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BUG: KCSAN: data-race in find_get_block_common / has_bh_in_lru

read-write to 0xffff888237d26b70 of 8 bytes by task 20190 on cpu 1:
 bh_lru_install fs/buffer.c:1350 [inline]
 find_get_block_common+0x4f0/0x960 fs/buffer.c:1415
 __find_get_block_nonatomic fs/buffer.c:1434 [inline]
 bdev_getblk+0x7f/0x3d0 fs/buffer.c:1458
 __getblk include/linux/buffer_head.h:382 [inline]
 sb_getblk include/linux/buffer_head.h:388 [inline]
 __ext4_get_inode_loc+0x303/0x930 fs/ext4/inode.c:4455
 ext4_get_inode_loc fs/ext4/inode.c:4583 [inline]
 ext4_reserve_inode_write+0xdb/0x230 fs/ext4/inode.c:5889
 __ext4_mark_inode_dirty+0x8c/0x3f0 fs/ext4/inode.c:6066
 ext4_dirty_inode+0x92/0xc0 fs/ext4/inode.c:6103
 __mark_inode_dirty+0x15c/0x760 fs/fs-writeback.c:2527
 ext4_mb_new_blocks+0x10b9/0x2050 fs/ext4/mballoc.c:-1
 ext4_alloc_branch fs/ext4/indirect.c:340 [inline]
 ext4_ind_map_blocks+0xb4c/0x14f0 fs/ext4/indirect.c:635
 ext4_map_create_blocks fs/ext4/inode.c:522 [inline]
 ext4_map_blocks+0x555/0xd00 fs/ext4/inode.c:706
 _ext4_get_block+0x10a/0x350 fs/ext4/inode.c:785
 ext4_get_block+0x39/0x50 fs/ext4/inode.c:802
 ext4_block_write_begin+0x300/0x970 fs/ext4/inode.c:1067
 ext4_write_begin+0x43c/0xc30 fs/ext4/ext4_jbd2.h:-1
 generic_perform_write+0x181/0x490 mm/filemap.c:4103
 ext4_buffered_write_iter+0x1ee/0x3c0 fs/ext4/file.c:299
 ext4_dio_write_iter fs/ext4/file.c:608 [inline]
 ext4_file_write_iter+0xdbf/0xf00 fs/ext4/file.c:716
 iter_file_splice_write+0x5ef/0x970 fs/splice.c:738
 do_splice_from fs/splice.c:935 [inline]
 direct_splice_actor+0x153/0x2a0 fs/splice.c:1158
 splice_direct_to_actor+0x30f/0x680 fs/splice.c:1102
 do_splice_direct_actor fs/splice.c:1201 [inline]
 do_splice_direct+0xda/0x150 fs/splice.c:1227
 do_sendfile+0x380/0x640 fs/read_write.c:1368
 __do_sys_sendfile64 fs/read_write.c:1429 [inline]
 __se_sys_sendfile64 fs/read_write.c:1415 [inline]
 __x64_sys_sendfile64+0x105/0x150 fs/read_write.c:1415
 x64_sys_call+0xb39/0x2fb0 arch/x86/include/generated/asm/syscalls_64.h:41
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd0/0x1a0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

read to 0xffff888237d26b70 of 8 bytes by task 16648 on cpu 0:
 has_bh_in_lru+0x35/0x1f0 fs/buffer.c:1556
 smp_call_function_many_cond+0x394/0xb20 kernel/smp.c:838
 on_each_cpu_cond_mask+0x3c/0x80 kernel/smp.c:1052
 on_each_cpu_cond include/linux/smp.h:105 [inline]
 invalidate_bh_lrus+0x2a/0x30 fs/buffer.c:1565
 kill_bdev block/bdev.c:90 [inline]
 blkdev_flush_mapping+0x9a/0x1a0 block/bdev.c:712
 blkdev_put_whole block/bdev.c:719 [inline]
 bdev_release+0x2bf/0x3d0 block/bdev.c:1144
 blkdev_release+0x15/0x20 block/fops.c:660
 __fput+0x298/0x650 fs/file_table.c:465
 ____fput+0x1c/0x30 fs/file_table.c:493
 task_work_run+0x12e/0x1a0 kernel/task_work.c:227
 resume_user_mode_work+0x6a/0x70 include/linux/resume_user_mode.h:50
 exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
 exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
 __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
 syscall_exit_to_user_mode+0x77/0xb0 kernel/entry/common.c:218
 do_syscall_64+0xdd/0x1a0 arch/x86/entry/syscall_64.c:100
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

value changed: 0xffff88810675fe38 -> 0xffff8881066d9208

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 UID: 0 PID: 16648 Comm: syz-executor Not tainted 6.15.0-rc3-syzkaller-00342-g5bc1018675ec #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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