Comment 16 for bug 1440536

BTW, looks it isn't related with specific filesystem, and from the recent triger, it happened when
walking path inside proc filesystem:

[24993.562923] Call trace:
[24993.565357] [<ffffffc00022a278>] __d_lookup+0x88/0x194
[24993.570467] [<ffffffc00022a3bc>] d_lookup+0x38/0x64
[24993.575319] [<ffffffc00022a43c>] d_hash_and_lookup+0x54/0x6c
[24993.580948] [<ffffffc00027e1a4>] proc_flush_task+0xa8/0x1a8
[24993.586491] [<ffffffc0000b6920>] release_task+0x5c/0x46c
[24993.591774] [<ffffffc0000b6e70>] wait_task_zombie+0x140/0x67c
[24993.597489] [<ffffffc0000b7734>] wait_consider_task+0x388/0x670
[24993.603377] [<ffffffc0000b7b04>] do_wait+0xe8/0x234
[24993.608229] [<ffffffc0000b8cf4>] SyS_wait4+0x7c/0xe8

Also from the link in #15, looks it is still triggered on arm64 from the register information
in the log.

So it might be one arm64 dependent issue.