Currently in journal_commit_transaction() if trace point
trace_jbd_end_commit() is enabled, it can access already freed part of
the memory via commit_transaction because it might have already been
freed earlier using __journal_drop_transaction().
Fix it by moving the tracepoint before the point where we can free
commit_transaction and set the commit_transaction to NULL after we free
it to make such cases easier to detect in the future.
Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
Reported-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
fs/jbd/commit.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index bb217dc..169cf72 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -991,10 +991,12 @@ restart_loop:
journal->j_average_commit_time = commit_time;
spin_unlock(&journal->j_state_lock);
+ trace_jbd_end_commit(journal, commit_transaction);
if (commit_transaction->t_checkpoint_list == NULL &&
commit_transaction->t_checkpoint_io_list == NULL) {
__journal_drop_transaction(journal, commit_transaction);
+ commit_transaction = NULL;
} else {
if (journal->j_checkpoint_transactions == NULL) {
journal->j_checkpoint_transactions = commit_transaction;
@@ -1013,7 +1015,6 @@ restart_loop:
}
spin_unlock(&journal->j_list_lock);
- trace_jbd_end_commit(journal, commit_transaction);
jbd_debug(1, "JBD: commit %d complete, head %d\n",
journal->j_commit_sequence, journal->j_tail_sequence);
--
1.8.3.1
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