The patch titled
pi-futex: set PF_EXITING without taking ->pi_lock
has been added to the -mm tree. Its filename is
pi-futex-set-pf_exiting-without-taking-pi_lock.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: pi-futex: set PF_EXITING without taking ->pi_lock
From: Oleg Nesterov <oleg@xxxxxxxxxx>
It is a bit annoying that do_exit() takes ->pi_lock to set PF_EXITING. All
we need is to synchronize with lookup_pi_state() which saw this task
without PF_EXITING under ->pi_lock.
Change do_exit() to use spin_unlock_wait().
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Acked-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
kernel/exit.c | 6 +++---
1 files changed, 3 insertions(+), 3 deletions(-)
diff -puN kernel/exit.c~pi-futex-set-pf_exiting-without-taking-pi_lock kernel/exit.c
--- a/kernel/exit.c~pi-futex-set-pf_exiting-without-taking-pi_lock
+++ a/kernel/exit.c
@@ -944,13 +944,13 @@ fastcall NORET_TYPE void do_exit(long co
schedule();
}
+ tsk->flags |= PF_EXITING;
/*
* tsk->flags are checked in the futex code to protect against
* an exiting task cleaning up the robust pi futexes.
*/
- spin_lock_irq(&tsk->pi_lock);
- tsk->flags |= PF_EXITING;
- spin_unlock_irq(&tsk->pi_lock);
+ smp_mb();
+ spin_unlock_wait(&tsk->pi_lock);
if (unlikely(in_atomic()))
printk(KERN_INFO "note: %s[%d] exited with preempt_count %d\n",
_
Patches currently in -mm which might be from oleg@xxxxxxxxxx are
origin.patch
fix-theoretical-ccids_readwrite_lock-race.patch
i386-remove-unnecessary-code.patch
clone-flag-clone_parent_tidptr-leaves-invalid-results-in-memory.patch
do_sys_poll-simplify-playing-with-on-stack-data.patch
do_sys_poll-simplify-playing-with-on-stack-data-fix.patch
do_poll-return-eintr-when-signalled.patch
pi-futex-set-pf_exiting-without-taking-pi_lock.patch
cpu-hotplug-slab-cleanup-cpuup_callback.patch
cpu-hotplug-slab-fix-memory-leak-in-cpu-hotplug-error-path.patch
cpu-hotplug-cpu-deliver-cpu_up_canceled-only-to-notify_oked-callbacks-with-cpu_up_prepare.patch
cpu-hotplug-topology-remove-topology_dev_map.patch
cpu-hotplug-thermal_throttle-fix-cpu-hotplug-error-handling.patch
cpu-hotplug-msr-fix-cpu-hotplug-error-handling.patch
cpu-hotplug-cpuid-fix-cpu-hotplug-error-handling.patch
cpu-hotplug-mce-fix-cpu-hotplug-error-handling.patch
cpu-hotplug-intel_cacheinfo-fix-cpu-hotplug-error-handling.patch
cpu-hotplug-intel_cacheinfo-fix-cpu-hotplug-error-handling-fix-a-section-mismatch-warning.patch
workqueue-debug-flushing-deadlocks-with-lockdep.patch
workqueue-debug-work-related-deadlocks-with-lockdep.patch
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