From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Bart Van Assche <bvanassche@acm.org>,
Hannes Reinecke <hare@suse.com>, Christoph Hellwig <hch@lst.de>,
Thomas Gleixner <tglx@linutronix.de>,
John Garry <john.garry@huawei.com>
Subject: Re: [PATCH 1/6] blk-mq: allocate request on cpu in hctx->cpumask for blk_mq_alloc_request_hctx
Date: Fri, 15 May 2020 17:32:48 +0200 [thread overview]
Message-ID: <20200515153248.GA29610@lst.de> (raw)
In-Reply-To: <20200515014153.2403464-2-ming.lei@redhat.com>
On Fri, May 15, 2020 at 09:41:48AM +0800, Ming Lei wrote:
> blk_mq_alloc_request_hctx() asks blk-mq to allocate request from
> specified hctx, which is usually bound with fixed cpu mapping, and
> request is supposed to be allocated on CPU in hctx->cpumask.
>
> So use smp_call_function_any() to allocate request on the cpu in
> hctx->cpumask for blk_mq_alloc_request_hctx().
>
> Dedclare blk_mq_get_request() beforehand because the following patches
> reuses __blk_mq_alloc_request for blk_mq_get_request().
>
> Prepare for improving cpu hotplug support.
With your series applied the kernel instantly panics when creating a
nvme-loop controller:
[ 27.189993] nvmet: creating controller 1 for subsystem testnqn for NQN
hostnqn.
[ 27.199370] nvme nvme0: creating 4 I/O queues.
[ 27.202650] BUG: kernel NULL pointer dereference, address: 0000000000000128
[ 27.205004] #PF: supervisor read access in kernel mode
[ 27.206382] #PF: error_code(0x0000) - not-present page
[ 27.207741] PGD 800000012dfc9067 P4D 800000012dfc9067 PUD 12dfae067 PMD 0
[ 27.209326] Oops: 0000 [#1] PREEMPT SMP PTI
[ 27.210214] CPU: 2 PID: 3786 Comm: bash Not tainted 5.7.0-rc2+ #44
[ 27.211511] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1 04/01/2014
[ 27.213626] RIP: 0010:smp_call_function_any+0x34/0xf0
[ 27.214736] Code: 41 54 49 89 f4 55 48 89 fd bf 01 00 00 00 e8 33 23 f8 ff 48 c7 c7 3b 0b 12 d
[ 27.218079] RSP: 0018:ffffc900003d3b90 EFLAGS: 00010202
[ 27.219340] RAX: 0000000000000002 RBX: 0000000000000000 RCX: 0000000000000001
[ 27.221199] RDX: 0000000000000000 RSI: ffffffff8198c920 RDI: ffffffff83120b3b
[ 27.222517] RBP: 0000000000000128 R08: 0000000000000002 R09: 0000000000020022
[ 27.223780] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8198c920
[ 27.225002] R13: ffffc900003d3bb8 R14: 0000000000000001 R15: ffff88812b488008
[ 27.226195] FS: 00007fca23cae740(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
[ 27.227520] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 27.228378] CR2: 0000000000000128 CR3: 000000012eba6000 CR4: 00000000000006e0
[ 27.229444] Call Trace:
[ 27.229810] blk_mq_alloc_request_hctx+0xe7/0x140
[ 27.230487] nvme_alloc_request+0x2d/0x70
[ 27.231053] __nvme_submit_sync_cmd+0x4a/0x1f0
[ 27.231720] ? mark_held_locks+0x49/0x70
[ 27.232279] ? __slab_alloc.isra.0.constprop.0+0x63/0x80
[ 27.233038] ? nvmf_connect_io_queue+0x85/0x180
[ 27.233687] nvmf_connect_io_queue+0x12d/0x180
[ 27.234296] ? cpumask_next_and+0x19/0x20
[ 27.234848] ? nvme_loop_connect_io_queues+0x4c/0x60
[ 27.235718] ? blk_mq_init_queue_data+0x36/0x60
[ 27.236598] nvme_loop_connect_io_queues+0x4c/0x60
[ 27.237379] nvme_loop_create_ctrl+0x2f0/0x450
[ 27.238016] nvmf_dev_write+0x7e3/0xb2f
[ 27.238541] ? find_held_lock+0x2b/0x80
[ 27.239080] ? do_user_addr_fault+0x205/0x480
[ 27.239763] vfs_write+0xb4/0x1a0
[ 27.240302] ksys_write+0x63/0xe0
[ 27.240845] do_syscall_64+0x4b/0x1e0
[ 27.241446] entry_SYSCALL_64_after_hwframe+0x49/0xb3
[ 27.242253] RIP: 0033:0x7fca233a2134
[ 27.242821] Code: 89 02 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 8d 05 5
[ 27.245798] RSP: 002b:00007ffe430d43e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 27.247255] RAX: ffffffffffffffda RBX: 000000000000002b RCX: 00007fca233a2134
[ 27.248525] RDX: 000000000000002b RSI: 000000000119f408 RDI: 0000000000000001
[ 27.249806] RBP: 000000000119f408 R08: 000000000000000a R09: 00000000011d8988
[ 27.251238] R10: 000000000000000a R11: 0000000000000246 R12: 00007fca2366f760
[ 27.252195] R13: 000000000000002b R14: 00007fca2366a760 R15: 000000000000002b
[ 27.253157] Modules linked in:
[ 27.253603] CR2: 0000000000000128
[ 27.254056] ---[ end trace 75ba575e2625a1c6 ]---
[ 27.254684] RIP: 0010:smp_call_function_any+0x34/0xf0
[ 27.255398] Code: 41 54 49 89 f4 55 48 89 fd bf 01 00 00 00 e8 33 23 f8 ff 48 c7 c7 3b 0b 12 d
[ 27.258140] RSP: 0018:ffffc900003d3b90 EFLAGS: 00010202
[ 27.258966] RAX: 0000000000000002 RBX: 0000000000000000 RCX: 0000000000000001
[ 27.260075] RDX: 0000000000000000 RSI: ffffffff8198c920 RDI: ffffffff83120b3b
[ 27.261166] RBP: 0000000000000128 R08: 0000000000000002 R09: 0000000000020022
[ 27.262278] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffff8198c920
[ 27.263219] R13: ffffc900003d3bb8 R14: 0000000000000001 R15: ffff88812b488008
[ 27.264139] FS: 00007fca23cae740(0000) GS:ffff88813bd00000(0000) knlGS:0000000000000000
[ 27.265175] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 27.265893] CR2: 0000000000000128 CR3: 000000012eba6000 CR4: 00000000000006e0
[ 27.266805] Kernel panic - not syncing: Fatal exception
[ 27.267640] Kernel Offset: disabled
[ 27.268087] ---[ end Kernel panic - not syncing: Fatal exception ]---
next prev parent reply other threads:[~2020-05-15 15:32 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 1:41 [PATCH 0/6] blk-mq: improvement CPU hotplug(simplified version) Ming Lei
2020-05-15 1:41 ` [PATCH 1/6] blk-mq: allocate request on cpu in hctx->cpumask for blk_mq_alloc_request_hctx Ming Lei
2020-05-15 15:32 ` Christoph Hellwig [this message]
2020-05-15 1:41 ` [PATCH 2/6] blk-mq: set data->ctx and data->hctx explicitly in blk_mq_get_request Ming Lei
2020-05-15 1:41 ` [PATCH 3/6] blk-mq: add blk_mq_all_tag_iter Ming Lei
2020-05-15 1:41 ` [PATCH 4/6] blk-mq: prepare for draining IO when hctx's all CPUs are offline Ming Lei
2020-05-15 1:41 ` [PATCH 5/6] blk-mq: disable preempt during allocating request tag Ming Lei
2020-05-15 15:38 ` Christoph Hellwig
2020-05-15 16:10 ` Christoph Hellwig
2020-05-15 1:41 ` [PATCH 6/6] blk-mq: stop to allocate new requst and drain request before hctx becomes inactive Ming Lei
2020-05-15 3:55 ` Bart Van Assche
2020-05-15 5:20 ` Ming Lei
2020-05-15 15:45 ` [PATCH 0/6] blk-mq: improvement CPU hotplug(simplified version) Christoph Hellwig
2020-05-16 12:35 ` Christoph Hellwig
2020-05-17 4:08 ` Ming Lei
2020-05-17 7:08 ` Christoph Hellwig
2020-05-18 4:07 ` Ming Lei
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