Hello,
We've hit the issue below twice during our tests on kernel 5.14.0-rc3.
Unfortunately, we don't have a reliable reproducer.
[ 496.176739] =====================================================
[ 496.182844] WARNING: SOFTIRQ-safe -> SOFTIRQ-unsafe lock order detected
[ 496.189471] 5.14.0-rc3 #1 Not tainted
[ 496.193152] -----------------------------------------------------
[ 496.199252] systemd-udevd/12979 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
[ 496.206399] ffff995b358dc5a0 (&q->queue_lock){....}-{2:2}, at:
bio_associate_blkg_from_css+0x3e5/0x650
[ 496.215726]
and this task is already holding:
[ 496.221563] ffff995b081d0ad8 (&pool->lock#3){..-.}-{2:2}, at:
pool_map+0x23/0x70 [dm_thin_pool]
[ 496.230282] which would create a new lock dependency:
[ 496.235344] (&pool->lock#3){..-.}-{2:2} -> (&q->queue_lock){....}-{2:2}
[ 496.242059]
but this new dependency connects a SOFTIRQ-irq-safe lock:
[ 496.249988] (&pool->lock#3){..-.}-{2:2}
[ 496.249993]
... which became SOFTIRQ-irq-safe at:
[ 496.260111] lock_acquire+0xb5/0x2b0
[ 496.263785] _raw_spin_lock_irqsave+0x48/0x60
[ 496.268240] overwrite_endio+0x46/0x70 [dm_thin_pool]
[ 496.273393] clone_endio+0xb9/0x1e0
[ 496.276979] clone_endio+0xb9/0x1e0
[ 496.280565] blk_update_request+0x25b/0x420
[ 496.284846] blk_mq_end_request+0x1c/0x130
[ 496.289041] blk_complete_reqs+0x37/0x40
[ 496.293071] __do_softirq+0xde/0x485
[ 496.296744] run_ksoftirqd+0x3a/0x70
[ 496.300427] smpboot_thread_fn+0xf2/0x1c0
[ 496.304534] kthread+0x143/0x160
[ 496.307863] ret_from_fork+0x22/0x30
[ 496.311538]
to a SOFTIRQ-irq-unsafe lock:
[ 496.317037] (&blkcg->lock){+.+.}-{2:2}
[ 496.317041]
... which became SOFTIRQ-irq-unsafe at:
[ 496.327243] ...
[ 496.327244] lock_acquire+0xb5/0x2b0
[ 496.332680] _raw_spin_lock+0x2c/0x40
[ 496.336443] ioc_weight_write+0x153/0x260
[ 496.340551] kernfs_fop_write_iter+0x134/0x1d0
[ 496.345095] new_sync_write+0x10b/0x180
[ 496.349030] vfs_write+0x26a/0x380
[ 496.352530] ksys_write+0x58/0xd0
[ 496.355944] do_syscall_64+0x5c/0x80
[ 496.359616] entry_SYSCALL_64_after_hwframe+0x44/0xae
[ 496.364776]
More logs are available on
https://arr-cki-prod-datawarehouse-public.s3.amazonaws.com/index.html?prefix=datawarehouse-public/2021/07/29/345042572/build_x86_64_redhat%3A1463074774/tests/lvm_snapper_test/
Thank you,
Bruno
