diff options
| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2020-04-25 12:03:06 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2020-04-25 12:22:28 +0200 |
| commit | b08418b54831255a7e3700d6bf7dfc2bdae25cd7 (patch) | |
| tree | a7c4976f966244d90218f97821eeb886676c398b /arch/x86/kernel/dumpstack_64.c | |
| parent | x86/unwind/orc: Convert global variables to static (diff) | |
| download | linux-b08418b54831255a7e3700d6bf7dfc2bdae25cd7.tar.xz linux-b08418b54831255a7e3700d6bf7dfc2bdae25cd7.zip | |
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/dumpstack_64.c')
| -rw-r--r-- | arch/x86/kernel/dumpstack_64.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c index 87b97897a881..460ae7f66818 100644 --- a/arch/x86/kernel/dumpstack_64.c +++ b/arch/x86/kernel/dumpstack_64.c @@ -183,7 +183,8 @@ recursion_check: */ if (visit_mask) { if (*visit_mask & (1UL << info->type)) { - printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); + if (task == current) + printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); goto unknown; } *visit_mask |= 1UL << info->type; |