Revert "x86/unwind: Detect bad stack return address"
authorJosh Poimboeuf <jpoimboe@redhat.com>
Thu, 22 Dec 2016 15:02:49 +0000 (09:02 -0600)
committerIngo Molnar <mingo@kernel.org>
Fri, 23 Dec 2016 19:32:30 +0000 (20:32 +0100)
commitc280f7736ab26a601932b1ce017a3840dbedcfdc
treeca07c17a22621acbfec0f03521ba9098de620629
parentcef4402d7627f14a08571e7c816b199edf8cc24b
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>
arch/x86/kernel/unwind_frame.c