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authorAndrey Ryabinin <aryabinin@virtuozzo.com>2016-07-20 15:45:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-23 10:25:54 +0900
commit3cb9185c67304b2a7ea9be73e7d13df6fb2793a1 (patch)
tree319fea4e03c86c2b086ec1a3a4df7baffe72dcc7
parent73f576c04b9410ed19660f74f97521bee6e1c546 (diff)
downloadlinux-3cb9185c67304b2a7ea9be73e7d13df6fb2793a1.tar.gz
linux-3cb9185c67304b2a7ea9be73e7d13df6fb2793a1.tar.xz
radix-tree: fix radix_tree_iter_retry() for tagged iterators.
radix_tree_iter_retry() resets slot to NULL, but it doesn't reset tags. Then NULL slot and non-zero iter.tags passed to radix_tree_next_slot() leading to crash: RIP: radix_tree_next_slot include/linux/radix-tree.h:473 find_get_pages_tag+0x334/0x930 mm/filemap.c:1452 .... Call Trace: pagevec_lookup_tag+0x3a/0x80 mm/swap.c:960 mpage_prepare_extent_to_map+0x321/0xa90 fs/ext4/inode.c:2516 ext4_writepages+0x10be/0x2b20 fs/ext4/inode.c:2736 do_writepages+0x97/0x100 mm/page-writeback.c:2364 __filemap_fdatawrite_range+0x248/0x2e0 mm/filemap.c:300 filemap_write_and_wait_range+0x121/0x1b0 mm/filemap.c:490 ext4_sync_file+0x34d/0xdb0 fs/ext4/fsync.c:115 vfs_fsync_range+0x10a/0x250 fs/sync.c:195 vfs_fsync fs/sync.c:209 do_fsync+0x42/0x70 fs/sync.c:219 SYSC_fdatasync fs/sync.c:232 SyS_fdatasync+0x19/0x20 fs/sync.c:230 entry_SYSCALL_64_fastpath+0x23/0xc1 arch/x86/entry/entry_64.S:207 We must reset iterator's tags to bail out from radix_tree_next_slot() and go to the slow-path in radix_tree_next_chunk(). Fixes: 46437f9a554f ("radix-tree: fix race in gang lookup") Link: http://lkml.kernel.org/r/1468495196-10604-1-git-send-email-aryabinin@virtuozzo.com Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com> Reported-by: Dmitry Vyukov <dvyukov@google.com> Acked-by: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ross Zwisler <ross.zwisler@linux.intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--include/linux/radix-tree.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index cb4b7e8..eca6f62 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -407,6 +407,7 @@ static inline __must_check
void **radix_tree_iter_retry(struct radix_tree_iter *iter)
{
iter->next_index = iter->index;
+ iter->tags = 0;
return NULL;
}