list_add double add in blk_mq_check_expired()

From: Borislav Petkov
Date: Sat Jun 16 2018 - 06:36:40 EST

Hi,

just triggered the below in a qemu guest, kernel is Linus' master from
yesterday + tip/master. It doesn't fire reliably so it could be some
transient thing of the merge window:

---

...

[ 2.387633] EXT4-fs (sda1): mounting ext3 file system using the ext4 subsystem
[ 2.500490] EXT4-fs (sda1): mounted filesystem with ordered data mode. Opts: (null)
[ 2.503122] VFS: Mounted root (ext3 filesystem) readonly on device 8:1.
[ 2.507917] Freeing unused kernel memory: 1332K
[ 2.509362] Write protecting the kernel read-only data: 16384k
[ 2.511774] Freeing unused kernel memory: 2008K
[ 2.514999] Freeing unused kernel memory: 956K
[ 2.523429] x86/mm: Checked W+X mappings: passed, no W+X pages found.
[ 3.485227] random: fast init done
[ 7.904105] ------------[ cut here ]------------
[ 7.906706] list_add double add: new=ffff88007b342180, prev=ffff88007b342180, next=ffff88007ad07060.
[ 7.910001] WARNING: CPU: 7 PID: 1543 at lib/list_debug.c:31 __list_add_valid+0x67/0x70
[ 7.910001] Modules linked in:
[ 7.910001] CPU: 7 PID: 1543 Comm: kworker/7:1H Not tainted 4.17.0+ #7
[ 7.910001] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014
[ 7.910001] Workqueue: kblockd blk_mq_timeout_work
[ 7.910001] RIP: 0010:__list_add_valid+0x67/0x70
[ 7.910001] Code: c1 4c 89 c6 48 c7 c7 30 27 e6 81 e8 63 50 d2 ff 0f 0b 31 c0 c3 48 89 f2 4c 89 c1 48 89 fe 48 c7 c7 80 27 e6 81 e8 49 50 d2 ff <0f> 0b 31 c0 c3 0f 1f 40 00 48 8b 07 48 b9 00 01 00 00 00 00 ad de
[ 7.910001] RSP: 0018:ffffc9000080fd68 EFLAGS: 00010096
[ 7.910001] RAX: 0000000000000058 RBX: ffff88007ad07000 RCX: ffffffff82042488
[ 7.910001] RDX: 0000000000000001 RSI: 0000000000000086 RDI: ffffffff824c2d8c
[ 7.910001] RBP: ffff88007b342130 R08: ffffffff814254a0 R09: 0000000000000181
[ 7.910001] R10: 0000000000aaaaaa R11: ffff88007c7056d0 R12: ffff88007b342180
[ 7.910001] R13: 0000000000000282 R14: ffff88007b342180 R15: ffff88007ad07060
[ 7.910001] FS: 0000000000000000(0000) GS:ffff88007d3c0000(0000) knlGS:0000000000000000
[ 7.910001] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7.910001] CR2: 00007f58744b3a80 CR3: 0000000002009000 CR4: 00000000003406e0
[ 7.910001] Call Trace:
[ 7.910001] scsi_eh_scmd_add+0xc5/0x160
[ 7.910001] scsi_times_out+0x9a/0x1a0
[ 7.910001] blk_mq_check_expired+0xf2/0x130
[ 7.910001] bt_iter+0x48/0x50
[ 7.910001] blk_mq_queue_tag_busy_iter+0x129/0x220
[ 7.910001] ? blk_mq_timeout_work+0x150/0x150
[ 7.910001] ? blk_mq_timeout_work+0x150/0x150
[ 7.910001] blk_mq_timeout_work+0x80/0x150
[ 7.910001] process_one_work+0x18c/0x3a0
[ 7.910001] worker_thread+0x30/0x3a0
[ 7.910001] ? process_one_work+0x3a0/0x3a0
[ 7.910001] kthread+0x113/0x130
[ 7.910001] ? kthread_create_worker_on_cpu+0x40/0x40
[ 7.910001] ret_from_fork+0x22/0x40
[ 7.910001] ---[ end trace 0d2f1accf0e2ed60 ]---
[ 7.992080] WARNING: CPU: 7 PID: 0 at kernel/rcu/tree.c:2596 rcu_process_callbacks+0x49a/0x4c0
[ 7.995041] Modules linked in:
[ 7.996049] CPU: 7 PID: 0 Comm: swapper/7 Tainted: G W 4.17.0+ #7
[ 7.996049] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.1-1 04/01/2014
[ 7.996049] RIP: 0010:rcu_process_callbacks+0x49a/0x4c0
[ 7.996049] Code: e9 56 fd ff ff 48 c7 83 90 00 00 00 00 00 00 00 48 8b 95 50 03 00 00 48 89 93 98 00 00 00 e9 60 fd ff ff 0f 0b e9 bb fb ff ff <0f> 0b e9 68 fd ff ff 0f 0b e9 89 fc ff ff 4c 89 ee 4c 89 e7 66 90
[ 7.996049] RSP: 0018:ffff88007d3c3f18 EFLAGS: 00010002
[ 7.996049] RAX: 0000000000000000 RBX: ffff88007d3e18c0 RCX: ffff88007c505e80
[ 7.996049] RDX: ffffffffffffd801 RSI: ffff88007d3c3f20 RDI: ffff88007d3e18f8
[ 7.996049] RBP: ffffffff82043a80 R08: ffff88007d3e1810 R09: 0000000000000101
[ 7.996049] R10: ffff88007c0ac6c0 R11: 0000000000000000 R12: ffff88007d3e18f8
[ 7.996049] R13: 0000000000000246 R14: 7fffffffffffffff R15: 0000000000000202
[ 7.996049] FS: 0000000000000000(0000) GS:ffff88007d3c0000(0000) knlGS:0000000000000000
[ 7.996049] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7.996049] CR2: 00007f58744b3a80 CR3: 0000000002009000 CR4: 00000000003406e0
[ 7.996049] Call Trace:
[ 7.996049] <IRQ>
[ 7.996049] __do_softirq+0xd6/0x2dc
[ 7.996049] irq_exit+0xaf/0xc0
[ 7.996049] smp_apic_timer_interrupt+0x6c/0x150
[ 7.996049] apic_timer_interrupt+0xf/0x20
[ 7.996049] </IRQ>
[ 7.996049] RIP: 0010:default_idle+0x25/0x140
[ 7.996049] Code: 90 90 90 90 90 0f 1f 44 00 00 48 83 ec 18 48 89 1c 24 48 89 6c 24 08 4c 89 64 24 10 65 8b 2d a2 98 93 7e 0f 1f 44 00 00 fb f4 <65> 8b 2d 94 98 93 7e 0f 1f 44 00 00 48 8b 1c 24 48 8b 6c 24 08 4c
[ 7.996049] RSP: 0018:ffffc900003bfed0 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
[ 7.996049] RAX: ffffffff816d5870 RBX: 0000000000000007 RCX: ffff88007d3d95c0
[ 7.996049] RDX: ffffffff82043af8 RSI: ffff88007d3d95c0 RDI: 00000001dc1f3500
[ 7.996049] RBP: 0000000000000007 R08: 0000000000001400 R09: 0000000000000000
[ 7.996049] R10: 0000000000001400 R11: 0000000000000001 R12: 0000000000000000
[ 7.996049] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
[ 7.996049] ? __sched_text_end+0x6/0x6
[ 7.996049] do_idle+0x18a/0x230
[ 7.996049] cpu_startup_entry+0x5f/0x70
[ 7.996049] start_secondary+0x189/0x1c0
[ 7.996049] secondary_startup_64+0xa5/0xb0
[ 7.996049] ---[ end trace 0d2f1accf0e2ed61 ]---
[ 10.612152] Adding 917500k swap on /dev/sda2. Priority:-2 extents:1 across:917500k
[ 10.631761] EXT4-fs (sda1): re-mounted. Opts: (null)
[ 11.505751] EXT4-fs (sda1): re-mounted. Opts: errors=remount-ro
[ 13.052771] random: dd: uninitialized urandom read (512 bytes read)
[ 13.822765] 8139cp 0000:00:03.0 eth0: link up, 100Mbps, full-duplex, lpa 0x05E1
[ 20.022242] random: dbus-daemon: uninitialized urandom read (12 bytes read)
[ 20.456262] random: dbus-daemon: uninitialized urandom read (12 bytes read)
[ 21.504397] random: exim4: uninitialized urandom read (120 bytes read)
[ 21.506713] random: exim4: uninitialized urandom read (120 bytes read)
[ 21.509112] random: exim4: uninitialized urandom read (120 bytes read)
[ 30.172294] random: crng init done
[ 30.173029] random: 4 urandom warning(s) missed due to ratelimiting

--
Regards/Gruss,
Boris.

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