syzbot

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BUG: KCSAN: data-race in write_cache_pages / write_cache_pages

write to 0xffff8881027dc710 of 8 bytes by task 3421 on cpu 0:
 write_cache_pages+0x9ea/0xa30 mm/page-writeback.c:2385
 generic_writepages+0x7c/0xc0 mm/page-writeback.c:2425
 blkdev_writepages+0x19/0x20 block/fops.c:407
 do_writepages+0x1db/0x350 mm/page-writeback.c:2443
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0xbf/0x2e0 mm/filemap.c:673
 filemap_write_and_wait include/linux/pagemap.h:60 [inline]
 sync_blockdev+0x3e/0x50 block/bdev.c:199
 sync_filesystem+0x158/0x180 fs/sync.c:70
 __do_sys_syncfs fs/sync.c:160 [inline]
 __se_sys_syncfs+0x5f/0xe0 fs/sync.c:149
 __x64_sys_syncfs+0x1b/0x20 fs/sync.c:149
 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+0x63/0xcd

write to 0xffff8881027dc710 of 8 bytes by task 3418 on cpu 1:
 write_cache_pages+0x9ea/0xa30 mm/page-writeback.c:2385
 generic_writepages+0x7c/0xc0 mm/page-writeback.c:2425
 blkdev_writepages+0x19/0x20 block/fops.c:407
 do_writepages+0x1db/0x350 mm/page-writeback.c:2443
 filemap_fdatawrite_wbc+0xd6/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 filemap_write_and_wait_range+0xbf/0x2e0 mm/filemap.c:673
 filemap_write_and_wait include/linux/pagemap.h:60 [inline]
 sync_blockdev+0x3e/0x50 block/bdev.c:199
 sync_filesystem+0x158/0x180 fs/sync.c:70
 __do_sys_syncfs fs/sync.c:160 [inline]
 __se_sys_syncfs+0x5f/0xe0 fs/sync.c:149
 __x64_sys_syncfs+0x1b/0x20 fs/sync.c:149
 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+0x63/0xcd

value changed: 0x0000000000001903 -> 0x0000000000001901

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 3418 Comm: syz-executor.2 Not tainted 5.19.0-rc8-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/29/2022
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