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authorJosh Poimboeuf <jpoimboe@redhat.com>2017-10-03 08:51:43 -0500
committerIngo Molnar <mingo@kernel.org>2017-10-03 19:11:27 +0200
commitee213fc72fd67d0988525af501534f4cb924d1e9 (patch)
tree707cf46233eba22b0cfaf0468cb2f50787d0d2dd /arch/x86/kernel/kprobes
parent9e66317d3c92ddaab330c125dfe9d06eee268aff (diff)
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>
Diffstat (limited to 'arch/x86/kernel/kprobes')
-rw-r--r--arch/x86/kernel/kprobes/common.h13
1 files changed, 11 insertions, 2 deletions
diff --git a/arch/x86/kernel/kprobes/common.h b/arch/x86/kernel/kprobes/common.h
index db2182d63ed0..3fc0f9a794cb 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" \