From b5e212a3051b65e426a513901d9c7001681c7215 Mon Sep 17 00:00:00 2001 From: Andy Lutomirski Date: Wed, 19 Nov 2014 13:56:19 -0800 Subject: [PATCH] x86, syscall: Fix _TIF_NOHZ handling in syscall_trace_enter_phase1 TIF_NOHZ is 19 (i.e. _TIF_SYSCALL_TRACE | _TIF_NOTIFY_RESUME | _TIF_SINGLESTEP), not (1<<19). This code is involved in Dave's trinity lockup, but I don't see why it would cause any of the problems he's seeing, except inadvertently by causing a different path through entry_64.S's syscall handling. Signed-off-by: Andy Lutomirski Cc: Don Zickus Cc: Peter Zijlstra Cc: Dave Jones Cc: Linus Torvalds Link: http://lkml.kernel.org/r/a6cd3b60a3f53afb6e1c8081b0ec30ff19003dd7.1416434075.git.luto@amacapital.net Signed-off-by: Thomas Gleixner --- arch/x86/kernel/ptrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 749b0e423419..e510618b2e91 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -1484,7 +1484,7 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch) */ if (work & _TIF_NOHZ) { user_exit(); - work &= ~TIF_NOHZ; + work &= ~_TIF_NOHZ; } #ifdef CONFIG_SECCOMP