The following commit has been merged into the x86/core branch of tip: Commit-ID: 004e8dce9c5595697951f7cd0e9f66b35c92265e Gitweb: https://git.kernel.org/tip/004e8dce9c5595697951f7cd0e9f66b35c92265e Author: Masami Hiramatsu <[email protected]> AuthorDate: Fri, 06 Sep 2019 22:14:20 +09:00 Committer: Peter Zijlstra <[email protected]> CommitterDate: Thu, 17 Oct 2019 21:31:57 +02:00
x86: kprobes: Prohibit probing on instruction which has emulate prefix Prohibit probing on instruction which has XEN_EMULATE_PREFIX or KVM's emulate prefix. Since that prefix is a marker for Xen and KVM, if we modify the marker by kprobe's int3, that doesn't work as expected. Signed-off-by: Masami Hiramatsu <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Cc: Juergen Gross <[email protected]> Cc: [email protected] Cc: Boris Ostrovsky <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Stefano Stabellini <[email protected]> Cc: Andrew Cooper <[email protected]> Cc: Borislav Petkov <[email protected]> Cc: [email protected] Cc: Randy Dunlap <[email protected]> Cc: Josh Poimboeuf <[email protected]> Link: https://lkml.kernel.org/r/156777566048.25081.6296162369492175325.stgit@devnote2 --- arch/x86/kernel/kprobes/core.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c index 43fc13c..4f13af7 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -351,6 +351,10 @@ int __copy_instruction(u8 *dest, u8 *src, u8 *real, struct insn *insn) kernel_insn_init(insn, dest, MAX_INSN_SIZE); insn_get_length(insn); + /* We can not probe force emulate prefixed instruction */ + if (insn_has_emulate_prefix(insn)) + return 0; + /* Another subsystem puts a breakpoint, failed to recover */ if (insn->opcode.bytes[0] == BREAKPOINT_INSTRUCTION) return 0;
