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authorJan Kara <jack@suse.cz>2013-03-11 13:24:56 -0400
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-03-28 12:12:15 -0700
commitac4f52e0fff3a2b5523655250cc2e7d77ba8c09b (patch)
tree94f566e310b0f8eefdbf2237b414b0f03f243760
parent056f8c8c85d53311530fd1940a68a390cc615bde (diff)
jbd2: fix use after free in jbd2_journal_dirty_metadata()
commit ad56edad089b56300fd13bb9eeb7d0424d978239 upstream. jbd2_journal_dirty_metadata() didn't get a reference to journal_head it was working with. This is OK in most of the cases since the journal head should be attached to a transaction but in rare occasions when we are journalling data, __ext4_journalled_writepage() can race with jbd2_journal_invalidatepage() stripping buffers from a page and thus journal head can be freed under hands of jbd2_journal_dirty_metadata(). Fix the problem by getting own journal head reference in jbd2_journal_dirty_metadata() (and also in jbd2_journal_set_triggers() which can possibly have the same issue). Reported-by: Zheng Liu <gnehzuil.liu@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--fs/jbd2/transaction.c15
1 files changed, 10 insertions, 5 deletions
diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
index de8b4cb7c31e..6075ac03b6d9 100644
--- a/fs/jbd2/transaction.c
+++ b/fs/jbd2/transaction.c
@@ -1047,9 +1047,12 @@ out:
void jbd2_journal_set_triggers(struct buffer_head *bh,
struct jbd2_buffer_trigger_type *type)
{
- struct journal_head *jh = bh2jh(bh);
+ struct journal_head *jh = jbd2_journal_grab_journal_head(bh);
+ if (WARN_ON(!jh))
+ return;
jh->b_triggers = type;
+ jbd2_journal_put_journal_head(jh);
}
void jbd2_buffer_frozen_trigger(struct journal_head *jh, void *mapped_data,
@@ -1101,17 +1104,18 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
{
transaction_t *transaction = handle->h_transaction;
journal_t *journal = transaction->t_journal;
- struct journal_head *jh = bh2jh(bh);
+ struct journal_head *jh;
int ret = 0;
- jbd_debug(5, "journal_head %p\n", jh);
- JBUFFER_TRACE(jh, "entry");
if (is_handle_aborted(handle))
goto out;
- if (!buffer_jbd(bh)) {
+ jh = jbd2_journal_grab_journal_head(bh);
+ if (!jh) {
ret = -EUCLEAN;
goto out;
}
+ jbd_debug(5, "journal_head %p\n", jh);
+ JBUFFER_TRACE(jh, "entry");
jbd_lock_bh_state(bh);
@@ -1202,6 +1206,7 @@ int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh)
spin_unlock(&journal->j_list_lock);
out_unlock_bh:
jbd_unlock_bh_state(bh);
+ jbd2_journal_put_journal_head(jh);
out:
JBUFFER_TRACE(jh, "exit");
WARN_ON(ret); /* All errors are bugs, so dump the stack */