Subject: + swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock.patch added to -mm tree
To: hughd@xxxxxxxxxx,hannes@xxxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Thu, 13 Feb 2014 14:27:19 -0800
The patch titled
Subject: lib/radix-tree.c: swapoff tmpfs radix_tree: remember to rcu_read_unlock
has been added to the -mm tree. Its filename is
swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock.patch
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------------------------------------------------------
From: Hugh Dickins <hughd@xxxxxxxxxx>
Subject: 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@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
lib/radix-tree.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff -puN lib/radix-tree.c~swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock lib/radix-tree.c
--- a/lib/radix-tree.c~swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock
+++ a/lib/radix-tree.c
@@ -1253,8 +1253,10 @@ unsigned long radix_tree_locate_item(str
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();
_
Patches currently in -mm which might be from hughd@xxxxxxxxxx are
swapoff-tmpfs-radix_tree-remember-to-rcu_read_unlock.patch
mm-vmstat-fix-up-zone-state-accounting.patch
fs-cachefiles-use-add_to_page_cache_lru.patch
lib-radix-tree-radix_tree_delete_item.patch
mm-shmem-save-one-radix-tree-lookup-when-truncating-swapped-pages.patch
mm-filemap-move-radix-tree-hole-searching-here.patch
mm-fs-prepare-for-non-page-entries-in-page-cache-radix-trees.patch
mm-fs-store-shadow-entries-in-page-cache.patch
mm-thrash-detection-based-file-cache-sizing.patch
lib-radix_tree-tree-node-interface.patch
mm-keep-page-cache-radix-tree-nodes-in-check.patch
mm-keep-page-cache-radix-tree-nodes-in-check-fix.patch
mm-keep-page-cache-radix-tree-nodes-in-check-fix-fix.patch
mm-compaction-avoid-isolating-pinned-pages.patch
linux-next.patch
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