linux_dsm_epyc7002/arch/x86/kernel/kprobes
Josh Poimboeuf ee213fc72f kprobes/x86: Set up frame pointer in kprobe trampoline
Richard Weinberger saw an unwinder warning when running bcc's opensnoop:

  WARNING: kernel stack frame pointer at ffff99ef4076bea0 in opensnoop:2008 has bad value 0000000000000008
  unwind stack type:0 next_sp:          (null) mask:0x2 graph_idx:0
  ...
  ffff99ef4076be88: ffff99ef4076bea0 (0xffff99ef4076bea0)
  ffff99ef4076be90: ffffffffac442721 (optimized_callback +0x81/0x90)
  ...

A lockdep stack trace was initiated from inside a kprobe handler, when
the unwinder noticed a bad frame pointer on the stack.  The bad frame
pointer is related to the fact that the kprobe optprobe trampoline
doesn't save the frame pointer before calling into optimized_callback().

Reported-and-tested-by: Richard Weinberger <richard@sigma-star.at>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
Cc: David S . Miller <davem@davemloft.net>
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/7aef2f8ecd75c2f505ef9b80490412262cf4a44c.1507038547.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-10-03 19:11:27 +02:00
..
common.h kprobes/x86: Set up frame pointer in kprobe trampoline 2017-10-03 19:11:27 +02:00
core.c kprobes/x86: Release insn_slot in failure path 2017-07-24 11:14:59 +02:00
ftrace.c kprobes/x86: Make boostable flag boolean 2017-04-12 09:23:46 +02:00
Makefile kprobes/x86: Move kprobes stuff under arch/x86/kernel/kprobes/ 2013-01-21 13:22:37 -05:00
opt.c kprobes/x86: Do not jump-optimize kprobes on irq entry code 2017-08-10 16:28:53 +02:00