syzbot

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BUG: KCSAN: data-race in dentry_lru_isolate / fsnotify_perm

write to 0xffff88811e058f00 of 4 bytes by task 1961 on cpu 0:
 d_lru_isolate fs/dcache.c:442 [inline]
 dentry_lru_isolate+0x9f/0x200 fs/dcache.c:1166
 __list_lru_walk_one+0xfb/0x320 mm/list_lru.c:222
 list_lru_walk_one+0x75/0x90 mm/list_lru.c:266
 list_lru_shrink_walk include/linux/list_lru.h:195 [inline]
 prune_dcache_sb+0x67/0xa0 fs/dcache.c:1220
 super_cache_scan+0x23b/0x2d0 fs/super.c:105
 do_shrink_slab+0x286/0x5c0 mm/vmscan.c:513
 shrink_slab+0xea/0x1c0 mm/vmscan.c:674
 shrink_node_memcgs+0x270/0x410 mm/vmscan.c:2653
 shrink_node+0x9ed/0x1230 mm/vmscan.c:2768
 shrink_zones+0x2af/0x490 mm/vmscan.c:2971
 do_try_to_free_pages+0x193/0x6e0 mm/vmscan.c:3026
 try_to_free_pages+0x38e/0x8b0 mm/vmscan.c:3265
 __perform_reclaim mm/page_alloc.c:4260 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4281 [inline]
 __alloc_pages_slowpath+0x55f/0x9e0 mm/page_alloc.c:4685
 __alloc_pages_nodemask+0x266/0x380 mm/page_alloc.c:4901
 __alloc_pages include/linux/gfp.h:509 [inline]
 __alloc_pages_node include/linux/gfp.h:522 [inline]
 khugepaged_alloc_page mm/khugepaged.c:867 [inline]
 collapse_file+0x124/0x21a0 mm/khugepaged.c:1627
 khugepaged_scan_file mm/khugepaged.c:2009 [inline]
 khugepaged_scan_mm_slot mm/khugepaged.c:2105 [inline]
 khugepaged_do_scan+0x1045/0x1440 mm/khugepaged.c:2191
 khugepaged+0x75/0x530 mm/khugepaged.c:2236
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

read to 0xffff88811e058f00 of 4 bytes by task 5086 on cpu 1:
 fsnotify_parent include/linux/fsnotify.h:60 [inline]
 fsnotify_file include/linux/fsnotify.h:90 [inline]
 fsnotify_perm+0x238/0x2d0 include/linux/fsnotify.h:115
 security_file_open+0x85/0x90 security/security.c:1578
 do_dentry_open+0x22d/0x890 fs/open.c:804
 vfs_open+0x43/0x50 fs/open.c:931
 do_open fs/namei.c:3251 [inline]
 path_openat+0x1844/0x20a0 fs/namei.c:3368
 do_filp_open+0xbd/0x1d0 fs/namei.c:3395
 do_sys_openat2+0x33b/0x500 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_open fs/open.c:1192 [inline]
 __se_sys_open fs/open.c:1188 [inline]
 __x64_sys_open+0xe2/0x110 fs/open.c:1188
 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: 1 PID: 5086 Comm: systemd-udevd Not tainted 5.9.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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