From: Masami Hiramatsu <[email protected]> [ Upstream commit bd0b90676c30fe640e7ead919b3e38846ac88ab7 ]
Fix the kprobe-booster not to boost far call instruction, because a call may store the address in the single-step execution buffer to the stack, which should be modified after single stepping. Currently, this instruction will be filtered as not boostable in resume_execution(), so this is not a critical issue. Signed-off-by: Masami Hiramatsu <[email protected]> Cc: Ananth N Mavinakayanahalli <[email protected]> Cc: Andrey Ryabinin <[email protected]> Cc: Anil S Keshavamurthy <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: Brian Gerst <[email protected]> Cc: David S . Miller <[email protected]> Cc: Denys Vlasenko <[email protected]> Cc: H. Peter Anvin <[email protected]> Cc: Josh Poimboeuf <[email protected]> Cc: Linus Torvalds <[email protected]> Cc: Peter Zijlstra <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Ye Xiaolong <[email protected]> Link: http://lkml.kernel.org/r/149076340615.22469.14066273186134229909.stgit@devbox Signed-off-by: Ingo Molnar <[email protected]> Signed-off-by: Sasha Levin <[email protected]> --- arch/x86/kernel/kprobes/core.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 99d293ea2b49..5d11d01f75de 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -196,6 +196,8 @@ int can_boost(kprobe_opcode_t *opcodes, void *addr) return (opcode != 0x62 && opcode != 0x67); case 0x70: return 0; /* can't boost conditional jump */ + case 0x90: + return opcode != 0x9a; /* can't boost call far */ case 0xc0: /* can't boost software-interruptions */ return (0xc1 < opcode && opcode < 0xcc) || opcode == 0xcf; -- 2.14.1
