diff options
| author | Mike Galbraith <bitbucket@online.de> | 2014-04-07 10:55:15 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-04-11 10:39:15 +0200 |
| commit | 60e69eed85bb7b5198ef70643b5895c26ad76ef7 (patch) | |
| tree | 4fa65bf81edbd0a28d5bc160f878341657f5ad82 /kernel | |
| parent | 467cbd207abdbfe29514b5804a22661ab6e80dc6 (diff) | |
sched/numa: Fix task_numa_free() lockdep splat
Sasha reported that lockdep claims that the following commit:
made numa_group.lock interrupt unsafe:
156654f491dd ("sched/numa: Move task_numa_free() to __put_task_struct()")
While I don't see how that could be, given the commit in question moved
task_numa_free() from one irq enabled region to another, the below does
make both gripes and lockups upon gripe with numa=fake=4 go away.
Reported-by: Sasha Levin <sasha.levin@oracle.com>
Fixes: 156654f491dd ("sched/numa: Move task_numa_free() to __put_task_struct()")
Signed-off-by: Mike Galbraith <bitbucket@online.de>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: torvalds@linux-foundation.org
Cc: mgorman@suse.com
Cc: akpm@linux-foundation.org
Cc: Dave Jones <davej@redhat.com>
Link: http://lkml.kernel.org/r/1396860915.5170.5.camel@marge.simpson.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/sched/fair.c | 13 | ||||
| -rw-r--r-- | kernel/sched/sched.h | 9 |
2 files changed, 16 insertions, 6 deletions
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 7e9bd0b1fa9e..4f14a656a720 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -1497,7 +1497,7 @@ static void task_numa_placement(struct task_struct *p) /* If the task is part of a group prevent parallel updates to group stats */ if (p->numa_group) { group_lock = &p->numa_group->lock; - spin_lock(group_lock); + spin_lock_irq(group_lock); } /* Find the node with the highest number of faults */ @@ -1572,7 +1572,7 @@ static void task_numa_placement(struct task_struct *p) } } - spin_unlock(group_lock); + spin_unlock_irq(group_lock); } /* Preferred node as the node with the most faults */ @@ -1677,7 +1677,8 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags, if (!join) return; - double_lock(&my_grp->lock, &grp->lock); + BUG_ON(irqs_disabled()); + double_lock_irq(&my_grp->lock, &grp->lock); for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) { my_grp->faults[i] -= p->numa_faults_memory[i]; @@ -1691,7 +1692,7 @@ static void task_numa_group(struct task_struct *p, int cpupid, int flags, grp->nr_tasks++; spin_unlock(&my_grp->lock); - spin_unlock(&grp->lock); + spin_unlock_irq(&grp->lock); rcu_assign_pointer(p->numa_group, grp); @@ -1710,14 +1711,14 @@ void task_numa_free(struct task_struct *p) void *numa_faults = p->numa_faults_memory; if (grp) { - spin_lock(&grp->lock); + spin_lock_irq(&grp->lock); for (i = 0; i < NR_NUMA_HINT_FAULT_STATS * nr_node_ids; i++) grp->faults[i] -= p->numa_faults_memory[i]; grp->total_faults -= p->total_numa_faults; list_del(&p->numa_entry); grp->nr_tasks--; - spin_unlock(&grp->lock); + spin_unlock_irq(&grp->lock); rcu_assign_pointer(p->numa_group, NULL); put_numa_group(grp); } diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index c9007f28d3a2..456e492a3dca 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1385,6 +1385,15 @@ static inline void double_lock(spinlock_t *l1, spinlock_t *l2) spin_lock_nested(l2, SINGLE_DEPTH_NESTING); } +static inline void double_lock_irq(spinlock_t *l1, spinlock_t *l2) +{ + if (l1 > l2) + swap(l1, l2); + + spin_lock_irq(l1); + spin_lock_nested(l2, SINGLE_DEPTH_NESTING); +} + static inline void double_raw_lock(raw_spinlock_t *l1, raw_spinlock_t *l2) { if (l1 > l2) |