370
[ 368.106005] [<ffffffff81098250>] ? wake_up_bit+0x30/0x30
[ 368.106005] [<ffffffff811146f0>] ? rcu_start_gp+0x40/0x40
[ 368.106005] [<ffffffff8109728f>] kthread+0xcf/0xe0
[ 368.106005] [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
[ 368.106005] [<ffffffff816147d8>] ret_from_fork+0x58/0x90
[ 368.106005] [<ffffffff810971c0>] ? kthread_create_on_node+0x140/0x140
==================================cut here==============================
It turns out that the rcuos callback-offload kthread is busy processing
a very large quantity of RCU callbacks, and it is not reliquishing the
CPU while doing so. This commit therefore adds an cond_resched_rcu_qs()
within the loop to allow other tasks to run.
Signed-off-by: Ding Tianhong <dingtianhong@huawei.com>
[ paulmck: Substituted cond_resched_rcu_qs for cond_resched. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Dhaval Giani <dhaval.giani@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ceb75787bc75d0a7b88519ab8a68067ac690f55a upstream.
Make sure to drop the reference taken by class_find_device() after
opening the RTC device.
Fixes: 77437fd4e61f (pm: boot time suspend selftest)
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit cfe02a8a973e7e5f66926b8ae38dfce404b19e29 upstream.
When all subsystems are disabled, gcc notices that cgroup_subsys_enabled_key
is a zero-length array and that any access to it must be out of bounds:
In file included from ../include/linux/cgroup.h:19:0,
from ../kernel/cgroup.c:31:
../kernel/cgroup.c: In function 'cgroup_add_cftypes':
../kernel/cgroup.c:261:53: error: array subscript is above array bounds [-Werror=array-bounds]
return static_key_enabled(cgroup_subsys_enabled_key[ssid]);
~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~~
../include/linux/jump_label.h:271:40: note: in definition of macro 'static_key_enabled'
static_key_count((struct static_key *)x) > 0; \
^
We should never call the function in this particular case, so this is
not a bug. In order to silence the warning, this adds an explicit check
for the CGROUP_SUBSYS_COUNT==0 case.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit ee26c013cdee0b947e29d6cadfb9ff3341c69ff9 upstream.
Without this patch irq_domain_disassociate() cannot properly release the
interrupt. In fact, irq_map_generic_chip() checks a bit on 'gc->installed'
but said bit is never cleared, only set.
Commit 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
added irq_map_generic_chip() function and also stated "This lacks a removal
function for now".
This commit provides an implementation of an unmap function that can be
called by irq_domain_disassociate().
[ tglx: Made the function static and removed the export as we have neither
a prototype nor a modular user. ]
Fixes: 088f40b7b027 ("genirq: Generic chip: Add linear irq domain support")
Signed-off-by: Sebastian Frias <sf84@laposte.net>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Cc: Mason <slash.tmp@free.fr>
Cc: Jason Cooper <jason@lakedaemon.net>
Link: http://lkml.kernel.org/r/579F5C5A.2070507@laposte.net
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 58bfea9532552d422bde7afa207e1a0f08dffa7d upstream.
In commit 27727df240c7 ("Avoid taking lock in NMI path with
CONFIG_DEBUG_TIMEKEEPING"), I changed the logic to open-code
the timekeeping_get_ns() function, but I forgot to include
the unit conversion from cycles to nanoseconds, breaking the
function's output, which impacts users like perf.
This results in bogus perf timestamps like:
swapper 0 [000] 253.427536: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426573: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426687: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426800: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.426905: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427022: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427127: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427239: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427346: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 254.427463: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 255.426572: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
Instead of more reasonable expected timestamps like:
swapper 0 [000] 39.953768: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.064839: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.175956: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.287103: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.398217: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.509324: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.620437: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.731546: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.842654: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 40.953772: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
swapper 0 [000] 41.064881: 111111111 cpu-clock: ffffffff810a0de6 native_safe_halt+0x6 ([kernel.kallsyms])
Add the proper use of timekeeping_delta_to_ns() to convert
the cycle delta to nanoseconds as needed.
Thanks to Brendan and Alexei for finding this quickly after
the v4.8 release. Unfortunately the problematic commit has
landed in some -stable trees so they'll need this fix as
well.
Many apologies for this mistake. I'll be looking to add a
perf-clock sanity test to the kselftest timers tests soon.
Fixes: 27727df240c7 "timekeeping: Avoid taking lock in NMI path with CONFIG_DEBUG_TIMEKEEPING"
Reported-by: Brendan Gregg <bgregg@netflix.com>
Reported-by: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Tested-and-reviewed-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/1475636148-26539-1-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
commit 6bd58f09e1d8cc6c50a824c00bf0d617919986a1 upstream.
The timekeeping code does not currently provide a way to translate
externally provided clocksource cycles to system time. The cycle count
is always provided by the result clocksource read() method internal to
the timekeeping code. The added function timekeeping_cycles_to_ns()
calculated a nanosecond value from a cycle count that can be added to
tk_read_base.base value yielding the current system time. This allows
clocksource cycle values external to the timekeeping code to provide a
cycle count that can be transformed to system time.
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: kevin.b.stanton@intel.com
Cc: kevin.j.clarke@intel.com
Cc: hpa@zytor.com
Cc: jeffrey.t.kirsher@intel.com
Cc: netdev@vger.kernel.org
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Christopher S. Hall <christopher.s.hall@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
