syzbot

==================================================================
BUG: KCSAN: data-race in __wb_update_bandwidth / percpu_counter_add_batch

read-write to 0xffff888101f19120 of 8 bytes by task 19868 on cpu 1:
 percpu_counter_add_batch+0xc9/0x140 lib/percpu_counter.c:96
 wb_stat_mod include/linux/backing-dev.h:66 [inline]
 folio_account_dirtied mm/page-writeback.c:2678 [inline]
 __folio_mark_dirty+0x28d/0x4e0 mm/page-writeback.c:2723
 mark_buffer_dirty+0x148/0x250 fs/buffer.c:1200
 __block_commit_write fs/buffer.c:2177 [inline]
 block_write_end+0x158/0x2e0 fs/buffer.c:2253
 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+0x276/0x410 mm/filemap.c:3985
 ext4_buffered_write_iter+0x1f6/0x380 fs/ext4/file.c:299
 ext4_file_write_iter+0x29f/0xe30
 call_write_iter include/linux/fs.h:2110 [inline]
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0x771/0x8e0 fs/read_write.c:590
 ksys_write+0xeb/0x1b0 fs/read_write.c:643
 __do_sys_write fs/read_write.c:655 [inline]
 __se_sys_write fs/read_write.c:652 [inline]
 __x64_sys_write+0x42/0x50 fs/read_write.c:652
 x64_sys_call+0x27b7/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888101f19120 of 8 bytes by task 19873 on cpu 0:
 percpu_counter_read include/linux/percpu_counter.h:110 [inline]
 __wb_update_bandwidth+0x83/0x5d0 mm/page-writeback.c:1461
 wb_update_bandwidth mm/page-writeback.c:1489 [inline]
 do_writepages+0x443/0x480 mm/page-writeback.c:2638
 filemap_fdatawrite_wbc+0xdb/0x100 mm/filemap.c:397
 __filemap_fdatawrite_range mm/filemap.c:430 [inline]
 file_write_and_wait_range+0xc8/0x170 mm/filemap.c:788
 ext4_sync_file+0x134/0x6c0 fs/ext4/fsync.c:158
 vfs_fsync_range+0x122/0x140 fs/sync.c:188
 generic_write_sync include/linux/fs.h:2795 [inline]
 ext4_buffered_write_iter+0x338/0x380 fs/ext4/file.c:305
 ext4_file_write_iter+0x29f/0xe30
 do_iter_readv_writev+0x339/0x3e0
 vfs_writev+0x2e9/0x860 fs/read_write.c:971
 do_pwritev fs/read_write.c:1072 [inline]
 __do_sys_pwritev fs/read_write.c:1119 [inline]
 __se_sys_pwritev fs/read_write.c:1114 [inline]
 __x64_sys_pwritev+0x100/0x1c0 fs/read_write.c:1114
 x64_sys_call+0x2a0f/0x2d30 arch/x86/include/generated/asm/syscalls_64.h:297
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xcd/0x1d0 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0x00000000000c9150 -> 0x00000000000c9160

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 19873 Comm: syz-executor.3 Tainted: G        W          6.9.0-rc6-syzkaller-00290-gb9158815de52 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
==================================================================