From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 454C3C4338F for ; Mon, 2 Aug 2021 20:40:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1BC8C61038 for ; Mon, 2 Aug 2021 20:40:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231231AbhHBUkk (ORCPT ); Mon, 2 Aug 2021 16:40:40 -0400 Received: from vulcan.natalenko.name ([104.207.131.136]:57508 "EHLO vulcan.natalenko.name" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230448AbhHBUkj (ORCPT ); Mon, 2 Aug 2021 16:40:39 -0400 Received: from spock.localnet (unknown [151.237.229.131]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by vulcan.natalenko.name (Postfix) with ESMTPSA id CF12EB6D165; Mon, 2 Aug 2021 22:40:27 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=natalenko.name; s=dkim-20170712; t=1627936828; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=V5Gf8WHIaRBgcRmpR02+bUOZmjIZRuc2TFbV62MBv24=; b=qqlLLpfd+AFqorlYKhqiuAIo/8NO0U/oOaCytTsVDYl3Yk1cGgrIrN8G29a5Y2WCA6rXCb EJF06G7iKxcPz9+Ae9R1UGgDkPqS4oEnNyi0xI876gXQkd8tMLQCmdtOd9XfkuIGXiC/+7 itPeC7rJXURvxe2n8xupbhBNlS/9iKI= From: Oleksandr Natalenko To: Jan Kara Cc: Paolo Valente , Jens Axboe , linux-block , Linux Kernel Mailing List , Luca Mariotti , Holger =?ISO-8859-1?Q?Hoffst=E4tte?= , Pietro Pedroni , Piotr Gorski , Khazhy Kumykov , Jan Kara Subject: Re: [PATCH FIXES/IMPROVEMENTS 0/7] block, bfq: preserve control, boost throughput, fix bugs Date: Mon, 02 Aug 2021 22:40:26 +0200 Message-ID: <1630141.ki6cbyAirf@natalenko.name> In-Reply-To: <2957867.CS06ZTPI5V@spock> References: <20210619140948.98712-1-paolo.valente@linaro.org> <20210622162948.GJ14261@quack2.suse.cz> <2957867.CS06ZTPI5V@spock> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org Hello. On sobota 3. =C4=8Dervence 2021 0:07:53 CEST Oleksandr Natalenko wrote: > On =C3=BAter=C3=BD 22. =C4=8Dervna 2021 18:29:48 CEST Jan Kara wrote: > > On Tue 22-06-21 09:35:05, Oleksandr Natalenko wrote: > > > On =C3=BAter=C3=BD 22. =C4=8Dervna 2021 9:08:43 CEST Paolo Valente wr= ote: > > > > CCing also Jan and Khazhy, because in your commit log I see also the > > > > commit on bfq_requests_merged(). > > > >=20 > > > > Is this OOPS reproducible for you? > > >=20 > > > No, I haven't found a reproducer, at least yet. It took half a day of > > > uptime to hit this, so might not be that easy. > >=20 > > Hum, if you can acquire a crash dump it would be the easiest I guess. W= e'd > > need to find out more about the request we crash on - whether it's > > otherwise valid, in what state it is etc... >=20 > Still have no reliable reproducer and no vmcore, however I'm running v5.13 > with the following patches applied on top of it: >=20 > ``` > blk: Fix lock inversion between ioc lock and bfqd lock > bfq: Remove merged request already in bfq_requests_merged() > block: Remove unnecessary elevator operation checks > block: Do not pull requests from the scheduler when we cannot dispatch th= em > block, bfq: reset waker pointer with shared queues > block, bfq: check waker only for queues with no in-flight I/O > block, bfq: avoid delayed merge of async queues > block, bfq: boost throughput by extending queue-merging times > block, bfq: consider also creation time in delayed stable merge > block, bfq: fix delayed stable merge check > block, bfq: let also stably merged queues enjoy weight raising > ``` >=20 > and just got the following crash: >=20 > ``` > [60313.522570] ------------[ cut here ]------------ > [60313.522579] WARNING: CPU: 20 PID: 388 at arch/x86/include/asm/kfence.h= :44 > kfence_protect_page+0x39/0xc0 > [60313.522586] Modules linked in: sctp ip6_udp_tunnel udp_tunnel uinput > netconsole blocklayoutdriver rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolv= er > nfs lockd grace sunrpc fscache netfs rfcomm nft_ct nf_conntrack > nf_defrag_ipv6 nf_defrag_ipv4 cmac algif_hash algif_skcipher nf_tables > af_alg bnep tun nfnetlink nls_iso8859_1 intel_rapl_msr vfat > intel_rapl_common iwlmvm fat mac80211 edac_mce_amd libarc4 btusb eeepc_wmi > btrtl asus_wmi iwlwifi btbcm snd_usb_audio sparse_keymap kvm_amd video > wmi_bmof mxm_wmi btintel uvcvideo snd_hda_codec_realtek videobuf2_vmalloc > videobuf2_memops snd_usbmidi_lib kvm snd_hda_codec_generic bluetooth > videobuf2_v4l2 ledtrig_audio > snd_hda_codec_hdmi joydev snd_rawmidi ecdh_generic irqbypass ecc > snd_hda_intel mousedev pl2303 cfg80211 snd_seq_device videobuf2_common > crc16 rapl k10temp snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec igb > r8169 sp5100_tco snd_hda_core realtek i2c_piix4 ipmi_devintf dca snd_hwdep > mdio_devres rfkill snd_pcm libphy ipmi_msghandler wmi > [60313.522630] pinctrl_amd mac_hid acpi_cpufreq tcp_bbr2 vhost_vsock > vmw_vsock_virtio_transport_common vhost vhost_iotlb vsock v4l2loopback > videodev mc snd_hrtimer snd_timer snd soundcore nct6775 hwmon_vid > crypto_user fuse ip_tables x_tables xfs dm_thin_pool dm_persistent_data > dm_bio_prison dm_bufio libcrc32c crc32c_generic dm_crypt cbc encrypted_ke= ys > trusted asn1_encoder tee hid_logitech_hidpp hid_logitech_dj usbhid dm_mod > crct10dif_pclmul crc32_pclmul crc32c_intel raid10 ghash_clmulni_intel > aesni_intel md_mod crypto_simd cryptd amdgpu ccp xhci_pci xhci_pci_renesas > tpm_crb tpm_tis tpm_tis_core tpm rng_core drm_ttm_helper ttm gpu_sched > i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops > cec drm agpgart > [60313.522665] CPU: 20 PID: 388 Comm: kworker/20:1H Tainted: G W > 5.13.0-pf2 #1 > [60313.522668] Hardware name: ASUS System Product Name/Pro WS X570-ACE, B= IOS > 3601 05/26/2021 > [60313.522671] Workqueue: kblockd blk_mq_run_work_fn > [60313.522675] RIP: 0010:kfence_protect_page+0x39/0xc0 > [60313.522679] Code: 04 65 48 8b 04 25 28 00 00 00 48 89 44 24 08 31 c0 c7 > 44 24 04 00 00 00 00 e8 83 20 d5 ff 48 85 c0 74 07 83 7c 24 04 01 74 06 > <0f> 0b 31 c0 eb 4c 48 8b 38 48 89 c2 84 db 75 59 48 89 f8 0f 1f 40 > [60313.522682] RSP: 0018:ffffb559c0affb28 EFLAGS: 00010046 > [60313.522684] RAX: 0000000000000000 RBX: 0000000000000000 RCX: > ffffb559c0affb2c [60313.522687] RDX: ffffb559c0affb2c RSI: 00000000000000= 00 > RDI: 0000000000000000 [60313.522690] RBP: 0000000000000000 R08: > 0000000000000000 R09: > 0000000000000000 > [60313.522692] R10: 0000000000000000 R11: 0000000000000000 R12: > 0000000000000002 > [60313.522694] R13: ffffb559c0affc28 R14: 00000000c0affc01 R15: > 0000000000000000 [60313.522696] FS: 0000000000000000(0000) > GS:ffff8cf44ef00000(0000) knlGS: 0000000000000000 > [60313.522698] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [60313.522700] CR2: 0000000000000120 CR3: 000000013ebce000 CR4: > 0000000000350ee0 > [60313.522702] Call Trace: > [60313.522707] kfence_handle_page_fault+0xa6/0x280 > [60313.522710] page_fault_oops+0x9d/0x2d0 > [60313.522714] exc_page_fault+0x78/0x180 > [60313.522718] asm_exc_page_fault+0x1e/0x30 > [60313.522721] RIP: 0010:bfq_dispatch_request+0x4c3/0x1280 > [60313.522725] Code: 4c 89 e7 e8 ef da ff ff 4c 89 ff 89 c6 e8 75 64 00 00 > 4c 39 bb a0 00 00 00 0f 84 86 04 00 00 49 8b 84 24 90 00 00 00 48 8b 33 > 80 20 01 00 00 48 89 34 24 48 8b 46 08 4c 8b 58 08 4c 89 5c 24 > [60313.522727] RSP: 0018:ffffb559c0affcd0 EFLAGS: 00010046 > [60313.522729] RAX: 0000000000000000 RBX: ffff8ced4d6a1000 RCX: > 0000000000000000 [60313.522731] RDX: 0000000000000000 RSI: ffff8ced4ad900= 00 > RDI: ffff8ced52fc9f40 [60313.522733] RBP: 0000000000000000 R08: > 0000000000000001 R09: > 0000000000000000 > [60313.522735] R10: 000000000000003f R11: 0000000000000000 R12: > ffff8cf20e5a5400 [60313.522737] R13: ffff8cf0e7e91c70 R14: ffff8ced4d6a14= 20 > R15: ffff8cf0e7e91c70 [60313.522741] ? mod_delayed_work_on+0x71/0xe0 > [60313.522745] ? __sbitmap_get_word+0x30/0x80 > [60313.522748] __blk_mq_do_dispatch_sched+0x218/0x320 > [60313.522752] __blk_mq_sched_dispatch_requests+0x107/0x150 > [60313.522755] blk_mq_sched_dispatch_requests+0x2f/0x60 > [60313.522758] blk_mq_run_work_fn+0x43/0xc0 > [60313.522761] process_one_work+0x24e/0x430 > [60313.522765] worker_thread+0x54/0x4d0 > [60313.522767] ? process_one_work+0x430/0x430 > [60313.522770] kthread+0x182/0x1b0 > [60313.522773] ? __kthread_init_worker+0x50/0x50 > [60313.522776] ret_from_fork+0x22/0x30 > [60313.522781] ---[ end trace 55ef262e614b59af ]--- > [60313.522786] ------------[ cut here ]------------ > [60313.522787] WARNING: CPU: 20 PID: 388 at mm/kfence/core.c:135 > kfence_handle_page_fault+0xaa/0x280 > [60313.522791] Modules linked in: sctp ip6_udp_tunnel udp_tunnel uinput > netconsole blocklayoutdriver rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolv= er > nfs lockd grace sunrpc fscache netfs rfcomm nft_ct nf_conntrack > nf_defrag_ipv6 nf_defrag_ipv4 cmac algif_hash algif_skcipher nf_tables > af_alg bnep tun nfnetlink nls_iso8859_1 intel_rapl_msr vfat > intel_rapl_common iwlmvm fat mac80211 edac_mce_amd libarc4 btusb eeepc_wmi > btrtl asus_wmi iwlwifi btbcm snd_usb_audio sparse_keymap kvm_amd video > wmi_bmof mxm_wmi btintel uvcvideo snd_hda_codec_realtek videobuf2_vmalloc > videobuf2_memops snd_usbmidi_lib kvm snd_hda_codec_generic bluetooth > videobuf2_v4l2 ledtrig_audio > snd_hda_codec_hdmi joydev snd_rawmidi ecdh_generic irqbypass ecc > snd_hda_intel mousedev pl2303 cfg80211 snd_seq_device videobuf2_common > crc16 rapl k10temp snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec igb > r8169 sp5100_tco snd_hda_core realtek i2c_piix4 ipmi_devintf dca snd_hwdep > mdio_devres rfkill snd_pcm libphy ipmi_msghandler wmi > [60313.522817] pinctrl_amd mac_hid acpi_cpufreq tcp_bbr2 vhost_vsock > vmw_vsock_virtio_transport_common vhost vhost_iotlb vsock v4l2loopback > videodev mc snd_hrtimer snd_timer snd soundcore nct6775 hwmon_vid > crypto_user fuse ip_tables x_tables xfs dm_thin_pool dm_persistent_data > dm_bio_prison dm_bufio libcrc32c crc32c_generic dm_crypt cbc encrypted_ke= ys > trusted asn1_encoder tee hid_logitech_hidpp hid_logitech_dj usbhid dm_mod > crct10dif_pclmul crc32_pclmul crc32c_intel raid10 ghash_clmulni_intel > aesni_intel md_mod crypto_simd cryptd amdgpu ccp xhci_pci xhci_pci_renesas > tpm_crb tpm_tis tpm_tis_core tpm rng_core drm_ttm_helper ttm gpu_sched > i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops > cec drm agpgart > [60313.522840] CPU: 20 PID: 388 Comm: kworker/20:1H Tainted: G W > 5.13.0-pf2 #1 > [60313.522843] Hardware name: ASUS System Product Name/Pro WS X570-ACE, B= IOS > 3601 05/26/2021 > [60313.522845] Workqueue: kblockd blk_mq_run_work_fn > [60313.522848] RIP: 0010:kfence_handle_page_fault+0xaa/0x280 > [60313.522851] Code: 0f 86 d4 00 00 00 0f b6 f3 41 b8 03 00 00 00 31 c9 4c > 89 ea 48 89 ef e8 e4 05 00 00 31 f6 4c 89 ff e8 6a f5 ff ff 84 c0 75 8d > <0f> 0b c6 05 7d fd 6b 01 00 45 31 f6 e9 7c ff ff ff 48 8b 0d 36 a0 > [60313.522853] RSP: 0018:ffffb559c0affb50 EFLAGS: 00010046 > [60313.522855] RAX: 0000000000000000 RBX: 0000000000000000 RCX: > ffffb559c0affb2c [60313.522857] RDX: 0000000000000000 RSI: 00000000000000= 00 > RDI: > 0000000000000000 > [60313.522859] RBP: 0000000000000120 R08: 0000000000000000 R09: > 0000000000000000 > [60313.522860] R10: 0000000000000000 R11: 0000000000000000 R12: > 0000000000000002 > [60313.522862] R13: ffffb559c0affc28 R14: 00000000c0affc01 R15: > 0000000000000000 [60313.522864] FS: 0000000000000000(0000) > GS:ffff8cf44ef00000(0000) knlGS: 0000000000000000 > [60313.522866] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [60313.522868] CR2: 0000000000000120 CR3: 000000013ebce000 CR4: > 0000000000350ee0 > [60313.522870] Call Trace: > [60313.522872] page_fault_oops+0x9d/0x2d0 > [60313.522875] exc_page_fault+0x78/0x180 > [60313.522878] asm_exc_page_fault+0x1e/0x30 > [60313.522880] RIP: 0010:bfq_dispatch_request+0x4c3/0x1280 > [60313.522883] Code: 4c 89 e7 e8 ef da ff ff 4c 89 ff 89 c6 e8 75 64 00 00 > 4c 39 bb a0 00 00 00 0f 84 86 04 00 00 49 8b 84 24 90 00 00 00 48 8b 33 > 80 20 01 00 00 48 89 34 24 48 8b 46 08 4c 8b 58 08 4c 89 5c 24 > [60313.522885] RSP: 0018:ffffb559c0affcd0 EFLAGS: 00010046 > [60313.522887] RAX: 0000000000000000 RBX: ffff8ced4d6a1000 RCX: > 0000000000000000 [60313.522889] RDX: 0000000000000000 RSI: ffff8ced4ad900= 00 > RDI: ffff8ced52fc9f40 [60313.522890] RBP: 0000000000000000 R08: > 0000000000000001 R09: > 0000000000000000 > [60313.522892] R10: 000000000000003f R11: 0000000000000000 R12: > ffff8cf20e5a5400 [60313.523148] R13: ffff8cf0e7e91c70 R14: ffff8ced4d6a14= 20 > R15: ffff8cf0e7e91c70 [60313.523150] ? mod_delayed_work_on+0x71/0xe0 > [60313.523153] ? __sbitmap_get_word+0x30/0x80 > [60313.523157] __blk_mq_do_dispatch_sched+0x218/0x320 > [60313.523161] __blk_mq_sched_dispatch_requests+0x107/0x150 > [60313.523165] blk_mq_sched_dispatch_requests+0x2f/0x60 > [60313.523167] blk_mq_run_work_fn+0x43/0xc0 > [60313.523170] process_one_work+0x24e/0x430 > [60313.523173] worker_thread+0x54/0x4d0 > [60313.523176] ? process_one_work+0x430/0x430 > [60313.523178] kthread+0x182/0x1b0 > [60313.523181] ? __kthread_init_worker+0x50/0x50 > [60313.523183] ret_from_fork+0x22/0x30 > [60313.523187] ---[ end trace 55ef262e614b59b0 ]--- > [60313.523189] BUG: kernel NULL pointer dereference, address: > 0000000000000120 [60313.523191] #PF: supervisor write access in kernel mo= de > [60313.523193] #PF: error_code(0x0002) - not-present page > [60313.523195] PGD 0 P4D 0 > [60313.523197] Oops: 0002 [#1] PREEMPT SMP NOPTI > [60313.523200] CPU: 20 PID: 388 Comm: kworker/20:1H Tainted: G W > 5.13.0-pf2 #1 > [60313.523202] Hardware name: ASUS System Product Name/Pro WS X570-ACE, B= IOS > 3601 05/26/2021 > [60313.523204] Workqueue: kblockd blk_mq_run_work_fn > [60313.523207] RIP: 0010:bfq_dispatch_request+0x4c3/0x1280 > [60313.523210] Code: 4c 89 e7 e8 ef da ff ff 4c 89 ff 89 c6 e8 75 64 00 00 > 4c 39 bb a0 00 00 00 0f 84 86 04 00 00 49 8b 84 24 90 00 00 00 48 8b 33 > 80 20 01 00 00 48 89 34 24 48 8b 46 08 4c 8b 58 08 4c 89 5c 24 > [60313.523213] RSP: 0018:ffffb559c0affcd0 EFLAGS: 00010046 > [60313.523215] RAX: 0000000000000000 RBX: ffff8ced4d6a1000 RCX: > 0000000000000000 [60313.523216] RDX: 0000000000000000 RSI: ffff8ced4ad900= 00 > RDI: ffff8ced52fc9f40 [60313.523218] RBP: 0000000000000000 R08: > 0000000000000001 R09: > 0000000000000000 > [60313.523220] R10: 000000000000003f R11: 0000000000000000 R12: > ffff8cf20e5a5400 [60313.523221] R13: ffff8cf0e7e91c70 R14: ffff8ced4d6a14= 20 > R15: ffff8cf0e7e91c70 [60313.523223] FS: 0000000000000000(0000) > GS:ffff8cf44ef00000(0000) knlGS: 0000000000000000 > [60313.523225] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [60313.523227] CR2: 0000000000000120 CR3: 000000013ebce000 CR4: > 0000000000350ee0 > [60313.523229] Call Trace: > [60313.523231] ? mod_delayed_work_on+0x71/0xe0 > [60313.523233] ? __sbitmap_get_word+0x30/0x80 > [60313.523237] __blk_mq_do_dispatch_sched+0x218/0x320 > [60313.523240] __blk_mq_sched_dispatch_requests+0x107/0x150 > [60313.523243] blk_mq_sched_dispatch_requests+0x2f/0x60 > [60313.523246] blk_mq_run_work_fn+0x43/0xc0 > [60313.523249] process_one_work+0x24e/0x430 > [60313.523251] worker_thread+0x54/0x4d0 > [60313.523254] ? process_one_work+0x430/0x430 > [60313.523257] kthread+0x182/0x1b0 > [60313.523259] ? __kthread_init_worker+0x50/0x50 > [60313.523261] ret_from_fork+0x22/0x30 > [60313.523265] Modules linked in: sctp ip6_udp_tunnel udp_tunnel uinput > netconsole blocklayoutdriver rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolv= er > nfs lockd grace sunrpc fscache netfs rfcomm nft_ct nf_conntrack > nf_defrag_ipv6 nf_defrag_ipv4 cmac algif_hash algif_skcipher nf_tables > af_alg bnep tun nfnetlink nls_iso8859_1 intel_rapl_msr vfat > intel_rapl_common iwlmvm fat mac80211 edac_mce_amd libarc4 btusb eeepc_wmi > btrtl asus_wmi iwlwifi btbcm snd_usb_audio sparse_keymap kvm_amd video > wmi_bmof mxm_wmi btintel uvcvideo snd_hda_codec_realtek videobuf2_vmalloc > videobuf2_memops snd_usbmidi_lib kvm snd_hda_codec_generic bluetooth > videobuf2_v4l2 ledtrig_audio > snd_hda_codec_hdmi joydev snd_rawmidi ecdh_generic irqbypass ecc > snd_hda_intel mousedev pl2303 cfg80211 snd_seq_device videobuf2_common > crc16 rapl k10temp snd_intel_dspcfg snd_intel_sdw_acpi snd_hda_codec igb > r8169 sp5100_tco snd_hda_core realtek i2c_piix4 ipmi_devintf dca snd_hwdep > mdio_devres rfkill snd_pcm libphy ipmi_msghandler wmi > [60313.523290] pinctrl_amd mac_hid acpi_cpufreq tcp_bbr2 vhost_vsock > vmw_vsock_virtio_transport_common vhost vhost_iotlb vsock v4l2loopback > videodev mc snd_hrtimer snd_timer snd soundcore nct6775 hwmon_vid > crypto_user fuse ip_tables x_tables xfs dm_thin_pool dm_persistent_data > dm_bio_prison dm_bufio libcrc32c crc32c_generic dm_crypt cbc encrypted_ke= ys > trusted asn1_encoder tee hid_logitech_hidpp hid_logitech_dj usbhid dm_mod > crct10dif_pclmul crc32_pclmul crc32c_intel raid10 ghash_clmulni_intel > aesni_intel md_mod crypto_simd cryptd amdgpu ccp xhci_pci xhci_pci_renesas > tpm_crb tpm_tis tpm_tis_core tpm rng_core drm_ttm_helper ttm gpu_sched > i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops > cec drm agpgart > [60313.523314] CR2: 0000000000000120 > [60313.523316] ---[ end trace 55ef262e614b59b1 ]--- > [60313.523318] RIP: 0010:bfq_dispatch_request+0x4c3/0x1280 > [60313.523321] Code: 4c 89 e7 e8 ef da ff ff 4c 89 ff 89 c6 e8 75 64 00 00 > 4c 39 bb a0 00 00 00 0f 84 86 04 00 00 49 8b 84 24 90 00 00 00 48 8b 33 > 80 20 01 00 00 48 89 34 24 48 8b 46 08 4c 8b 58 08 4c 89 5c 24 > [60313.523323] RSP: 0018:ffffb559c0affcd0 EFLAGS: 00010046 > [60313.523325] RAX: 0000000000000000 RBX: ffff8ced4d6a1000 RCX: > 0000000000000000 [60313.523326] RDX: 0000000000000000 RSI: ffff8ced4ad900= 00 > RDI: ffff8ced52fc9f40 [60313.523328] RBP: 0000000000000000 R08: > 0000000000000001 R09: > 0000000000000000 > [60313.523330] R10: 000000000000003f R11: 0000000000000000 R12: > ffff8cf20e5a5400 [60313.523332] R13: ffff8cf0e7e91c70 R14: ffff8ced4d6a14= 20 > R15: ffff8cf0e7e91c70 [60313.523334] FS: 0000000000000000(0000) > GS:ffff8cf44ef00000(0000) knlGS: 0000000000000000 > [60313.523336] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > [60313.523338] CR2: 0000000000000120 CR3: 000000013ebce000 CR4: > 0000000000350ee0 > [60313.523339] note: kworker/20:1H[388] exited with preempt_count 1 > ``` This is just to let you know that I'm running v5.13.7 without any extra=20 patches under block/ applied, and the issue is not reproducible. I'll probably defer investigating this till v5.14 unless it is fixed there= =20 already. =2D-=20 Oleksandr Natalenko (post-factum)