syzbot

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BUG: KCSAN: data-race in dentry_lru_isolate / fsnotify_parent

write to 0xffff88811e922480 of 4 bytes by task 1937 on cpu 1:
 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:518
 shrink_slab+0xea/0x1c0 mm/vmscan.c:679
 shrink_node_memcgs+0x1f9/0x360 mm/vmscan.c:2658
 shrink_node+0x94e/0x1170 mm/vmscan.c:2770
 shrink_zones+0x2af/0x490 mm/vmscan.c:2973
 do_try_to_free_pages+0x1b4/0x6c0 mm/vmscan.c:3026
 try_to_free_pages+0x38d/0x8d0 mm/vmscan.c:3265
 __perform_reclaim mm/page_alloc.c:4223 [inline]
 __alloc_pages_direct_reclaim mm/page_alloc.c:4244 [inline]
 __alloc_pages_slowpath+0x50a/0x970 mm/page_alloc.c:4650
 __alloc_pages_nodemask+0x235/0x390 mm/page_alloc.c:4863
 __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_huge_page+0x99/0x1680 mm/khugepaged.c:1056
 khugepaged_scan_pmd+0xdcd/0xf10 mm/khugepaged.c:1349
 khugepaged_scan_mm_slot mm/khugepaged.c:2110 [inline]
 khugepaged_do_scan+0x49f/0x1410 mm/khugepaged.c:2193
 khugepaged+0x75/0x670 mm/khugepaged.c:2238
 kthread+0x20d/0x230 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293

read to 0xffff88811e922480 of 4 bytes by task 5033 on cpu 0:
 fsnotify_parent+0x36/0x180 fs/notify/fsnotify.c:153
 fsnotify_file include/linux/fsnotify.h:74 [inline]
 fsnotify_close include/linux/fsnotify.h:281 [inline]
 __fput+0x104/0x460 fs/file_table.c:267
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:135
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop arch/x86/entry/common.c:239 [inline]
 __prepare_exit_to_usermode+0x1c6/0x230 arch/x86/entry/common.c:269
 __syscall_return_slowpath+0x47/0x60 arch/x86/entry/common.c:352
 do_syscall_64+0x5d/0xb0 arch/x86/entry/common.c:393
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5033 Comm: systemd-udevd Not tainted 5.8.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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