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authorAndy Lutomirski <luto@amacapital.net>2014-11-19 13:56:19 -0800
committerThomas Gleixner <tglx@linutronix.de>2014-11-20 23:01:53 +0100
commitb5e212a3051b65e426a513901d9c7001681c7215 (patch)
tree61ee6c5bb71364d1436136cfb4c1e318f533594b
parent70b61e362187b5fccac206506d402f3424e3e749 (diff)
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 <luto@amacapital.net> Cc: Don Zickus <dzickus@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Jones <davej@redhat.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Link: http://lkml.kernel.org/r/a6cd3b60a3f53afb6e1c8081b0ec30ff19003dd7.1416434075.git.luto@amacapital.net Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
-rw-r--r--arch/x86/kernel/ptrace.c2
1 files changed, 1 insertions, 1 deletions
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