On Tue, 3 Oct 2017 08:51:43 -0500 Josh Poimboeuf <jpoim...@redhat.com> wrote:
> 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(). OK, this looks good to me :) Acked-by: Masami Hiramatsu <mhira...@kernel.org> Thanks! > > Reported-and-tested-by: Richard Weinberger <rich...@sigma-star.at> > Signed-off-by: Josh Poimboeuf <jpoim...@redhat.com> > --- > arch/x86/kernel/kprobes/common.h | 13 +++++++++++-- > 1 file changed, 11 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/kernel/kprobes/common.h > b/arch/x86/kernel/kprobes/common.h > index e2c2a1970869..595b56b37d27 100644 > --- a/arch/x86/kernel/kprobes/common.h > +++ b/arch/x86/kernel/kprobes/common.h > @@ -3,6 +3,15 @@ > > /* Kprobes and Optprobes common header */ > > +#include <asm/asm.h> > + > +#ifdef CONFIG_FRAME_POINTER > +# define SAVE_RBP_STRING " push %" _ASM_BP "\n" \ > + " mov %" _ASM_SP ", %" _ASM_BP "\n" > +#else > +# define SAVE_RBP_STRING " push %" _ASM_BP "\n" > +#endif > + > #ifdef CONFIG_X86_64 > #define SAVE_REGS_STRING \ > /* Skip cs, ip, orig_ax. */ \ > @@ -17,7 +26,7 @@ > " pushq %r10\n" \ > " pushq %r11\n" \ > " pushq %rbx\n" \ > - " pushq %rbp\n" \ > + SAVE_RBP_STRING \ > " pushq %r12\n" \ > " pushq %r13\n" \ > " pushq %r14\n" \ > @@ -48,7 +57,7 @@ > " pushl %es\n" \ > " pushl %ds\n" \ > " pushl %eax\n" \ > - " pushl %ebp\n" \ > + SAVE_RBP_STRING \ > " pushl %edi\n" \ > " pushl %esi\n" \ > " pushl %edx\n" \ > -- > 2.13.6 > -- Masami Hiramatsu <mhira...@kernel.org>
