Hello, syzbot found the following issue on: HEAD commit: d082ecbc71e9 Linux 6.14-rc4 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=130277f8580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e9dd6c7eeba2114e dashboard link: https://syzkaller.appspot.com/bug?extid=912f708269025e337cba compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/2b352c2abb77/disk-d082ecbc.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/c5f4a062a264/vmlinux-d082ecbc.xz kernel image: https://storage.googleapis.com/syzbot-assets/c3a86625df5a/bzImage-d082ecbc.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+912f708269025e337cba@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KCSAN: data-race in netfs_advance_write / netfs_write_collection_worker write to 0xffff8881188765b8 of 8 bytes by task 3523 on cpu 0: netfs_prepare_write fs/netfs/write_issue.c:210 [inline] netfs_advance_write+0x36f/0x610 fs/netfs/write_issue.c:298 netfs_unbuffered_write+0xde/0x330 fs/netfs/write_issue.c:721 netfs_unbuffered_write_iter_locked+0x2b7/0x570 fs/netfs/direct_write.c:100 netfs_unbuffered_write_iter+0x2b7/0x3b0 fs/netfs/direct_write.c:195 v9fs_file_write_iter+0x60/0x80 fs/9p/vfs_file.c:404 new_sync_write fs/read_write.c:586 [inline] vfs_write+0x77b/0x920 fs/read_write.c:679 ksys_write+0xe8/0x1b0 fs/read_write.c:731 __do_sys_write fs/read_write.c:742 [inline] __se_sys_write fs/read_write.c:739 [inline] __x64_sys_write+0x42/0x50 fs/read_write.c:739 x64_sys_call+0x287e/0x2dc0 arch/x86/include/generated/asm/syscalls_64.h:2 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 0xffff8881188765b8 of 8 bytes by task 50 on cpu 1: netfs_collect_write_results fs/netfs/write_collect.c:231 [inline] netfs_write_collection_worker+0x3ee/0x2530 fs/netfs/write_collect.c:374 process_one_work kernel/workqueue.c:3236 [inline] process_scheduled_works+0x4db/0xa20 kernel/workqueue.c:3317 worker_thread+0x51d/0x6f0 kernel/workqueue.c:3398 kthread+0x4ae/0x520 kernel/kthread.c:464 ret_from_fork+0x4b/0x60 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244 value changed: 0x0000000000000000 -> 0xffff888103259900 Reported by Kernel Concurrency Sanitizer on: CPU: 1 UID: 0 PID: 50 Comm: kworker/u8:3 Not tainted 6.14.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Workqueue: events_unbound netfs_write_collection_worker ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
