syzbot

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BUG: KCSAN: data-race in link_path_walk / shrink_dentry_list

read-write to 0xffff888143e23780 of 4 bytes by task 3650 on cpu 0:
 d_shrink_del fs/dcache.c:448 [inline]
 shrink_dentry_list+0x16f/0x380 fs/dcache.c:1197
 prune_dcache_sb+0x72/0xa0 fs/dcache.c:1282
 super_cache_scan+0x24e/0x300 fs/super.c:104
 do_shrink_slab+0x2ad/0x600 mm/vmscan.c:774
 shrink_slab_memcg+0x1b9/0x440 mm/vmscan.c:843
 shrink_slab+0x5c/0x1c0 mm/vmscan.c:922
 shrink_node_memcgs+0x27a/0x400 mm/vmscan.c:3100
 shrink_node+0x8c3/0x1110 mm/vmscan.c:3221
 shrink_zones+0x2c1/0x5d0 mm/vmscan.c:3458
 do_try_to_free_pages+0x165/0x720 mm/vmscan.c:3516
 try_to_free_mem_cgroup_pages+0x1cd/0x420 mm/vmscan.c:3830
 reclaim_high+0xcd/0x110 mm/memcontrol.c:2325
 mem_cgroup_handle_over_high+0x75/0x120 mm/memcontrol.c:2509
 resume_user_mode_work include/linux/resume_user_mode.h:58 [inline]
 exit_to_user_mode_loop+0xa5/0x130 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0x69/0x90 kernel/entry/common.c:201
 irqentry_exit_to_user_mode+0x5/0x10 kernel/entry/common.c:307
 irqentry_exit+0xe/0x40 kernel/entry/common.c:408
 asm_exc_page_fault+0x1e/0x30

read to 0xffff888143e23780 of 4 bytes by task 3653 on cpu 1:
 link_path_walk+0x336/0x7a0 fs/namei.c:2309
 path_openat+0x199/0x1b30 fs/namei.c:3605
 do_filp_open+0x105/0x220 fs/namei.c:3636
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1213
 do_sys_open fs/open.c:1229 [inline]
 __do_sys_openat fs/open.c:1245 [inline]
 __se_sys_openat fs/open.c:1240 [inline]
 __x64_sys_openat+0xef/0x110 fs/open.c:1240
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x0028040c -> 0x0000800c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3653 Comm: syz-executor.0 Not tainted 5.18.0-rc6-syzkaller-00123-gf2dd007445b1-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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