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commit b401efc120a399dfda1f4d2858a4de365c9b08ef upstream.
If a switch jump table's indirect branch is in a ".cold" subfunction in
.text.unlikely, objtool doesn't detect it, and instead prints a false
warning:
drivers/media/v4l2-core/v4l2-ioctl.o: warning: objtool: v4l_print_format.cold()+0xd6: sibling call from callable instruction with modified stack frame
drivers/hwmon/max6650.o: warning: objtool: max6650_probe.cold()+0xa5: sibling call from callable instruction with modified stack frame
drivers/media/dvb-frontends/drxk_hard.o: warning: objtool: init_drxk.cold()+0x16f: sibling call from callable instruction with modified stack frame
Fix it by comparing the function, instead of the section and offset.
Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/157c35d42ca9b6354bbb1604fe9ad7d1153ccb21.1585761021.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 4fa5ecda2bf96be7464eb406df8aba9d89260227 upstream.
This fixes the following warning seen on GCC 7.3:
arch/x86/kernel/dumpstack.o: warning: objtool: oops_end() falls through to next function show_regs()
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/3418ebf5a5a9f6ed7e80954c741c0b904b67b5dc.1554398240.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 684fb246578b9e81fc7b4ca5c71eae22edb650b2 upstream.
machine_real_restart() is annotated as '__noreturn", so add it to the
objtool noreturn list. This fixes the following warning with clang and
CONFIG_CC_OPTIMIZE_FOR_SIZE=y:
arch/x86/kernel/reboot.o: warning: objtool: native_machine_emergency_restart() falls through to next function machine_power_off()
Reported-by: Matthias Kaehlcke <mka@chromium.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: Matthias Kaehlcke <mka@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
Link: https://lkml.kernel.org/r/791712792aa4431bdd55bf1beb33a169ddf3b4a2.1529423255.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit e6da9567959e164f82bc81967e0d5b10dee870b4 ]
The ignore flag is set on fake jumps in order to keep
add_jump_destinations() from setting their jump_dest, since it already
got set when the fake jump was created.
But using the ignore flag is a bit of a hack. It's normally used to
skip validation of an instruction, which doesn't really make sense for
fake jumps.
Also, after the next patch, using the ignore flag for fake jumps can
trigger a false "why am I validating an ignored function?" warning.
Instead just add an explicit check in add_jump_destinations() to skip
fake jumps.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.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/71abc072ff48b2feccc197723a9c52859476c068.1557766718.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit e6f393bc939d566ce3def71232d8013de9aaadde upstream.
When a function falls through to the next function due to a compiler
bug, objtool prints some obscure warnings. For example:
drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x95: return with modified stack frame
drivers/regulator/core.o: warning: objtool: regulator_count_voltages()+0x0: stack state mismatch: cfa1=7+32 cfa2=7+8
Instead it should be printing:
drivers/regulator/core.o: warning: objtool: regulator_supply_is_couple() falls through to next function regulator_count_voltages()
This used to work, but was broken by the following commit:
13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
The padding nops at the end of a function aren't actually part of the
function, as defined by the symbol table. So the 'func' variable in
validate_branch() is getting cleared to NULL when a padding nop is
encountered, breaking the fallthrough detection.
If the current instruction doesn't have a function associated with it,
just consider it to be part of the previously detected function by not
overwriting the previous value of 'func'.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: <stable@vger.kernel.org>
Fixes: 13810435b9a7 ("objtool: Support GCC 8's cold subfunctions")
Link: http://lkml.kernel.org/r/546d143820cd08a46624ae8440d093dd6c902cae.1557766718.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0c671812f152b628bd87c0af49da032cc2a2c319 upstream.
Objtool uses over 512k of stack, thanks to the hash table embedded in
the objtool_file struct. This causes an unnecessarily large stack
allocation and breaks users with low stack limits.
Move the struct off the stack.
Fixes: 042ba73fe7eb ("objtool: Add several performance improvements")
Reported-by: Vassili Karpov <moosotc@gmail.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/df92dcbc4b84b02ffa252f46876df125fb56e2d7.1552954176.git.jpoimboe@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0afd0d9e0e7879d666c1df2fa1bea4d8716909fe upstream.
Objtool has some crude logic for detecting static "noreturn" functions
(aka "dead ends"). This is necessary for being able to correctly follow
GCC code flow when such functions are called.
It's remotely possible for two functions to call each other via sibling
calls. If they don't have RET instructions, objtool's noreturn
detection logic goes into a recursive loop:
drivers/char/ipmi/ipmi_ssif.o: warning: objtool: return_hosed_msg()+0x0: infinite recursion (objtool bug!)
drivers/char/ipmi/ipmi_ssif.o: warning: objtool: deliver_recv_msg()+0x0: infinite recursion (objtool bug!)
Instead of reporting an error in this case, consider the functions to be
non-dead-ends.
Reported-and-tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: damian <damian.tometzki@icloud.com>
Link: http://lkml.kernel.org/r/7cc156408c5781a1f62085d352ced1fe39fe2f91.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 7dec80ccbe310fb7e225bf21c48c672bb780ce7b upstream.
With the following commit:
fd35c88b7417 ("objtool: Support GCC 8 switch tables")
I added a "can't find switch jump table" warning, to stop covering up
silent failures if add_switch_table() can't find anything.
That warning found yet another bug in the objtool switch table detection
logic. For cases 1 and 2 (as described in the comments of
find_switch_table()), the find_symbol_containing() check doesn't adjust
the offset for RIP-relative switch jumps.
Incidentally, this bug was already fixed for case 3 with:
6f5ec2993b1f ("objtool: Detect RIP-relative switch table references")
However, that commit missed the fix for cases 1 and 2.
The different cases are now starting to look more and more alike. So
fix the bug by consolidating them into a single case, by checking the
original dynamic jump instruction in the case 3 loop.
This also simplifies the code and makes it more robust against future
switch table detection issues -- of which I'm sure there will be many...
Switch table detection has been the most fragile area of objtool, by
far. I long for the day when we'll have a GCC plugin for annotating
switch tables. Linus asked me to delay such a plugin due to the
flakiness of the plugin infrastructure in older versions of GCC, so this
rickety code is what we're stuck with for now. At least the code is now
a little simpler than it was.
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.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/f400541613d45689086329432f3095119ffbc328.1526674218.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6f5ec2993b1f39aed12fa6fd56e8dc2272ee8a33 upstream.
Typically a switch table can be found by detecting a .rodata access
followed an indirect jump:
1969: 4a 8b 0c e5 00 00 00 mov 0x0(,%r12,8),%rcx
1970: 00
196d: R_X86_64_32S .rodata+0x438
1971: e9 00 00 00 00 jmpq 1976 <dispc_runtime_suspend+0xb6a>
1972: R_X86_64_PC32 __x86_indirect_thunk_rcx-0x4
Randy Dunlap reported a case (seen with GCC 4.8) where the .rodata
access uses RIP-relative addressing:
19bd: 48 8b 3d 00 00 00 00 mov 0x0(%rip),%rdi # 19c4 <dispc_runtime_suspend+0xbb8>
19c0: R_X86_64_PC32 .rodata+0x45c
19c4: e9 00 00 00 00 jmpq 19c9 <dispc_runtime_suspend+0xbbd>
19c5: R_X86_64_PC32 __x86_indirect_thunk_rdi-0x4
In this case the relocation addend needs to be adjusted accordingly in
order to find the location of the switch table.
The fix is for case 3 (as described in the comments), but also make the
existing case 1 & 2 checks more precise by only adjusting the addend for
R_X86_64_PC32 relocations.
This fixes the following warnings:
drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_suspend()+0xbb8: sibling call from callable instruction with modified stack frame
drivers/video/fbdev/omap2/omapfb/dss/dispc.o: warning: objtool: dispc_runtime_resume()+0xcc5: sibling call from callable instruction with modified stack frame
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.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/b6098294fd67afb69af8c47c9883d7a68bf0f8ea.1526305958.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit fd35c88b74170d9335530d9abf271d5d73eb5401 upstream.
With GCC 8, some issues were found with the objtool switch table
detection.
1) In the .rodata section, immediately after the switch table, there can
be another object which contains a pointer to the function which had
the switch statement. In this case objtool wrongly considers the
function pointer to be part of the switch table. Fix it by:
a) making sure there are no pointers to the beginning of the
function; and
b) making sure there are no gaps in the switch table.
Only the former was needed, the latter adds additional protection for
future optimizations.
2) In find_switch_table(), case 1 and case 2 are missing the check to
ensure that the .rodata switch table data is anonymous, i.e. that it
isn't already associated with an ELF symbol. Fix it by adding the
same find_symbol_containing() check which is used for case 3.
This fixes the following warnings with GCC 8:
drivers/block/virtio_blk.o: warning: objtool: virtio_queue_rq()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+72
net/ipv6/icmp.o: warning: objtool: icmpv6_rcv()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
drivers/usb/core/quirks.o: warning: objtool: quirks_param_set()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+48
drivers/mtd/nand/raw/nand_hynix.o: warning: objtool: hynix_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+24
drivers/mtd/nand/raw/nand_samsung.o: warning: objtool: samsung_nand_decode_id()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+32
drivers/gpu/drm/nouveau/nvkm/subdev/top/gk104.o: warning: objtool: gk104_top_oneinit()+0x0: stack state mismatch: cfa1=7+8 cfa2=7+64
Reported-by: Arnd Bergmann <arnd@arndb.de>
Reported-by: kbuild test robot <lkp@intel.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: damian <damian.tometzki@icloud.com>
Link: http://lkml.kernel.org/r/20180510224849.xwi34d6tzheb5wgw@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 13810435b9a7014fb92eb715f77da488f3b65b99 upstream.
GCC 8 moves a lot of unlikely code out of line to "cold" subfunctions in
.text.unlikely. Properly detect the new subfunctions and treat them as
extensions of the original functions.
This fixes a bunch of warnings like:
kernel/cgroup/cgroup.o: warning: objtool: parse_cgroup_root_flags()+0x33: sibling call from callable instruction with modified stack frame
kernel/cgroup/cgroup.o: warning: objtool: cgroup_addrm_files()+0x290: sibling call from callable instruction with modified stack frame
kernel/cgroup/cgroup.o: warning: objtool: cgroup_apply_control_enable()+0x25b: sibling call from callable instruction with modified stack frame
kernel/cgroup/cgroup.o: warning: objtool: rebind_subsystems()+0x325: sibling call from callable instruction with modified stack frame
Reported-and-tested-by: damian <damian.tometzki@icloud.com>
Reported-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: David Laight <David.Laight@ACULAB.COM>
Cc: Greg KH <gregkh@linuxfoundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/0965e7fcfc5f31a276f0c7f298ff770c19b68706.1525923412.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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There are pros and cons of dealing with tools in the kernel directory.
The pros are the fact that development happens fast, and new features
can be added to the kernel and the tools at the same times. The cons
are when dealing with backported kernel patches, it can be necessary to
backport parts of the tool changes as well.
For 4.9.y so far, we have backported individual patches. That quickly
breaks down when there are minor differences between how backports were
handled, so grabbing 40+ patch long series can be difficult, not
impossible, but really frustrating to attempt.
To help mitigate this mess, here's a single big patch to sync up the
objtool logic to the 4.14.47 version of the tool. From this point
forward (after some other minor header file patches are applied), the
tool should be in sync and much easier to maintain over time.
This has survivied my limited testing, and as the codebase is identical
to 4.14.47, I'm pretty comfortable dropping this big change in here in
4.9.y. Hopefully all goes well...
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit dcc914f44f065ef73685b37e59877a5bb3cb7358 upstream.
In preparation for the new 'objtool undwarf generate' command, which
will rely on 'objtool check', move the checking code from
builtin-check.c to check.c where it can be used by other commands.
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Link: http://lkml.kernel.org/r/294c5c695fd73c1a5000bbe5960a7c9bec4ee6b4.1498659915.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[backported by hand to 4.9, this was a pain... - gregkh]
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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