The vsyscall emulation code sets orig_ax for seccomp's benefit, but it forgot to set it back.
I'm not sure that this is observable at all, but it could cause confusion to various /proc or ptrace users, and it's possible that it could cause minor artifacts if a signal were to be delivered on return from vsyscall emulation. Signed-off-by: Andy Lutomirski <[email protected]> --- I misplaced this somehow as part of my vsyscall series. It's very minor, so I don't care much whether it makes 3.19. My vsyscall seccomp tests all pass with or without this change. arch/x86/kernel/vsyscall_64.c | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/x86/kernel/vsyscall_64.c b/arch/x86/kernel/vsyscall_64.c index 7d9eb4bc10ac..2dcc6ff6fdcc 100644 --- a/arch/x86/kernel/vsyscall_64.c +++ b/arch/x86/kernel/vsyscall_64.c @@ -206,6 +206,7 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address) "seccomp tried to change syscall nr or ip"); do_exit(SIGSYS); } + regs->orig_ax = -1; if (tmp) goto do_ret; /* skip requested */ -- 1.9.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
