Hello, syzbot found the following issue on: HEAD commit: 4b290aae788e Merge tag 'sysctl-6.17-rc1' of git://git.kern.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=110d2ca2580000 kernel config: https://syzkaller.appspot.com/x/.config?x=1638650a7e3ca3ea dashboard link: https://syzkaller.appspot.com/bug?extid=a288de079aaa1fa42f6f compiler: aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 userspace arch: arm64 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/fa3fbcfdac58/non_bootable_disk-4b290aae.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/5f278b497a6e/vmlinux-4b290aae.xz kernel image: https://storage.googleapis.com/syzbot-assets/c6155ee31a71/Image-4b290aae.gz.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+a288de079aaa1fa42f6f@xxxxxxxxxxxxxxxxxxxxxxxxx ------------[ cut here ]------------ refcount_t: underflow; use-after-free. WARNING: CPU: 1 PID: 962 at lib/refcount.c:28 refcount_warn_saturate+0x138/0x19c lib/refcount.c:28 Modules linked in: CPU: 1 UID: 0 PID: 962 Comm: kworker/1:2 Not tainted 6.16.0-syzkaller-04405-g4b290aae788e #0 PREEMPT Hardware name: linux,dummy-virt (DT) Workqueue: md_misc mddev_delayed_delete pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--) pc : refcount_warn_saturate+0x138/0x19c lib/refcount.c:28 lr : refcount_warn_saturate+0x138/0x19c lib/refcount.c:28 sp : ffff80008e927a80 x29: ffff80008e927a80 x28: 0000000000000001 x27: ffff80008708df78 x26: 0000000000000000 x25: ffff0000150e1f00 x24: ffff800087090000 x23: ffff000026240130 x22: 0000000000000004 x21: 1fffe00004c48026 x20: ffff000026240130 x19: 0000000000000003 x18: 0000000000000000 x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 x14: 0000000000000000 x13: 0000000000000000 x12: ffff700011d24ec7 x11: 1ffff00011d24ec6 x10: ffff700011d24ec6 x9 : dfff800000000000 x8 : ffff80008e927638 x7 : ffff80008e927760 x6 : ffff80008e9276b0 x5 : ffff80008e927698 x4 : 0000000000000002 x3 : 1fffe0000d419d16 x2 : 0000000000000000 x1 : 0000000000000000 x0 : ffff0000152c5ac0 Call trace: refcount_warn_saturate+0x138/0x19c lib/refcount.c:28 (P) __refcount_sub_and_test include/linux/refcount.h:400 [inline] __refcount_dec_and_test include/linux/refcount.h:432 [inline] refcount_dec_and_test include/linux/refcount.h:450 [inline] kref_put include/linux/kref.h:64 [inline] kobject_put+0x29c/0x430 lib/kobject.c:737 mddev_delayed_delete+0x14/0x20 drivers/md/md.c:5893 process_one_work+0x7cc/0x18d4 kernel/workqueue.c:3238 process_scheduled_works kernel/workqueue.c:3321 [inline] worker_thread+0x734/0xb84 kernel/workqueue.c:3402 kthread+0x348/0x5fc kernel/kthread.c:464 ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:860 irq event stamp: 146962 hardirqs last enabled at (146961): [<ffff800085407ea4>] raw_spin_rq_unlock_irq kernel/sched/sched.h:1534 [inline] hardirqs last enabled at (146961): [<ffff800085407ea4>] __schedule+0x23c0/0x31cc kernel/sched/core.c:6962 hardirqs last disabled at (146962): [<ffff8000853f7d30>] el1_brk64+0x1c/0x48 arch/arm64/kernel/entry-common.c:574 softirqs last enabled at (146934): [<ffff8000801b7810>] softirq_handle_end kernel/softirq.c:425 [inline] softirqs last enabled at (146934): [<ffff8000801b7810>] handle_softirqs+0x88c/0xdb4 kernel/softirq.c:607 softirqs last disabled at (146921): [<ffff800080010760>] __do_softirq+0x14/0x20 kernel/softirq.c:613 ---[ end trace 0000000000000000 ]--- --- 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
