Date:   Sat, 18 Mar 2017 12:24:44 +0100
From:   Hannes Reinecke <hare@...e.de>
To:     Ming Lei <tom.leiming@...il.com>, Jens Axboe <axboe@...com>,
        linux-kernel@...r.kernel.org, linux-block@...r.kernel.org,
        Christoph Hellwig <hch@...radead.org>
Cc:     Yi Zhang <yizhan@...hat.com>,
        Bart Van Assche <bart.vanassche@...disk.com>,
        stable@...r.kernel.org
Subject: Re: [PATCH v1 1/3] blk-mq: don't complete un-started request in
 timeout handler

On 03/17/2017 10:57 AM, Ming Lei wrote:
> When iterating busy requests in timeout handler,
> if the STARTED flag of one request isn't set, that means
> the request is being processed in block layer or driver, and
> isn't dispatch to hardware yet.
> 
> In current implementation of blk_mq_check_expired(),
> if the request queue becomes dying, un-started requests are
> handled as being completed/freed immediately. This way is
> wrong, and can cause use-after-free issue easily[1][2], when
> doing I/O and removing&resetting NVMe device at the sametime.
> 
> This patch fixes several issues reported by Yi Zhang.
> 
> [1]. oops log 1
> [  581.789754] ------------[ cut here ]------------
> [  581.789758] kernel BUG at block/blk-mq.c:374!
> [  581.789760] invalid opcode: 0000 [#1] SMP
> [  581.789761] Modules linked in: vfat fat ipmi_ssif intel_rapl sb_edac
> edac_core x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm nvme
> irqbypass crct10dif_pclmul nvme_core crc32_pclmul ghash_clmulni_intel
> intel_cstate ipmi_si mei_me ipmi_devintf intel_uncore sg ipmi_msghandler
> intel_rapl_perf iTCO_wdt mei iTCO_vendor_support mxm_wmi lpc_ich dcdbas shpchp
> pcspkr acpi_power_meter wmi nfsd auth_rpcgss nfs_acl lockd dm_multipath grace
> sunrpc ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper
> syscopyarea sysfillrect sysimgblt fb_sys_fops ttm drm ahci libahci
> crc32c_intel tg3 libata megaraid_sas i2c_core ptp fjes pps_core dm_mirror
> dm_region_hash dm_log dm_mod
> [  581.789796] CPU: 1 PID: 1617 Comm: kworker/1:1H Not tainted 4.10.0.bz1420297+ #4
> [  581.789797] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.2.5 09/06/2016
> [  581.789804] Workqueue: kblockd blk_mq_timeout_work
> [  581.789806] task: ffff8804721c8000 task.stack: ffffc90006ee4000
> [  581.789809] RIP: 0010:blk_mq_end_request+0x58/0x70
> [  581.789810] RSP: 0018:ffffc90006ee7d50 EFLAGS: 00010202
> [  581.789811] RAX: 0000000000000001 RBX: ffff8802e4195340 RCX: ffff88028e2f4b88
> [  581.789812] RDX: 0000000000001000 RSI: 0000000000001000 RDI: 0000000000000000
> [  581.789813] RBP: ffffc90006ee7d60 R08: 0000000000000003 R09: ffff88028e2f4b00
> [  581.789814] R10: 0000000000001000 R11: 0000000000000001 R12: 00000000fffffffb
> [  581.789815] R13: ffff88042abe5780 R14: 000000000000002d R15: ffff88046fbdff80
> [  581.789817] FS:  0000000000000000(0000) GS:ffff88047fc00000(0000) knlGS:0000000000000000
> [  581.789818] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [  581.789819] CR2: 00007f64f403a008 CR3: 000000014d078000 CR4: 00000000001406e0
> [  581.789820] Call Trace:
> [  581.789825]  blk_mq_check_expired+0x76/0x80
> [  581.789828]  bt_iter+0x45/0x50
> [  581.789830]  blk_mq_queue_tag_busy_iter+0xdd/0x1f0
> [  581.789832]  ? blk_mq_rq_timed_out+0x70/0x70
> [  581.789833]  ? blk_mq_rq_timed_out+0x70/0x70
> [  581.789840]  ? __switch_to+0x140/0x450
> [  581.789841]  blk_mq_timeout_work+0x88/0x170
> [  581.789845]  process_one_work+0x165/0x410
> [  581.789847]  worker_thread+0x137/0x4c0
> [  581.789851]  kthread+0x101/0x140
> [  581.789853]  ? rescuer_thread+0x3b0/0x3b0
> [  581.789855]  ? kthread_park+0x90/0x90
> [  581.789860]  ret_from_fork+0x2c/0x40
> [  581.789861] Code: 48 85 c0 74 0d 44 89 e6 48 89 df ff d0 5b 41 5c 5d c3 48
> 8b bb 70 01 00 00 48 85 ff 75 0f 48 89 df e8 7d f0 ff ff 5b 41 5c 5d c3 <0f>
> 0b e8 71 f0 ff ff 90 eb e9 0f 1f 40 00 66 2e 0f 1f 84 00 00
> [  581.789882] RIP: blk_mq_end_request+0x58/0x70 RSP: ffffc90006ee7d50
> [  581.789889] ---[ end trace bcaf03d9a14a0a70 ]---
> 
> [2]. oops log2
> [ 6984.857362] BUG: unable to handle kernel NULL pointer dereference at 0000000000000010
> [ 6984.857372] IP: nvme_queue_rq+0x6e6/0x8cd [nvme]
> [ 6984.857373] PGD 0
> [ 6984.857374]
> [ 6984.857376] Oops: 0000 [#1] SMP
> [ 6984.857379] Modules linked in: ipmi_ssif vfat fat intel_rapl sb_edac
> edac_core x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm
> irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel ipmi_si iTCO_wdt
> iTCO_vendor_support mxm_wmi ipmi_devintf intel_cstate sg dcdbas intel_uncore
> mei_me intel_rapl_perf mei pcspkr lpc_ich ipmi_msghandler shpchp
> acpi_power_meter wmi nfsd auth_rpcgss dm_multipath nfs_acl lockd grace sunrpc
> ip_tables xfs libcrc32c sd_mod mgag200 i2c_algo_bit drm_kms_helper syscopyarea
> sysfillrect crc32c_intel sysimgblt fb_sys_fops ttm nvme drm nvme_core ahci
> libahci i2c_core tg3 libata ptp megaraid_sas pps_core fjes dm_mirror
> dm_region_hash dm_log dm_mod
> [ 6984.857416] CPU: 7 PID: 1635 Comm: kworker/7:1H Not tainted
> 4.10.0-2.el7.bz1420297.x86_64 #1
> [ 6984.857417] Hardware name: Dell Inc. PowerEdge R730xd/072T6D, BIOS 2.2.5 09/06/2016
> [ 6984.857427] Workqueue: kblockd blk_mq_run_work_fn
> [ 6984.857429] task: ffff880476e3da00 task.stack: ffffc90002e90000
> [ 6984.857432] RIP: 0010:nvme_queue_rq+0x6e6/0x8cd [nvme]
> [ 6984.857433] RSP: 0018:ffffc90002e93c50 EFLAGS: 00010246
> [ 6984.857434] RAX: 0000000000000000 RBX: ffff880275646600 RCX: 0000000000001000
> [ 6984.857435] RDX: 0000000000000fff RSI: 00000002fba2a000 RDI: ffff8804734e6950
> [ 6984.857436] RBP: ffffc90002e93d30 R08: 0000000000002000 R09: 0000000000001000
> [ 6984.857437] R10: 0000000000001000 R11: 0000000000000000 R12: ffff8804741d8000
> [ 6984.857438] R13: 0000000000000040 R14: ffff880475649f80 R15: ffff8804734e6780
> [ 6984.857439] FS:  0000000000000000(0000) GS:ffff88047fcc0000(0000) knlGS:0000000000000000
> [ 6984.857440] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 6984.857442] CR2: 0000000000000010 CR3: 0000000001c09000 CR4: 00000000001406e0
> [ 6984.857443] Call Trace:
> [ 6984.857451]  ? mempool_free+0x2b/0x80
> [ 6984.857455]  ? bio_free+0x4e/0x60
> [ 6984.857459]  blk_mq_dispatch_rq_list+0xf5/0x230
> [ 6984.857462]  blk_mq_process_rq_list+0x133/0x170
> [ 6984.857465]  __blk_mq_run_hw_queue+0x8c/0xa0
> [ 6984.857467]  blk_mq_run_work_fn+0x12/0x20
> [ 6984.857473]  process_one_work+0x165/0x410
> [ 6984.857475]  worker_thread+0x137/0x4c0
> [ 6984.857478]  kthread+0x101/0x140
> [ 6984.857480]  ? rescuer_thread+0x3b0/0x3b0
> [ 6984.857481]  ? kthread_park+0x90/0x90
> [ 6984.857489]  ret_from_fork+0x2c/0x40
> [ 6984.857490] Code: 8b bd 70 ff ff ff 89 95 50 ff ff ff 89 8d 58 ff ff ff 44
> 89 95 60 ff ff ff e8 b7 dd 12 e1 8b 95 50 ff ff ff 48 89 85 68 ff ff ff <4c>
> 8b 48 10 44 8b 58 18 8b 8d 58 ff ff ff 44 8b 95 60 ff ff ff
> [ 6984.857511] RIP: nvme_queue_rq+0x6e6/0x8cd [nvme] RSP: ffffc90002e93c50
> [ 6984.857512] CR2: 0000000000000010
> [ 6984.895359] ---[ end trace 2d7ceb528432bf83 ]---
> 
> Cc: stable@...r.kernel.org
> Reported-by: Yi Zhang <yizhan@...hat.com>
> Tested-by: Yi Zhang <yizhan@...hat.com>
> Reviewed-by: Bart Van Assche <bart.vanassche@...disk.com>
> Signed-off-by: Ming Lei <tom.leiming@...il.com>
> ---
>  block/blk-mq.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
Reviewed-by: Hannes Reinecke <hare@...e.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
hare@...e.de			      +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)

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