================================================================== BUG: KCSAN: data-race in mb_mark_used / mb_update_avg_fragment_size write to 0xffff88810043f9d8 of 4 bytes by task 32645 on cpu 0: mb_mark_used+0x2f2/0xc50 fs/ext4/mballoc.c:1954 ext4_mb_use_best_found+0x102/0x320 fs/ext4/mballoc.c:2014 ext4_mb_try_best_found+0x234/0x3d0 fs/ext4/mballoc.c:2180 ext4_mb_regular_allocator+0x22bd/0x2520 fs/ext4/mballoc.c:2778 ext4_mb_new_blocks+0x762/0x1f90 fs/ext4/mballoc.c:5514 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4238 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638 ext4_alloc_file_blocks+0x271/0x720 fs/ext4/extents.c:4425 ext4_fallocate+0x2a7/0x4d0 fs/ext4/extents.c:4705 vfs_fallocate+0x463/0x660 fs/open.c:311 ksys_fallocate fs/open.c:334 [inline] __do_sys_fallocate fs/open.c:342 [inline] __se_sys_fallocate fs/open.c:340 [inline] __x64_sys_fallocate+0x75/0xc0 fs/open.c:340 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae read to 0xffff88810043f9d8 of 4 bytes by task 32169 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:1993 ext4_mb_use_best_found+0x102/0x320 fs/ext4/mballoc.c:2014 ext4_mb_measure_extent fs/ext4/mballoc.c:2130 [inline] ext4_mb_complex_scan_group+0x349/0x850 fs/ext4/mballoc.c:2360 ext4_mb_regular_allocator+0x1a22/0x2520 fs/ext4/mballoc.c:2759 ext4_mb_new_blocks+0x762/0x1f90 fs/ext4/mballoc.c:5514 ext4_ext_map_blocks+0x1569/0x1f00 fs/ext4/extents.c:4238 ext4_map_blocks+0x70d/0xef0 fs/ext4/inode.c:638 ext4_getblk+0xb1/0x3d0 fs/ext4/inode.c:848 ext4_bread+0x28/0x130 fs/ext4/inode.c:900 ext4_append+0xd1/0x1c0 fs/ext4/namei.c:67 ext4_init_new_dir+0x177/0x500 fs/ext4/namei.c:2883 ext4_mkdir+0x329/0x760 fs/ext4/namei.c:2929 vfs_mkdir+0x2a4/0x370 fs/namei.c:3813 do_mkdirat+0x11d/0x200 fs/namei.c:3838 __do_sys_mkdir fs/namei.c:3856 [inline] __se_sys_mkdir fs/namei.c:3854 [inline] __x64_sys_mkdir+0x32/0x40 fs/namei.c:3854 do_syscall_64+0x4a/0x90 arch/x86/entry/common.c:47 entry_SYSCALL_64_after_hwframe+0x44/0xae Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 32169 Comm: syz-executor.4 Tainted: G W 5.13.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================