From: Masami Hiramatsu <mhiramat@xxxxxxxxxx> commit 004e8dce9c5595697951f7cd0e9f66b35c92265e upstream 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 <mhiramat@xxxxxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Cc: Juergen Gross <jgross@xxxxxxxx> Cc: x86@xxxxxxxxxx Cc: Boris Ostrovsky <boris.ostrovsky@xxxxxxxxxx> Cc: Ingo Molnar <mingo@xxxxxxxxxx> Cc: Stefano Stabellini <sstabellini@xxxxxxxxxx> Cc: Andrew Cooper <andrew.cooper3@xxxxxxxxxx> Cc: Borislav Petkov <bp@xxxxxxxxx> Cc: xen-devel@xxxxxxxxxxxxxxxxxxxx Cc: Randy Dunlap <rdunlap@xxxxxxxxxxxxx> Cc: Josh Poimboeuf <jpoimboe@xxxxxxxxxx> Link: https://lkml.kernel.org/r/156777566048.25081.6296162369492175325.stgit@devnote2 Signed-off-by: Maximilian Heyne <mheyne@xxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx # 5.4.x --- 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 c205d77d57da..3700dc94847c 100644 --- a/arch/x86/kernel/kprobes/core.c +++ b/arch/x86/kernel/kprobes/core.c @@ -358,6 +358,10 @@ 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; -- 2.32.0 Amazon Development Center Germany GmbH Krausenstr. 38 10117 Berlin Geschaeftsfuehrung: Christian Schlaeger, Jonathan Weiss Eingetragen am Amtsgericht Charlottenburg unter HRB 149173 B Sitz: Berlin Ust-ID: DE 289 237 879
