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BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

write to 0xffff888102893140 of 8 bytes by interrupt on cpu 1:
 percpu_counter_add_batch+0x9c/0xd0 lib/percpu_counter.c:91
 __add_wb_stat include/linux/backing-dev.h:70 [inline]
 inc_wb_stat include/linux/backing-dev.h:75 [inline]
 __wb_writeout_inc mm/page-writeback.c:592 [inline]
 test_clear_page_writeback+0x37c/0x600 mm/page-writeback.c:2789
 end_page_writeback+0xd7/0x1b0 mm/filemap.c:1603
 ext4_finish_bio+0x3e2/0x430 fs/ext4/page-io.c:143
 ext4_end_bio+0x1bc/0x310
 bio_endio+0x2e4/0x310 block/bio.c:1494
 req_bio_endio block/blk-core.c:261 [inline]
 blk_update_request+0x435/0xa40 block/blk-core.c:1425
 scsi_end_request+0x4b/0x440 drivers/scsi/scsi_lib.c:542
 scsi_io_completion+0xd0/0x10c0 drivers/scsi/scsi_lib.c:938
 scsi_finish_command+0x1ba/0x1d0 drivers/scsi/scsi.c:207
 scsi_complete+0x1aa/0x1e0 drivers/scsi/scsi_lib.c:1432
 blk_complete_reqs block/blk-mq.c:577 [inline]
 blk_done_softirq+0x69/0x90 block/blk-mq.c:582
 __do_softirq+0x12c/0x26e kernel/softirq.c:558
 invoke_softirq kernel/softirq.c:432 [inline]
 __irq_exit_rcu kernel/softirq.c:636 [inline]
 irq_exit_rcu+0x4e/0xa0 kernel/softirq.c:648
 common_interrupt+0x78/0x90 arch/x86/kernel/irq.c:240
 asm_common_interrupt+0x1e/0x40
 check_access kernel/kcsan/core.c:631 [inline]
 __tsan_read8+0x108/0x180 kernel/kcsan/core.c:855
 EXT4_SB fs/ext4/ext4.h:1758 [inline]
 __ext4_mark_inode_dirty+0x5c/0x5c0 fs/ext4/inode.c:5866
 ext4_dirty_inode+0x86/0xa0 fs/ext4/inode.c:5908
 __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+0x4cc/0x5e0 fs/ext4/inode.c:3062
 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]
 aio_write+0x2b4/0x390 fs/aio.c:1578
 io_submit_one+0x86f/0x13b0 fs/aio.c:1880
 __do_sys_io_submit fs/aio.c:1939 [inline]
 __se_sys_io_submit+0x105/0x270 fs/aio.c:1909
 __x64_sys_io_submit+0x3f/0x50 fs/aio.c:1909
 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

read to 0xffff888102893140 of 8 bytes by task 11874 on cpu 0:
 percpu_counter_read include/linux/percpu_counter.h:72 [inline]
 __wb_update_bandwidth+0x9f/0x470 mm/page-writeback.c:1353
 wb_update_bandwidth mm/page-writeback.c:1380 [inline]
 do_writepages+0x391/0x3c0 mm/page-writeback.c:2379
 filemap_fdatawrite_wbc mm/filemap.c:400 [inline]
 __filemap_fdatawrite_range mm/filemap.c:433 [inline]
 __filemap_fdatawrite mm/filemap.c:439 [inline]
 filemap_flush+0x154/0x180 mm/filemap.c:466
 ext4_alloc_da_blocks+0x47/0xd0 fs/ext4/inode.c:3106
 ext4_release_file+0x5b/0x1d0 fs/ext4/file.c:141
 __fput+0x295/0x520 fs/file_table.c:280
 ____fput+0x11/0x20 fs/file_table.c:313
 task_work_run+0xae/0x130 kernel/task_work.c:164
 tracehook_notify_resume include/linux/tracehook.h:189 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:175 [inline]
 exit_to_user_mode_prepare+0x156/0x190 kernel/entry/common.c:207
 __syscall_exit_to_user_mode_work kernel/entry/common.c:289 [inline]
 syscall_exit_to_user_mode+0x20/0x40 kernel/entry/common.c:300
 do_syscall_64+0x50/0xa0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x44/0xae

value changed: 0x00000000001ac6f0 -> 0x00000000001ac700

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 11874 Comm: syz-executor.4 Tainted: G        W         5.15.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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