From: Immad Mir mirimmad17@gmail.com
[ Upstream commit 95e2b352c03b0a86c5717ba1d24ea20969abcacc ]
This patch adds a check for read-only mounted filesystem in txBegin before starting a transaction potentially saving from NULL pointer deref.
Signed-off-by: Immad Mir mirimmad17@gmail.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/jfs/jfs_txnmgr.c | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/fs/jfs/jfs_txnmgr.c b/fs/jfs/jfs_txnmgr.c index 042bbe6d8ac2e..6c8680d3907af 100644 --- a/fs/jfs/jfs_txnmgr.c +++ b/fs/jfs/jfs_txnmgr.c @@ -354,6 +354,11 @@ tid_t txBegin(struct super_block *sb, int flag) jfs_info("txBegin: flag = 0x%x", flag); log = JFS_SBI(sb)->log;
+ if (!log) { + jfs_error(sb, "read-only filesystem\n"); + return 0; + } + TXN_LOCK();
INCREMENT(TxStat.txBegin);