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authorHugh Dickins <hughd@google.com>2014-06-04 16:05:33 -0700
committerBen Hutchings <ben@decadent.org.uk>2014-07-11 13:33:46 +0100
commite3ffaedcd935237fa5f1d820cb6ad33810593079 (patch)
tree2bc7bef8e0cdf8c760187d44bfa13add2e1f2293 /mm
parentba1ef838a9e275933683edbd08b6e2226f16e351 (diff)
mm: fix sleeping function warning from __put_anon_vma
commit 7f39dda9d86fb4f4f17af0de170decf125726f8c upstream. Trinity reports BUG: sleeping function called from invalid context at kernel/locking/rwsem.c:47 in_atomic(): 0, irqs_disabled(): 0, pid: 5787, name: trinity-c27 __might_sleep < down_write < __put_anon_vma < page_get_anon_vma < migrate_pages < compact_zone < compact_zone_order < try_to_compact_pages .. Right, since conversion to mutex then rwsem, we should not put_anon_vma() from inside an rcu_read_lock()ed section: fix the two places that did so. And add might_sleep() to anon_vma_free(), as suggested by Peter Zijlstra. Fixes: 88c22088bf23 ("mm: optimize page_lock_anon_vma() fast-path") Reported-by: Dave Jones <davej@redhat.com> Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Diffstat (limited to 'mm')
-rw-r--r--mm/rmap.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/mm/rmap.c b/mm/rmap.c
index 9ac405ba91df..ae27d95072c8 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -103,6 +103,7 @@ static inline void anon_vma_free(struct anon_vma *anon_vma)
* LOCK should suffice since the actual taking of the lock must
* happen _before_ what follows.
*/
+ might_sleep();
if (mutex_is_locked(&anon_vma->root->mutex)) {
anon_vma_lock(anon_vma);
anon_vma_unlock(anon_vma);
@@ -434,8 +435,9 @@ struct anon_vma *page_get_anon_vma(struct page *page)
* above cannot corrupt).
*/
if (!page_mapped(page)) {
+ rcu_read_unlock();
put_anon_vma(anon_vma);
- anon_vma = NULL;
+ return NULL;
}
out:
rcu_read_unlock();
@@ -485,9 +487,9 @@ struct anon_vma *page_lock_anon_vma(struct page *page)
}
if (!page_mapped(page)) {
+ rcu_read_unlock();
put_anon_vma(anon_vma);
- anon_vma = NULL;
- goto out;
+ return NULL;
}
/* we pinned the anon_vma, its safe to sleep */