hi,

With this new patch, xfstest/generic/475 and xfstest/generic/650 works well.

Thanks a lot.

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/10/23

On Fri, Oct 22, 2021 at 1:12 PM Wang Yugui [off-list ref] wrote:

quoted

Hi,

quoted

On Fri, Oct 22, 2021 at 6:59 AM Wang Yugui [off-list ref] wrote:

quoted

Hi,

I noticed a infinite loop of fstests/generic/475 when I apply this patch
and "[PATCH v9 00/17] gfs2: Fix mmap + page fault deadlocks"

You mean v8? I can't find v9 anywhere.

Yes. It is v8.

quoted

quoted

reproduce frequency: about 50%.

with v8, on top of current misc-next, I couldn't trigger any issues
after running g/475 for 50+ times.

quoted

Call Trace 1:
Oct 22 06:13:06 T7610 kernel: task:fsstress        state:R  running task     stack:    0 pid:2652125 ppid:     1 flags:0x00004006
Oct 22 06:13:06 T7610 kernel: Call Trace:
Oct 22 06:13:06 T7610 kernel: ? iomap_dio_rw+0xa/0x30
Oct 22 06:13:06 T7610 kernel: ? btrfs_file_read_iter+0x157/0x1c0 [btrfs]
Oct 22 06:13:06 T7610 kernel: ? new_sync_read+0x118/0x1a0
Oct 22 06:13:06 T7610 kernel: ? vfs_read+0xf1/0x190
Oct 22 06:13:06 T7610 kernel: ? ksys_read+0x59/0xd0
Oct 22 06:13:06 T7610 kernel: ? do_syscall_64+0x37/0x80
Oct 22 06:13:06 T7610 kernel: ? entry_SYSCALL_64_after_hwframe+0x44/0xae


Call Trace 2:
Oct 22 07:45:37 T7610 kernel: task:fsstress        state:R  running task     stack:    0 pid: 9584 ppid:     1 flags:0x00004006
Oct 22 07:45:37 T7610 kernel: Call Trace:
Oct 22 07:45:37 T7610 kernel: ? iomap_dio_complete+0x9e/0x140
Oct 22 07:45:37 T7610 kernel: ? btrfs_file_read_iter+0x124/0x1c0 [btrfs]
Oct 22 07:45:37 T7610 kernel: ? new_sync_read+0x118/0x1a0
Oct 22 07:45:37 T7610 kernel: ? vfs_read+0xf1/0x190
Oct 22 07:45:37 T7610 kernel: ? ksys_read+0x59/0xd0
Oct 22 07:45:37 T7610 kernel: ? do_syscall_64+0x37/0x80
Oct 22 07:45:37 T7610 kernel: ? entry_SYSCALL_64_after_hwframe+0x44/0xae

Are those the complete traces?
It looks like too little, and inexact (the prefix ?).

Yes. these are complete traces.  I do not know the reason of 'the prefix ?'

I run fstests/generic/475 2 times again.
- failed to reproduce on SSD/SAS
- sucessed to reproduce on SSD/NVMe

Then I gathered 'sysrq -t' for 3 times.

[  909.099550] task:fsstress        state:R  running task     stack:    0 pid: 9269 ppid:     1 flags:0x00004006
[  909.100594] Call Trace:
[  909.101633]  ? __clear_user+0x40/0x70
[  909.102675]  ? lock_release+0x1c6/0x270
[  909.103717]  ? alloc_extent_state+0xc1/0x190 [btrfs]
[  909.104822]  ? fixup_exception+0x41/0x60
[  909.105881]  ? rcu_read_lock_held_common+0xe/0x40
[  909.106924]  ? rcu_read_lock_sched_held+0x23/0x80
[  909.107947]  ? rcu_read_lock_sched_held+0x23/0x80
[  909.108966]  ? slab_post_alloc_hook+0x50/0x340
[  909.109993]  ? trace_hardirqs_on+0x1a/0xd0
[  909.111039]  ? lock_extent_bits+0x64/0x90 [btrfs]
[  909.112202]  ? __clear_extent_bit+0x37a/0x530 [btrfs]
[  909.113366]  ? filemap_write_and_wait_range+0x87/0xd0
[  909.114455]  ? clear_extent_bit+0x15/0x20 [btrfs]
[  909.115628]  ? __iomap_dio_rw+0x284/0x830
[  909.116741]  ? find_vma+0x32/0xb0
[  909.117868]  ? __get_user_pages+0xba/0x740
[  909.118971]  ? iomap_dio_rw+0xa/0x30
[  909.120069]  ? btrfs_file_read_iter+0x157/0x1c0 [btrfs]
[  909.121219]  ? new_sync_read+0x11b/0x1b0
[  909.122301]  ? vfs_read+0xf7/0x190
[  909.123373]  ? ksys_read+0x5f/0xe0
[  909.124451]  ? do_syscall_64+0x37/0x80
[  909.125556]  ? entry_SYSCALL_64_after_hwframe+0x44/0xae

[ 1066.293028] task:fsstress        state:R  running task     stack:    0 pid: 9269 ppid:     1 flags:0x00004006
[ 1066.294069] Call Trace:
[ 1066.295111]  ? btrfs_file_read_iter+0x157/0x1c0 [btrfs]
[ 1066.296213]  ? new_sync_read+0x11b/0x1b0
[ 1066.297268]  ? vfs_read+0xf7/0x190
[ 1066.298314]  ? ksys_read+0x5f/0xe0
[ 1066.299359]  ? do_syscall_64+0x37/0x80
[ 1066.300394]  ? entry_SYSCALL_64_after_hwframe+0x44/0xae


[ 1201.027178] task:fsstress        state:R  running task     stack:    0 pid: 9269 ppid:     1 flags:0x00004006
[ 1201.028233] Call Trace:
[ 1201.029298]  ? iomap_dio_rw+0xa/0x30
[ 1201.030352]  ? btrfs_file_read_iter+0x157/0x1c0 [btrfs]
[ 1201.031465]  ? new_sync_read+0x11b/0x1b0
[ 1201.032534]  ? vfs_read+0xf7/0x190
[ 1201.033592]  ? ksys_read+0x5f/0xe0
[ 1201.034633]  ? do_syscall_64+0x37/0x80
[ 1201.035661]  ? entry_SYSCALL_64_after_hwframe+0x44/0xae

By the way, I enable ' -O no-holes -R free-space-tree' for mkfs.btrfs by
default.

Those mkfs options/fs features should be irrelevant.

Can you try with the attached patch applied on top of those patches?

Thanks.

quoted

quoted

quoted

We noticed some  error in dmesg before this infinite loop.
[15590.720909] BTRFS: error (device dm-0) in __btrfs_free_extent:3069: errno=-5 IO failure
[15590.723014] BTRFS info (device dm-0): forced readonly
[15590.725115] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2150: errno=-5 IO failure

Yes, that's expected, the test intentionally triggers simulated IO
failures, which can happen anywhere, not just when running delayed
references.

Best Regards
Wang Yugui (wangyugui@e16-tech.com)
2021/10/22