On Mon, Aug 05, 2019 at 09:38:00AM +0530, Chandan Rajendra wrote: > When executing generic/388 on a ppc64le machine, we notice the following > call trace, > > VFS: brelse: Trying to free free buffer > WARNING: CPU: 0 PID: 6637 at /root/repos/linux/fs/buffer.c:1195 __brelse+0x84/0xc0 > > Call Trace: > __brelse+0x80/0xc0 (unreliable) > invalidate_bh_lru+0x78/0xc0 > on_each_cpu_mask+0xa8/0x130 > on_each_cpu_cond_mask+0x130/0x170 > invalidate_bh_lrus+0x44/0x60 > invalidate_bdev+0x38/0x70 > ext4_put_super+0x294/0x560 > generic_shutdown_super+0xb0/0x170 > kill_block_super+0x38/0xb0 > deactivate_locked_super+0xa4/0xf0 > cleanup_mnt+0x164/0x1d0 > task_work_run+0x110/0x160 > do_notify_resume+0x414/0x460 > ret_from_except_lite+0x70/0x74 > > The warning happens because flush_descriptor() drops bh reference it > does not own. The bh reference acquired by > jbd2_journal_get_descriptor_buffer() is owned by the log_bufs list and > gets released when this list is processed. The reference for doing IO is > only acquired in write_dirty_buffer() later in flush_descriptor(). > > Reported-by: Harish Sriram <harish@xxxxxxxxxxxxx> > Reviewed-by: Jan Kara <jack@xxxxxxx> > Signed-off-by: Chandan Rajendra <chandan@xxxxxxxxxxxxx> Thanks, applied. - Ted
