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BUG: KCSAN: data-race in dec_zone_page_state / release_pages

write to 0xffffea0004101100 of 8 bytes by task 6899 on cpu 0:
 instrument_write include/linux/instrumented.h:42 [inline]
 __clear_bit include/asm-generic/bitops/instrumented-non-atomic.h:42 [inline]
 __ClearPageLRU include/linux/page-flags.h:328 [inline]
 release_pages+0x402/0x8f0 mm/swap.c:899
 __pagevec_release+0x96/0xc0 mm/swap.c:933
 pagevec_release include/linux/pagevec.h:88 [inline]
 invalidate_mapping_pages+0x6c6/0x720 mm/truncate.c:620
 generic_fadvise+0x3c4/0x420 mm/fadvise.c:157
 vfs_fadvise mm/fadvise.c:185 [inline]
 ksys_fadvise64_64 mm/fadvise.c:199 [inline]
 __do_sys_fadvise64 mm/fadvise.c:214 [inline]
 __se_sys_fadvise64 mm/fadvise.c:212 [inline]
 __x64_sys_fadvise64+0xc5/0x100 mm/fadvise.c:212
 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffffea0004101100 of 8 bytes by task 3400 on cpu 1:
 page_to_nid include/linux/mm.h:1294 [inline]
 page_zone include/linux/mm.h:1436 [inline]
 dec_zone_page_state+0x13/0x110 mm/vmstat.c:542
 test_clear_page_writeback+0x3fb/0x480 mm/page-writeback.c:2765
 end_page_writeback+0xa7/0x110 mm/filemap.c:1467
 ext4_finish_bio+0x429/0x490 fs/ext4/page-io.c:146
 ext4_release_io_end+0x98/0x200 fs/ext4/page-io.c:161
 ext4_end_io_end fs/ext4/page-io.c:195 [inline]
 ext4_do_flush_completed_IO fs/ext4/page-io.c:260 [inline]
 ext4_end_io_rsv_work+0x306/0x360 fs/ext4/page-io.c:274
 process_one_work+0x3e1/0x9a0 kernel/workqueue.c:2269
 worker_thread+0x665/0xbe0 kernel/workqueue.c:2415
 kthread+0x20d/0x230 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3400 Comm: kworker/u4:4 Not tainted 5.9.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: ext4-rsv-conversion ext4_end_io_rsv_work
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