From: Masami Hiramatsu <mhira...@kernel.org> [ 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 <mhira...@kernel.org> Cc: Ananth N Mavinakayanahalli <ana...@linux.vnet.ibm.com> Cc: Andrey Ryabinin <aryabi...@virtuozzo.com> Cc: Anil S Keshavamurthy <anil.s.keshavamur...@intel.com> Cc: Borislav Petkov <b...@alien8.de> Cc: Brian Gerst <brge...@gmail.com> Cc: David S . Miller <da...@davemloft.net> Cc: Denys Vlasenko <dvlas...@redhat.com> Cc: H. Peter Anvin <h...@zytor.com> Cc: Josh Poimboeuf <jpoim...@redhat.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Peter Zijlstra <pet...@infradead.org> Cc: Thomas Gleixner <t...@linutronix.de> Cc: Ye Xiaolong <xiaolong...@intel.com> Link: http://lkml.kernel.org/r/149076340615.22469.14066273186134229909.stgit@devbox Signed-off-by: Ingo Molnar <mi...@kernel.org> Signed-off-by: Sasha Levin <alexander.le...@microsoft.com> --- 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 b55d07b9d530..808ee7f566f8 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -199,6 +199,8 @@ 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
