4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Oleg Nesterov <oleg@xxxxxxxxxx> commit 90718e32e1dcc2479acfa208ccfc6442850b594c upstream. insn_get_length() has the side-effect of processing the entire instruction but only if it was decoded successfully, otherwise insn_complete() can fail and in this case we need to just return an error without warning. Reported-by: syzbot+30d675e3ca03c1c351e7@xxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> Reviewed-by: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: syzkaller-bugs@xxxxxxxxxxxxxxxx Link: https://lkml.kernel.org/lkml/20180518162739.GA5559@xxxxxxxxxx Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- arch/x86/kernel/uprobes.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -290,7 +290,7 @@ static int uprobe_init_insn(struct arch_ insn_init(insn, auprobe->insn, sizeof(auprobe->insn), x86_64); /* has the side-effect of processing the entire instruction */ insn_get_length(insn); - if (WARN_ON_ONCE(!insn_complete(insn))) + if (!insn_complete(insn)) return -ENOEXEC; if (is_prefix_bad(insn))
