5.4-stable review patch. If anyone has any objections, please let me know.
From: Shaurya Rane ssrane_b23@ee.vjti.ac.in
[ Upstream commit 300b072df72694ea330c4c673c035253e07827b8 ]
The transaction manager initialization in txInit() was not properly initializing TxBlock[0].waitor waitqueue, causing a crash when txEnd(0) is called on read-only filesystems.
When a filesystem is mounted read-only, txBegin() returns tid=0 to indicate no transaction. However, txEnd(0) still gets called and tries to access TxBlock[0].waitor via tid_to_tblock(0), but this waitqueue was never initialized because the initialization loop started at index 1 instead of 0.
This causes a 'non-static key' lockdep warning and system crash: INFO: trying to register non-static key in txEnd
Fix by ensuring all transaction blocks including TxBlock[0] have their waitqueues properly initialized during txInit().
Reported-by: syzbot+c4f3462d8b2ad7977bea@syzkaller.appspotmail.com
Signed-off-by: Shaurya Rane ssrane_b23@ee.vjti.ac.in Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org
fs/jfs/jfs_txnmgr.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c index 6f6a5b9203d3f..97a2eb0f0b75d 100644 --- a/fs/jfs/jfs_txnmgr.c +++ b/fs/jfs/jfs_txnmgr.c @@ -272,14 +272,15 @@ int txInit(void) if (TxBlock == NULL) return -ENOMEM;
- for (k = 1; k < nTxBlock - 1; k++) {
TxBlock[k].next = k + 1;
- for (k = 0; k < nTxBlock; k++) { init_waitqueue_head(&TxBlock[k].gcwait); init_waitqueue_head(&TxBlock[k].waitor); }
- for (k = 1; k < nTxBlock - 1; k++) {
TxBlock[k].next = k + 1;- } TxBlock[k].next = 0;
- init_waitqueue_head(&TxBlock[k].gcwait);
- init_waitqueue_head(&TxBlock[k].waitor);
TxAnchor.freetid = 1; init_waitqueue_head(&TxAnchor.freewait); -- 2.51.0
I see the command but can't find the corresponding bug. The email is sent to syzbot+HASH@syzkaller.appspotmail.com address but the HASH does not correspond to any known bug. Please double check the address.