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| author | Alexander Gordeev <agordeev@redhat.com> | 2012-03-09 14:59:59 +0100 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2012-03-09 17:19:09 +0100 |
| commit | 5234ffb9f74cfa8993d174782bc861dd9b7b5bfb (patch) | |
| tree | c3933cd6177cde81a99f0bcdadb333b1233e007d /kernel/exit.c | |
| parent | 05d74efa3c72a5c40b0edeb15856c0230126313b (diff) | |
| download | lwn-5234ffb9f74cfa8993d174782bc861dd9b7b5bfb.tar.gz lwn-5234ffb9f74cfa8993d174782bc861dd9b7b5bfb.zip | |
genirq: Get rid of unnecessary IRQTF_DIED flag
Currently IRQTF_DIED flag is set when a IRQ thread handler calls do_exit()
But also PF_EXITING per process flag gets set when a thread exits. This
fix eliminates the duplicate by using PF_EXITING flag.
Also, there is a race condition in exit_irq_thread(). In case a thread's
bit is cleared in desc->threads_oneshot (and the IRQ line gets unmasked),
but before IRQTF_DIED flag is set, a new interrupt might come in and set
just cleared bit again, this time forever. This fix throws IRQTF_DIED flag
away, eliminating the race as a result.
[ tglx: Test THREAD_EXITING first as suggested by Oleg ]
Reported-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Link: http://lkml.kernel.org/r/20120309135958.GD2114@dhcp-26-207.brq.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/exit.c')
| -rw-r--r-- | kernel/exit.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/exit.c b/kernel/exit.c index 4b4042f9bc6a..752d2c0abd19 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -935,8 +935,6 @@ void do_exit(long code) schedule(); } - exit_irq_thread(); - exit_signals(tsk); /* sets PF_EXITING */ /* * tsk->flags are checked in the futex code to protect against @@ -945,6 +943,8 @@ void do_exit(long code) smp_mb(); raw_spin_unlock_wait(&tsk->pi_lock); + exit_irq_thread(); + if (unlikely(in_atomic())) printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n", current->comm, task_pid_nr(current), |