Messages in this thread Patch in this message | | | Date | Thu, 20 Nov 2014 14:04:26 -0800 | From | tip-bot for Andy Lutomirski <> | Subject | [tip:x86/urgent] x86, syscall: Fix _TIF_NOHZ handling in syscall_trace_enter_phase1 |
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Commit-ID: b5e212a3051b65e426a513901d9c7001681c7215 Gitweb: http://git.kernel.org/tip/b5e212a3051b65e426a513901d9c7001681c7215 Author: Andy Lutomirski <luto@amacapital.net> AuthorDate: Wed, 19 Nov 2014 13:56:19 -0800 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Thu, 20 Nov 2014 23:01:53 +0100
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> --- 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 749b0e4..e510618 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
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