Re: [bcachefs] BUG: soft lockup - CPU#0 stuck for 22s! [bch_copygc_read:5328]

[Kent Overstreet <kent.overstreet@gmail.com>]

On Sat, Sep 03, 2016 at 11:29:49PM +0200, Marcin wrote:
> Hi!
> Kernel at commit c820493652e830dc050e1418301e1bdec5691a1e
> 
> I createt to devices, fast has size
> # blockdev --getsz /dev/sde1
> 20971520
> and slower device:
> # blockdev --getsz /dev/sdd1
> 2930209551
> 
> I was copying files from one disk to bcache, after some time I got:
>  BUG: soft lockup - CPU#0 stuck for 22s! [bch_copygc_read:5328]

Thanks for the report - can you run addr2line with your vmlinux file, and the
RIP?

addr2line -i -e vmlinux ffffffffc028795b

> 
> # cat /sys/fs/bcache/5ad3d751-cb40-4bb7-9546-3e5b48ccd3cf/cache0/dirty_bytes
> /sys/fs/bcache/5ad3d751-cb40-4bb7-9546-3e5b48ccd3cf/cache1/dirty_bytes
> 9269264384
> 2540163072
> 
> dmesg says:
> [ 9088.110001] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s!
> [bch_copygc_read:5328]
> [ 9088.110001] Modules linked in: bcache lz4_compress zlib_deflate libcrc32c
> lz4_decompress sha1_generic cpufreq_ondemand msr af_packet fuse pcrypt
> nf_nat_ftp nf_conntrack_ftp nf_nat nf_conntrack ipv6 coretemp hwmon
> kvm_intel kvm irqbypass i2c_i801 i2c_core sky2 hpsa acpi_cpufreq
> scsi_transport_sas processor button raid1 md_mod pata_jmicron ehci_pci
> ehci_hcd dm_mod
> [ 9088.110001] CPU: 0 PID: 5328 Comm: bch_copygc_read Not tainted 4.7.0+ #2
> [ 9088.110001] Hardware name: Gigabyte Technology Co., Ltd.
> 965P-DS3/965P-DS3, BIOS F14 06/25/2009
> [ 9088.110001] task: ffff88001b561a80 ti: ffff880002810000 task.ti:
> ffff880002810000
> [ 9088.110001] RIP: 0010:[<ffffffffc028795b>]  [<ffffffffc028795b>]
> bch_moving_gc+0xcb/0xd90 [bcache]
> [ 9088.110001] RSP: 0018:ffff880002813d20  EFLAGS: 00000287
> [ 9088.110001] RAX: ffffc900001f6e78 RBX: ffff8800102c5000 RCX:
> 000000000003c000
> [ 9088.110001] RDX: ffffc9000027f000 RSI: ffff8800102c5000 RDI:
> ffff8800102c5608
> [ 9088.110001] RBP: ffff880002813e40 R08: ffff880002813d90 R09:
> 0000000002000000
> [ 9088.110001] R10: 0000000000000bc6 R11: 0000000000064000 R12:
> ffff8800014d0000
> [ 9088.110001] R13: ffff8800102c5000 R14: 0000000000027800 R15:
> 0000000001b6c6e0
> [ 9088.110001] FS:  0000000000000000(0000) GS:ffff88003fc00000(0000)
> knlGS:0000000000000000
> [ 9088.110001] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 9088.110001] CR2: 000056048ce06f62 CR3: 000000003d0ce000 CR4:
> 00000000000006f0
> [ 9088.110001] Stack:
> [ 9088.110001]  0000000000015f00 0000000000015f00 ffffffff8107bd3f
> ffff8800102c5000
> [ 9088.110001]  ffff880002813de0 0000000000000000 ffff880002813e68
> ffff880002813e40
> [ 9088.110001]  0000000000000002 0000000000064000 ffff8800102c5608
> 000000000000000f
> [ 9088.110001] Call Trace:
> [ 9088.110001]  [<ffffffff8107bd3f>] ? sched_clock_cpu+0x7f/0xa0
> [ 9088.110001]  [<ffffffffc028878c>] bch_moving_gc_thread+0x16c/0x180
> [bcache]
> [ 9088.110001]  [<ffffffffc0288620>] ? bch_moving_gc+0xd90/0xd90 [bcache]
> [ 9088.110001]  [<ffffffff8106e874>] kthread+0xc4/0xe0
> [ 9088.110001]  [<ffffffff8146b0bf>] ret_from_fork+0x1f/0x40
> [ 9088.110001]  [<ffffffff8106e7b0>] ? kthread_worker_fn+0x150/0x150
> [ 9088.110001] Code: 00 48 8b 8b a8 02 00 00 48 8b 93 a8 05 00 00 48 8d 04
> 40 48 8d 0c 49 48 8d 04 82 48 8d 14 8a 48 39 d0 0f 83 7e 08 00 00 48 89 de
> <44> 8b 48 04 c6 40 09 00 45 85 c9 74 2e f7 40 04 01 00 01 00 75
> 
> 
> Compression wasn't turned on.
> 
> Marcin
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