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 <mhira...@kernel.org> AuthorDate: Fri, 06 Sep 2019 22:14:20 +09:00 Committer: Peter Zijlstra <pet...@infradead.org> 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 <mhira...@kernel.org> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Cc: Juergen Gross <jgr...@suse.com> Cc: x...@kernel.org Cc: Boris Ostrovsky <boris.ostrov...@oracle.com> Cc: Ingo Molnar <mi...@kernel.org> Cc: Stefano Stabellini <sstabell...@kernel.org> Cc: Andrew Cooper <andrew.coop...@citrix.com> Cc: Borislav Petkov <b...@alien8.de> Cc: xen-de...@lists.xenproject.org Cc: Randy Dunlap <rdun...@infradead.org> Cc: Josh Poimboeuf <jpoim...@redhat.com> 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;
