On Tue, May 30, 2017 at 02:00:44PM -0300, Gabriel Krisman Bertazi wrote: > Since the merge window for 4.12, one of the machines in Intel's CI > started to hit the WARN_ON below at blk_mq_update_nr_hw_queues during an > nvme_reset_work. The issue persists with the latest 4.12-rc3, and full > dmesg from boot, up to the moment where the WARN_ON triggers is > available at the following link: > > https://intel-gfx-ci.01.org/CI/CI_DRM_2672/fi-kbl-7500u/igt@kms_pipe_crc_basic@xxxxxxxxxxxxxxxxxxxxxxxxxxxx > > Please notice that the test we do in the CI involves putting the > machine to sleep (PM), and the issue triggers when resuming execution. > > I have not been able to get my hands on the machine yet to do an actual > bisect, but I'm wondering if you guys might have an idea of what is > wrong. > > Any help is appreciated :) Hi Gabriel, This appears to be new behavior in blk-mq's tag set update with commit 705cda97e. This is asserting a lock is held, but none of the drivers that call the export are take that lock. I think the below should fix it (CC'ing block list and developers). --- diff --git a/block/blk-mq.c b/block/blk-mq.c index f2224ffd..1bccced 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -2641,7 +2641,8 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) return ret; } -void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) +static void __blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, + int nr_hw_queues) { struct request_queue *q; @@ -2665,6 +2666,13 @@ void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) list_for_each_entry(q, &set->tag_list, tag_set_list) blk_mq_unfreeze_queue(q); } + +void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues) +{ + mutex_lock(&set->tag_list_lock); + __blk_mq_update_nr_hw_queues(set, nr_hw_queues); + mutex_unlock(&set->tag_list_lock); +} EXPORT_SYMBOL_GPL(blk_mq_update_nr_hw_queues); /* Enable polling stats and return whether they were already enabled. */ -- > [ 382.419309] ------------[ cut here ]------------ > [ 382.419314] WARNING: CPU: 3 PID: 3098 at block/blk-mq.c:2648 blk_mq_update_nr_hw_queues+0x118/0x120 > [ 382.419315] Modules linked in: vgem snd_hda_codec_hdmi > snd_hda_codec_realtek snd_hda_codec_generic i915 x86_pkg_temp_thermal > intel_powerclamp coretemp crct10dif_pclmul crc32_pclmul > ghash_clmulni_intel snd_hda_intel snd_hda_codec snd_hwdep snd_hda_core > snd_pcm e1000e mei_me mei ptp pps_core prime_numbers > pinctrl_sunrisepoint > pinctrl_intel i2c_hid > [ 382.419345] CPU: 3 PID: 3098 Comm: kworker/u8:5 Tainted: G U W 4.12.0-rc3-CI-CI_DRM_2672+ #1 > [ 382.419346] Hardware name: GIGABYTE GB-BKi7(H)A-7500/MFLP7AP-00, BIOSF4 02/20/2017 > [ 382.419349] Workqueue: nvme nvme_reset_work > [ 382.419351] task: ffff88025e2f4f40 task.stack: ffffc90000464000 > [ 382.419353] RIP: 0010:blk_mq_update_nr_hw_queues+0x118/0x120 > [ 382.419355] RSP: 0000:ffffc90000467d50 EFLAGS: 00010246 > [ 382.419357] RAX: 0000000000000000 RBX: 0000000000000004 RCX:0000000000000001 > [ 382.419358] RDX: 0000000000000000 RSI: 00000000ffffffff RDI:ffff8802618d80b0 > [ 382.419359] RBP: ffffc90000467d70 R08: ffff88025e2f5778 R09:0000000000000000 > [ 382.419361] R10: 00000000ef6f2e9b R11: 0000000000000001 R12:ffff8802618d8368 > [ 382.419362] R13: ffff8802618d8010 R14: ffff8802618d81f0 R15:0000000000000000 > [ 382.419363] FS: 0000000000000000(0000) GS:ffff88026dd80000(0000) knlGS:0000000000000000 > [ 382.419364] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [ 382.419366] CR2: 0000000000000000 CR3: 000000025a06e000 CR4: 00000000003406e0 > [ 382.419367] Call Trace: > [ 382.419370] nvme_reset_work+0x948/0xff0 > [ 382.419374] ? lock_acquire+0xb5/0x210 > [ 382.419379] process_one_work+0x1fe/0x670 > [ 382.419390] ? kthread_create_on_node+0x40/0x40 > [ 382.419394] ret_from_fork+0x27/0x40 > [ 382.419398] Code: 48 8d 98 58 f6 ff ff 75 e5 5b 41 5c 41 5d 41 5e 5d > c3 48 8d bf a0 00 00 00 be ff ff ff ff e8 c0 48 ca ff 85 c0 0f 85 06 ff > ff ff <0f> ff e9 ff fe ff ff 90 55 31 f6 48 c7 c7 80 b2 ea 81 48 89 e5 > [ 382.419463] ---[ end trace 603ee21a3184ac90 ]---
