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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2020-04-25 13:03:06 +0300 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-04-25 13:22:28 +0300 |
| commit | b08418b54831255a7e3700d6bf7dfc2bdae25cd7 (patch) | |
| tree | a7c4976f966244d90218f97821eeb886676c398b /arch/x86/kernel/unwind_frame.c | |
| parent | 153eb2223c794251b28400f3f74862e090d23f16 (diff) | |
| download | linux-b08418b54831255a7e3700d6bf7dfc2bdae25cd7.tar.xz | |
x86/unwind: Prevent false warnings for non-current tasks
There's some daring kernel code out there which dumps the stack of
another task without first making sure the task is inactive. If the
task happens to be running while the unwinder is reading the stack,
unusual unwinder warnings can result.
There's no race-free way for the unwinder to know whether such a warning
is legitimate, so just disable unwinder warnings for all non-current
tasks.
Reviewed-by: Miroslav Benes <mbenes@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Jones <dsj@fb.com>
Cc: Jann Horn <jannh@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Link: https://lore.kernel.org/r/ec424a2aea1d461eb30cab48a28c6433de2ab784.1587808742.git.jpoimboe@redhat.com
Diffstat (limited to 'arch/x86/kernel/unwind_frame.c')
| -rw-r--r-- | arch/x86/kernel/unwind_frame.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index a224b5ab103f..54226110bc7f 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -344,6 +344,9 @@ bad_address: if (IS_ENABLED(CONFIG_X86_32)) goto the_end; + if (state->task != current) + goto the_end; + if (state->regs) { printk_deferred_once(KERN_WARNING "WARNING: kernel stack regs at %p in %s:%d has bad 'bp' value %p\n", |