================================================================== BUG: KCSAN: data-race in ext4_ext_try_to_merge_right / ext4_mark_iloc_dirty write to 0xffff8881299ebb32 of 2 bytes by task 7 on cpu 1: le16_add_cpu include/linux/byteorder/generic.h:146 [inline] ext4_ext_try_to_merge_right+0x15a/0x2a0 fs/ext4/extents.c:1777 ext4_ext_try_to_merge+0x337/0x360 fs/ext4/extents.c:1851 ext4_convert_unwritten_extents_endio fs/ext4/extents.c:3868 [inline] ext4_ext_handle_unwritten_extents+0x29d/0x18f0 fs/ext4/extents.c:4048 ext4_ext_map_blocks+0xa78/0x20f0 fs/ext4/extents.c:4318 ext4_map_blocks+0x230/0xcf0 fs/ext4/inode.c:622 ext4_convert_unwritten_extents+0x18b/0x3b0 fs/ext4/extents.c:4964 ext4_convert_unwritten_io_end_vec+0xe0/0x1b0 fs/ext4/extents.c:4999 ext4_end_io_end fs/ext4/page-io.c:189 [inline] ext4_do_flush_completed_IO fs/ext4/page-io.c:262 [inline] ext4_end_io_rsv_work+0x2c2/0x400 fs/ext4/page-io.c:276 process_one_work+0x424/0x930 kernel/workqueue.c:2264 worker_thread+0x9a/0x7e0 kernel/workqueue.c:2410 kthread+0x1cb/0x1f0 kernel/kthread.c:255 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352 read to 0xffff8881299ebb30 of 4 bytes by task 10876 on cpu 0: ext4_do_update_inode fs/ext4/inode.c:4997 [inline] ext4_mark_iloc_dirty+0x9f0/0x1500 fs/ext4/inode.c:5578 ext4_mark_inode_dirty+0xe6/0x420 fs/ext4/inode.c:5771 ext4_dirty_inode+0xad/0xd0 fs/ext4/inode.c:5802 __mark_inode_dirty+0x5b7/0x940 fs/fs-writeback.c:2258 mark_inode_dirty include/linux/fs.h:2183 [inline] generic_write_end+0x1ba/0x1f0 fs/buffer.c:2199 ext4_da_write_end+0x162/0x670 fs/ext4/inode.c:3092 generic_perform_write+0x1d7/0x320 mm/filemap.c:3298 ext4_buffered_write_iter+0x14e/0x280 fs/ext4/file.c:270 ext4_file_write_iter+0xf4/0xd30 fs/ext4/file.c:642 call_write_iter include/linux/fs.h:1901 [inline] do_iter_readv_writev+0x4a7/0x5d0 fs/read_write.c:693 do_iter_write fs/read_write.c:998 [inline] do_iter_write+0x137/0x3a0 fs/read_write.c:979 vfs_iter_write+0x56/0x80 fs/read_write.c:1039 iter_file_splice_write+0x530/0x830 fs/splice.c:760 do_splice_from fs/splice.c:863 [inline] direct_splice_actor+0x97/0xb0 fs/splice.c:1037 splice_direct_to_actor+0x22f/0x540 fs/splice.c:992 do_splice_direct+0x152/0x1d0 fs/splice.c:1080 do_sendfile+0x396/0x810 fs/read_write.c:1520 __do_sys_sendfile64 fs/read_write.c:1581 [inline] __se_sys_sendfile64 fs/read_write.c:1567 [inline] __x64_sys_sendfile64+0x121/0x140 fs/read_write.c:1567 do_syscall_64+0xc7/0x390 arch/x86/entry/common.c:294 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 10876 Comm: syz-executor.5 Not tainted 5.6.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================