From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oo1-f78.google.com (mail-oo1-f78.google.com [209.85.161.78]) (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 02E4F2AE7A for ; Sat, 8 Aug 2026 20:11:27 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.161.78 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786219889; cv=none; b=V8rLkBlNGlr8cQwgPAcLKTHO7LdOJmXuoggzuzzEhNf3uJpeSmfXQAgZBVJBg/QXuuezH5d/cezeAZcZzViJrQIQplVOL/iaKpccWiDrG09CM6ikyAWvrv8LcZRJ9HGglE42u4BD3mtkbPXo8r8TS0qpBPPZwloVZ3Emkt5Yorw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786219889; c=relaxed/simple; bh=UEG+4au5moEj09jl0/QDt5rruk2Z/zOjp23f0lRqULY=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=KDiBG7sRtBfU1n+N5xFYYbAzB62IWK5KBaBhKLvwFmey2AVUHIhX5pIOCgpDRW2a+nKzyMQcO9Rcia7HIqVZT475skdKDzQ+kDz/Lj1w7EfhP7IpfyIS5gC189OSrh3SC0S3DgsvHZWBnXZWXK4QCaS4/pVZruIwp5pPVxkFt1o= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.161.78 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-oo1-f78.google.com with SMTP id 006d021491bc7-6a196857c7aso770970eaf.2 for ; Sat, 08 Aug 2026 13:11:27 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1786219887; x=1786824687; h=content-type:to:from:subject:message-id:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=PgBLCiFvaDCfPbmVvLQfWAlNQsylrX8C81QgfBuh/0s=; b=EXsQKPpRI3kEKB+Lr1scdYy29v2lTk+6BHT1/PwKmNWbhHkmvZz3b4NEgg/3ToyLkS utYLmuBVDeSP9qBIAwu6gdT6aqWY164sjU0AjqtTy8AM/PoP88oEJBgUSMac1qdmtp9Z GwzNR0stt04v/GzMk/3p3DMCM8fO9XZZFODAVGf70iJiQFU1Fybblt2zNfeC4hc+IfEr 747ySGx0N6j0YlDmlSg4gG/otHQAFesVBnR3qigPSbwWCYQP37T4KhmRPSM8fmqSYVnt +d+kVz6tVadag2CfRMs6vqh4evJHrlMF5v/V5+M/GOXLSLaHz5hB7WMI8Lp+ZWEs5HW0 Kv9g== X-Forwarded-Encrypted: i=1; AHgh+RrVjQvJQMb0gI4P+rkiR9h8aDIoldpZd142lDL/UfmPLxCIXWuohumanrQ2og1d8BBa+qHi8RY1TS7UA0U=@vger.kernel.org X-Gm-Message-State: AOJu0YxVLwlodcpixSG0xpNTU1D8Opm+fvbPhEo4S7j3YARWUZfaZRIy iIwePyEvbh3pErTVQ2VEMrg9v4HivE9Tts2NsxsoK5Nc6npfKrqVmm19oYD4rKqhyTW7rwtznJS pz/y06woKAtHsSLJ7RuvbQutofGfEoVEDE2Bz5+OHsn6btK/vpdlEgnMB5jE= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:1ca8:b0:6ac:a175:fe7e with SMTP id 006d021491bc7-6b0421148f2mr3828322eaf.25.1786219886988; Sat, 08 Aug 2026 13:11:26 -0700 (PDT) Date: Sat, 08 Aug 2026 13:11:26 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a778d6e.9c11d2ce.289b96.00ba.GAE@google.com> Subject: [syzbot] [dri?] WARNING in drm_fbdev_shmem_helper_fb_dirty From: syzbot To: airlied@gmail.com, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, maarten.lankhorst@linux.intel.com, mripard@kernel.org, simona@ffwll.ch, syzkaller-bugs@googlegroups.com, tzimmermann@suse.de Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: a59f57e2aa12 Merge tag 'watchdog-for-v7.2-rc7' of git://gi.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=1328c2c6580000 kernel config: https://syzkaller.appspot.com/x/.config?x=a59830cba91a1981 dashboard link: https://syzkaller.appspot.com/bug?extid=369ee6a6e9d0bbf14b37 compiler: Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-a59f57e2.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/3b0b58b842b2/vmlinux-a59f57e2.xz kernel image: https://storage.googleapis.com/syzbot-assets/48759b65e153/bzImage-a59f57e2.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+369ee6a6e9d0bbf14b37@syzkaller.appspotmail.com FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 100, space 0, times 1 CPU: 0 UID: 0 PID: 805 Comm: kworker/0:2 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 Workqueue: events drm_fb_helper_damage_work Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 fail_dump lib/fault-inject.c:73 [inline] should_fail_ex+0x40c/0x560 lib/fault-inject.c:174 should_failslab+0xa8/0x100 mm/failslab.c:46 slab_pre_alloc_hook mm/slub.c:4539 [inline] slab_alloc_node mm/slub.c:4897 [inline] __kmalloc_cache_noprof+0xa8/0x660 mm/slub.c:5485 _kmalloc_noprof include/linux/slab.h:988 [inline] _kzalloc_noprof include/linux/slab.h:1309 [inline] drm_atomic_commit_alloc+0xa9/0x100 drivers/gpu/drm/drm_atomic.c:178 drm_atomic_helper_dirtyfb+0x129/0xfd0 drivers/gpu/drm/drm_damage_helper.c:128 drm_fbdev_shmem_helper_fb_dirty+0x160/0x310 drivers/gpu/drm/drm_fbdev_shmem.c:117 drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:339 [inline] drm_fb_helper_damage_work+0x84c/0xf20 drivers/gpu/drm/drm_fb_helper.c:365 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ------------[ cut here ]------------ virtio-pci 0000:00:01.0: [drm] Dirty helper failed: ret=-12 WARNING: drivers/gpu/drm/drm_fbdev_shmem.c:118 at drm_fbdev_shmem_helper_fb_dirty+0x1e1/0x310 drivers/gpu/drm/drm_fbdev_shmem.c:118, CPU#0: kworker/0:2/805 Modules linked in: CPU: 0 UID: 0 PID: 805 Comm: kworker/0:2 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 Workqueue: events drm_fb_helper_damage_work RIP: 0010:drm_fbdev_shmem_helper_fb_dirty+0x288/0x310 drivers/gpu/drm/drm_fbdev_shmem.c:118 Code: 35 fc 4c 89 f8 48 c1 e8 03 42 80 3c 28 00 74 08 4c 89 ff e8 da 5b a4 fc 4d 8b 27 48 89 df 4c 89 f6 4c 89 e2 8b 5c 24 04 89 d9 <67> 48 0f b9 3a 89 d8 e9 f7 fe ff ff 89 d9 80 e1 07 fe c1 38 c1 0f RSP: 0018:ffffc90003ebf8b8 EFLAGS: 00010246 RAX: 1ffff11003f0801a RBX: 00000000fffffff4 RCX: 00000000fffffff4 RDX: ffff88801f64ce40 RSI: ffffffff8c57c700 RDI: ffffffff90638ce0 RBP: ffff88801d350008 R08: 0000000000000dc0 R09: 00000000ffffffff R10: dffffc0000000000 R11: fffffbfff1d94963 R12: ffff88801f64ce40 R13: dffffc0000000000 R14: ffffffff8c57c700 R15: ffff88801f8400d0 FS: 0000000000000000(0000) GS:ffff88808c549000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2ef6a77218 CR3: 0000000033b08000 CR4: 0000000000352ef0 Call Trace: drm_fb_helper_fb_dirty drivers/gpu/drm/drm_fb_helper.c:339 [inline] drm_fb_helper_damage_work+0x84c/0xf20 drivers/gpu/drm/drm_fb_helper.c:365 process_one_work kernel/workqueue.c:3322 [inline] process_scheduled_works+0xa8e/0x14e0 kernel/workqueue.c:3405 worker_thread+0xa47/0xfb0 kernel/workqueue.c:3486 kthread+0x388/0x470 kernel/kthread.c:436 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 ---------------- Code disassembly (best guess): 0: 35 fc 4c 89 f8 xor $0xf8894cfc,%eax 5: 48 c1 e8 03 shr $0x3,%rax 9: 42 80 3c 28 00 cmpb $0x0,(%rax,%r13,1) e: 74 08 je 0x18 10: 4c 89 ff mov %r15,%rdi 13: e8 da 5b a4 fc call 0xfca45bf2 18: 4d 8b 27 mov (%r15),%r12 1b: 48 89 df mov %rbx,%rdi 1e: 4c 89 f6 mov %r14,%rsi 21: 4c 89 e2 mov %r12,%rdx 24: 8b 5c 24 04 mov 0x4(%rsp),%ebx 28: 89 d9 mov %ebx,%ecx * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: 89 d8 mov %ebx,%eax 31: e9 f7 fe ff ff jmp 0xffffff2d 36: 89 d9 mov %ebx,%ecx 38: 80 e1 07 and $0x7,%cl 3b: fe c1 inc %cl 3d: 38 c1 cmp %al,%cl 3f: 0f .byte 0xf --- 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@googlegroups.com. 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