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BUG: KCSAN: data-race in delete_from_page_cache_batch / page_mapping

read to 0xffffea00047f0298 of 8 bytes by task 8140 on cpu 0:
 page_mapping+0x185/0x2a0 mm/util.c:675
 page_evictable+0x3a/0x110 mm/vmscan.c:4313
 move_pages_to_lru+0xed/0xa40 mm/vmscan.c:1855
 shrink_inactive_list+0x4c7/0x920 mm/vmscan.c:1971
 shrink_list mm/vmscan.c:2178 [inline]
 shrink_lruvec+0x4c8/0xd20 mm/vmscan.c:2496
 shrink_node_memcgs mm/vmscan.c:2685 [inline]
 shrink_node+0x2fe/0xfe0 mm/vmscan.c:2791
 shrink_zones mm/vmscan.c:2996 [inline]
 do_try_to_free_pages+0x245/0xb60 mm/vmscan.c:3049
 try_to_free_mem_cgroup_pages+0x205/0x4d0 mm/vmscan.c:3371
 reclaim_high.constprop.0+0xf7/0x140 mm/memcontrol.c:2232
 mem_cgroup_handle_over_high+0x96/0x180 mm/memcontrol.c:2313
 tracehook_notify_resume include/linux/tracehook.h:197 [inline]
 exit_to_usermode_loop+0x20c/0x2c0 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:278 [inline]
 do_syscall_64+0x384/0x3a0 arch/x86/entry/common.c:304
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

write to 0xffffea00047f0298 of 8 bytes by task 8141 on cpu 1:
 page_cache_delete_batch mm/filemap.c:326 [inline]
 delete_from_page_cache_batch+0x674/0x790 mm/filemap.c:357
 truncate_inode_pages_range+0x593/0x1120 mm/truncate.c:366
 truncate_inode_pages mm/truncate.c:476 [inline]
 truncate_pagecache+0x60/0x80 mm/truncate.c:817
 ext4_setattr+0xbd6/0x1670 fs/ext4/inode.c:5327
 notify_change+0x7e1/0xaa0 fs/attr.c:337
 do_truncate+0xfb/0x180 fs/open.c:64
 do_sys_ftruncate+0x30f/0x340 fs/open.c:195
 __do_sys_ftruncate fs/open.c:205 [inline]
 __se_sys_ftruncate fs/open.c:203 [inline]
 __x64_sys_ftruncate+0x3f/0x50 fs/open.c:203
 do_syscall_64+0xcc/0x3a0 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 8141 Comm: syz-executor.1 Not tainted 5.5.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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