================================================================== BUG: KCSAN: data-race in mark_buffer_dirty_inode / sync_mapping_buffers write to 0xffff888106885740 of 8 bytes by task 4470 on cpu 0: __remove_assoc_queue fs/buffer.c:514 [inline] fsync_buffers_list fs/buffer.c:789 [inline] sync_mapping_buffers+0x162/0x7e0 fs/buffer.c:575 fat_file_fsync+0xad/0x100 fs/fat/file.c:195 vfs_fsync_range+0x122/0x140 fs/sync.c:188 generic_write_sync include/linux/fs.h:2816 [inline] generic_file_write_iter+0x191/0x1d0 mm/filemap.c:4151 iter_file_splice_write+0x5e6/0x970 fs/splice.c:743 do_splice_from fs/splice.c:941 [inline] direct_splice_actor+0x16c/0x2c0 fs/splice.c:1164 splice_direct_to_actor+0x305/0x670 fs/splice.c:1108 do_splice_direct_actor fs/splice.c:1207 [inline] do_splice_direct+0xd7/0x150 fs/splice.c:1233 do_sendfile+0x3ab/0x950 fs/read_write.c:1295 __do_sys_sendfile64 fs/read_write.c:1356 [inline] __se_sys_sendfile64 fs/read_write.c:1348 [inline] __x64_sys_sendfile64+0xbd/0x150 fs/read_write.c:1348 x64_sys_call+0xfc3/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:41 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f read to 0xffff888106885740 of 8 bytes by task 4482 on cpu 1: mark_buffer_dirty_inode+0x96/0x1c0 fs/buffer.c:678 fat_mirror_bhs+0x241/0x330 fs/fat/fatent.c:398 fat_alloc_clusters+0x994/0xa80 fs/fat/fatent.c:543 fat_add_cluster+0x47/0xe0 fs/fat/inode.c:107 fat_fallocate+0x129/0x1d0 fs/fat/file.c:292 vfs_fallocate+0x392/0x3e0 fs/open.c:334 do_vfs_ioctl+0x1481/0x1560 fs/ioctl.c:886 __do_sys_ioctl fs/ioctl.c:905 [inline] __se_sys_ioctl+0x81/0x150 fs/ioctl.c:893 __x64_sys_ioctl+0x43/0x50 fs/ioctl.c:893 x64_sys_call+0x1688/0x2e00 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xc9/0x1c0 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f value changed: 0xffff8881068ce608 -> 0x0000000000000000 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 4482 Comm: syz.3.438 Not tainted 6.10.0-syzkaller-12246-g786c8248dbd3 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/27/2024 ==================================================================