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authorHugh Dickins <hughd@google.com>2014-03-03 15:38:23 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2014-03-04 07:55:47 -0800
commit5f30fc94ca985974fd54de454c7a6070388443db (patch)
tree61eaa530adadd74be8a5b80d5cbc547505ac0f48 /lib/radix-tree.c
parent3b7a6418c7494b8bf0bf0537ddee1dedbca10f51 (diff)
lib/radix-tree.c: swapoff tmpfs radix_tree: remember to rcu_read_unlock
Running fsx on tmpfs with concurrent memhog-swapoff-swapon, lots of BUG: sleeping function called from invalid context at kernel/fork.c:606 in_atomic(): 0, irqs_disabled(): 0, pid: 1394, name: swapoff 1 lock held by swapoff/1394: #0: (rcu_read_lock){.+.+.+}, at: [<ffffffff812520a1>] radix_tree_locate_item+0x1f/0x2b6 followed by ================================================ [ BUG: lock held when returning to user space! ] 3.14.0-rc1 #3 Not tainted ------------------------------------------------ swapoff/1394 is leaving the kernel with locks still held! 1 lock held by swapoff/1394: #0: (rcu_read_lock){.+.+.+}, at: [<ffffffff812520a1>] radix_tree_locate_item+0x1f/0x2b6 after which the system recovered nicely. Whoops, I long ago forgot the rcu_read_unlock() on one unlikely branch. Fixes e504f3fdd63d ("tmpfs radix_tree: locate_item to speed up swapoff") Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/radix-tree.c')
-rw-r--r--lib/radix-tree.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 7811ed3b4e70..bd4a8dfdf0b8 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1253,8 +1253,10 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
node = indirect_to_ptr(node);
max_index = radix_tree_maxindex(node->height);
- if (cur_index > max_index)
+ if (cur_index > max_index) {
+ rcu_read_unlock();
break;
+ }
cur_index = __locate(node, item, cur_index, &found_index);
rcu_read_unlock();