================================================================== BUG: KCSAN: data-race in mark_buffer_dirty_inode / mark_buffer_dirty_inode write to 0xffff88813b822cf0 of 8 bytes by task 670 on cpu 0: mark_buffer_dirty_inode+0x188/0x1d0 fs/buffer.c:585 fat_mirror_bhs+0x205/0x330 fs/fat/fatent.c:396 fat_alloc_clusters+0x95e/0xa50 fs/fat/fatent.c:541 fat_add_cluster fs/fat/inode.c:108 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x213/0x5a0 fs/fat/inode.c:190 __block_write_begin_int+0x4a2/0x1060 fs/buffer.c:2006 __block_write_begin fs/buffer.c:2056 [inline] block_write_begin fs/buffer.c:2116 [inline] cont_write_begin+0x522/0x850 fs/buffer.c:2465 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 generic_perform_write+0x196/0x3c0 mm/filemap.c:3656 __generic_file_write_iter+0x161/0x300 mm/filemap.c:3783 generic_file_write_iter+0x75/0x130 mm/filemap.c:3815 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 0xffff88813b822cf0 of 8 bytes by task 682 on cpu 1: mark_buffer_dirty_inode+0x92/0x1d0 fs/buffer.c:581 fat_mirror_bhs+0x205/0x330 fs/fat/fatent.c:396 fat_alloc_clusters+0x95e/0xa50 fs/fat/fatent.c:541 fat_alloc_new_dir+0x63/0x4b0 fs/fat/dir.c:1144 vfat_mkdir+0x70/0x210 fs/fat/namei_vfat.c:861 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: 0x0000000000000000 -> 0xffff88810684a528 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 682 Comm: syz-executor.0 Not tainted 5.14.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================