From: Steven Rostedt The dynamic function tracer relys on the macro P6_NOP5 always being an atomic NOP. If for some reason it is changed to be two operations (like a nop2 nop3) it can faults within the kernel when the function tracer modifies the code. This patch adds a comment to note that the P6_NOPs are expected to be atomic. This will hopefully prevent anyone from changing that. Reported-by: Mathieu Desnoyer Signed-off-by: Steven Rostedt --- arch/x86/include/asm/nops.h | 2 ++ 1 files changed, 2 insertions(+), 0 deletions(-) diff --git a/arch/x86/include/asm/nops.h b/arch/x86/include/asm/nops.h index ad2668e..6d8723a 100644 --- a/arch/x86/include/asm/nops.h +++ b/arch/x86/include/asm/nops.h @@ -65,6 +65,8 @@ 6: osp nopl 0x00(%eax,%eax,1) 7: nopl 0x00000000(%eax) 8: nopl 0x00000000(%eax,%eax,1) + Note: All the above are assumed to be a single instruction. + There is kernel code that depends on this. */ #define P6_NOP1 GENERIC_NOP1 #define P6_NOP2 ".byte 0x66,0x90\n" -- 1.6.3.3 -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/