From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f80.google.com (mail-ot1-f80.google.com [209.85.210.80]) (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 BFB20396560 for ; Sun, 2 Aug 2026 10:22:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.80 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785666157; cv=none; b=BmKl4k9V/5EsEM3YDKq9iBxcT/QOEm8UF6+Xz5WP3+o+5pIamxVrJSghB9QMdHz8AboxbrRCBTTlpo1Uzz3GzNCpJJ11qZ4JvQvg9iBLqpxmvNiYlTZ0TkceYRy8XMEAQ9fYW1mFo9H/YcCbFRczigBOQpwKldqyQx0gWQ4sS2Q= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785666157; c=relaxed/simple; bh=OT/Dc+lMVpDfh9sGLbACA/G1hOk+l6ryJZ/DEFpW2f8=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; 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2002:a05:6808:c1e8:b0:497:d371:21c8 with SMTP id 5614622812f47-4af5e2cd936mr10075081b6e.19.1785666153520; Sun, 02 Aug 2026 03:22:33 -0700 (PDT) Date: Sun, 02 Aug 2026 03:22:33 -0700 In-Reply-To: <6a6a9634.57649fcc.360844.000a.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a6f1a69.1aa927e4.17d4bf.0017.GAE@google.com> Subject: Re: [syzbot] [virt?] [dri?] WARNING in virtio_gpu_alloc_vbufs 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, 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: 2d2338c93da7 Merge tag 'i2c-fixes-7.2-rc6' of git://git.ke.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=15f3edb9580000 kernel config: https://syzkaller.appspot.com/x/.config?x=145fa60d73086782 dashboard link: https://syzkaller.appspot.com/bug?extid=1b129b44597a126d2d79 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=173115b9580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1782f4c6580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-2d2338c9.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/89fdd9cdbdc2/vmlinux-2d2338c9.xz kernel image: https://storage.googleapis.com/syzbot-assets/a7930b1db6cb/bzImage-2d2338c9.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+1b129b44597a126d2d79@syzkaller.appspotmail.com [drm] features: -virgl +edid -resource_blob -host_visible [drm] features: -context_init -blob_alignment ------------[ cut here ]------------ kmem_cache of name 'virtio-gpu-vbufs' already exists WARNING: mm/slab_common.c:111 at kmem_cache_sanity_check mm/slab_common.c:111 [inline], CPU#0: syz.0.17/5926 WARNING: mm/slab_common.c:111 at __kmem_cache_create_args+0xa6/0x420 mm/slab_common.c:352, CPU#0: syz.0.17/5926 Modules linked in: CPU: 0 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:kmem_cache_sanity_check mm/slab_common.c:111 [inline] RIP: 0010:__kmem_cache_create_args+0xa9/0x420 mm/slab_common.c:352 Code: 48 8b 43 60 48 8d 58 a0 48 3d b0 82 d8 8e 74 1f 48 8b 7b 58 48 89 ee e8 c5 50 5e 09 85 c0 75 e0 48 8d 3d 1a 39 ce 0e 48 89 ee <67> 48 0f b9 3a be 20 00 00 00 48 89 ef e8 45 52 5e 09 48 85 c0 0f RSP: 0018:ffffc9000388ef58 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff8881012c77c0 RCX: fffff52000711dc6 RDX: 0000000000000000 RSI: ffffffff8c6f8d40 RDI: ffffffff91275ec0 RBP: ffffffff8c6f8d40 R08: 0000000000000000 R09: fffffbfff22450fa R10: ffffc9000388ef58 R11: 0000000000000000 R12: 0000000000000000 R13: ffffc9000388efc8 R14: 00000000000000d8 R15: 0000000000000000 FS: 000055557ecab500(0000) GS:ffff8880d5dd8000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b33324008 CR3: 000000002ad27000 CR4: 0000000000352ef0 Call Trace: __kmem_cache_create include/linux/slab.h:399 [inline] virtio_gpu_alloc_vbufs+0xc2/0x150 drivers/gpu/drm/virtio/virtgpu_vq.c:75 virtio_gpu_init.cold+0x51c/0x126e drivers/gpu/drm/virtio/virtgpu_kms.c:228 virtio_gpu_probe+0x21c/0x360 drivers/gpu/drm/virtio/virtgpu_drv.c:103 virtio_dev_probe+0x6a2/0xbe0 drivers/virtio/virtio.c:347 call_driver_probe drivers/base/dd.c:628 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:706 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153 bus_probe_device+0x64/0x160 drivers/base/bus.c:620 device_add+0x121d/0x1970 drivers/base/core.c:3772 register_virtio_device+0x4f0/0x5d0 drivers/virtio/virtio.c:568 virtio_pci_probe+0x255/0x410 drivers/virtio/virtio_pci_common.c:722 local_pci_probe+0xdd/0x1b0 drivers/pci/pci-driver.c:332 pci_call_probe+0x176/0x800 drivers/pci/pci-driver.c:394 __pci_device_probe drivers/pci/pci-driver.c:455 [inline] pci_device_probe+0x1cd/0x370 drivers/pci/pci-driver.c:489 call_driver_probe drivers/base/dd.c:628 [inline] really_probe+0x241/0xa60 drivers/base/dd.c:706 __driver_probe_device+0x20e/0x450 drivers/base/dd.c:868 driver_probe_device+0x4a/0x140 drivers/base/dd.c:898 __device_attach_driver+0x1df/0x320 drivers/base/dd.c:1026 bus_for_each_drv+0x159/0x1e0 drivers/base/bus.c:500 __device_attach+0x1e4/0x4d0 drivers/base/dd.c:1098 device_initial_probe+0xaf/0xd0 drivers/base/dd.c:1153 pci_bus_add_device+0xc5/0x100 drivers/pci/bus.c:373 pci_bus_add_devices+0x9a/0x1f0 drivers/pci/bus.c:394 pci_rescan_bus+0x2a/0x40 drivers/pci/probe.c:3500 rescan_store+0xfb/0x130 drivers/pci/pci-sysfs.c:473 bus_attr_store+0x74/0xb0 drivers/base/bus.c:172 sysfs_kf_write+0xf2/0x150 fs/sysfs/file.c:145 kernfs_fop_write_iter+0x3e0/0x5f0 fs/kernfs/file.c:345 new_sync_write fs/read_write.c:595 [inline] vfs_write+0x6ac/0x1050 fs/read_write.c:687 ksys_write+0x12a/0x250 fs/read_write.c:739 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fba4739e019 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:00007ffeb190b8e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fba47625fa0 RCX: 00007fba4739e019 RDX: 0000000000000001 RSI: 0000200000000a00 RDI: 0000000000000005 RBP: 00007fba4743500c R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fba47625fac R14: 00007fba47625fa0 R15: 00007fba47625fa0 ---------------- Code disassembly (best guess): 0: 48 8b 43 60 mov 0x60(%rbx),%rax 4: 48 8d 58 a0 lea -0x60(%rax),%rbx 8: 48 3d b0 82 d8 8e cmp $0xffffffff8ed882b0,%rax e: 74 1f je 0x2f 10: 48 8b 7b 58 mov 0x58(%rbx),%rdi 14: 48 89 ee mov %rbp,%rsi 17: e8 c5 50 5e 09 call 0x95e50e1 1c: 85 c0 test %eax,%eax 1e: 75 e0 jne 0x0 20: 48 8d 3d 1a 39 ce 0e lea 0xece391a(%rip),%rdi # 0xece3941 27: 48 89 ee mov %rbp,%rsi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: be 20 00 00 00 mov $0x20,%esi 34: 48 89 ef mov %rbp,%rdi 37: e8 45 52 5e 09 call 0x95e5281 3c: 48 85 c0 test %rax,%rax 3f: 0f .byte 0xf --- 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.