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authorRyusuke Konishi <konishi.ryusuke@gmail.com>2023-05-13 19:24:28 +0900
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2023-06-21 15:44:10 +0200
commit0dd2d8331eb45357a69c523333b48622907e7757 (patch)
treef2c471bc200a4b328de6bdd27c40428e144dc92e /fs/nilfs2
parente1fb47f13970063557c4723e420d57291aeb12e1 (diff)
nilfs2: fix incomplete buffer cleanup in nilfs_btnode_abort_change_key()
commit 2f012f2baca140c488e43d27a374029c1e59098d upstream. A syzbot fault injection test reported that nilfs_btnode_create_block, a helper function that allocates a new node block for b-trees, causes a kernel BUG for disk images where the file system block size is smaller than the page size. This was due to unexpected flags on the newly allocated buffer head, and it turned out to be because the buffer flags were not cleared by nilfs_btnode_abort_change_key() after an error occurred during a b-tree update operation and the buffer was later reused in that state. Fix this issue by using nilfs_btnode_delete() to abandon the unused preallocated buffer in nilfs_btnode_abort_change_key(). Link: https://lkml.kernel.org/r/20230513102428.10223-1-konishi.ryusuke@gmail.com Signed-off-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Reported-by: syzbot+b0a35a5c1f7e846d3b09@syzkaller.appspotmail.com Closes: https://lkml.kernel.org/r/000000000000d1d6c205ebc4d512@google.com Tested-by: Ryusuke Konishi <konishi.ryusuke@gmail.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'fs/nilfs2')
-rw-r--r--fs/nilfs2/btnode.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/fs/nilfs2/btnode.c b/fs/nilfs2/btnode.c
index e00e184b1261..1776121677e2 100644
--- a/fs/nilfs2/btnode.c
+++ b/fs/nilfs2/btnode.c
@@ -285,6 +285,14 @@ void nilfs_btnode_abort_change_key(struct address_space *btnc,
if (nbh == NULL) { /* blocksize == pagesize */
xa_erase_irq(&btnc->i_pages, newkey);
unlock_page(ctxt->bh->b_page);
- } else
- brelse(nbh);
+ } else {
+ /*
+ * When canceling a buffer that a prepare operation has
+ * allocated to copy a node block to another location, use
+ * nilfs_btnode_delete() to initialize and release the buffer
+ * so that the buffer flags will not be in an inconsistent
+ * state when it is reallocated.
+ */
+ nilfs_btnode_delete(nbh);
+ }
}