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| author | Josh Poimboeuf <jpoimboe@redhat.com> | 2016-12-22 16:02:49 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-12-23 20:32:30 +0100 |
| commit | c280f7736ab26a601932b1ce017a3840dbedcfdc (patch) | |
| tree | ca07c17a22621acbfec0f03521ba9098de620629 | |
| parent | x86/paravirt: Mark unused patch_default label (diff) | |
| download | linux-c280f7736ab26a601932b1ce017a3840dbedcfdc.tar.xz linux-c280f7736ab26a601932b1ce017a3840dbedcfdc.zip | |
Revert "x86/unwind: Detect bad stack return address"
Revert the following commit:
b6959a362177 ("x86/unwind: Detect bad stack return address")
... because Andrey Konovalov reported an unwinder warning:
WARNING: unrecognized kernel stack return address ffffffffa0000001 at ffff88006377fa18 in a.out:4467
The unwind was initiated from an interrupt which occurred while running in the
generated code for a kprobe. The unwinder printed the warning because it
expected regs->ip to point to a valid text address, but instead it pointed to
the generated code.
Eventually we may want come up with a way to identify generated kprobe
code so the unwinder can know that it's a valid return address. Until
then, just remove the warning.
Reported-by: Andrey Konovalov <andreyknvl@google.com>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/02f296848fbf49fb72dfeea706413ecbd9d4caf6.1482418739.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/kernel/unwind_frame.c | 11 |
1 files changed, 1 insertions, 10 deletions
diff --git a/arch/x86/kernel/unwind_frame.c b/arch/x86/kernel/unwind_frame.c index 20d4b4e0800c..4443e499f279 100644 --- a/arch/x86/kernel/unwind_frame.c +++ b/arch/x86/kernel/unwind_frame.c @@ -51,16 +51,7 @@ unsigned long unwind_get_return_address(struct unwind_state *state) addr = ftrace_graph_ret_addr(state->task, &state->graph_idx, *addr_p, addr_p); - if (!__kernel_text_address(addr)) { - printk_deferred_once(KERN_WARNING - "WARNING: unrecognized kernel stack return address %p at %p in %s:%d\n", - (void *)addr, addr_p, state->task->comm, - state->task->pid); - unwind_dump(state, addr_p); - return 0; - } - - return addr; + return __kernel_text_address(addr) ? addr : 0; } EXPORT_SYMBOL_GPL(unwind_get_return_address); |