From: tip-bot for Josh Poimboeuf <tipbot@zytor.com>
To: linux-tip-commits@vger.kernel.org
Cc: jpoimboe@redhat.com, davem@davemloft.net,
torvalds@linux-foundation.org, anil.s.keshavamurthy@intel.com,
mingo@kernel.org, mhiramat@kernel.org, hpa@zytor.com,
linux-kernel@vger.kernel.org, tglx@linutronix.de,
ananth@linux.vnet.ibm.com, richard@sigma-star.at,
peterz@infradead.org
Subject: [tip:x86/urgent] kprobes/x86: Set up frame pointer in kprobe trampoline
Date: Tue, 3 Oct 2017 10:42:42 -0700 [thread overview]
Message-ID: <tip-ee213fc72fd67d0988525af501534f4cb924d1e9@git.kernel.org> (raw)
In-Reply-To: <7aef2f8ecd75c2f505ef9b80490412262cf4a44c.1507038547.git.jpoimboe@redhat.com>
Commit-ID: ee213fc72fd67d0988525af501534f4cb924d1e9
Gitweb: https://git.kernel.org/tip/ee213fc72fd67d0988525af501534f4cb924d1e9
Author: Josh Poimboeuf <jpoimboe@redhat.com>
AuthorDate: Tue, 3 Oct 2017 08:51:43 -0500
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 3 Oct 2017 19:11:27 +0200
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>
---
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 db2182d..3fc0f9a 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" \
prev parent reply other threads:[~2017-10-03 17:46 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-03 13:51 [PATCH] x86/kprobes: " Josh Poimboeuf
2017-10-03 15:37 ` Masami Hiramatsu
2017-10-03 17:42 ` tip-bot for Josh Poimboeuf [this message]
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