forked from Minki/linux
e2daec488c
I got follow issue: [ 247.381177] INFO: task kworker/u10:0:47 blocked for more than 120 seconds. [ 247.382644] Not tainted 4.19.90-dirty #140 [ 247.383502] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [ 247.385027] Call Trace: [ 247.388384] schedule+0xb8/0x3c0 [ 247.388966] schedule_timeout+0x2b4/0x380 [ 247.392815] wait_for_completion+0x367/0x510 [ 247.397713] flush_workqueue+0x32b/0x1340 [ 247.402700] drain_workqueue+0xda/0x3c0 [ 247.403442] destroy_workqueue+0x7b/0x690 [ 247.405014] nbd_config_put.cold+0x2f9/0x5b6 [ 247.405823] recv_work+0x1fd/0x2b0 [ 247.406485] process_one_work+0x70b/0x1610 [ 247.407262] worker_thread+0x5a9/0x1060 [ 247.408699] kthread+0x35e/0x430 [ 247.410918] ret_from_fork+0x1f/0x30 We can reproduce issue as follows: 1. Inject memory fault in nbd_start_device -1244,10 +1248,18 @@ static int nbd_start_device(struct nbd_device *nbd) nbd_dev_dbg_init(nbd); for (i = 0; i < num_connections; i++) { struct recv_thread_args *args; - - args = kzalloc(sizeof(*args), GFP_KERNEL); + + if (i == 1) { + args = NULL; + printk("%s: inject malloc error\n", __func__); + } + else + args = kzalloc(sizeof(*args), GFP_KERNEL); 2. Inject delay in recv_work -757,6 +760,8 @@ static void recv_work(struct work_struct *work) blk_mq_complete_request(blk_mq_rq_from_pdu(cmd)); } + printk("%s: comm=%s pid=%d\n", __func__, current->comm, current->pid); + mdelay(5 * 1000); nbd_config_put(nbd); atomic_dec(&config->recv_threads); wake_up(&config->recv_wq); 3. Create nbd server nbd-server 8000 /tmp/disk 4. Create nbd client nbd-client localhost 8000 /dev/nbd1 Then will trigger above issue. Reason is when add delay in recv_work, lead to release the last reference of 'nbd->config_refs'. nbd_config_put will call flush_workqueue to make all work finish. Obviously, it will lead to deadloop. To solve this issue, according to Josef's suggestion move 'recv_work' init from start device to nbd_dev_add, then destroy 'recv_work'when nbd device teardown. Signed-off-by: Ye Bin <yebin10@huawei.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Link: https://lore.kernel.org/r/20211102015237.2309763-5-yebin10@huawei.com Signed-off-by: Jens Axboe <axboe@kernel.dk> |
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| .. | ||
| aoe | ||
| drbd | ||
| mtip32xx | ||
| null_blk | ||
| paride | ||
| rnbd | ||
| rsxx | ||
| xen-blkback | ||
| zram | ||
| amiflop.c | ||
| ataflop.c | ||
| brd.c | ||
| floppy.c | ||
| Kconfig | ||
| loop.c | ||
| loop.h | ||
| Makefile | ||
| n64cart.c | ||
| nbd.c | ||
| pktcdvd.c | ||
| ps3disk.c | ||
| ps3vram.c | ||
| rbd_types.h | ||
| rbd.c | ||
| sunvdc.c | ||
| swim3.c | ||
| swim_asm.S | ||
| swim.c | ||
| sx8.c | ||
| virtio_blk.c | ||
| xen-blkfront.c | ||
| z2ram.c | ||