On 04/21/2017 11:58 AM, Bart Van Assche wrote:
> Avoid that the following kernel bug gets triggered:
>
> BUG: sleeping function called from invalid context at ./include/linux/buffer_head.h:349
> in_atomic(): 1, irqs_disabled(): 0, pid: 8019, name: find
> CPU: 10 PID: 8019 Comm: find Tainted: G W I 4.11.0-rc4-dbg+ #2
> Call Trace:
> dump_stack+0x68/0x93
> ___might_sleep+0x16e/0x230
> __might_sleep+0x4a/0x80
> __ext4_get_inode_loc+0x1e0/0x4e0
> ext4_iget+0x70/0xbc0
> ext4_iget_normal+0x2f/0x40
> ext4_lookup+0xb6/0x1f0
> lookup_slow+0x104/0x1e0
> walk_component+0x19a/0x330
> path_lookupat+0x4b/0x100
> filename_lookup+0x9a/0x110
> user_path_at_empty+0x36/0x40
> vfs_statx+0x67/0xc0
> SYSC_newfstatat+0x20/0x40
> SyS_newfstatat+0xe/0x10
> entry_SYSCALL_64_fastpath+0x18/0xad
>
> Fixes: b00c53e8f411 ("blk-mq: fix schedule-while-atomic with scheduler attached")
> Signed-off-by: Bart Van Assche <bart.vanassche@xxxxxxxxxxx>
> Cc: Omar Sandoval <osandov@xxxxxx>
> ---
> block/blk-mq.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index 4130c7730d6d..f5d24a94ae68 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1631,6 +1631,8 @@ static blk_qc_t blk_mq_make_request(struct request_queue *q, struct bio *bio)
> } else if (!blk_mq_merge_queue_io(data.hctx, data.ctx, rq, bio)) {
> blk_mq_put_ctx(data.ctx);
> blk_mq_run_hw_queue(data.hctx, true);
> + } else {
> + blk_mq_put_ctx(data.ctx);
> }
>
> return cookie;
Good catch! Thanks Bart, will add.
--
Jens Axboe
