[tip:x86/debug] x86/asm/bpf: Create stack frames in bpf_jit.S

[tip-bot for Josh Poimboeuf]

Commit-ID:  d21001cc15ba9f63b0334d60942278587471a451
Gitweb:     http://git.kernel.org/tip/d21001cc15ba9f63b0334d60942278587471a451
Author:     Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
AuthorDate: Thu, 21 Jan 2016 16:49:27 -0600
Committer:  Ingo Molnar <mingo@xxxxxxxxxx>
CommitDate: Wed, 24 Feb 2016 08:35:44 +0100

x86/asm/bpf: Create stack frames in bpf_jit.S

bpf_jit.S has several callable non-leaf functions which don't honor
CONFIG_FRAME_POINTER, which can result in bad stack traces.

Create a stack frame before the call instructions when
CONFIG_FRAME_POINTER is enabled.

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxxxxxx>
Cc: Andy Lutomirski <luto@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Bernd Petrovitsch <bernd@xxxxxxxxxxxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brian Gerst <brgerst@xxxxxxxxx>
Cc: Chris J Arges <chris.j.arges@xxxxxxxxxxxxx>
Cc: Denys Vlasenko <dvlasenk@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jiri Slaby <jslaby@xxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Marek <mmarek@xxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxx>
Cc: Pedro Alves <palves@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: live-patching@xxxxxxxxxxxxxxx
Cc: netdev@xxxxxxxxxxxxxxx
Link: http://lkml.kernel.org/r/fa4c41976b438b51954cb8021f06bceb1d1d66cc.1453405861.git.jpoimboe@xxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
---
 arch/x86/net/bpf_jit.S | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/arch/x86/net/bpf_jit.S b/arch/x86/net/bpf_jit.S
index eb4a3bd..f2a7faf 100644
--- a/arch/x86/net/bpf_jit.S
+++ b/arch/x86/net/bpf_jit.S
@@ -8,6 +8,7 @@
  * of the License.
  */
 #include <linux/linkage.h>
+#include <asm/frame.h>
 
 /*
  * Calling convention :
@@ -65,16 +66,18 @@ FUNC(sk_load_byte_positive_offset)
 
 /* rsi contains offset and can be scratched */
 #define bpf_slow_path_common(LEN)		\
+	lea	-MAX_BPF_STACK + 32(%rbp), %rdx;\
+	FRAME_BEGIN;				\
 	mov	%rbx, %rdi; /* arg1 == skb */	\
 	push	%r9;				\
 	push	SKBDATA;			\
 /* rsi already has offset */			\
 	mov	$LEN,%ecx;	/* len */	\
-	lea	- MAX_BPF_STACK + 32(%rbp),%rdx;			\
 	call	skb_copy_bits;			\
 	test    %eax,%eax;			\
 	pop	SKBDATA;			\
-	pop	%r9;
+	pop	%r9;				\
+	FRAME_END
 
 
 bpf_slow_path_word:
@@ -99,6 +102,7 @@ bpf_slow_path_byte:
 	ret
 
 #define sk_negative_common(SIZE)				\
+	FRAME_BEGIN;						\
 	mov	%rbx, %rdi; /* arg1 == skb */			\
 	push	%r9;						\
 	push	SKBDATA;					\
@@ -108,6 +112,7 @@ bpf_slow_path_byte:
 	test	%rax,%rax;					\
 	pop	SKBDATA;					\
 	pop	%r9;						\
+	FRAME_END;						\
 	jz	bpf_error
 
 bpf_slow_path_word_neg: