================================================================== BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers write to 0xffff88813c9bc4d0 of 8 bytes by task 28031 on cpu 0: __remove_assoc_queue fs/buffer.c:481 [inline] fsync_buffers_list fs/buffer.c:688 [inline] sync_mapping_buffers+0x155/0x8b0 fs/buffer.c:548 fat_file_fsync+0xa9/0x100 fs/fat/file.c:194 vfs_fsync_range+0x107/0x120 fs/sync.c:200 generic_write_sync include/linux/fs.h:2987 [inline] generic_file_write_iter+0x103/0x130 mm/filemap.c:3819 call_write_iter include/linux/fs.h:2114 [inline] do_iter_readv_writev+0x2cb/0x360 fs/read_write.c:740 do_iter_write+0x112/0x4c0 fs/read_write.c:866 vfs_iter_write+0x4c/0x70 fs/read_write.c:907 iter_file_splice_write+0x40a/0x750 fs/splice.c:689 do_splice_from fs/splice.c:767 [inline] direct_splice_actor+0x80/0xa0 fs/splice.c:936 splice_direct_to_actor+0x345/0x650 fs/splice.c:891 do_splice_direct+0xf5/0x170 fs/splice.c:979 do_sendfile+0x773/0xda0 fs/read_write.c:1260 __do_sys_sendfile64 fs/read_write.c:1319 [inline] __se_sys_sendfile64 fs/read_write.c:1311 [inline] __x64_sys_sendfile64+0xa9/0x130 fs/read_write.c:1311 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 0xffff88813c9bc4d0 of 8 bytes by task 28042 on cpu 1: mark_buffer_dirty_inode+0x92/0x1d0 fs/buffer.c:581 fat16_ent_put+0x4b/0x50 fs/fat/fatent.c:182 fat_ent_write+0x5e/0xd0 fs/fat/fatent.c:415 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+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 value changed: 0xffff88813c9b9e90 -> 0x0000000000000000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 28042 Comm: syz-executor.4 Tainted: G W 5.14.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ==================================================================