Issue 5:
Race between close_ctree() and casualty_kthread():
close_ctree():
if (fs_info->casualty_kthread)
kthread_stop(fs_info->casualty_kthread);
casualty_kthread():
out:
fs_info->casualty_kthread = NULL;
At SMP system, kthread_stop() argument can be changed to NULL after
check in if (). Some kind of synchronization is needed.
Oops:
[48878.674314] BUG: unable to handle kernel paging request at 0000000000001347
[48878.686252] IP: [<ffffffff810a73a4>] kthread_stop+0x54/0x280
[48878.687530] PGD 5f2c6067 PUD 62c63067 PMD 0
[48878.688780] Oops: 0002 [#1] SMP
[48878.689701] Modules linked in: cpuid cpufreq_powersave
cpufreq_stats cpufreq_userspace cpufreq_conservative softdog nfsd
auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc
ipmi_devintf ipmi_msghandler iosf_mbi crct10dif_pclmul crc32_pclmul
sha256_ssse3 sha256_generic hmac drbg ansi_cprng iTCO_wdt
iTCO_vendor_support snd_pcm snd_timer snd soundcore aesni_intel
aes_x86_64 lrw gf128mul glue_helper ablk_helper lpc_ich cryptd
mfd_core psmouse serio_raw 8250_fintek parport_pc evdev parport video
pcspkr ac battery acpi_cpufreq tpm_tis tpm processor i2c_piix4
rng_core button btrfs xor raid6_pq dm_mod raid1 md_mod sg sd_mod ahci
libahci libata pcnet32 crc32c_intel scsi_mod mii
[48879.282797] CPU: 1 PID: 24369 Comm: umount Not tainted 4.4.5-scst31x+ #16
[48879.283976] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS
VirtualBox 12/01/2006
[48879.285532] task: ffff880036438440 ti: ffff88006242c000 task.ti:
ffff88006242c000
[48879.288022] RIP: 0010:[<ffffffff810a73a4>] [<ffffffff810a73a4>]
kthread_stop+0x54/0x280
[48879.289681] RSP: 0018:ffff88006242fd78 EFLAGS: 00010206
[48879.290678] RAX: 0000000000000001 RBX: 00000000000013af RCX: 0000000000000003
[48879.291889] RDX: 0000000000000000 RSI: 0000000000001347 RDI: 0000000000000246
[48879.293096] RBP: ffff88006242fd90 R08: ffff88006242fd38 R09: 0000000000000000
[48879.449616] R10: 0000000000000000 R11: 0000000000000000 R12: ffff88002642e840
[48879.494970] R13: ffff880036438440 R14: 0000000000000000 R15: ffff880048b7f000
[48879.496219] FS: 00007f95236c27e0(0000) GS:ffff880066b00000(0000)
knlGS:0000000000000000
[48879.497767] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[48879.498806] CR2: 0000000000001347 CR3: 000000005ed74000 CR4: 00000000000406e0
[48879.500027] Stack:
[48879.500603] ffff880027f4a2d0 ffff880027f48000 ffff880036438440
ffff88006242fdf0
[48879.502516] ffffffffa016713d ffff88006242fe00 ffffffff81239ff5
ffff880039cf2000
[48879.505658] ffff880039cf2a40 ffff880062430000 ffff880039cf2000
ffffffffa01edae0
[48879.507584] Call Trace:
[48879.508239] [<ffffffffa016713d>] close_ctree+0x13d/0x390 [btrfs]
[48879.509328] [<ffffffff81239ff5>] ? evict_inodes+0x165/0x180
[48879.510360] [<ffffffffa0135f99>] btrfs_put_super+0x19/0x20 [btrfs]
[48879.511467] [<ffffffff8121d0ff>] generic_shutdown_super+0x6f/0xf0
[48879.512570] [<ffffffff8121d3f2>] kill_anon_super+0x12/0x20
[48879.594205] [<ffffffffa0136a88>] btrfs_kill_super+0x18/0x120 [btrfs]
[48879.714563] [<ffffffff8121d66e>] deactivate_locked_super+0x3e/0x70
[48879.715691] [<ffffffff8121dabc>] deactivate_super+0x5c/0x60
[48879.716720] [<ffffffff8123e07f>] cleanup_mnt+0x3f/0x90
[48879.717695] [<ffffffff8123e112>] __cleanup_mnt+0x12/0x20
[48879.718695] [<ffffffff810a5423>] task_work_run+0x73/0xa0
[48879.719692] [<ffffffff810032ac>] exit_to_usermode_loop+0xcc/0xd0
[48879.720773] [<ffffffff81003e0c>] syscall_return_slowpath+0xcc/0xe0
[48879.721880] [<ffffffff81634022>] int_ret_from_sys_call+0x25/0x9f
[48879.722962] Code: 85 c0 0f 85 90 01 00 00 65 ff 0d 48 4b f6 7e f0
41 ff 44 24 10 49 8b 9c 24 38 04 00 00 48 85 db 74 26 48 89 de 48 83
ee 68 74 1d <f0> 80 4b 98 02 4c 89 e7 e8 ff fe ff ff 4c 89 e7 e8 a7 ca
00 00
[48879.891283] RIP [<ffffffff810a73a4>] kthread_stop+0x54/0x280
[48880.019550] RSP <ffff88006242fd78>
[48880.091281] CR2: 0000000000001347
[48880.133312] ---[ end trace 8f0228d92754702e ]---
--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
