================================================================== BUG: KCSAN: data-race in mark_buffer_dirty_inode / mark_buffer_dirty_inode write to 0xffff888011e55058 of 8 bytes by task 12851 on cpu 1: mark_buffer_dirty_inode+0x18c/0x1b0 fs/buffer.c:585 fat_mirror_bhs+0x205/0x330 fs/fat/fatent.c:396 fat_ent_write+0xc2/0xd0 fs/fat/fatent.c:421 fat_chain_add+0x149/0x400 fs/fat/misc.c:130 fat_add_cluster fs/fat/inode.c:113 [inline] __fat_get_block fs/fat/inode.c:155 [inline] fat_get_block+0x429/0x5a0 fs/fat/inode.c:190 __block_write_begin_int+0x4c0/0x10d0 fs/buffer.c:2011 __block_write_begin fs/buffer.c:2061 [inline] block_write_begin+0x4f/0x1b0 fs/buffer.c:2120 cont_write_begin+0x508/0x7b0 fs/buffer.c:2469 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 generic_perform_write+0x196/0x3a0 mm/filemap.c:3408 __generic_file_write_iter+0x15c/0x330 mm/filemap.c:3537 generic_file_write_iter+0x75/0x130 mm/filemap.c:3569 call_write_iter include/linux/fs.h:1901 [inline] new_sync_write fs/read_write.c:518 [inline] vfs_write+0x6d4/0x7c0 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_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 read to 0xffff888011e55058 of 8 bytes by task 12873 on cpu 0: mark_buffer_dirty_inode+0x92/0x1b0 fs/buffer.c:581 fat_mirror_bhs+0x205/0x330 fs/fat/fatent.c:396 fat_alloc_clusters+0x957/0xa50 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+0x4c0/0x10d0 fs/buffer.c:2011 __block_write_begin fs/buffer.c:2061 [inline] block_write_begin+0x4f/0x1b0 fs/buffer.c:2120 cont_write_begin+0x508/0x7b0 fs/buffer.c:2469 fat_write_begin+0x61/0xf0 fs/fat/inode.c:235 generic_perform_write+0x196/0x3a0 mm/filemap.c:3408 __generic_file_write_iter+0x15c/0x330 mm/filemap.c:3537 generic_file_write_iter+0x75/0x130 mm/filemap.c:3569 call_write_iter include/linux/fs.h:1901 [inline] do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740 do_iter_write+0x112/0x4b0 fs/read_write.c:866 vfs_iter_write+0x4c/0x70 fs/read_write.c:907 iter_file_splice_write+0x42a/0x780 fs/splice.c:686 do_splice_from fs/splice.c:764 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:933 splice_direct_to_actor+0x345/0x650 fs/splice.c:888 do_splice_direct+0xf5/0x170 fs/splice.c:976 do_sendfile+0x5db/0xca0 fs/read_write.c:1257 __do_sys_sendfile64 fs/read_write.c:1318 [inline] __se_sys_sendfile64 fs/read_write.c:1304 [inline] __x64_sys_sendfile64+0xf2/0x130 fs/read_write.c:1304 do_syscall_64+0x39/0x80 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 0 PID: 12873 Comm: syz-executor.3 Not tainted 5.10.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================