================================================================== BUG: KCSAN: data-race in mb_free_blocks / mb_update_avg_fragment_size write to 0xffff8881017ffa98 of 4 bytes by task 1833 on cpu 0: mb_free_blocks+0x323/0xb40 fs/ext4/mballoc.c:1833 ext4_free_blocks+0x1418/0x1b50 fs/ext4/mballoc.c:5989 ext4_remove_blocks+0x61a/0x800 fs/ext4/extents.c:2502 ext4_ext_rm_leaf+0x670/0xd20 fs/ext4/extents.c:2668 ext4_ext_remove_space+0x901/0x1300 fs/ext4/extents.c:2916 ext4_ext_truncate+0xfe/0x170 fs/ext4/extents.c:4377 ext4_truncate+0x76e/0xa80 fs/ext4/inode.c:4262 ext4_truncate_failed_write fs/ext4/truncate.h:20 [inline] ext4_da_write_begin+0x56e/0x820 fs/ext4/inode.c:3029 generic_perform_write+0x196/0x3c0 mm/filemap.c:3656 ext4_buffered_write_iter+0x2f2/0x3f0 fs/ext4/file.c:269 ext4_file_write_iter+0x2e7/0x11d0 fs/ext4/file.c:519 call_write_iter include/linux/fs.h:2114 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x69d/0x770 fs/read_write.c:605 ksys_write+0xce/0x180 fs/read_write.c:658 __do_sys_write fs/read_write.c:670 [inline] __se_sys_write fs/read_write.c:667 [inline] __x64_sys_write+0x3e/0x50 fs/read_write.c:667 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff8881017ffa98 of 4 bytes by task 29482 on cpu 1: ext4_mb_avg_fragment_size_cmp fs/ext4/mballoc.c:834 [inline] ext4_mb_rb_insert fs/ext4/mballoc.c:811 [inline] mb_update_avg_fragment_size+0x161/0x260 fs/ext4/mballoc.c:859 mb_mark_used+0xae0/0xc50 fs/ext4/mballoc.c:1994 ext4_mb_use_best_found+0x102/0x320 fs/ext4/mballoc.c:2015 ext4_mb_measure_extent fs/ext4/mballoc.c:2131 [inline] ext4_mb_complex_scan_group+0x349/0x850 fs/ext4/mballoc.c:2361 ext4_mb_regular_allocator+0x1a22/0x2520 fs/ext4/mballoc.c:2760 ext4_mb_new_blocks+0x762/0x1f90 fs/ext4/mballoc.c:5515 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4245 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638 ext4_getblk+0xb1/0x3d0 fs/ext4/inode.c:848 ext4_bread+0x28/0x100 fs/ext4/inode.c:900 ext4_append+0xd1/0x1c0 fs/ext4/namei.c:67 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2885 ext4_mkdir+0x329/0x760 fs/ext4/namei.c:2931 vfs_mkdir+0x2a4/0x370 fs/namei.c:3823 do_mkdirat+0x11d/0x200 fs/namei.c:3848 __do_sys_mkdir fs/namei.c:3866 [inline] __se_sys_mkdir fs/namei.c:3864 [inline] __x64_sys_mkdir+0x32/0x40 fs/namei.c:3864 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3d/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae value changed: 0x00000001 -> 0x00000002 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 29482 Comm: syz-executor.2 Tainted: G W 5.14.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================