================================================================== BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers read to 0xffff8881250b6740 of 8 bytes by task 23252 on cpu 0: mark_buffer_dirty_inode+0xa1/0x260 fs/buffer.c:556 fat12_ent_put+0xf8/0x1b0 fs/fat/fatent.c:171 fat_alloc_clusters+0x507/0xc40 fs/fat/fatent.c:501 fat_add_cluster+0x3d/0xd0 fs/fat/inode.c:107 __fat_get_block fs/fat/inode.c:154 [inline] fat_get_block+0x3ae/0x4e0 fs/fat/inode.c:189 __block_write_begin_int+0x2ea/0xf20 fs/buffer.c:1968 __block_write_begin fs/buffer.c:2018 [inline] block_write_begin+0x77/0x160 fs/buffer.c:2077 cont_write_begin+0x3d6/0x670 fs/buffer.c:2426 fat_write_begin+0x72/0xc0 fs/fat/inode.c:235 generic_perform_write+0x136/0x320 mm/filemap.c:3305 __generic_file_write_iter+0x251/0x380 mm/filemap.c:3434 generic_file_write_iter+0x28c/0x390 mm/filemap.c:3466 call_write_iter include/linux/fs.h:1895 [inline] new_sync_write+0x388/0x4a0 fs/read_write.c:483 __vfs_write+0xb1/0xc0 fs/read_write.c:496 vfs_write fs/read_write.c:558 [inline] vfs_write+0x18a/0x390 fs/read_write.c:542 ksys_write+0xd5/0x1b0 fs/read_write.c:611 __do_sys_write fs/read_write.c:623 [inline] __se_sys_write fs/read_write.c:620 [inline] __x64_sys_write+0x4c/0x60 fs/read_write.c:620 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 write to 0xffff8881250b6740 of 8 bytes by task 23257 on cpu 1: fsync_buffers_list fs/buffer.c:734 [inline] sync_mapping_buffers+0x4eb/0x6e0 fs/buffer.c:523 fat_file_fsync+0xd4/0x120 fs/fat/file.c:203 vfs_fsync_range+0x82/0x150 fs/sync.c:197 generic_write_sync include/linux/fs.h:2853 [inline] generic_file_write_iter+0x318/0x390 mm/filemap.c:3470 call_write_iter include/linux/fs.h:1895 [inline] do_iter_readv_writev+0x487/0x5b0 fs/read_write.c:693 do_iter_write fs/read_write.c:970 [inline] do_iter_write+0x13b/0x3c0 fs/read_write.c:951 vfs_iter_write+0x5c/0x80 fs/read_write.c:983 iter_file_splice_write+0x4c0/0x7f0 fs/splice.c:746 do_splice_from fs/splice.c:848 [inline] direct_splice_actor+0xa0/0xc0 fs/splice.c:1020 splice_direct_to_actor+0x215/0x510 fs/splice.c:975 do_splice_direct+0x161/0x1e0 fs/splice.c:1063 do_sendfile+0x384/0x7f0 fs/read_write.c:1464 __do_sys_sendfile64 fs/read_write.c:1519 [inline] __se_sys_sendfile64 fs/read_write.c:1511 [inline] __x64_sys_sendfile64+0xbe/0x140 fs/read_write.c:1511 do_syscall_64+0xcc/0x370 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 23257 Comm: syz-executor.5 Not tainted 5.4.0-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================