Commit d21001cc authored Jan 21, 2016 by Josh Poimboeuf Committed by Ingo Molnar Feb 24, 2016

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@redhat.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Bernd Petrovitsch <bernd@petrovitsch.priv.at>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chris J Arges <chris.j.arges@canonical.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Michal Marek <mmarek@suse.cz>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Pedro Alves <palves@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: live-patching@vger.kernel.org
Cc: netdev@vger.kernel.org
Link: http://lkml.kernel.org/r/fa4c41976b438b51954cb8021f06bceb1d1d66cc.1453405861.git.jpoimboe@redhat.com


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent 2d8fe90a

arch/x86/net/bpf_jit.S

+7 −2

Original line number	Diff line number	Diff line
		@@ -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:

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