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BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

read-write to 0xffff8881010ff120 of 8 bytes by task 6817 on cpu 0:
 percpu_counter_add_batch+0xc9/0x140 lib/percpu_counter.c:96
 wb_stat_mod include/linux/backing-dev.h:67 [inline]
 folio_account_dirtied mm/page-writeback.c:2624 [inline]
 __folio_mark_dirty+0x28d/0x4e0 mm/page-writeback.c:2669
 mark_buffer_dirty+0x148/0x250 fs/buffer.c:1200
 __block_commit_write fs/buffer.c:2175 [inline]
 block_write_end+0x158/0x2e0 fs/buffer.c:2251
 ext4_da_do_write_end fs/ext4/inode.c:2955 [inline]
 ext4_da_write_end+0x1ad/0x860 fs/ext4/inode.c:3028
 generic_perform_write+0x267/0x410 mm/filemap.c:3941
 ext4_buffered_write_iter+0x1f6/0x370 fs/ext4/file.c:299
 ext4_file_write_iter+0x297/0xe10
 __kernel_write_iter+0x25f/0x480 fs/read_write.c:523
 dump_emit_page fs/coredump.c:888 [inline]
 dump_user_range+0x25d/0x480 fs/coredump.c:915
 elf_core_dump+0x1a8e/0x1bb0 fs/binfmt_elf.c:2077
 do_coredump+0x102a/0x1890 fs/coredump.c:764
 get_signal+0xdb5/0x10a0 kernel/signal.c:2879
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x8f/0x120 kernel/entry/common.c:225
 irqentry_exit+0x12/0x40 kernel/entry/common.c:328
 asm_exc_stack_segment+0x26/0x30 arch/x86/include/asm/idtentry.h:563

read to 0xffff8881010ff120 of 8 bytes by task 6807 on cpu 1:
 percpu_counter_read include/linux/percpu_counter.h:110 [inline]
 __wb_update_bandwidth+0x83/0x5c0 mm/page-writeback.c:1461
 wb_update_bandwidth mm/page-writeback.c:1489 [inline]
 do_writepages+0x30a/0x340 mm/page-writeback.c:2584
 filemap_fdatawrite_wbc+0xdb/0xf0 mm/filemap.c:388
 __filemap_fdatawrite_range mm/filemap.c:421 [inline]
 __filemap_fdatawrite mm/filemap.c:427 [inline]
 filemap_flush+0x95/0xc0 mm/filemap.c:454
 ext4_alloc_da_blocks+0x50/0x130 fs/ext4/inode.c:3072
 ext4_release_file+0x5f/0x1c0 fs/ext4/file.c:169
 __fput+0x299/0x630 fs/file_table.c:376
 ____fput+0x15/0x20 fs/file_table.c:404
 task_work_run+0x135/0x1a0 kernel/task_work.c:180
 exit_task_work include/linux/task_work.h:38 [inline]
 do_exit+0x604/0x16d0 kernel/exit.c:871
 do_group_exit+0x101/0x150 kernel/exit.c:1020
 get_signal+0xf4e/0x10a0 kernel/signal.c:2893
 arch_do_signal_or_restart+0x95/0x4b0 arch/x86/kernel/signal.c:310
 exit_to_user_mode_loop kernel/entry/common.c:105 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
 irqentry_exit_to_user_mode+0x8f/0x120 kernel/entry/common.c:225
 irqentry_exit+0x12/0x40 kernel/entry/common.c:328
 asm_exc_stack_segment+0x26/0x30 arch/x86/include/asm/idtentry.h:563

value changed: 0x0000000000036630 -> 0x0000000000036640

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 6807 Comm: syz-executor.4 Not tainted 6.8.0-rc6-syzkaller-00120-g87adedeba51a #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
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