syzbot

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BUG: KCSAN: data-race in link_path_walk / shrink_dentry_list

read-write to 0xffff88810ad80840 of 4 bytes by task 27842 on cpu 0:
 d_shrink_del fs/dcache.c:448 [inline]
 shrink_dentry_list+0x169/0x380 fs/dcache.c:1197
 prune_dcache_sb+0x81/0xb0 fs/dcache.c:1282
 super_cache_scan+0x26c/0x310 fs/super.c:104
 do_shrink_slab+0x2a0/0x640 mm/vmscan.c:843
 shrink_slab_memcg mm/vmscan.c:912 [inline]
 shrink_slab+0x2bc/0x520 mm/vmscan.c:991
 shrink_node_memcgs mm/vmscan.c:6143 [inline]
 shrink_node+0xaf5/0x14f0 mm/vmscan.c:6172
 shrink_zones mm/vmscan.c:6410 [inline]
 do_try_to_free_pages+0x40d/0xc80 mm/vmscan.c:6472
 try_to_free_mem_cgroup_pages+0x1e2/0x480 mm/vmscan.c:6787
 reclaim_high+0xca/0x110 mm/memcontrol.c:2393
 mem_cgroup_handle_over_high+0x8c/0x1a0 mm/memcontrol.c:2578
 resume_user_mode_work include/linux/resume_user_mode.h:58 [inline]
 exit_to_user_mode_loop+0x99/0xe0 kernel/entry/common.c:171
 exit_to_user_mode_prepare+0x6a/0xa0 kernel/entry/common.c:203
 __syscall_exit_to_user_mode_work kernel/entry/common.c:285 [inline]
 syscall_exit_to_user_mode+0x26/0x140 kernel/entry/common.c:296
 do_syscall_64+0x4d/0xc0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffff88810ad80840 of 4 bytes by task 27847 on cpu 1:
 __d_entry_type include/linux/dcache.h:385 [inline]
 d_can_lookup include/linux/dcache.h:400 [inline]
 link_path_walk+0x50e/0x860 fs/namei.c:2330
 path_openat+0x19c/0x1b70 fs/namei.c:3710
 do_filp_open+0xf6/0x200 fs/namei.c:3741
 do_sys_openat2+0xb5/0x2a0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0xf3/0x120 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0028040c -> 0x0000800c

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 27847 Comm: syz-executor.3 Tainted: G        W          6.2.0-rc7-syzkaller-00213-g47e9aa14ce5a-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/21/2023
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