From: Ye Bin <yebin10@xxxxxxxxxx> commit 243d1a5d505d0b0460c9af0ad56ed4a56ef0bebd upstream. In 'jbd2_fc_wait_bufs' use 'bh' after put buffer head reference count which may lead to use-after-free. So judge buffer if uptodate before put buffer head reference count. Cc: stable@xxxxxxxxxx Signed-off-by: Ye Bin <yebin10@xxxxxxxxxx> Reviewed-by: Jan Kara <jack@xxxxxxx> Link: https://lore.kernel.org/r/20220914100812.1414768-3-yebin10@xxxxxxxxxx Signed-off-by: Theodore Ts'o <tytso@xxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/jbd2/journal.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/fs/jbd2/journal.c +++ b/fs/jbd2/journal.c @@ -923,16 +923,16 @@ int jbd2_fc_wait_bufs(journal_t *journal for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) { bh = journal->j_fc_wbuf[i]; wait_on_buffer(bh); - put_bh(bh); - journal->j_fc_wbuf[i] = NULL; /* * Update j_fc_off so jbd2_fc_release_bufs can release remain * buffer head. */ if (unlikely(!buffer_uptodate(bh))) { - journal->j_fc_off = i; + journal->j_fc_off = i + 1; return -EIO; } + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; } return 0;
