linux-kernel - [tip:x86/urgent] kprobes/x86: Set up frame pointer in kprobe trampoline

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:   Tue, 3 Oct 2017 10:42:42 -0700
From:   tip-bot for Josh Poimboeuf <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     jpoimboe@...hat.com, davem@...emloft.net,
        torvalds@...ux-foundation.org, anil.s.keshavamurthy@...el.com,
        mingo@...nel.org, mhiramat@...nel.org, hpa@...or.com,
        linux-kernel@...r.kernel.org, tglx@...utronix.de,
        ananth@...ux.vnet.ibm.com, richard@...ma-star.at,
        peterz@...radead.org
Subject: [tip:x86/urgent] kprobes/x86: Set up frame pointer in kprobe
 trampoline

Commit-ID:  ee213fc72fd67d0988525af501534f4cb924d1e9
Gitweb:     https://git.kernel.org/tip/ee213fc72fd67d0988525af501534f4cb924d1e9
Author:     Josh Poimboeuf <jpoimboe@...hat.com>
AuthorDate: Tue, 3 Oct 2017 08:51:43 -0500
Committer:  Ingo Molnar <mingo@...nel.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@...ma-star.at>
Signed-off-by: Josh Poimboeuf <jpoimboe@...hat.com>
Acked-by: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>
Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@...el.com>
Cc: David S . Miller <davem@...emloft.net>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Link: http://lkml.kernel.org/r/7aef2f8ecd75c2f505ef9b80490412262cf4a44c.1507038547.git.jpoimboe@redhat.com
Signed-off-by: Ingo Molnar <mingo@...nel.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"			\