On Mar 2, 2026, at 17:55, Milos Nikic <nikic.milos@gmail.com> wrote:
>
> In jbd2_journal_get_create_access(), if the caller passes an unlocked
> buffer, the code currently triggers a fatal J_ASSERT.
>
> While an unlocked buffer here is a clear API violation and a bug in the
> caller, crashing the entire system is an overly severe response. It brings
> down the whole machine for a localized filesystem inconsistency.
>
> Replace the J_ASSERT with a WARN_ON_ONCE to capture the offending caller's
> stack trace, and return an error (-EINVAL). This allows the journal to
> gracefully abort the transaction, protecting data integrity without
> causing a kernel panic.
>
> Signed-off-by: Milos Nikic <nikic.milos@gmail.com>
> Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
> Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Andreas Dilger <adilger@dilger.ca <mailto:adilger@dilger.ca>>
> ---
> fs/jbd2/transaction.c | 7 ++++++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c
> index dca4b5d8aaaa..04d17a5f2a82 100644
> --- a/fs/jbd2/transaction.c
> +++ b/fs/jbd2/transaction.c
> @@ -1302,7 +1302,12 @@ int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh)
> goto out;
> }
>
> - J_ASSERT_JH(jh, buffer_locked(jh2bh(jh)));
> + if (WARN_ON_ONCE(!buffer_locked(jh2bh(jh)))) {
> + err = -EINVAL;
> + spin_unlock(&jh->b_state_lock);
> + jbd2_journal_abort(journal, err);
> + goto out;
> + }
>
> if (jh->b_transaction == NULL) {
> /*
> --
> 2.53.0
>
>