>From f32ca41396f1d71a689f86ba3e7372a1ad1fdba2 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Mon, 11 Mar 2013 16:49:16 +0100 Subject: [PATCH] jbd2: Fix use after free in jbd2_journal_dirty_metadata() 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 Signed-off-by: Jan Kara --- fs/jbd2/transaction.c | 15 ++++++++++----- 1 files changed, 10 insertions(+), 5 deletions(-) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index d6ee5ae..325bc01 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -1065,9 +1065,12 @@ 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, @@ -1119,17 +1122,18 @@ 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); @@ -1220,6 +1224,7 @@ 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 */ -- 1.7.1