On Fri, Jun 02, 2017 at 02:04:57PM +0800, Eryu Guan wrote:
> Hi all,
>
> Starting from 4.12-rc1 kernel, I saw Linux nfs server crashes all the
> time in my fstests (xfstests) runs, I appended the console log of an
> NFSv3 crash to the end of this mail.
>
> I was exporting a directory resided on XFS, and loopback mounted the NFS
> export on localhost. Both NFSv3 and NFSv4 could hit this crash. The
> crash usually happens when running test case generic/029 or generic/095.
>
> But the problem is, there's no easy and efficient way to reproduce it, I
> tried run only generic/029 and generic/095 in a loop for 1000 times but
> failed, I also tried run the 'quick' group tests only for 50 iterations
> but failed again. It seems that the only reliable way to reproduce it is
> run the 'auto' group tests for 20 iterations.
>
> i=0
> while [ $i -lt 20 ]; do
> ./check -nfs -g auto
> ((i++))
> done
>
> And usually server crashed within 5 iterations, but at times it could
> survive 10 iterations and only crashed if you left it running for more
> iterations. This makes it hard to bisect and bisecting is very
> time-consuming.
>
> (The bisecting is running now, it needs a few days to finish. My first
> two attempts pointed first bad commit to some mm patches, but reverting
> that patch didn't prevent server from crashing, so I enlarged the loop
> count and started bisecting for the third time).
>
> If more info is needed please let me know.
>
> Thanks,
> Eryu
>
>
> [88895.796834] run fstests generic/028 at 2017-06-01 00:43:18
> [88900.945420] run fstests generic/029 at 2017-06-01 00:43:23
> [88901.127315] BUG: unable to handle kernel paging request at ffffffffc0360e12
> [88901.135095] IP: report_bug+0x64/0x100
> [88901.139177] PGD 3b7c0c067
> [88901.139177] P4D 3b7c0c067
> [88901.142194] PUD 3b7c0e067
> [88901.145209] PMD 469e33067
> [88901.148225] PTE 80000004675f4161
> [88901.151240]
> [88901.156497] Oops: 0003 [#1] SMP
> [88901.159997] Modules linked in: loop dm_mod nfsv3 nfs fscache ext4 jbd2 mbcache intel_rapl sb_edac x86_pkg_temp_thermal intel_powerclamp coretemp kvm_intel kvm nfsd irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc ipmi_ssif cdc_ether aesni_intel iTCO_wdt usbnet crypto_simd ipmi_si glue_helper sg iTCO_vendor_support wmi mii cryptd ipmi_devintf ipmi_msghandler auth_rpcgss shpchp i2c_i801 pcspkr ioatdma lpc_ich nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c sd_mod mgag200 drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops igb ttm drm ptp pps_core dca megaraid_sas crc32c_intel i2c_algo_bit i2c_core
> [88901.221606] CPU: 9 PID: 3278 Comm: nfsd Not tainted 4.12.0-rc3 #42
> [88901.228500] Hardware name: IBM System x3650 M4 -[7915ON3]-/00J6520, BIOS -[VVE124AUS-1.30]- 11/21/2012
> [88901.238885] task: ffffa10062d12d00 task.stack: ffffc2820478c000
> [88901.245488] RIP: 0010:report_bug+0x64/0x100
> [88901.250153] RSP: 0018:ffffc2820478f598 EFLAGS: 00010202
> [88901.255980] RAX: ffffffffc0360e08 RBX: ffffffffc0301cdc RCX: 0000000000000001
> [88901.263940] RDX: 0000000000000907 RSI: ffffffffc038bc80 RDI: ffffffffffff0d22
> [88901.271901] RBP: ffffc2820478f5b8 R08: 0000000000000001 R09: 00000000000001cc
> [88901.279861] R10: ffffffffb6a36f67 R11: 0000000000000000 R12: ffffc2820478f6e8
> [88901.287821] R13: ffffffffc0351b2a R14: 00000000000003fb R15: 0000000000000004
> [88901.295783] FS: 0000000000000000(0000) GS:ffffa1007f6c0000(0000) knlGS:0000000000000000
> [88901.304818] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [88901.311227] CR2: ffffffffc0360e12 CR3: 00000003b7c09000 CR4: 00000000000406e0
> [88901.319188] Call Trace:
> [88901.321920] do_trap+0x16a/0x190
> [88901.325519] do_error_trap+0x89/0x110
> [88901.329652] ? xfs_do_writepage+0x65c/0x680 [xfs]
Hmm, does gdb think this address is at:
(gdb) l *(xfs_do_writepage+0x65c)
0x7c17c is in xfs_do_writepage (/storage/home/djwong/cdev/work/linux-xfs/include/linux/highmem.h:77).
like my system? That location is preempt_disable() in kunmap_atomic(),
which is ... odd. I tried to run your reproducer script but smashed
into this instead:
[ 826.735882] ============================================
[ 826.736952] WARNING: possible recursive locking detected
[ 826.737992] 4.12.0-rc4-xfsx #7 Not tainted
[ 826.738636] --------------------------------------------
[ 826.739700] nfsd/1416 is trying to acquire lock:
[ 826.740423] (&stp->st_mutex){+.+.+.}, at: [<ffffffffa004cda6>] nfsd4_process_open2+0x4f6/0x1360 [nfsd]
[ 826.741749]
[ 826.741749] but task is already holding lock:
[ 826.742897] (&stp->st_mutex){+.+.+.}, at: [<ffffffffa004cd3f>] nfsd4_process_open2+0x48f/0x1360 [nfsd]
[ 826.744211]
[ 826.744211] other info that might help us debug this:
[ 826.745262] Possible unsafe locking scenario:
[ 826.745262]
[ 826.746203] CPU0
[ 826.746651] ----
[ 826.747071] lock(&stp->st_mutex);
[ 826.747795] lock(&stp->st_mutex);
[ 826.748392]
[ 826.748392] *** DEADLOCK ***
[ 826.748392]
[ 826.749577] May be due to missing lock nesting notation
[ 826.749577]
[ 826.750912] 1 lock held by nfsd/1416:
[ 826.751570] #0: (&stp->st_mutex){+.+.+.}, at: [<ffffffffa004cd3f>] nfsd4_process_open2+0x48f/0x1360 [nfsd]
[ 826.753350]
[ 826.753350] stack backtrace:
[ 826.754122] CPU: 3 PID: 1416 Comm: nfsd Not tainted 4.12.0-rc4-xfsx #7
[ 826.755258] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
[ 826.756856] Call Trace:
[ 826.757381] dump_stack+0x85/0xc7
[ 826.758029] __lock_acquire+0x1567/0x15c0
[ 826.758771] ? kvm_clock_read+0x23/0x40
[ 826.759423] lock_acquire+0xac/0x200
[ 826.760014] ? lock_acquire+0xac/0x200
[ 826.760665] ? nfsd4_process_open2+0x4f6/0x1360 [nfsd]
[ 826.761618] ? nfsd4_process_open2+0x4f6/0x1360 [nfsd]
[ 826.762549] __mutex_lock+0x75/0x9c0
[ 826.763160] ? nfsd4_process_open2+0x4f6/0x1360 [nfsd]
[ 826.763995] ? nfsd4_process_open2+0x4e1/0x1360 [nfsd]
[ 826.764836] ? nfsd4_process_open2+0x4e1/0x1360 [nfsd]
[ 826.765675] mutex_lock_nested+0x1b/0x20
[ 826.766334] ? _raw_spin_unlock+0x31/0x50
[ 826.767014] ? mutex_lock_nested+0x1b/0x20
[ 826.767690] nfsd4_process_open2+0x4f6/0x1360 [nfsd]
[ 826.768561] nfsd4_open+0x574/0x830 [nfsd]
[ 826.769248] ? nfsd4_open+0x574/0x830 [nfsd]
[ 826.769991] nfsd4_proc_compound+0x31b/0x620 [nfsd]
[ 826.770796] nfsd_dispatch+0xc8/0x260 [nfsd]
[ 826.771547] svc_process_common+0x351/0x690
[ 826.772270] svc_process+0x11f/0x380
[ 826.772879] nfsd+0x176/0x280 [nfsd]
[ 826.773539] kthread+0x117/0x150
[ 826.774124] ? nfsd_destroy+0x180/0x180 [nfsd]
[ 826.774969] ? kthread_create_on_node+0x40/0x40
[ 826.775889] ret_from_fork+0x2a/0x40
[ 826.778354] NFS: nfs4_reclaim_open_state: Lock reclaim failed!
After which the NFS mounts were all wedged up and wouldn't unmount.
<shrug>
--D
> [88901.334917] ? _xfs_buf_find+0x2a2/0x510 [xfs]
> [88901.339875] ? kmem_cache_alloc+0x194/0x1a0
> [88901.344561] ? kmem_zone_alloc+0x96/0x100 [xfs]
> [88901.349615] do_invalid_op+0x20/0x30
> [88901.353604] invalid_op+0x1e/0x30
> [88901.357318] RIP: 0010:xfs_do_writepage+0x65c/0x680 [xfs]
> [88901.363242] RSP: 0018:ffffc2820478f790 EFLAGS: 00010206
> [88901.369069] RAX: 0000000000340140 RBX: ffffc2820478f8b8 RCX: 0000000000000000
> [88901.377030] RDX: 0000000000000000 RSI: ffffc2820478f9f8 RDI: fffffc2be1095400
> [88901.384991] RBP: ffffc2820478f838 R08: 0000000000000002 R09: 000000000001ff20
> [88901.392950] R10: ffffa1007ffd1d00 R11: 0000000000000000 R12: ffffa10053c2ea58
> [88901.400911] R13: fffffc2be1095400 R14: ffffc2820478f960 R15: ffffc2820478f9f8
> [88901.408876] ? page_mkclean+0x69/0xb0
> [88901.412960] ? invalid_page_referenced_vma+0x90/0x90
> [88901.418500] write_cache_pages+0x26f/0x510
> [88901.423085] ? xfs_vm_set_page_dirty+0x1d0/0x1d0 [xfs]
> [88901.428819] ? block_write_end+0x36/0x80
> [88901.433193] ? generic_write_end+0x54/0xc0
> [88901.437791] xfs_vm_writepages+0xb6/0xd0 [xfs]
> [88901.442741] do_writepages+0x1c/0x70
> [88901.446727] __filemap_fdatawrite_range+0xc6/0x100
> [88901.452071] filemap_write_and_wait_range+0x41/0x90
> [88901.457532] xfs_file_fsync+0x63/0x1d0 [xfs]
> [88901.462294] vfs_fsync_range+0x3d/0xb0
> [88901.466491] xfs_file_write_iter+0x121/0x140 [xfs]
> [88901.471835] __do_readv_writev+0x2d3/0x360
> [88901.476402] do_readv_writev+0x76/0xb0
> [88901.480582] ? do_dentry_open+0x261/0x310
> [88901.485069] ? xfs_extent_busy_ag_cmp+0x20/0x20 [xfs]
> [88901.490704] vfs_writev+0x3c/0x50
> [88901.494409] nfsd_vfs_write+0xd0/0x360 [nfsd]
> [88901.499271] ? ima_file_check+0x20/0x30
> [88901.503553] nfsd_write+0x15a/0x210 [nfsd]
> [88901.508116] nfsd3_proc_write+0x9d/0x130 [nfsd]
> [88901.513172] nfsd_dispatch+0xce/0x270 [nfsd]
> [88901.517950] svc_process_common+0x387/0x740 [sunrpc]
> [88901.523492] svc_process+0xfc/0x1c0 [sunrpc]
> [88901.528248] nfsd+0xe9/0x160 [nfsd]
> [88901.532137] kthread+0x109/0x140
> [88901.535740] ? nfsd_destroy+0x60/0x60 [nfsd]
> [88901.540501] ? kthread_park+0x60/0x60
> [88901.544586] ret_from_fork+0x25/0x30
> [88901.548572] Code: 63 78 04 44 0f b7 70 08 41 89 d0 4c 8d 2c 38 41 83 e0 01 f6 c2 02 74 17 66 45 85 c0 74 11 f6 c2 04 b9 01 00 00 00 75 bb 83 ca 04 <66> 89 50 0a 66 45 85 c0 74 52 0f b6 48 0b 41 0f b7 f6 4d 89 e0
> [88901.569642] RIP: report_bug+0x64/0x100 RSP: ffffc2820478f598
> [88901.575955] CR2: ffffffffc0360e12
> [88901.579663] ---[ end trace 62c63b9fb594e7f4 ]---
> [88901.584811] Kernel panic - not syncing: Fatal exception
> [88901.590694] Kernel Offset: 0x35000000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
> [88901.602731] Rebooting in 3 seconds..
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