From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f198.google.com (mail-oi1-f198.google.com [209.85.167.198]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 4A7F64C1512 for ; Mon, 28 Sep 2026 14:21:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.198 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790605299; cv=none; b=pdI2R8IIXl12//Xfl6wr3sI6d8XwEQYiVN9wAAtA5QA/rWdK4xS9OG2XR57Df2/B2Tz93uaRRosXlVl11fqGxopB0Kz/Q3IzM90XJnoDOwgbjg8s/OgsKOjhV+9/Bls3EkgJndjGEfhB/9/HuJ+guGYuXJlYC1Eq16xSg7n4Z1Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790605299; c=relaxed/simple; bh=l8LnOTZIQoA0h2h21hFNgU7pEPJnhkdZGBQKHKFCzbs=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; 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2002:a05:6808:1914:b0:4ca:8d6f:4258 with SMTP id 5614622812f47-4d72e06ff3dmr12786028b6e.37.1790605297180; Mon, 28 Sep 2026 07:21:37 -0700 (PDT) Date: Mon, 28 Sep 2026 07:21:37 -0700 In-Reply-To: <6a9826cf.9266084e.bf0d7.0008.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6aba77f1.e548f532.1ca396.0049.GAE@google.com> Subject: Re: [syzbot] [dri?] [virt?] WARNING in virtio_gpu_free_object From: syzbot To: airlied@redhat.com, dmitry.osipenko@collabora.com, dri-devel@lists.freedesktop.org, gurchetansingh@chromium.org, kraxel@redhat.com, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, olvaffe@gmail.com, simona@ffwll.ch, syzkaller-bugs@googlegroups.com, tao1.yu@intel.com, tzimmermann@suse.de, virtualization@lists.linux.dev Content-Type: text/plain; charset="UTF-8" syzbot has found a reproducer for the following issue on: HEAD commit: 72d3fcf802c4 Linux 7.3-rc5 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=168a2ac9580000 kernel config: https://syzkaller.appspot.com/x/.config?x=7d012d9c67977ee4 dashboard link: https://syzkaller.appspot.com/bug?extid=3590d97d8a586fa955c2 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=118a2ac9580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1324e325580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-72d3fcf8.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/57f8c24b5f88/vmlinux-72d3fcf8.xz kernel image: https://storage.googleapis.com/syzbot-assets/6587a00eaa7f/bzImage-72d3fcf8.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+3590d97d8a586fa955c2@syzkaller.appspotmail.com Console: switching to colour dummy device 80x25 ------------[ cut here ]------------ DEBUG_LOCKS_WARN_ON(lock->magic != lock) WARNING: kernel/locking/mutex.c:625 at __mutex_lock_common kernel/locking/mutex.c:625 [inline], CPU#2: syz.0.17/5926 WARNING: kernel/locking/mutex.c:625 at __mutex_lock+0x944/0x1bd0 kernel/locking/mutex.c:821, CPU#2: syz.0.17/5926 Modules linked in: CPU: 2 UID: 0 PID: 5926 Comm: syz.0.17 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 RIP: 0010:__mutex_lock_common kernel/locking/mutex.c:625 [inline] RIP: 0010:__mutex_lock+0x94b/0x1bd0 kernel/locking/mutex.c:821 Code: 0f b6 14 11 38 d0 7c 08 84 d2 0f 85 c0 10 00 00 44 8b 05 e8 55 71 05 45 85 c0 75 13 48 8d 3d ac 61 74 05 48 c7 c6 c0 f6 ef 8b <67> 48 0f b9 3a 90 e9 1b f8 ff ff 4d 8d a7 f0 0a 00 00 4c 89 e7 e8 RSP: 0018:ffffc900043f7b30 EFLAGS: 00010246 RAX: 0000000000000003 RBX: ffff888100b551c0 RCX: 1ffffffff228b180 RDX: 0000000000000000 RSI: ffffffff8beff6c0 RDI: ffffffff914897d0 RBP: ffffc900043f7ca0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000000 R13: 0000000000000000 R14: dffffc0000000000 R15: ffff888027028b60 FS: 0000555564139500(0000) GS:ffff8880d5d4f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32f24008 CR3: 00000000296f3000 CR4: 0000000000352ef0 Call Trace: virtio_gpu_remove_from_restore_list drivers/gpu/drm/virtio/virtgpu_object.c:70 [inline] virtio_gpu_free_object+0xec/0x280 drivers/gpu/drm/virtio/virtgpu_object.c:106 drm_gem_object_free+0x60/0xa0 drivers/gpu/drm/drm_gem.c:1164 kref_put include/linux/kref.h:65 [inline] __drm_gem_object_put include/drm/drm_gem.h:562 [inline] drm_gem_object_put include/drm/drm_gem.h:575 [inline] drm_gem_object_put include/drm/drm_gem.h:572 [inline] drm_client_buffer_delete drivers/gpu/drm/drm_client.c:201 [inline] drm_client_buffer_delete+0x1d8/0x270 drivers/gpu/drm/drm_client.c:185 drm_fbdev_shmem_fb_destroy+0xc5/0x110 drivers/gpu/drm/drm_fbdev_shmem.c:67 put_fb_info drivers/video/fbdev/core/fbmem.c:61 [inline] put_fb_info+0xb8/0xf0 drivers/video/fbdev/core/fbmem.c:56 fb_release+0x13e/0x190 drivers/video/fbdev/core/fb_chrdev.c:381 __fput+0x3ff/0xb50 fs/file_table.c:512 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:70 [inline] exit_to_user_mode_loop+0x1d8/0x700 kernel/entry/common.c:101 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:207 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:230 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:343 [inline] do_syscall_64+0x661/0x790 arch/x86/entry/syscall_64.c:89 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f1e7cf9e159 Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fffb76db628 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007fffb76db710 RCX: 00007f1e7cf9e159 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 000000000000e123 R08: 0000000000000001 R09: 0000000000000000 R10: 0000001b32320000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f1e7d225fac R14: 00007f1e7d225fa8 R15: 00007f1e7d225fa0 ---------------- Code disassembly (best guess): 0: 0f b6 14 11 movzbl (%rcx,%rdx,1),%edx 4: 38 d0 cmp %dl,%al 6: 7c 08 jl 0x10 8: 84 d2 test %dl,%dl a: 0f 85 c0 10 00 00 jne 0x10d0 10: 44 8b 05 e8 55 71 05 mov 0x57155e8(%rip),%r8d # 0x57155ff 17: 45 85 c0 test %r8d,%r8d 1a: 75 13 jne 0x2f 1c: 48 8d 3d ac 61 74 05 lea 0x57461ac(%rip),%rdi # 0x57461cf 23: 48 c7 c6 c0 f6 ef 8b mov $0xffffffff8beff6c0,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 90 nop 30: e9 1b f8 ff ff jmp 0xfffff850 35: 4d 8d a7 f0 0a 00 00 lea 0xaf0(%r15),%r12 3c: 4c 89 e7 mov %r12,%rdi 3f: e8 .byte 0xe8 --- 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.