syzbot

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BUG: KCSAN: data-race in d_alloc_parallel / d_set_d_op

write to 0xffff888125090f00 of 4 bytes by task 22508 on cpu 1:
 d_set_d_op+0x10f/0x220 fs/dcache.c:1871
 proc_pid_instantiate+0xf3/0x120 fs/proc/base.c:3337
 proc_fill_cache+0x18e/0x220 fs/proc/base.c:2042
 proc_pid_readdir+0x324/0x410 fs/proc/base.c:3446
 proc_root_readdir+0x7a/0x90 fs/proc/root.c:336
 iterate_dir+0x16e/0x370 fs/readdir.c:65
 __do_sys_getdents fs/readdir.c:283 [inline]
 __se_sys_getdents+0x7f/0x190 fs/readdir.c:268
 __x64_sys_getdents+0x3f/0x50 fs/readdir.c:268
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff888125090f00 of 4 bytes by task 22507 on cpu 0:
 d_in_lookup include/linux/dcache.h:362 [inline]
 d_wait_lookup fs/dcache.c:2521 [inline]
 d_alloc_parallel+0x5f8/0xd10 fs/dcache.c:2609
 proc_fill_cache+0x134/0x220 fs/proc/base.c:2037
 proc_pid_readdir+0x324/0x410 fs/proc/base.c:3446
 proc_root_readdir+0x7a/0x90 fs/proc/root.c:336
 iterate_dir+0x16e/0x370 fs/readdir.c:65
 __do_sys_getdents fs/readdir.c:283 [inline]
 __se_sys_getdents+0x7f/0x190 fs/readdir.c:268
 __x64_sys_getdents+0x3f/0x50 fs/readdir.c:268
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 22507 Comm: syz-executor.0 Not tainted 5.9.0-rc2-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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