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Tue, 03 Mar 2026 10:02:04 -0800 (PST) From: Milos Nikic To: jack@suse.cz Cc: tytso@mit.edu, linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org, Milos Nikic Subject: [PATCH v4 2/2] jbd2: gracefully abort on transaction state corruptions Date: Tue, 3 Mar 2026 10:01:57 -0800 Message-ID: <20260303180157.53061-3-nikic.milos@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260303180157.53061-1-nikic.milos@gmail.com> References: <20260303180157.53061-1-nikic.milos@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Auditing the jbd2 codebase reveals several legacy J_ASSERT calls that enforce internal state machine invariants (e.g., verifying jh->b_transaction or jh->b_next_transaction pointers). When these invariants are broken, the journal is in a corrupted state. However, triggering a fatal panic brings down the entire system for a localized filesystem error. This patch targets a specific class of these asserts: those residing inside functions that natively return integer error codes, booleans, or error pointers. It replaces the hard J_ASSERTs with WARN_ON_ONCE to capture the offending stack trace, safely drops any held locks, gracefully aborts the journal, and returns -EINVAL. This prevents a catastrophic kernel panic while ensuring the corrupted journal state is safely contained and upstream callers (like ext4 or ocfs2) can gracefully handle the aborted handle. Functions modified in fs/jbd2/transaction.c: - jbd2__journal_start() - do_get_write_access() - jbd2_journal_dirty_metadata() - jbd2_journal_forget() - jbd2_journal_try_to_free_buffers() - jbd2_journal_file_inode() Signed-off-by: Milos Nikic Reviewed-by: Andreas Dilger > Reviewed-by: Jan Kara Reviewed-by: Zhang Yi --- fs/jbd2/transaction.c | 112 ++++++++++++++++++++++++++++++++---------- 1 file changed, 86 insertions(+), 26 deletions(-) diff --git a/fs/jbd2/transaction.c b/fs/jbd2/transaction.c index 04d17a5f2a82..bae6c99d635c 100644 --- a/fs/jbd2/transaction.c +++ b/fs/jbd2/transaction.c @@ -474,7 +474,8 @@ handle_t *jbd2__journal_start(journal_t *journal, int n= blocks, int rsv_blocks, return ERR_PTR(-EROFS); =20 if (handle) { - J_ASSERT(handle->h_transaction->t_journal =3D=3D journal); + if (WARN_ON_ONCE(handle->h_transaction->t_journal !=3D journal)) + return ERR_PTR(-EINVAL); handle->h_ref++; return handle; } @@ -1036,7 +1037,13 @@ do_get_write_access(handle_t *handle, struct journal= _head *jh, */ if (!jh->b_transaction) { JBUFFER_TRACE(jh, "no transaction"); - J_ASSERT_JH(jh, !jh->b_next_transaction); + if (WARN_ON_ONCE(jh->b_next_transaction)) { + spin_unlock(&jh->b_state_lock); + unlock_buffer(bh); + error =3D -EINVAL; + jbd2_journal_abort(journal, error); + goto out; + } JBUFFER_TRACE(jh, "file as BJ_Reserved"); /* * Make sure all stores to jh (b_modified, b_frozen_data) are @@ -1069,13 +1076,27 @@ do_get_write_access(handle_t *handle, struct journa= l_head *jh, */ if (jh->b_frozen_data) { JBUFFER_TRACE(jh, "has frozen data"); - J_ASSERT_JH(jh, jh->b_next_transaction =3D=3D NULL); + if (WARN_ON_ONCE(jh->b_next_transaction)) { + spin_unlock(&jh->b_state_lock); + error =3D -EINVAL; + jbd2_journal_abort(journal, error); + goto out; + } goto attach_next; } =20 JBUFFER_TRACE(jh, "owned by older transaction"); - J_ASSERT_JH(jh, jh->b_next_transaction =3D=3D NULL); - J_ASSERT_JH(jh, jh->b_transaction =3D=3D journal->j_committing_transactio= n); + if (WARN_ON_ONCE(jh->b_next_transaction || + jh->b_transaction !=3D + journal->j_committing_transaction)) { + pr_err("JBD2: %s: assertion failure: b_next_transaction=3D%p b_transacti= on=3D%p j_committing_transaction=3D%p\n", + journal->j_devname, jh->b_next_transaction, + jh->b_transaction, journal->j_committing_transaction); + spin_unlock(&jh->b_state_lock); + error =3D -EINVAL; + jbd2_journal_abort(journal, error); + goto out; + } =20 /* * There is one case we have to be very careful about. If the @@ -1496,7 +1517,7 @@ void jbd2_buffer_abort_trigger(struct journal_head *j= h, int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) { transaction_t *transaction =3D handle->h_transaction; - journal_t *journal; + journal_t *journal =3D transaction->t_journal; struct journal_head *jh; int ret =3D 0; =20 @@ -1520,8 +1541,14 @@ int jbd2_journal_dirty_metadata(handle_t *handle, st= ruct buffer_head *bh) if (data_race(jh->b_transaction !=3D transaction && jh->b_next_transaction !=3D transaction)) { spin_lock(&jh->b_state_lock); - J_ASSERT_JH(jh, jh->b_transaction =3D=3D transaction || - jh->b_next_transaction =3D=3D transaction); + if (WARN_ON_ONCE(jh->b_transaction !=3D transaction && + jh->b_next_transaction !=3D transaction)) { + pr_err("JBD2: %s: assertion failure: b_transaction=3D%p transaction=3D%= p b_next_transaction=3D%p\n", + journal->j_devname, jh->b_transaction, + transaction, jh->b_next_transaction); + ret =3D -EINVAL; + goto out_unlock_bh; + } spin_unlock(&jh->b_state_lock); } if (data_race(jh->b_modified =3D=3D 1)) { @@ -1531,13 +1558,15 @@ int jbd2_journal_dirty_metadata(handle_t *handle, s= truct buffer_head *bh) spin_lock(&jh->b_state_lock); if (jh->b_transaction =3D=3D transaction && jh->b_jlist !=3D BJ_Metadata) - pr_err("JBD2: assertion failure: h_type=3D%u " - "h_line_no=3D%u block_no=3D%llu jlist=3D%u\n", + pr_err("JBD2: assertion failure: h_type=3D%u h_line_no=3D%u block_no= =3D%llu jlist=3D%u\n", handle->h_type, handle->h_line_no, (unsigned long long) bh->b_blocknr, jh->b_jlist); - J_ASSERT_JH(jh, jh->b_transaction !=3D transaction || - jh->b_jlist =3D=3D BJ_Metadata); + if (WARN_ON_ONCE(jh->b_transaction =3D=3D transaction && + jh->b_jlist !=3D BJ_Metadata)) { + ret =3D -EINVAL; + goto out_unlock_bh; + } spin_unlock(&jh->b_state_lock); } goto out; @@ -1557,8 +1586,6 @@ int jbd2_journal_dirty_metadata(handle_t *handle, str= uct buffer_head *bh) goto out_unlock_bh; } =20 - journal =3D transaction->t_journal; - if (jh->b_modified =3D=3D 0) { /* * This buffer's got modified and becoming part @@ -1636,7 +1663,10 @@ int jbd2_journal_dirty_metadata(handle_t *handle, st= ruct buffer_head *bh) } =20 /* That test should have eliminated the following case: */ - J_ASSERT_JH(jh, jh->b_frozen_data =3D=3D NULL); + if (WARN_ON_ONCE(jh->b_frozen_data)) { + ret =3D -EINVAL; + goto out_unlock_bh; + } =20 JBUFFER_TRACE(jh, "file as BJ_Metadata"); spin_lock(&journal->j_list_lock); @@ -1675,6 +1705,7 @@ int jbd2_journal_forget(handle_t *handle, struct buff= er_head *bh) int err =3D 0; int was_modified =3D 0; int wait_for_writeback =3D 0; + int abort_journal =3D 0; =20 if (is_handle_aborted(handle)) return -EROFS; @@ -1708,7 +1739,11 @@ int jbd2_journal_forget(handle_t *handle, struct buf= fer_head *bh) jh->b_modified =3D 0; =20 if (jh->b_transaction =3D=3D transaction) { - J_ASSERT_JH(jh, !jh->b_frozen_data); + if (WARN_ON_ONCE(jh->b_frozen_data)) { + err =3D -EINVAL; + abort_journal =3D 1; + goto drop; + } =20 /* If we are forgetting a buffer which is already part * of this transaction, then we can just drop it from @@ -1747,8 +1782,11 @@ int jbd2_journal_forget(handle_t *handle, struct buf= fer_head *bh) } spin_unlock(&journal->j_list_lock); } else if (jh->b_transaction) { - J_ASSERT_JH(jh, (jh->b_transaction =3D=3D - journal->j_committing_transaction)); + if (WARN_ON_ONCE(jh->b_transaction !=3D journal->j_committing_transactio= n)) { + err =3D -EINVAL; + abort_journal =3D 1; + goto drop; + } /* However, if the buffer is still owned by a prior * (committing) transaction, we can't drop it yet... */ JBUFFER_TRACE(jh, "belongs to older transaction"); @@ -1766,7 +1804,11 @@ int jbd2_journal_forget(handle_t *handle, struct buf= fer_head *bh) jh->b_next_transaction =3D transaction; spin_unlock(&journal->j_list_lock); } else { - J_ASSERT(jh->b_next_transaction =3D=3D transaction); + if (WARN_ON_ONCE(jh->b_next_transaction !=3D transaction)) { + err =3D -EINVAL; + abort_journal =3D 1; + goto drop; + } =20 /* * only drop a reference if this transaction modified @@ -1812,6 +1854,8 @@ int jbd2_journal_forget(handle_t *handle, struct buff= er_head *bh) drop: __brelse(bh); spin_unlock(&jh->b_state_lock); + if (abort_journal) + jbd2_journal_abort(journal, err); if (wait_for_writeback) wait_on_buffer(bh); jbd2_journal_put_journal_head(jh); @@ -2136,7 +2180,8 @@ bool jbd2_journal_try_to_free_buffers(journal_t *jour= nal, struct folio *folio) struct buffer_head *bh; bool ret =3D false; =20 - J_ASSERT(folio_test_locked(folio)); + if (WARN_ON_ONCE(!folio_test_locked(folio))) + return false; =20 head =3D folio_buffers(folio); bh =3D head; @@ -2651,6 +2696,8 @@ static int jbd2_journal_file_inode(handle_t *handle, = struct jbd2_inode *jinode, { transaction_t *transaction =3D handle->h_transaction; journal_t *journal; + int err =3D 0; + int abort_transaction =3D 0; =20 if (is_handle_aborted(handle)) return -EROFS; @@ -2685,20 +2732,33 @@ static int jbd2_journal_file_inode(handle_t *handle= , struct jbd2_inode *jinode, /* On some different transaction's list - should be * the committing one */ if (jinode->i_transaction) { - J_ASSERT(jinode->i_next_transaction =3D=3D NULL); - J_ASSERT(jinode->i_transaction =3D=3D - journal->j_committing_transaction); + if (WARN_ON_ONCE(jinode->i_next_transaction || + jinode->i_transaction !=3D + journal->j_committing_transaction)) { + pr_err("JBD2: %s: assertion failure: i_next_transaction=3D%p i_transact= ion=3D%p j_committing_transaction=3D%p\n", + journal->j_devname, jinode->i_next_transaction, + jinode->i_transaction, + journal->j_committing_transaction); + err =3D -EINVAL; + abort_transaction =3D 1; + goto done; + } jinode->i_next_transaction =3D transaction; goto done; } /* Not on any transaction list... */ - J_ASSERT(!jinode->i_next_transaction); + if (WARN_ON_ONCE(jinode->i_next_transaction)) { + err =3D -EINVAL; + abort_transaction =3D 1; + goto done; + } jinode->i_transaction =3D transaction; list_add(&jinode->i_list, &transaction->t_inode_list); done: spin_unlock(&journal->j_list_lock); - - return 0; + if (abort_transaction) + jbd2_journal_abort(journal, err); + return err; } =20 int jbd2_journal_inode_ranged_write(handle_t *handle, --=20 2.53.0