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2020-03-09Merge remote-tracking branch 'fslc/4.14-2.3.x-imx' into toradex_4.14-2.3.x-imxMarcel Ziswiler
Conflicts: arch/arm64/boot/dts/freescale/Makefile arch/arm64/boot/dts/freescale/fsl-imx8qm-device.dtsi
2020-03-08Merge tag 'v4.14.170' into 4.14-2.3.x-imxMarcel Ziswiler
This is the 4.14.170 stable release Conflicts: drivers/net/phy/phy_device.c drivers/tty/serial/imx.c include/linux/platform_data/dma-imx-sdma.h net/wireless/util.c
2020-02-12timer: Convert schedule_timeout() to use from_timer()Kees Cook
In preparation for unconditionally passing the struct timer_list pointer to all timer callbacks, switch to using the new from_timer() helper and passing the timer pointer explicitly. Since this special timer is on the stack, it needs to have a wrapper structure to carry state once .data is eliminated. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: linux-mips@linux-mips.org Cc: Petr Mladek <pmladek@suse.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Lai Jiangshan <jiangshanlai@gmail.com> Cc: Sebastian Reichel <sre@kernel.org> Cc: Kalle Valo <kvalo@qca.qualcomm.com> Cc: Paul Mackerras <paulus@samba.org> Cc: Pavel Machek <pavel@ucw.cz> Cc: linux1394-devel@lists.sourceforge.net Cc: Chris Metcalf <cmetcalf@mellanox.com> Cc: linux-s390@vger.kernel.org Cc: linux-wireless@vger.kernel.org Cc: "James E.J. Bottomley" <jejb@linux.vnet.ibm.com> Cc: Wim Van Sebroeck <wim@iguana.be> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Ursula Braun <ubraun@linux.vnet.ibm.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Viresh Kumar <viresh.kumar@linaro.org> Cc: Harish Patil <harish.patil@cavium.com> Cc: Guenter Roeck <linux@roeck-us.net> Cc: Manish Chopra <manish.chopra@cavium.com> Cc: Len Brown <len.brown@intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: linux-pm@vger.kernel.org Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Tejun Heo <tj@kernel.org> Cc: Julian Wiedmann <jwi@linux.vnet.ibm.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Mark Gross <mark.gross@intel.com> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net> Cc: linux-watchdog@vger.kernel.org Cc: linux-scsi@vger.kernel.org Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Stephen Boyd <sboyd@codeaurora.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Stefan Richter <stefanr@s5r6.in-berlin.de> Cc: Michael Reed <mdr@sgi.com> Cc: netdev@vger.kernel.org Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: linuxppc-dev@lists.ozlabs.org Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com> Link: https://lkml.kernel.org/r/1507159627-127660-2-git-send-email-keescook@chromium.org (cherry picked from commit 58e1177b4cd10b0d358faf7d7ebb3779f98bc3ea)
2020-02-07Merge tag 'v4.14.164' into 4.14-2.3.x-imxMarcel Ziswiler
This is the 4.14.164 stable release Conflicts: arch/arm/Kconfig.debug arch/arm/boot/dts/imx7s.dtsi arch/arm/mach-imx/cpuidle-imx6q.c arch/arm/mach-imx/cpuidle-imx6sx.c arch/arm64/kernel/cpu_errata.c arch/arm64/kvm/hyp/tlb.c drivers/crypto/caam/caamalg.c drivers/crypto/mxs-dcp.c drivers/dma/imx-sdma.c drivers/gpio/gpio-vf610.c drivers/gpu/drm/bridge/adv7511/adv7511_drv.c drivers/input/keyboard/imx_keypad.c drivers/input/keyboard/snvs_pwrkey.c drivers/mmc/core/block.c drivers/mmc/core/queue.h drivers/mmc/host/sdhci-esdhc-imx.c drivers/net/can/flexcan.c drivers/net/can/rx-offload.c drivers/net/ethernet/freescale/fec_main.c drivers/net/wireless/ath/ath10k/pci.c drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c drivers/pci/dwc/pci-imx6.c drivers/spi/spi-fsl-lpspi.c drivers/usb/dwc3/gadget.c include/net/tcp.h sound/soc/fsl/Kconfig sound/soc/fsl/fsl_esai.c
2020-02-05cgroup: Prevent double killing of css when enabling threaded cgroupMichal Koutný
commit 3bc0bb36fa30e95ca829e9cf480e1ef7f7638333 upstream. The test_cgcore_no_internal_process_constraint_on_threads selftest when running with subsystem controlling noise triggers two warnings: > [ 597.443115] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3131 cgroup_apply_control_enable+0xe0/0x3f0 > [ 597.443413] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3177 cgroup_apply_control_disable+0xa6/0x160 Both stem from a call to cgroup_type_write. The first warning was also triggered by syzkaller. When we're switching cgroup to threaded mode shortly after a subsystem was disabled on it, we can see the respective subsystem css dying there. The warning in cgroup_apply_control_enable is harmless in this case since we're not adding new subsys anyway. The warning in cgroup_apply_control_disable indicates an attempt to kill css of recently disabled subsystem repeatedly. The commit prevents these situations by making cgroup_type_write wait for all dying csses to go away before re-applying subtree controls. When at it, the locations of WARN_ON_ONCE calls are moved so that warning is triggered only when we are about to misuse the dying css. Reported-by: syzbot+5493b2a54d31d6aea629@syzkaller.appspotmail.com Reported-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Michal Koutný <mkoutny@suse.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-27irqdomain: Add the missing assignment of domain->fwnode for named fwnodeDexuan Cui
[ Upstream commit 711419e504ebd68c8f03656616829c8ad7829389 ] Recently device pass-through stops working for Linux VM running on Hyper-V. git-bisect shows the regression is caused by the recent commit 467a3bb97432 ("PCI: hv: Allocate a named fwnode ..."), but the root cause is that the commit d59f6617eef0 forgets to set the domain->fwnode for IRQCHIP_FWNODE_NAMED*, and as a result: 1. The domain->fwnode remains to be NULL. 2. irq_find_matching_fwspec() returns NULL since "h->fwnode == fwnode" is false, and pci_set_bus_msi_domain() sets the Hyper-V PCI root bus's msi_domain to NULL. 3. When the device is added onto the root bus, the device's dev->msi_domain is set to NULL in pci_set_msi_domain(). 4. When a device driver tries to enable MSI-X, pci_msi_setup_msi_irqs() calls arch_setup_msi_irqs(), which uses the native MSI chip (i.e. arch/x86/kernel/apic/msi.c: pci_msi_controller) to set up the irqs, but actually pci_msi_setup_msi_irqs() is supposed to call msi_domain_alloc_irqs() with the hbus->irq_domain, which is created in hv_pcie_init_irq_domain() and is associated with the Hyper-V chip hv_msi_irq_chip. Consequently, the irq line is not properly set up, and the device driver can not receive any interrupt. Fixes: d59f6617eef0 ("genirq: Allow fwnode to carry name information only") Fixes: 467a3bb97432 ("PCI: hv: Allocate a named fwnode instead of an address-based one") Reported-by: Lili Deng <v-lide@microsoft.com> Signed-off-by: Dexuan Cui <decui@microsoft.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/PU1P153MB01694D9AF625AC335C600C5FBFBE0@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-27signal: Allow cifs and drbd to receive their terminating signalsEric W. Biederman
[ Upstream commit 33da8e7c814f77310250bb54a9db36a44c5de784 ] My recent to change to only use force_sig for a synchronous events wound up breaking signal reception cifs and drbd. I had overlooked the fact that by default kthreads start out with all signals set to SIG_IGN. So a change I thought was safe turned out to have made it impossible for those kernel thread to catch their signals. Reverting the work on force_sig is a bad idea because what the code was doing was very much a misuse of force_sig. As the way force_sig ultimately allowed the signal to happen was to change the signal handler to SIG_DFL. Which after the first signal will allow userspace to send signals to these kernel threads. At least for wake_ack_receiver in drbd that does not appear actively wrong. So correct this problem by adding allow_kernel_signal that will allow signals whose siginfo reports they were sent by the kernel through, but will not allow userspace generated signals, and update cifs and drbd to call allow_kernel_signal in an appropriate place so that their thread can receive this signal. Fixing things this way ensures that userspace won't be able to send signals and cause problems, that it is clear which signals the threads are expecting to receive, and it guarantees that nothing else in the system will be affected. This change was partly inspired by similar cifs and drbd patches that added allow_signal. Reported-by: ronnie sahlberg <ronniesahlberg@gmail.com> Reported-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Tested-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com> Cc: Steve French <smfrench@gmail.com> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: David Laight <David.Laight@ACULAB.COM> Fixes: 247bc9470b1e ("cifs: fix rmmod regression in cifs.ko caused by force_sig changes") Fixes: 72abe3bcf091 ("signal/cifs: Fix cifs_put_tcp_session to call send_sig instead of force_sig") Fixes: fee109901f39 ("signal/drbd: Use send_sig not force_sig") Fixes: 3cf5d076fb4d ("signal: Remove task parameter from force_sig") Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-27perf/ioctl: Add check for the sample_period valueRavi Bangoria
[ Upstream commit 913a90bc5a3a06b1f04c337320e9aeee2328dd77 ] perf_event_open() limits the sample_period to 63 bits. See: 0819b2e30ccb ("perf: Limit perf_event_attr::sample_period to 63 bits") Make ioctl() consistent with it. Also on PowerPC, negative sample_period could cause a recursive PMIs leading to a hang (reported when running perf-fuzzer). Signed-off-by: Ravi Bangoria <ravi.bangoria@linux.ibm.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: 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: linuxppc-dev@lists.ozlabs.org Cc: maddy@linux.vnet.ibm.com Cc: mpe@ellerman.id.au Fixes: 0819b2e30ccb ("perf: Limit perf_event_attr::sample_period to 63 bits") Link: https://lkml.kernel.org/r/20190604042953.914-1-ravi.bangoria@linux.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-27kdb: do a sanity check on the cpu in kdb_per_cpu()Dan Carpenter
[ Upstream commit b586627e10f57ee3aa8f0cfab0d6f7dc4ae63760 ] The "whichcpu" comes from argv[3]. The cpu_online() macro looks up the cpu in a bitmap of online cpus, but if the value is too high then it could read beyond the end of the bitmap and possibly Oops. Fixes: 5d5314d6795f ("kdb: core for kgdb back end (1 of 2)") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Douglas Anderson <dianders@chromium.org> Signed-off-by: Daniel Thompson <daniel.thompson@linaro.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-23tick/sched: Annotate lockless access to last_jiffies_updateEric Dumazet
commit de95a991bb72e009f47e0c4bbc90fc5f594588d5 upstream. syzbot (KCSAN) reported a data-race in tick_do_update_jiffies64(): BUG: KCSAN: data-race in tick_do_update_jiffies64 / tick_do_update_jiffies64 write to 0xffffffff8603d008 of 8 bytes by interrupt on cpu 1: tick_do_update_jiffies64+0x100/0x250 kernel/time/tick-sched.c:73 tick_sched_do_timer+0xd4/0xe0 kernel/time/tick-sched.c:138 tick_sched_timer+0x43/0xe0 kernel/time/tick-sched.c:1292 __run_hrtimer kernel/time/hrtimer.c:1514 [inline] __hrtimer_run_queues+0x274/0x5f0 kernel/time/hrtimer.c:1576 hrtimer_interrupt+0x22a/0x480 kernel/time/hrtimer.c:1638 local_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1110 [inline] smp_apic_timer_interrupt+0xdc/0x280 arch/x86/kernel/apic/apic.c:1135 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 arch_local_irq_restore arch/x86/include/asm/paravirt.h:756 [inline] kcsan_setup_watchpoint+0x1d4/0x460 kernel/kcsan/core.c:436 check_access kernel/kcsan/core.c:466 [inline] __tsan_read1 kernel/kcsan/core.c:593 [inline] __tsan_read1+0xc2/0x100 kernel/kcsan/core.c:593 kallsyms_expand_symbol.constprop.0+0x70/0x160 kernel/kallsyms.c:79 kallsyms_lookup_name+0x7f/0x120 kernel/kallsyms.c:170 insert_report_filterlist kernel/kcsan/debugfs.c:155 [inline] debugfs_write+0x14b/0x2d0 kernel/kcsan/debugfs.c:256 full_proxy_write+0xbd/0x100 fs/debugfs/file.c:225 __vfs_write+0x67/0xc0 fs/read_write.c:494 vfs_write fs/read_write.c:558 [inline] vfs_write+0x18a/0x390 fs/read_write.c:542 ksys_write+0xd5/0x1b0 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x4c/0x60 fs/read_write.c:620 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffffffff8603d008 of 8 bytes by task 0 on cpu 0: tick_do_update_jiffies64+0x2b/0x250 kernel/time/tick-sched.c:62 tick_nohz_update_jiffies kernel/time/tick-sched.c:505 [inline] tick_nohz_irq_enter kernel/time/tick-sched.c:1257 [inline] tick_irq_enter+0x139/0x1c0 kernel/time/tick-sched.c:1274 irq_enter+0x4f/0x60 kernel/softirq.c:354 entering_irq arch/x86/include/asm/apic.h:517 [inline] entering_ack_irq arch/x86/include/asm/apic.h:523 [inline] smp_apic_timer_interrupt+0x55/0x280 arch/x86/kernel/apic/apic.c:1133 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:571 default_idle_call+0x1e/0x40 kernel/sched/idle.c:94 cpuidle_idle_call kernel/sched/idle.c:154 [inline] do_idle+0x1af/0x280 kernel/sched/idle.c:263 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:355 rest_init+0xec/0xf6 init/main.c:452 arch_call_rest_init+0x17/0x37 start_kernel+0x838/0x85e init/main.c:786 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:490 x86_64_start_kernel+0x72/0x76 arch/x86/kernel/head64.c:471 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:241 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.4.0-rc7+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Use READ_ONCE() and WRITE_ONCE() to annotate this expected race. Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/20191205045619.204946-1-edumazet@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-23ptrace: reintroduce usage of subjective credentials in ptrace_has_cap()Christian Brauner
commit 6b3ad6649a4c75504edeba242d3fd36b3096a57f upstream. Commit 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") introduced the ability to opt out of audit messages for accesses to various proc files since they are not violations of policy. While doing so it somehow switched the check from ns_capable() to has_ns_capability{_noaudit}(). That means it switched from checking the subjective credentials of the task to using the objective credentials. This is wrong since. ptrace_has_cap() is currently only used in ptrace_may_access() And is used to check whether the calling task (subject) has the CAP_SYS_PTRACE capability in the provided user namespace to operate on the target task (object). According to the cred.h comments this would mean the subjective credentials of the calling task need to be used. This switches ptrace_has_cap() to use security_capable(). Because we only call ptrace_has_cap() in ptrace_may_access() and in there we already have a stable reference to the calling task's creds under rcu_read_lock() there's no need to go through another series of dereferences and rcu locking done in ns_capable{_noaudit}(). As one example where this might be particularly problematic, Jann pointed out that in combination with the upcoming IORING_OP_OPENAT feature, this bug might allow unprivileged users to bypass the capability checks while asynchronously opening files like /proc/*/mem, because the capability checks for this would be performed against kernel credentials. To illustrate on the former point about this being exploitable: When io_uring creates a new context it records the subjective credentials of the caller. Later on, when it starts to do work it creates a kernel thread and registers a callback. The callback runs with kernel creds for ktask->real_cred and ktask->cred. To prevent this from becoming a full-blown 0-day io_uring will call override_cred() and override ktask->cred with the subjective credentials of the creator of the io_uring instance. With ptrace_has_cap() currently looking at ktask->real_cred this override will be ineffective and the caller will be able to open arbitray proc files as mentioned above. Luckily, this is currently not exploitable but will turn into a 0-day once IORING_OP_OPENAT{2} land in v5.6. Fix it now! Cc: Oleg Nesterov <oleg@redhat.com> Cc: Eric Paris <eparis@redhat.com> Cc: stable@vger.kernel.org Reviewed-by: Kees Cook <keescook@chromium.org> Reviewed-by: Serge Hallyn <serge@hallyn.com> Reviewed-by: Jann Horn <jannh@google.com> Fixes: 69f594a38967 ("ptrace: do not audit capability check when outputing /proc/pid/stat") Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14tracing: Have stack tracer compile when MCOUNT_INSN_SIZE is not definedSteven Rostedt (VMware)
commit b8299d362d0837ae39e87e9019ebe6b736e0f035 upstream. On some archs with some configurations, MCOUNT_INSN_SIZE is not defined, and this makes the stack tracer fail to compile. Just define it to zero in this case. Link: https://lore.kernel.org/r/202001020219.zvE3vsty%lkp@intel.com Cc: stable@vger.kernel.org Fixes: 4df297129f622 ("tracing: Remove most or all of stack tracer stack size from stack_max_size") Reported-by: kbuild test robot <lkp@intel.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-14kernel/trace: Fix do not unregister tracepoints when register ↵Kaitao Cheng
sched_migrate_task fail commit 50f9ad607ea891a9308e67b81f774c71736d1098 upstream. In the function, if register_trace_sched_migrate_task() returns error, sched_switch/sched_wakeup_new/sched_wakeup won't unregister. That is why fail_deprobe_sched_switch was added. Link: http://lkml.kernel.org/r/20191231133530.2794-1-pilgrimtao@gmail.com Cc: stable@vger.kernel.org Fixes: 478142c39c8c2 ("tracing: do not grab lock in wakeup latency function tracing") Signed-off-by: Kaitao Cheng <pilgrimtao@gmail.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-12bpf: Fix passing modified ctx to ld/abs/ind instructionDaniel Borkmann
commit 6d4f151acf9a4f6fab09b615f246c717ddedcf0c upstream. Anatoly has been fuzzing with kBdysch harness and reported a KASAN slab oob in one of the outcomes: [...] [ 77.359642] BUG: KASAN: slab-out-of-bounds in bpf_skb_load_helper_8_no_cache+0x71/0x130 [ 77.360463] Read of size 4 at addr ffff8880679bac68 by task bpf/406 [ 77.361119] [ 77.361289] CPU: 2 PID: 406 Comm: bpf Not tainted 5.5.0-rc2-xfstests-00157-g2187f215eba #1 [ 77.362134] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014 [ 77.362984] Call Trace: [ 77.363249] dump_stack+0x97/0xe0 [ 77.363603] print_address_description.constprop.0+0x1d/0x220 [ 77.364251] ? bpf_skb_load_helper_8_no_cache+0x71/0x130 [ 77.365030] ? bpf_skb_load_helper_8_no_cache+0x71/0x130 [ 77.365860] __kasan_report.cold+0x37/0x7b [ 77.366365] ? bpf_skb_load_helper_8_no_cache+0x71/0x130 [ 77.366940] kasan_report+0xe/0x20 [ 77.367295] bpf_skb_load_helper_8_no_cache+0x71/0x130 [ 77.367821] ? bpf_skb_load_helper_8+0xf0/0xf0 [ 77.368278] ? mark_lock+0xa3/0x9b0 [ 77.368641] ? kvm_sched_clock_read+0x14/0x30 [ 77.369096] ? sched_clock+0x5/0x10 [ 77.369460] ? sched_clock_cpu+0x18/0x110 [ 77.369876] ? bpf_skb_load_helper_8+0xf0/0xf0 [ 77.370330] ___bpf_prog_run+0x16c0/0x28f0 [ 77.370755] __bpf_prog_run32+0x83/0xc0 [ 77.371153] ? __bpf_prog_run64+0xc0/0xc0 [ 77.371568] ? match_held_lock+0x1b/0x230 [ 77.371984] ? rcu_read_lock_held+0xa1/0xb0 [ 77.372416] ? rcu_is_watching+0x34/0x50 [ 77.372826] sk_filter_trim_cap+0x17c/0x4d0 [ 77.373259] ? sock_kzfree_s+0x40/0x40 [ 77.373648] ? __get_filter+0x150/0x150 [ 77.374059] ? skb_copy_datagram_from_iter+0x80/0x280 [ 77.374581] ? do_raw_spin_unlock+0xa5/0x140 [ 77.375025] unix_dgram_sendmsg+0x33a/0xa70 [ 77.375459] ? do_raw_spin_lock+0x1d0/0x1d0 [ 77.375893] ? unix_peer_get+0xa0/0xa0 [ 77.376287] ? __fget_light+0xa4/0xf0 [ 77.376670] __sys_sendto+0x265/0x280 [ 77.377056] ? __ia32_sys_getpeername+0x50/0x50 [ 77.377523] ? lock_downgrade+0x350/0x350 [ 77.377940] ? __sys_setsockopt+0x2a6/0x2c0 [ 77.378374] ? sock_read_iter+0x240/0x240 [ 77.378789] ? __sys_socketpair+0x22a/0x300 [ 77.379221] ? __ia32_sys_socket+0x50/0x50 [ 77.379649] ? mark_held_locks+0x1d/0x90 [ 77.380059] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 77.380536] __x64_sys_sendto+0x74/0x90 [ 77.380938] do_syscall_64+0x68/0x2a0 [ 77.381324] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 77.381878] RIP: 0033:0x44c070 [...] After further debugging, turns out while in case of other helper functions we disallow passing modified ctx, the special case of ld/abs/ind instruction which has similar semantics (except r6 being the ctx argument) is missing such check. Modified ctx is impossible here as bpf_skb_load_helper_8_no_cache() and others are expecting skb fields in original position, hence, add check_ctx_reg() to reject any modified ctx. Issue was first introduced back in f1174f77b50c ("bpf/verifier: rework value tracking"). Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Reported-by: Anatoly Trosinenko <anatoly.trosinenko@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Link: https://lore.kernel.org/bpf/20200106215157.3553-1-daniel@iogearbox.net Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-12bpf: reject passing modified ctx to helper functionsDaniel Borkmann
commit 58990d1ff3f7896ee341030e9a7c2e4002570683 upstream. As commit 28e33f9d78ee ("bpf: disallow arithmetic operations on context pointer") already describes, f1174f77b50c ("bpf/verifier: rework value tracking") removed the specific white-listed cases we had previously where we would allow for pointer arithmetic in order to further generalize it, and allow e.g. context access via modified registers. While the dereferencing of modified context pointers had been forbidden through 28e33f9d78ee, syzkaller did recently manage to trigger several KASAN splats for slab out of bounds access and use after frees by simply passing a modified context pointer to a helper function which would then do the bad access since verifier allowed it in adjust_ptr_min_max_vals(). Rejecting arithmetic on ctx pointer in adjust_ptr_min_max_vals() generally could break existing programs as there's a valid use case in tracing in combination with passing the ctx to helpers as bpf_probe_read(), where the register then becomes unknown at verification time due to adding a non-constant offset to it. An access sequence may look like the following: offset = args->filename; /* field __data_loc filename */ bpf_probe_read(&dst, len, (char *)args + offset); // args is ctx There are two options: i) we could special case the ctx and as soon as we add a constant or bounded offset to it (hence ctx type wouldn't change) we could turn the ctx into an unknown scalar, or ii) we generalize the sanity test for ctx member access into a small helper and assert it on the ctx register that was passed as a function argument. Fwiw, latter is more obvious and less complex at the same time, and one case that may potentially be legitimate in future for ctx member access at least would be for ctx to carry a const offset. Therefore, fix follows approach from ii) and adds test cases to BPF kselftests. Fixes: f1174f77b50c ("bpf/verifier: rework value tracking") Reported-by: syzbot+3d0b2441dbb71751615e@syzkaller.appspotmail.com Reported-by: syzbot+c8504affd4fdd0c1b626@syzkaller.appspotmail.com Reported-by: syzbot+e5190cb881d8660fb1a3@syzkaller.appspotmail.com Reported-by: syzbot+efae31b384d5badbd620@syzkaller.appspotmail.com Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Edward Cree <ecree@solarflare.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-12locking/spinlock/debug: Fix various data racesMarco Elver
[ Upstream commit 1a365e822372ba24c9da0822bc583894f6f3d821 ] This fixes various data races in spinlock_debug. By testing with KCSAN, it is observable that the console gets spammed with data races reports, suggesting these are extremely frequent. Example data race report: read to 0xffff8ab24f403c48 of 4 bytes by task 221 on cpu 2: debug_spin_lock_before kernel/locking/spinlock_debug.c:85 [inline] do_raw_spin_lock+0x9b/0x210 kernel/locking/spinlock_debug.c:112 __raw_spin_lock include/linux/spinlock_api_smp.h:143 [inline] _raw_spin_lock+0x39/0x40 kernel/locking/spinlock.c:151 spin_lock include/linux/spinlock.h:338 [inline] get_partial_node.isra.0.part.0+0x32/0x2f0 mm/slub.c:1873 get_partial_node mm/slub.c:1870 [inline] <snip> write to 0xffff8ab24f403c48 of 4 bytes by task 167 on cpu 3: debug_spin_unlock kernel/locking/spinlock_debug.c:103 [inline] do_raw_spin_unlock+0xc9/0x1a0 kernel/locking/spinlock_debug.c:138 __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:159 [inline] _raw_spin_unlock_irqrestore+0x2d/0x50 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:393 [inline] free_debug_processing+0x1b3/0x210 mm/slub.c:1214 __slab_free+0x292/0x400 mm/slub.c:2864 <snip> As a side-effect, with KCSAN, this eventually locks up the console, most likely due to deadlock, e.g. .. -> printk lock -> spinlock_debug -> KCSAN detects data race -> kcsan_print_report() -> printk lock -> deadlock. This fix will 1) avoid the data races, and 2) allow using lock debugging together with KCSAN. Reported-by: Qian Cai <cai@lca.pw> Signed-off-by: Marco Elver <elver@google.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Will Deacon <will.deacon@arm.com> Link: https://lkml.kernel.org/r/20191120155715.28089-1-elver@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-09ftrace: Avoid potential division by zero in function profilerWen Yang
commit e31f7939c1c27faa5d0e3f14519eaf7c89e8a69d upstream. The ftrace_profile->counter is unsigned long and do_div truncates it to 32 bits, which means it can test non-zero and be truncated to zero for division. Fix this issue by using div64_ul() instead. Link: http://lkml.kernel.org/r/20200103030248.14516-1-wenyang@linux.alibaba.com Cc: stable@vger.kernel.org Fixes: e330b3bcd8319 ("tracing: Show sample std dev in function profiling") Fixes: 34886c8bc590f ("tracing: add average time in function to function profiler") Signed-off-by: Wen Yang <wenyang@linux.alibaba.com> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-09exit: panic before exit_mm() on global init exitchenqiwu
commit 43cf75d96409a20ef06b756877a2e72b10a026fc upstream. Currently, when global init and all threads in its thread-group have exited we panic via: do_exit() -> exit_notify() -> forget_original_parent() -> find_child_reaper() This makes it hard to extract a useable coredump for global init from a kernel crashdump because by the time we panic exit_mm() will have already released global init's mm. This patch moves the panic futher up before exit_mm() is called. As was the case previously, we only panic when global init and all its threads in the thread-group have exited. Signed-off-by: chenqiwu <chenqiwu@xiaomi.com> Acked-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Oleg Nesterov <oleg@redhat.com> [christian.brauner@ubuntu.com: fix typo, rewrite commit message] Link: https://lore.kernel.org/r/1576736993-10121-1-git-send-email-qiwuchen55@gmail.com Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-09tracing: Have the histogram compare functions convert to u64 firstSteven Rostedt (VMware)
commit 106f41f5a302cb1f36c7543fae6a05de12e96fa4 upstream. The compare functions of the histogram code would be specific for the size of the value being compared (byte, short, int, long long). It would reference the value from the array via the type of the compare, but the value was stored in a 64 bit number. This is fine for little endian machines, but for big endian machines, it would end up comparing zeros or all ones (depending on the sign) for anything but 64 bit numbers. To fix this, first derference the value as a u64 then convert it to the type being compared. Link: http://lkml.kernel.org/r/20191211103557.7bed6928@gandalf.local.home Cc: stable@vger.kernel.org Fixes: 08d43a5fa063e ("tracing: Add lock-free tracing_map") Acked-by: Tom Zanussi <zanussi@kernel.org> Reported-by: Sven Schnelle <svens@stackframe.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-09tracing: Fix lock inversion in trace_event_enable_tgid_record()Prateek Sood
commit 3a53acf1d9bea11b57c1f6205e3fe73f9d8a3688 upstream. Task T2 Task T3 trace_options_core_write() subsystem_open() mutex_lock(trace_types_lock) mutex_lock(event_mutex) set_tracer_flag() trace_event_enable_tgid_record() mutex_lock(trace_types_lock) mutex_lock(event_mutex) This gives a circular dependency deadlock between trace_types_lock and event_mutex. To fix this invert the usage of trace_types_lock and event_mutex in trace_options_core_write(). This keeps the sequence of lock usage consistent. Link: http://lkml.kernel.org/r/0101016eef175e38-8ca71caf-a4eb-480d-a1e6-6f0bbc015495-000000@us-west-2.amazonses.com Cc: stable@vger.kernel.org Fixes: d914ba37d7145 ("tracing: Add support for recording tgid of tasks") Signed-off-by: Prateek Sood <prsood@codeaurora.org> Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-09memcg: account security cred as well to kmemcgShakeel Butt
commit 84029fd04c201a4c7e0b07ba262664900f47c6f5 upstream. The cred_jar kmem_cache is already memcg accounted in the current kernel but cred->security is not. Account cred->security to kmemcg. Recently we saw high root slab usage on our production and on further inspection, we found a buggy application leaking processes. Though that buggy application was contained within its memcg but we observe much more system memory overhead, couple of GiBs, during that period. This overhead can adversely impact the isolation on the system. One source of high overhead we found was cred->security objects, which have a lifetime of at least the life of the process which allocated them. Link: http://lkml.kernel.org/r/20191205223721.40034-1-shakeelb@google.com Signed-off-by: Shakeel Butt <shakeelb@google.com> Acked-by: Chris Down <chris@chrisdown.name> Reviewed-by: Roman Gushchin <guro@fb.com> Acked-by: Michal Hocko <mhocko@suse.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: <stable@vger.kernel.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>
2020-01-09taskstats: fix data-raceChristian Brauner
[ Upstream commit 0b8d616fb5a8ffa307b1d3af37f55c15dae14f28 ] When assiging and testing taskstats in taskstats_exit() there's a race when setting up and reading sig->stats when a thread-group with more than one thread exits: write to 0xffff8881157bbe10 of 8 bytes by task 7951 on cpu 0: taskstats_tgid_alloc kernel/taskstats.c:567 [inline] taskstats_exit+0x6b7/0x717 kernel/taskstats.c:596 do_exit+0x2c2/0x18e0 kernel/exit.c:864 do_group_exit+0xb4/0x1c0 kernel/exit.c:983 get_signal+0x2a2/0x1320 kernel/signal.c:2734 do_signal+0x3b/0xc00 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x250/0x2c0 arch/x86/entry/common.c:159 prepare_exit_to_usermode arch/x86/entry/common.c:194 [inline] syscall_return_slowpath arch/x86/entry/common.c:274 [inline] do_syscall_64+0x2d7/0x2f0 arch/x86/entry/common.c:299 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff8881157bbe10 of 8 bytes by task 7949 on cpu 1: taskstats_tgid_alloc kernel/taskstats.c:559 [inline] taskstats_exit+0xb2/0x717 kernel/taskstats.c:596 do_exit+0x2c2/0x18e0 kernel/exit.c:864 do_group_exit+0xb4/0x1c0 kernel/exit.c:983 __do_sys_exit_group kernel/exit.c:994 [inline] __se_sys_exit_group kernel/exit.c:992 [inline] __x64_sys_exit_group+0x2e/0x30 kernel/exit.c:992 do_syscall_64+0xcf/0x2f0 arch/x86/entry/common.c:296 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Fix this by using smp_load_acquire() and smp_store_release(). Reported-by: syzbot+c5d03165a1bd1dead0c1@syzkaller.appspotmail.com Fixes: 34ec12349c8a ("taskstats: cleanup ->signal->stats allocation") Cc: stable@vger.kernel.org Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com> Acked-by: Marco Elver <elver@google.com> Reviewed-by: Will Deacon <will@kernel.org> Reviewed-by: Andrea Parri <parri.andrea@gmail.com> Reviewed-by: Dmitry Vyukov <dvyukov@google.com> Link: https://lore.kernel.org/r/20191009114809.8643-1-christian.brauner@ubuntu.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-09PM / hibernate: memory_bm_find_bit(): Tighten node optimisationAndy Whitcroft
[ Upstream commit da6043fe85eb5ec621e34a92540735dcebbea134 ] When looking for a bit by number we make use of the cached result from the preceding lookup to speed up operation. Firstly we check if the requested pfn is within the cached zone and if not lookup the new zone. We then check if the offset for that pfn falls within the existing cached node. This happens regardless of whether the node is within the zone we are now scanning. With certain memory layouts it is possible for this to false trigger creating a temporary alias for the pfn to a different bit. This leads the hibernation code to free memory which it was never allocated with the expected fallout. Ensure the zone we are scanning matches the cached zone before considering the cached node. Deep thanks go to Andrea for many, many, many hours of hacking and testing that went into cornering this bug. Reported-by: Andrea Righi <andrea.righi@canonical.com> Tested-by: Andrea Righi <andrea.righi@canonical.com> Signed-off-by: Andy Whitcroft <apw@canonical.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-01-04ptp: fix the race between the release of ptp_clock and cdevVladis Dronov
[ Upstream commit a33121e5487b424339636b25c35d3a180eaa5f5e ] In a case when a ptp chardev (like /dev/ptp0) is open but an underlying device is removed, closing this file leads to a race. This reproduces easily in a kvm virtual machine: ts# cat openptp0.c int main() { ... fp = fopen("/dev/ptp0", "r"); ... sleep(10); } ts# uname -r 5.5.0-rc3-46cf053e ts# cat /proc/cmdline ... slub_debug=FZP ts# modprobe ptp_kvm ts# ./openptp0 & [1] 670 opened /dev/ptp0, sleeping 10s... ts# rmmod ptp_kvm ts# ls /dev/ptp* ls: cannot access '/dev/ptp*': No such file or directory ts# ...woken up [ 48.010809] general protection fault: 0000 [#1] SMP [ 48.012502] CPU: 6 PID: 658 Comm: openptp0 Not tainted 5.5.0-rc3-46cf053e #25 [ 48.014624] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), ... [ 48.016270] RIP: 0010:module_put.part.0+0x7/0x80 [ 48.017939] RSP: 0018:ffffb3850073be00 EFLAGS: 00010202 [ 48.018339] RAX: 000000006b6b6b6b RBX: 6b6b6b6b6b6b6b6b RCX: ffff89a476c00ad0 [ 48.018936] RDX: fffff65a08d3ea08 RSI: 0000000000000247 RDI: 6b6b6b6b6b6b6b6b [ 48.019470] ... ^^^ a slub poison [ 48.023854] Call Trace: [ 48.024050] __fput+0x21f/0x240 [ 48.024288] task_work_run+0x79/0x90 [ 48.024555] do_exit+0x2af/0xab0 [ 48.024799] ? vfs_write+0x16a/0x190 [ 48.025082] do_group_exit+0x35/0x90 [ 48.025387] __x64_sys_exit_group+0xf/0x10 [ 48.025737] do_syscall_64+0x3d/0x130 [ 48.026056] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 48.026479] RIP: 0033:0x7f53b12082f6 [ 48.026792] ... [ 48.030945] Modules linked in: ptp i6300esb watchdog [last unloaded: ptp_kvm] [ 48.045001] Fixing recursive fault but reboot is needed! This happens in: static void __fput(struct file *file) { ... if (file->f_op->release) file->f_op->release(inode, file); <<< cdev is kfree'd here if (unlikely(S_ISCHR(inode->i_mode) && inode->i_cdev != NULL && !(mode & FMODE_PATH))) { cdev_put(inode->i_cdev); <<< cdev fields are accessed here Namely: __fput() posix_clock_release() kref_put(&clk->kref, delete_clock) <<< the last reference delete_clock() delete_ptp_clock() kfree(ptp) <<< cdev is embedded in ptp cdev_put module_put(p->owner) <<< *p is kfree'd, bang! Here cdev is embedded in posix_clock which is embedded in ptp_clock. The race happens because ptp_clock's lifetime is controlled by two refcounts: kref and cdev.kobj in posix_clock. This is wrong. Make ptp_clock's sysfs device a parent of cdev with cdev_device_add() created especially for such cases. This way the parent device with its ptp_clock is not released until all references to the cdev are released. This adds a requirement that an initialized but not exposed struct device should be provided to posix_clock_register() by a caller instead of a simple dev_t. This approach was adopted from the commit 72139dfa2464 ("watchdog: Fix the race between the release of watchdog_core_data and cdev"). See details of the implementation in the commit 233ed09d7fda ("chardev: add helper function to register char devs with a struct device"). Link: https://lore.kernel.org/linux-fsdevel/20191125125342.6189-1-vdronov@redhat.com/T/#u Analyzed-by: Stephen Johnston <sjohnsto@redhat.com> Analyzed-by: Vern Lovejoy <vlovejoy@redhat.com> Signed-off-by: Vladis Dronov <vdronov@redhat.com> Acked-by: Richard Cochran <richardcochran@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-04hrtimer: Annotate lockless access to timer->stateEric Dumazet
commit 56144737e67329c9aaed15f942d46a6302e2e3d8 upstream. syzbot reported various data-race caused by hrtimer_is_queued() reading timer->state. A READ_ONCE() is required there to silence the warning. Also add the corresponding WRITE_ONCE() when timer->state is set. In remove_hrtimer() the hrtimer_is_queued() helper is open coded to avoid loading timer->state twice. KCSAN reported these cases: BUG: KCSAN: data-race in __remove_hrtimer / tcp_pacing_check write to 0xffff8880b2a7d388 of 1 bytes by interrupt on cpu 0: __remove_hrtimer+0x52/0x130 kernel/time/hrtimer.c:991 __run_hrtimer kernel/time/hrtimer.c:1496 [inline] __hrtimer_run_queues+0x250/0x600 kernel/time/hrtimer.c:1576 hrtimer_run_softirq+0x10e/0x150 kernel/time/hrtimer.c:1593 __do_softirq+0x115/0x33f kernel/softirq.c:292 run_ksoftirqd+0x46/0x60 kernel/softirq.c:603 smpboot_thread_fn+0x37d/0x4a0 kernel/smpboot.c:165 kthread+0x1d4/0x200 drivers/block/aoe/aoecmd.c:1253 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 read to 0xffff8880b2a7d388 of 1 bytes by task 24652 on cpu 1: tcp_pacing_check net/ipv4/tcp_output.c:2235 [inline] tcp_pacing_check+0xba/0x130 net/ipv4/tcp_output.c:2225 tcp_xmit_retransmit_queue+0x32c/0x5a0 net/ipv4/tcp_output.c:3044 tcp_xmit_recovery+0x7c/0x120 net/ipv4/tcp_input.c:3558 tcp_ack+0x17b6/0x3170 net/ipv4/tcp_input.c:3717 tcp_rcv_established+0x37e/0xf50 net/ipv4/tcp_input.c:5696 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1561 sk_backlog_rcv include/net/sock.h:945 [inline] __release_sock+0x135/0x1e0 net/core/sock.c:2435 release_sock+0x61/0x160 net/core/sock.c:2951 sk_stream_wait_memory+0x3d7/0x7c0 net/core/stream.c:145 tcp_sendmsg_locked+0xb47/0x1f30 net/ipv4/tcp.c:1393 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1434 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x9f/0xc0 net/socket.c:657 BUG: KCSAN: data-race in __remove_hrtimer / __tcp_ack_snd_check write to 0xffff8880a3a65588 of 1 bytes by interrupt on cpu 0: __remove_hrtimer+0x52/0x130 kernel/time/hrtimer.c:991 __run_hrtimer kernel/time/hrtimer.c:1496 [inline] __hrtimer_run_queues+0x250/0x600 kernel/time/hrtimer.c:1576 hrtimer_run_softirq+0x10e/0x150 kernel/time/hrtimer.c:1593 __do_softirq+0x115/0x33f kernel/softirq.c:292 invoke_softirq kernel/softirq.c:373 [inline] irq_exit+0xbb/0xe0 kernel/softirq.c:413 exiting_irq arch/x86/include/asm/apic.h:536 [inline] smp_apic_timer_interrupt+0xe6/0x280 arch/x86/kernel/apic/apic.c:1137 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:830 read to 0xffff8880a3a65588 of 1 bytes by task 22891 on cpu 1: __tcp_ack_snd_check+0x415/0x4f0 net/ipv4/tcp_input.c:5265 tcp_ack_snd_check net/ipv4/tcp_input.c:5287 [inline] tcp_rcv_established+0x750/0xf50 net/ipv4/tcp_input.c:5708 tcp_v4_do_rcv+0x381/0x4e0 net/ipv4/tcp_ipv4.c:1561 sk_backlog_rcv include/net/sock.h:945 [inline] __release_sock+0x135/0x1e0 net/core/sock.c:2435 release_sock+0x61/0x160 net/core/sock.c:2951 sk_stream_wait_memory+0x3d7/0x7c0 net/core/stream.c:145 tcp_sendmsg_locked+0xb47/0x1f30 net/ipv4/tcp.c:1393 tcp_sendmsg+0x39/0x60 net/ipv4/tcp.c:1434 inet_sendmsg+0x6d/0x90 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:637 [inline] sock_sendmsg+0x9f/0xc0 net/socket.c:657 __sys_sendto+0x21f/0x320 net/socket.c:1952 __do_sys_sendto net/socket.c:1964 [inline] __se_sys_sendto net/socket.c:1960 [inline] __x64_sys_sendto+0x89/0xb0 net/socket.c:1960 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 24652 Comm: syz-executor.3 Not tainted 5.4.0-rc3+ #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 [ tglx: Added comments ] Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lkml.kernel.org/r/20191106174804.74723-1-edumazet@google.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-01-04kernel: sysctl: make drop_caches write-onlyJohannes Weiner
[ Upstream commit 204cb79ad42f015312a5bbd7012d09c93d9b46fb ] Currently, the drop_caches proc file and sysctl read back the last value written, suggesting this is somehow a stateful setting instead of a one-time command. Make it write-only, like e.g. compact_memory. While mitigating a VM problem at scale in our fleet, there was confusion about whether writing to this file will permanently switch the kernel into a non-caching mode. This influences the decision making in a tense situation, where tens of people are trying to fix tens of thousands of affected machines: Do we need a rollback strategy? What are the performance implications of operating in a non-caching state for several days? It also caused confusion when the kernel team said we may need to write the file several times to make sure it's effective ("But it already reads back 3?"). Link: http://lkml.kernel.org/r/20191031221602.9375-1-hannes@cmpxchg.org Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Chris Down <chris@chrisdown.name> Acked-by: Vlastimil Babka <vbabka@suse.cz> Acked-by: David Hildenbrand <david@redhat.com> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-17kernel/module.c: wakeup processes in module_wq on module unloadKonstantin Khorenko
[ Upstream commit 5d603311615f612320bb77bd2a82553ef1ced5b7 ] Fix the race between load and unload a kernel module. sys_delete_module() try_stop_module() mod->state = _GOING add_unformed_module() old = find_module_all() (old->state == _GOING => wait_event_interruptible()) During pre-condition finished_loading() rets 0 schedule() (never gets waken up later) free_module() mod->state = _UNFORMED list_del_rcu(&mod->list) (dels mod from "modules" list) return The race above leads to modprobe hanging forever on loading a module. Error paths on loading module call wake_up_all(&module_wq) after freeing module, so let's do the same on straight module unload. Fixes: 6e6de3dee51a ("kernel/module.c: Only return -EEXIST for modules that have finished loading") Reviewed-by: Prarit Bhargava <prarit@redhat.com> Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com> Signed-off-by: Jessica Yu <jeyu@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-17workqueue: Fix missing kfree(rescuer) in destroy_workqueue()Tejun Heo
commit 8efe1223d73c218ce7e8b2e0e9aadb974b582d7f upstream. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Qian Cai <cai@lca.pw> Fixes: def98c84b6cd ("workqueue: Fix spurious sanity check failures in destroy_workqueue()") Cc: Nobuhiro Iwamatsu <nobuhiro1.iwamatsu@toshiba.co.jp> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17cgroup: pids: use atomic64_t for pids->limitAleksa Sarai
commit a713af394cf382a30dd28a1015cbe572f1b9ca75 upstream. Because pids->limit can be changed concurrently (but we don't want to take a lock because it would be needlessly expensive), use atomic64_ts instead. Fixes: commit 49b786ea146f ("cgroup: implement the PIDs subsystem") Cc: stable@vger.kernel.org # v4.3+ Signed-off-by: Aleksa Sarai <cyphar@cyphar.com> Signed-off-by: Tejun Heo <tj@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17workqueue: Fix pwq ref leak in rescuer_thread()Tejun Heo
commit e66b39af00f426b3356b96433d620cb3367ba1ff upstream. 008847f66c3 ("workqueue: allow rescuer thread to do more work.") made the rescuer worker requeue the pwq immediately if there may be more work items which need rescuing instead of waiting for the next mayday timer expiration. Unfortunately, it doesn't check whether the pwq is already on the mayday list and unconditionally gets the ref and moves it onto the list. This doesn't corrupt the list but creates an additional reference to the pwq. It got queued twice but will only be removed once. This leak later can trigger pwq refcnt warning on workqueue destruction and prevent freeing of the workqueue. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: "Williams, Gerald S" <gerald.s.williams@intel.com> Cc: NeilBrown <neilb@suse.de> Cc: stable@vger.kernel.org # v3.19+ Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17workqueue: Fix spurious sanity check failures in destroy_workqueue()Tejun Heo
commit def98c84b6cdf2eeea19ec5736e90e316df5206b upstream. Before actually destrying a workqueue, destroy_workqueue() checks whether it's actually idle. If it isn't, it prints out a bunch of warning messages and leaves the workqueue dangling. It unfortunately has a couple issues. * Mayday list queueing increments pwq's refcnts which gets detected as busy and fails the sanity checks. However, because mayday list queueing is asynchronous, this condition can happen without any actual work items left in the workqueue. * Sanity check failure leaves the sysfs interface behind too which can lead to init failure of newer instances of the workqueue. This patch fixes the above two by * If a workqueue has a rescuer, disable and kill the rescuer before sanity checks. Disabling and killing is guaranteed to flush the existing mayday list. * Remove sysfs interface before sanity checks. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Marcin Pawlowski <mpawlowski@fb.com> Reported-by: "Williams, Gerald S" <gerald.s.williams@intel.com> Cc: stable@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17sched/fair: Scale bandwidth quota and period without losing quota/period ↵Xuewei Zhang
ratio precision commit 4929a4e6faa0f13289a67cae98139e727f0d4a97 upstream. The quota/period ratio is used to ensure a child task group won't get more bandwidth than the parent task group, and is calculated as: normalized_cfs_quota() = [(quota_us << 20) / period_us] If the quota/period ratio was changed during this scaling due to precision loss, it will cause inconsistency between parent and child task groups. See below example: A userspace container manager (kubelet) does three operations: 1) Create a parent cgroup, set quota to 1,000us and period to 10,000us. 2) Create a few children cgroups. 3) Set quota to 1,000us and period to 10,000us on a child cgroup. These operations are expected to succeed. However, if the scaling of 147/128 happens before step 3, quota and period of the parent cgroup will be changed: new_quota: 1148437ns, 1148us new_period: 11484375ns, 11484us And when step 3 comes in, the ratio of the child cgroup will be 104857, which will be larger than the parent cgroup ratio (104821), and will fail. Scaling them by a factor of 2 will fix the problem. Tested-by: Phil Auld <pauld@redhat.com> Signed-off-by: Xuewei Zhang <xueweiz@google.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Phil Auld <pauld@redhat.com> Cc: Anton Blanchard <anton@ozlabs.org> Cc: Ben Segall <bsegall@google.com> Cc: Dietmar Eggemann <dietmar.eggemann@arm.com> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Vincent Guittot <vincent.guittot@linaro.org> Fixes: 2e8e19226398 ("sched/fair: Limit sched_cfs_period_timer() loop to avoid hard lockup") Link: https://lkml.kernel.org/r/20191004001243.140897-1-xueweiz@google.com Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-17sched/core: Avoid spurious lock dependenciesPeter Zijlstra
[ Upstream commit ff51ff84d82aea5a889b85f2b9fb3aa2b8691668 ] While seemingly harmless, __sched_fork() does hrtimer_init(), which, when DEBUG_OBJETS, can end up doing allocations. This then results in the following lock order: rq->lock zone->lock.rlock batched_entropy_u64.lock Which in turn causes deadlocks when we do wakeups while holding that batched_entropy lock -- as the random code does. Solve this by moving __sched_fork() out from under rq->lock. This is safe because nothing there relies on rq->lock, as also evident from the other __sched_fork() callsite. Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Qian Cai <cai@lca.pw> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akpm@linux-foundation.org Cc: bigeasy@linutronix.de Cc: cl@linux.com Cc: keescook@chromium.org Cc: penberg@kernel.org Cc: rientjes@google.com Cc: thgarnie@google.com Cc: tytso@mit.edu Cc: will@kernel.org Fixes: b7d5dc21072c ("random: add a spinlock_t to struct batched_entropy") Link: https://lkml.kernel.org/r/20191001091837.GK4536@hirez.programming.kicks-ass.net Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-17audit_get_nd(): don't unlock parent too earlyAl Viro
[ Upstream commit 69924b89687a2923e88cc42144aea27868913d0e ] if the child has been negative and just went positive under us, we want coherent d_is_positive() and ->d_inode. Don't unlock the parent until we'd done that work... Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-05futex: Prevent exit livelockThomas Gleixner
commit 3ef240eaff36b8119ac9e2ea17cbf41179c930ba upstream. Oleg provided the following test case: int main(void) { struct sched_param sp = {}; sp.sched_priority = 2; assert(sched_setscheduler(0, SCHED_FIFO, &sp) == 0); int lock = vfork(); if (!lock) { sp.sched_priority = 1; assert(sched_setscheduler(0, SCHED_FIFO, &sp) == 0); _exit(0); } syscall(__NR_futex, &lock, FUTEX_LOCK_PI, 0,0,0); return 0; } This creates an unkillable RT process spinning in futex_lock_pi() on a UP machine or if the process is affine to a single CPU. The reason is: parent child set FIFO prio 2 vfork() -> set FIFO prio 1 implies wait_for_child() sched_setscheduler(...) exit() do_exit() .... mm_release() tsk->futex_state = FUTEX_STATE_EXITING; exit_futex(); (NOOP in this case) complete() --> wakes parent sys_futex() loop infinite because tsk->futex_state == FUTEX_STATE_EXITING The same problem can happen just by regular preemption as well: task holds futex ... do_exit() tsk->futex_state = FUTEX_STATE_EXITING; --> preemption (unrelated wakeup of some other higher prio task, e.g. timer) switch_to(other_task) return to user sys_futex() loop infinite as above Just for the fun of it the futex exit cleanup could trigger the wakeup itself before the task sets its futex state to DEAD. To cure this, the handling of the exiting owner is changed so: - A refcount is held on the task - The task pointer is stored in a caller visible location - The caller drops all locks (hash bucket, mmap_sem) and blocks on task::futex_exit_mutex. When the mutex is acquired then the exiting task has completed the cleanup and the state is consistent and can be reevaluated. This is not a pretty solution, but there is no choice other than returning an error code to user space, which would break the state consistency guarantee and open another can of problems including regressions. For stable backports the preparatory commits ac31c7ff8624 .. ba31c1a48538 are required as well, but for anything older than 5.3.y the backports are going to be provided when this hits mainline as the other dependencies for those kernels are definitely not stable material. Fixes: 778e9a9c3e71 ("pi-futex: fix exit races and locking problems") Reported-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: Stable Team <stable@vger.kernel.org> Link: https://lkml.kernel.org/r/20191106224557.041676471@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Provide distinct return value when owner is exitingThomas Gleixner
commit ac31c7ff8624409ba3c4901df9237a616c187a5d upstream. attach_to_pi_owner() returns -EAGAIN for various cases: - Owner task is exiting - Futex value has changed The caller drops the held locks (hash bucket, mmap_sem) and retries the operation. In case of the owner task exiting this can result in a live lock. As a preparatory step for seperating those cases, provide a distinct return value (EBUSY) for the owner exiting case. No functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.935606117@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Add mutex around futex exitThomas Gleixner
commit 3f186d974826847a07bc7964d79ec4eded475ad9 upstream. The mutex will be used in subsequent changes to replace the busy looping of a waiter when the futex owner is currently executing the exit cleanup to prevent a potential live lock. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.845798895@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Provide state handling for exec() as wellThomas Gleixner
commit af8cbda2cfcaa5515d61ec500498d46e9a8247e2 upstream. exec() attempts to handle potentially held futexes gracefully by running the futex exit handling code like exit() does. The current implementation has no protection against concurrent incoming waiters. The reason is that the futex state cannot be set to FUTEX_STATE_DEAD after the cleanup because the task struct is still active and just about to execute the new binary. While its arguably buggy when a task holds a futex over exec(), for consistency sake the state handling can at least cover the actual futex exit cleanup section. This provides state consistency protection accross the cleanup. As the futex state of the task becomes FUTEX_STATE_OK after the cleanup has been finished, this cannot prevent subsequent attempts to attach to the task in case that the cleanup was not successfull in mopping up all leftovers. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.753355618@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Sanitize exit state handlingThomas Gleixner
commit 4a8e991b91aca9e20705d434677ac013974e0e30 upstream. Instead of having a smp_mb() and an empty lock/unlock of task::pi_lock move the state setting into to the lock section. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.645603214@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Mark the begin of futex exit explicitlyThomas Gleixner
commit 18f694385c4fd77a09851fd301236746ca83f3cb upstream. Instead of relying on PF_EXITING use an explicit state for the futex exit and set it in the futex exit function. This moves the smp barrier and the lock/unlock serialization into the futex code. As with the DEAD state this is restricted to the exit path as exec continues to use the same task struct. This allows to simplify that logic in a next step. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.539409004@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Set task::futex_state to DEAD right after handling futex exitThomas Gleixner
commit f24f22435dcc11389acc87e5586239c1819d217c upstream. Setting task::futex_state in do_exit() is rather arbitrarily placed for no reason. Move it into the futex code. Note, this is only done for the exit cleanup as the exec cleanup cannot set the state to FUTEX_STATE_DEAD because the task struct is still in active use. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.439511191@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Split futex_mm_release() for exit/execThomas Gleixner
commit 150d71584b12809144b8145b817e83b81158ae5f upstream. To allow separate handling of the futex exit state in the futex exit code for exit and exec, split futex_mm_release() into two functions and invoke them from the corresponding exit/exec_mm_release() callsites. Preparatory only, no functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.332094221@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05exit/exec: Seperate mm_release()Thomas Gleixner
commit 4610ba7ad877fafc0a25a30c6c82015304120426 upstream. mm_release() contains the futex exit handling. mm_release() is called from do_exit()->exit_mm() and from exec()->exec_mm(). In the exit_mm() case PF_EXITING and the futex state is updated. In the exec_mm() case these states are not touched. As the futex exit code needs further protections against exit races, this needs to be split into two functions. Preparatory only, no functional change. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.240518241@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Replace PF_EXITPIDONE with a stateThomas Gleixner
commit 3d4775df0a89240f671861c6ab6e8d59af8e9e41 upstream. The futex exit handling relies on PF_ flags. That's suboptimal as it requires a smp_mb() and an ugly lock/unlock of the exiting tasks pi_lock in the middle of do_exit() to enforce the observability of PF_EXITING in the futex code. Add a futex_state member to task_struct and convert the PF_EXITPIDONE logic over to the new state. The PF_EXITING dependency will be cleaned up in a later step. This prepares for handling various futex exit issues later. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.149449274@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Move futex exit handling into futex codeThomas Gleixner
commit ba31c1a48538992316cc71ce94fa9cd3e7b427c0 upstream. The futex exit handling is #ifdeffed into mm_release() which is not pretty to begin with. But upcoming changes to address futex exit races need to add more functionality to this exit code. Split it out into a function, move it into futex code and make the various futex exit functions static. Preparatory only and no functional change. Folded build fix from Borislav. Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lkml.kernel.org/r/20191106224556.049705556@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05futex: Prevent robust futex exit raceYang Tao
commit ca16d5bee59807bf04deaab0a8eccecd5061528c upstream. Robust futexes utilize the robust_list mechanism to allow the kernel to release futexes which are held when a task exits. The exit can be voluntary or caused by a signal or fault. This prevents that waiters block forever. The futex operations in user space store a pointer to the futex they are either locking or unlocking in the op_pending member of the per task robust list. After a lock operation has succeeded the futex is queued in the robust list linked list and the op_pending pointer is cleared. After an unlock operation has succeeded the futex is removed from the robust list linked list and the op_pending pointer is cleared. The robust list exit code checks for the pending operation and any futex which is queued in the linked list. It carefully checks whether the futex value is the TID of the exiting task. If so, it sets the OWNER_DIED bit and tries to wake up a potential waiter. This is race free for the lock operation but unlock has two race scenarios where waiters might not be woken up. These issues can be observed with regular robust pthread mutexes. PI aware pthread mutexes are not affected. (1) Unlocking task is killed after unlocking the futex value in user space before being able to wake a waiter. pthread_mutex_unlock() | V atomic_exchange_rel (&mutex->__data.__lock, 0) <------------------------killed lll_futex_wake () | | |(__lock = 0) |(enter kernel) | V do_exit() exit_mm() mm_release() exit_robust_list() handle_futex_death() | |(__lock = 0) |(uval = 0) | V if ((uval & FUTEX_TID_MASK) != task_pid_vnr(curr)) return 0; The sanity check which ensures that the user space futex is owned by the exiting task prevents the wakeup of waiters which in consequence block infinitely. (2) Waiting task is killed after a wakeup and before it can acquire the futex in user space. OWNER WAITER futex_wait() pthread_mutex_unlock() | | | |(__lock = 0) | | | V | futex_wake() ------------> wakeup() | |(return to userspace) |(__lock = 0) | V oldval = mutex->__data.__lock <-----------------killed atomic_compare_and_exchange_val_acq (&mutex->__data.__lock, | id | assume_other_futex_waiters, 0) | | | (enter kernel)| | V do_exit() | | V handle_futex_death() | |(__lock = 0) |(uval = 0) | V if ((uval & FUTEX_TID_MASK) != task_pid_vnr(curr)) return 0; The sanity check which ensures that the user space futex is owned by the exiting task prevents the wakeup of waiters, which seems to be correct as the exiting task does not own the futex value, but the consequence is that other waiters wont be woken up and block infinitely. In both scenarios the following conditions are true: - task->robust_list->list_op_pending != NULL - user space futex value == 0 - Regular futex (not PI) If these conditions are met then it is reasonably safe to wake up a potential waiter in order to prevent the above problems. As this might be a false positive it can cause spurious wakeups, but the waiter side has to handle other types of unrelated wakeups, e.g. signals gracefully anyway. So such a spurious wakeup will not affect the correctness of these operations. This workaround must not touch the user space futex value and cannot set the OWNER_DIED bit because the lock value is 0, i.e. uncontended. Setting OWNER_DIED in this case would result in inconsistent state and subsequently in malfunction of the owner died handling in user space. The rest of the user space state is still consistent as no other task can observe the list_op_pending entry in the exiting tasks robust list. The eventually woken up waiter will observe the uncontended lock value and take it over. [ tglx: Massaged changelog and comment. Made the return explicit and not depend on the subsequent check and added constants to hand into handle_futex_death() instead of plain numbers. Fixed a few coding style issues. ] Fixes: 0771dfefc9e5 ("[PATCH] lightweight robust futexes: core") Signed-off-by: Yang Tao <yang.tao172@zte.com.cn> Signed-off-by: Yi Wang <wang.yi59@zte.com.cn> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Ingo Molnar <mingo@kernel.org> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Cc: stable@vger.kernel.org Link: https://lkml.kernel.org/r/1573010582-35297-1-git-send-email-wang.yi59@zte.com.cn Link: https://lkml.kernel.org/r/20191106224555.943191378@linutronix.de Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05y2038: futex: Move compat implementation into futex.cArnd Bergmann
commit 04e7712f4460585e5eed5b853fd8b82a9943958f upstream. We are going to share the compat_sys_futex() handler between 64-bit architectures and 32-bit architectures that need to deal with both 32-bit and 64-bit time_t, and this is easier if both entry points are in the same file. In fact, most other system call handlers do the same thing these days, so let's follow the trend here and merge all of futex_compat.c into futex.c. In the process, a few minor changes have to be done to make sure everything still makes sense: handle_futex_death() and futex_cmpxchg_enabled() become local symbol, and the compat version of the fetch_robust_entry() function gets renamed to compat_fetch_robust_entry() to avoid a symbol clash. This is intended as a purely cosmetic patch, no behavior should change. Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-12-05bpf: drop refcount if bpf_map_new_fd() fails in map_create()Peng Sun
[ Upstream commit 352d20d611414715353ee65fc206ee57ab1a6984 ] In bpf/syscall.c, map_create() first set map->usercnt to 1, a file descriptor is supposed to return to userspace. When bpf_map_new_fd() fails, drop the refcount. Fixes: bd5f5f4ecb78 ("bpf: Add BPF_MAP_GET_FD_BY_ID") Signed-off-by: Peng Sun <sironhide0null@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-05bpf: decrease usercnt if bpf_map_new_fd() fails in bpf_map_get_fd_by_id()Peng Sun
[ Upstream commit 781e62823cb81b972dc8652c1827205cda2ac9ac ] In bpf/syscall.c, bpf_map_get_fd_by_id() use bpf_map_inc_not_zero() to increase the refcount, both map->refcnt and map->usercnt. Then, if bpf_map_new_fd() fails, should handle map->usercnt too. Fixes: bd5f5f4ecb78 ("bpf: Add BPF_MAP_GET_FD_BY_ID") Signed-off-by: Peng Sun <sironhide0null@gmail.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-05fork: fix some -Wmissing-prototypes warningsYi Wang
[ Upstream commit fb5bf31722d0805a3f394f7d59f2e8cd07acccb7 ] We get a warning when building kernel with W=1: kernel/fork.c:167:13: warning: no previous prototype for `arch_release_thread_stack' [-Wmissing-prototypes] kernel/fork.c:779:13: warning: no previous prototype for `fork_init' [-Wmissing-prototypes] Add the missing declaration in head file to fix this. Also, remove arch_release_thread_stack() completely because no arch seems to implement it since bb9d81264 (arch: remove tile port). Link: http://lkml.kernel.org/r/1542170087-23645-1-git-send-email-wang.yi59@zte.com.cn Signed-off-by: Yi Wang <wang.yi59@zte.com.cn> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: Mike Rapoport <rppt@linux.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Sasha Levin <sashal@kernel.org>