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BUG: KCSAN: data-race in ext4_ext_insert_extent / ext4_mark_iloc_dirty

write to 0xffff8881725a9092 of 2 bytes by task 28696 on cpu 1:
 ext4_ext_store_pblock fs/ext4/ext4_extents.h:257 [inline]
 ext4_ext_insert_extent+0x1b1d/0x2d90 fs/ext4/extents.c:2124
 ext4_ext_map_blocks+0x1714/0x1ff0 fs/ext4/extents.c:4271
 ext4_map_blocks+0x71e/0xf00 fs/ext4/inode.c:637
 mpage_map_one_extent+0x10d/0x360 fs/ext4/inode.c:2401
 mpage_map_and_submit_extent fs/ext4/inode.c:2454 [inline]
 ext4_writepages+0xc5a/0x1d70 fs/ext4/inode.c:2806
 do_writepages+0x26b/0x3c0 mm/page-writeback.c:2364
 __writeback_single_inode+0x80/0x440 fs/fs-writeback.c:1616
 writeback_sb_inodes+0x563/0xd30 fs/fs-writeback.c:1881
 __writeback_inodes_wb fs/fs-writeback.c:1950 [inline]
 wb_writeback+0x31f/0x6d0 fs/fs-writeback.c:2055
 wb_check_start_all fs/fs-writeback.c:2177 [inline]
 wb_do_writeback+0x33f/0x530 fs/fs-writeback.c:2203
 wb_workfn+0xc8/0x540 fs/fs-writeback.c:2237
 process_one_work+0x402/0x910 kernel/workqueue.c:2297
 worker_thread+0x636/0xae0 kernel/workqueue.c:2444
 kthread+0x262/0x280 kernel/kthread.c:319
 ret_from_fork+0x1f/0x30

read to 0xffff8881725a9090 of 4 bytes by task 5713 on cpu 0:
 ext4_do_update_inode fs/ext4/inode.c:5117 [inline]
 ext4_mark_iloc_dirty+0xcc8/0x1700 fs/ext4/inode.c:5741
 __ext4_mark_inode_dirty+0x4ec/0x5c0 fs/ext4/inode.c:5937
 ext4_dirty_inode+0x86/0xa0 fs/ext4/inode.c:5966
 __mark_inode_dirty+0x77/0x6a0 fs/fs-writeback.c:2398
 mark_inode_dirty include/linux/fs.h:2452 [inline]
 generic_write_end+0x157/0x180 fs/buffer.c:2202
 ext4_da_write_end+0x59b/0x730 fs/ext4/inode.c:3116
 generic_perform_write+0x251/0x3e0 mm/filemap.c:3781
 ext4_buffered_write_iter+0x305/0x400 fs/ext4/file.c:269
 ext4_file_write_iter+0x2e7/0x11f0
 call_write_iter include/linux/fs.h:2163 [inline]
 new_sync_write fs/read_write.c:507 [inline]
 vfs_write+0x7bc/0x900 fs/read_write.c:594
 ksys_write+0xd9/0x190 fs/read_write.c:647
 __do_sys_write fs/read_write.c:659 [inline]
 __se_sys_write fs/read_write.c:656 [inline]
 __x64_sys_write+0x3e/0x50 fs/read_write.c:656
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x44/0xa0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000 -> 0x00008108

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 5713 Comm: syz-executor.4 Not tainted 5.15.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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