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AFNElJ/d0ClIHx6uq7fZllCtZPlDaP46q4CGWFKwQ1pVKaHZ0tNU/nto88JJmu9YL1+C7se7FU4vEs9geN8=@vger.kernel.org X-Gm-Message-State: AOJu0YyJY1A1mL+q0g7mv1e0+6Ikj6BkbUwWJagKON68QNKZ8agfo5XD m6vAxUmK9CSEkrE4YoBA32O+kBi42DYtYWYOgeMhQ1An+z5aGMc1S1OQJEeNbEkclcg4xUJy947 sssPXI6oTJV9TcXLNCD7wCM6LAEEgcSqRZxP9foomzV+jtUStX+kHrNfg2pU= Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1717:b0:485:3a28:a83f with SMTP id 5614622812f47-48ac0d5c327mr1942641b6e.32.1781933838801; Fri, 19 Jun 2026 22:37:18 -0700 (PDT) Date: Fri, 19 Jun 2026 22:37:18 -0700 In-Reply-To: <6742b399.050a0220.1cc393.0033.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a36270e.bf7b9415.58413.0000.GAE@google.com> Subject: Re: [syzbot] [usb?] general protection fault in dummy_timer (2) From: syzbot To: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: a975094bf98c Merge tag 'exfat-for-7.2-rc1' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=125ea50e580000 kernel config: https://syzkaller.appspot.com/x/.config?x=26c7945305cfa3b1 dashboard link: https://syzkaller.appspot.com/bug?extid=faf3a6cf579fc65591ca compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=16750356580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=132d4586580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-a975094b.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/e4435d766294/vmlinux-a975094b.xz kernel image: https://storage.googleapis.com/syzbot-assets/c6c16f744e16/bzImage-a975094b.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+faf3a6cf579fc65591ca@syzkaller.appspotmail.com ------------[ cut here ]------------ UBSAN: array-index-out-of-bounds in kernel/locking/qspinlock.h:68:9 index 16382 is out of range for type 'long unsigned int [8]' CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 ubsan_epilogue+0xa/0x30 lib/ubsan.c:233 __ubsan_handle_out_of_bounds+0xcc/0xf0 lib/ubsan.c:455 decode_tail kernel/locking/qspinlock.h:68 [inline] __pv_queued_spin_lock_slowpath+0xbd7/0xc00 kernel/locking/qspinlock.c:285 pv_queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:35 [inline] queued_spin_lock_slowpath arch/x86/include/asm/paravirt-spinlock.h:66 [inline] queued_spin_lock include/asm-generic/qspinlock.h:114 [inline] do_raw_spin_lock+0x1e0/0x260 kernel/locking/spinlock_debug.c:116 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock_irqsave+0x42/0x60 kernel/locking/spinlock.c:166 complete_with_flags kernel/sched/completion.c:25 [inline] complete+0x1d/0x200 kernel/sched/completion.c:52 transfer drivers/usb/gadget/udc/dummy_hcd.c:1527 [inline] dummy_timer+0x121c/0x36c0 drivers/usb/gadget/udc/dummy_hcd.c:1989 __run_hrtimer kernel/time/hrtimer.c:2032 [inline] __hrtimer_run_queues+0x462/0x9c0 kernel/time/hrtimer.c:2096 hrtimer_run_softirq+0x17d/0x2c0 kernel/time/hrtimer.c:2113 handle_softirqs+0x1ea/0x9b0 kernel/softirq.c:622 __do_softirq kernel/softirq.c:656 [inline] invoke_softirq kernel/softirq.c:496 [inline] __irq_exit_rcu+0x162/0x210 kernel/softirq.c:735 irq_exit_rcu+0x9/0x30 kernel/softirq.c:752 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0xa3/0xc0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: 96 88 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa eb 07 0f 00 2d 23 d8 14 00 fb f4 fc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffc90000177e00 EFLAGS: 00000246 RAX: 0000000000400dbc RBX: ffff88801e6c2540 RCX: ffffffff8b96c2d5 RDX: 0000000000000001 RSI: ffffffff8c1d2700 RDI: ffffffff81de3aa7 RBP: ffffed1003cd84a8 R08: 0000000000000000 R09: ffffed100d4a678d R10: ffff88806a533c6b R11: ffffffff81d50f9c R12: 0000000000000000 R13: 0000000000000000 R14: 1ffff9200002efc4 R15: dffffc0000000000 arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:767 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 start_secondary+0x21d/0x2d0 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x158 ---[ end trace ]--- ---------------- Code disassembly (best guess): 0: 96 xchg %eax,%esi 1: 88 02 mov %al,(%rdx) 3: c3 ret 4: cc int3 5: cc int3 6: cc int3 7: cc int3 8: 0f 1f 00 nopl (%rax) b: 90 nop c: 90 nop d: 90 nop e: 90 nop f: 90 nop 10: 90 nop 11: 90 nop 12: 90 nop 13: 90 nop 14: 90 nop 15: 90 nop 16: 90 nop 17: 90 nop 18: 90 nop 19: 90 nop 1a: 90 nop 1b: f3 0f 1e fa endbr64 1f: eb 07 jmp 0x28 21: 0f 00 2d 23 d8 14 00 verw 0x14d823(%rip) # 0x14d84b 28: fb sti 29: f4 hlt * 2a: e9 fc 48 03 00 jmp 0x3492b <-- trapping instruction 2f: 66 2e 0f 1f 84 00 00 cs nopw 0x0(%rax,%rax,1) 36: 00 00 00 39: 66 90 xchg %ax,%ax 3b: 90 nop 3c: 90 nop 3d: 90 nop 3e: 90 nop 3f: 90 nop --- If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing.