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AHgh+RojlNFxm2wuyt9Fh67jzWjyZSt29Zp7F5CRFhX0seT7dpx6bCGQNfbF1G7yYToTz6yNbdkR+95MPAIqnfA=@vger.kernel.org X-Gm-Message-State: AOJu0Ywi9x1sovP92K1r9FebLW90FDgXPWZhFjcD84XSgEr0s/amky57 gnUMlcHtrA9KGGNDrSGV1BBbEsXRRFz18DzYnZWmBqgo1L0AWblG654zxYawyhNQTy8Qy8RYO33 q0+hdQe4jhB3lnUn90VQfhppDdX1o9t075imE3MBB70x7QpeApF0oGxj9ymY= Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:c14a:b0:486:4892:d553 with SMTP id 5614622812f47-4afadc03178mr22397759b6e.0.1786324050514; Sun, 09 Aug 2026 18:07:30 -0700 (PDT) Date: Sun, 09 Aug 2026 18:07:30 -0700 In-Reply-To: <6a176ae6.d07c18fe.1069e4.0016.GAE@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a792452.9c11d2ce.289b96.00e6.GAE@google.com> Subject: Re: [syzbot] [dri?] WARNING in drm_atomic_helper_wait_for_vblanks (6) 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" syzbot has found a reproducer for the following issue on: HEAD commit: b643e495ae92 Merge tag 's390-7.2-7' of git://git.kernel.or.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=176c0079580000 kernel config: https://syzkaller.appspot.com/x/.config?x=c44651ea7dd2f307 dashboard link: https://syzkaller.appspot.com/bug?extid=45bc7264de77caad91cb 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=15cbc079580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=138fa2c6580000 Downloadable assets: disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-b643e495.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/9eb4fbda136d/vmlinux-b643e495.xz kernel image: https://storage.googleapis.com/syzbot-assets/53cbbd75c40a/bzImage-b643e495.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+45bc7264de77caad91cb@syzkaller.appspotmail.com ------------[ cut here ]------------ [CRTC:39:crtc-0] vblank wait timed out WARNING: drivers/gpu/drm/drm_atomic_helper.c:1921 at drm_atomic_helper_wait_for_vblanks.part.0+0x738/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1921, CPU#3: syz.0.17/5906 Modules linked in: CPU: 3 UID: 0 PID: 5906 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:drm_atomic_helper_wait_for_vblanks.part.0+0x73e/0x8a0 drivers/gpu/drm/drm_atomic_helper.c:1921 Code: 00 00 00 fc ff df 48 89 f9 48 c1 e9 03 0f b6 04 01 84 c0 74 08 3c 03 0f 8e 44 01 00 00 48 8d 3d 48 de 5f 0b 8b b3 d0 00 00 00 <67> 48 0f b9 3a e9 e1 fc ff ff e8 93 10 3d fc e9 7c fe ff ff e8 99 RSP: 0018:ffffc90003847710 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffff888028680040 RCX: 1ffff110050d0022 RDX: ffff8880285a50e0 RSI: 0000000000000027 RDI: ffffffff912d4120 RBP: dffffc0000000000 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: ffff88802e1f5000 FS: 000055557c115500(0000) GS:ffff8880d60ec000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055777c801168 CR3: 000000005176b000 CR4: 0000000000352ef0 Call Trace: drm_atomic_helper_wait_for_vblanks drivers/gpu/drm/drm_atomic_helper.c:1895 [inline] drm_atomic_helper_commit_tail+0xff/0x130 drivers/gpu/drm/drm_atomic_helper.c:1997 commit_tail+0x338/0x430 drivers/gpu/drm/drm_atomic_helper.c:2074 drm_atomic_helper_commit+0x303/0x380 drivers/gpu/drm/drm_atomic_helper.c:2312 drm_atomic_commit+0x230/0x300 drivers/gpu/drm/drm_atomic.c:1789 drm_atomic_helper_set_config+0x13a/0x190 drivers/gpu/drm/drm_atomic_helper.c:3523 drm_mode_setcrtc+0xeca/0x1d50 drivers/gpu/drm/drm_crtc.c:885 drm_ioctl_kernel+0x1f3/0x3e0 drivers/gpu/drm/drm_ioctl.c:817 drm_ioctl+0x5e6/0xc60 drivers/gpu/drm/drm_ioctl.c:914 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x18e/0x210 fs/ioctl.c:583 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: 0033:0x7f6d5bf9e0d9 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:00007ffe900c07d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f6d5c225fa0 RCX: 00007f6d5bf9e0d9 RDX: 0000200000000300 RSI: 00000000c06864a2 RDI: 0000000000000003 RBP: 00007f6d5c035024 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6d5c225fac R14: 00007f6d5c225fa0 R15: 00007f6d5c225fa0 ---------------- Code disassembly (best guess): 0: 00 00 add %al,(%rax) 2: 00 fc add %bh,%ah 4: ff lcall (bad) 5: df 48 89 fisttps -0x77(%rax) 8: f9 stc 9: 48 c1 e9 03 shr $0x3,%rcx d: 0f b6 04 01 movzbl (%rcx,%rax,1),%eax 11: 84 c0 test %al,%al 13: 74 08 je 0x1d 15: 3c 03 cmp $0x3,%al 17: 0f 8e 44 01 00 00 jle 0x161 1d: 48 8d 3d 48 de 5f 0b lea 0xb5fde48(%rip),%rdi # 0xb5fde6c 24: 8b b3 d0 00 00 00 mov 0xd0(%rbx),%esi * 2a: 67 48 0f b9 3a ud1 (%edx),%rdi <-- trapping instruction 2f: e9 e1 fc ff ff jmp 0xfffffd15 34: e8 93 10 3d fc call 0xfc3d10cc 39: e9 7c fe ff ff jmp 0xfffffeba 3e: e8 .byte 0xe8 3f: 99 cltd --- 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.