On Mon, 13 Jun 2022 at 11:29, Ed Tsai <ed.tsai@xxxxxxxxxxxx> wrote:
>
> On Mon, 2022-06-13 at 16:45 +0800, Miklos Szeredi wrote:
> > On Fri, 10 Jun 2022 at 09:48, Ed Tsai <ed.tsai@xxxxxxxxxxxx> wrote:
> >
> > > Recently, we get this deadlock issue again.
> > > fuse_flush_time_update()
> > > use sync_inode_metadata() and it only write the metadata, so the
> > > writeback worker could still be blocked becaused of file data.
> > >
> > > I try to use write_inode_now() instead of sync_inode_metadata() and
> > > the
> > > writeback thread will not be blocked anymore. I don't think this is
> > > a
> > > good solution, but this confirm that there is still a potential
> > > deadlock because of file data. WDYT.
> >
> > I'm not sure how that happens. Normally writeback doesn't
> > block. Can
> > you provide the stack traces of all related tasks in the deadlock?
> >
> > Thanks,
> > Miklos
>
> The writeback worker
> ppid=22915 pid=22915 S cpu=6 prio=120 wait=3614s kworker/u16:21
> vmlinux request_wait_answer + 64
> vmlinux __fuse_request_send + 328
> vmlinux fuse_request_send + 60
> vmlinux fuse_simple_request + 376
> vmlinux fuse_flush_times + 276
> vmlinux fuse_write_inode + 104 (inode=0xFFFFFFD516CC4780, ff=0)
> vmlinux write_inode + 384
> vmlinux __writeback_single_inode + 960
> vmlinux writeback_sb_inodes + 892
> vmlinux __writeback_inodes_wb + 156
> vmlinux wb_writeback + 512
> vmlinux wb_check_background_flush + 600
> vmlinux wb_do_writeback + 644
> vmlinux wb_workfn + 756
> vmlinux process_one_work + 628
> vmlinux worker_thread + 708
> vmlinux kthread + 376
> vmlinux ret_from_fork + 16
>
> Thread-11
> ppid=3961 pid=26057 D cpu=4 prio=120 wait=3614s Thread-11
> vmlinux __inode_wait_for_writeback + 108
> vmlinux inode_wait_for_writeback + 156
> vmlinux evict + 160
> vmlinux iput_final + 292
> vmlinux iput + 600
> vmlinux dentry_unlink_inode + 212
> vmlinux __dentry_kill + 228
> vmlinux shrink_dentry_list + 408
> vmlinux prune_dcache_sb + 80
> vmlinux super_cache_scan + 272
> vmlinux do_shrink_slab + 944
> vmlinux shrink_slab + 1104
> vmlinux shrink_node + 712
> vmlinux shrink_zones + 188
> vmlinux do_try_to_free_pages + 348
> vmlinux try_to_free_pages + 848
> vmlinux __perform_reclaim + 64
> vmlinux __alloc_pages_direct_reclaim + 64
> vmlinux __alloc_pages_slowpath + 1296
> vmlinux __alloc_pages_nodemask + 2004
> vmlinux __alloc_pages + 16
> vmlinux __alloc_pages_node + 16
> vmlinux alloc_pages_node + 16
> vmlinux __read_swap_cache_async + 172
> vmlinux read_swap_cache_async + 12
> vmlinux swapin_readahead + 328
> vmlinux do_swap_page + 844
> vmlinux handle_pte_fault + 268
> vmlinux __handle_speculative_fault + 548
> vmlinux handle_speculative_fault + 44
> vmlinux do_page_fault + 500
> vmlinux do_translation_fault + 64
> vmlinux do_mem_abort + 72
> vmlinux el0_sync + 1032
>
> ppid=3961 is com.google.android.providers.media.module, and it is the
> android fuse daemon.
>
> So, the daemon and wb worker were wait for each other.
Is commit 5c791fe1e2a4 ("fuse: make sure reclaim doesn't write the
inode") applied to this kernel?
Thanks,
Miklos
