From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f205.google.com (mail-il1-f205.google.com [209.85.166.205]) (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 027F7247284 for ; Mon, 8 Sep 2025 19:19:28 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.205 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757359170; cv=none; b=PAxko/IyMRjYxDHZXI5YE2oXZyLKgV8LEOHK7VC4S5zXTrEbYG4YaZLuWpZOy41acOKnOZbH9SUB2PREDTq7YvNDb2P1+lvbGLrxtGI0FVwiQw/x+hqBbIZq3FyatPd+sW0kL8x8HyPZIs6MiID83n5iccy5XUgNFrE9z9bFuhc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757359170; c=relaxed/simple; bh=qAFcrVBOup5OQXNEdOgYwcxxaA5N6iyAxjDJOx0IFRo=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=JeBwJd4myCLTfYbqAFu+Abrdtp+TIEH/ENchwhuw1JUruJSvHJ5n6DqvhTKmdg+Fx3Nytpgov9IgP6yIOSnYYLqRe82ian7lb1VPzc9d7QYfQvhpMxiVwsZa3/mHtHFy45pjQGA8KshlJZ0iMuG8ocHav8EGGIly0L71yevECuo= 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=209.85.166.205 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-il1-f205.google.com with SMTP id e9e14a558f8ab-40babea9468so14044035ab.2 for ; Mon, 08 Sep 2025 12:19:28 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757359168; x=1757963968; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=GS51yBm+KZpy05gOITF+TyPHlJCUTXtwtV3UCcoHVHI=; b=poXLl4NA2VaUf7z+BArwkxLfnUKlj9Oi3W8MM+FT9vy7FGJ6L/kPDRwH0K9Mh1Y+8E ZuWbjSYZv9hBrQ4QDgTdNo/ty71Bcf0EbC2472ml2Wcc4wsc+9XO7z/GqSylvOp78InB /MK+SpRedYOlvUbVfalpjBblmSTmpy3LXxD7lkV6ddVJ6ROxHf5WeYYw7+e5Hj0LheZy 7TFpC6HX06cJ7JWSqxHP5asZcrLtQBtuwaDpi65XL1E9g8YckgpMIOkTr3TDaYK2nuE5 eDbsAtAnhsQX7NHqoefEbEda1yVS3vG9/JV49MLWl7/9Ih1sS6YKHvAEwFe0rJSGGopO GlfQ== X-Forwarded-Encrypted: i=1; AJvYcCXqsG/VZPqcojmGBR3WgcobgiTDe0sbWsjqiedc2fwrKdfnCCvRcT+Gh+n78M7gf9glxz1tdkTreZNkb0Q=@vger.kernel.org X-Gm-Message-State: AOJu0YzLiIRvBrfBL1jvVB2VcIB+/rGUBakgiAgcMHVJddMbQ6vdQsJx 9PBO1mUsldk0hPXDr+F7iS8zCLor6/loK+vJamNZk9BKocyQSn5uL1azts2+FkCh9c1AXJbpADf kkmdMRWOIfYlppdN9ZQ6zqbDjsYKB3YKDPDcolnQSiKFNPPDCcvbL9j0ZOhM= X-Google-Smtp-Source: AGHT+IEES7IE7iRjJaxYjfY8EtJaJrjfyO12oDu3Dxea0hsbmIRzW3W9wfliz6N4OT7EukOeIr7wEqRT3bnbv1mqF8q806YnN/Vc Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:2194:b0:40e:fe2a:b321 with SMTP id e9e14a558f8ab-40efe2ab529mr12939775ab.15.1757359168014; Mon, 08 Sep 2025 12:19:28 -0700 (PDT) Date: Mon, 08 Sep 2025 12:19:27 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68bf2c3f.050a0220.192772.0884.GAE@google.com> Subject: [syzbot] [fbdev?] KASAN: vmalloc-out-of-bounds Write in imageblit (5) From: syzbot To: deller@gmx.de, dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org, simona@ffwll.ch, soci@c64.rulez.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 76eeb9b8de98 Linux 6.17-rc5 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=14379562580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e0bea6c0b97a2002 dashboard link: https://syzkaller.appspot.com/bug?extid=48b0652a95834717f190 compiler: gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b2c9b90de8ba/disk-76eeb9b8.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/dd1bcf1fd25e/vmlinux-76eeb9b8.xz kernel image: https://storage.googleapis.com/syzbot-assets/dc7e94f5dffb/bzImage-76eeb9b8.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+48b0652a95834717f190@syzkaller.appspotmail.com ================================================================== BUG: KASAN: vmalloc-out-of-bounds in fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline] BUG: KASAN: vmalloc-out-of-bounds in fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline] BUG: KASAN: vmalloc-out-of-bounds in sys_imageblit+0x1a6f/0x1e60 drivers/video/fbdev/core/sysimgblt.c:24 Write of size 8 at addr ffffc90003649000 by task syz.1.259/7231 CPU: 0 UID: 0 PID: 7231 Comm: syz.1.259 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0xcd/0x630 mm/kasan/report.c:482 kasan_report+0xe0/0x110 mm/kasan/report.c:595 fb_write_offset drivers/video/fbdev/core/sysmem.h:30 [inline] fb_bitmap_2ppw drivers/video/fbdev/core/fb_imageblit.h:364 [inline] fb_bitmap_imageblit drivers/video/fbdev/core/fb_imageblit.h:462 [inline] fb_imageblit drivers/video/fbdev/core/fb_imageblit.h:492 [inline] sys_imageblit+0x1a6f/0x1e60 drivers/video/fbdev/core/sysimgblt.c:24 drm_fbdev_shmem_defio_imageblit+0x20/0x130 drivers/gpu/drm/drm_fbdev_shmem.c:38 bit_putcs_unaligned drivers/video/fbdev/core/bitblit.c:138 [inline] bit_putcs+0x90f/0xde0 drivers/video/fbdev/core/bitblit.c:187 fbcon_putcs+0x384/0x4a0 drivers/video/fbdev/core/fbcon.c:1327 do_update_region+0x2e6/0x3f0 drivers/tty/vt/vt.c:627 update_region+0xc1/0x160 drivers/tty/vt/vt.c:641 vcs_write+0x7c7/0xdb0 drivers/tty/vt/vc_screen.c:698 vfs_write+0x29d/0x11d0 fs/read_write.c:684 ksys_write+0x12a/0x250 fs/read_write.c:738 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7effcbf8ebe9 Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007effccda6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007effcc1c6270 RCX: 00007effcbf8ebe9 RDX: 000000000000ffd8 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007effcc011e19 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007effcc1c6308 R14: 00007effcc1c6270 R15: 00007ffd4fcb0c08 The buggy address belongs to a 0-page vmalloc region starting at 0xffffc90003349000 allocated at drm_gem_shmem_vmap_locked+0x561/0x7e0 drivers/gpu/drm/drm_gem_shmem_helper.c:371 Memory state around the buggy address: ffffc90003648f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ffffc90003648f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 >ffffc90003649000: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ^ ffffc90003649080: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ffffc90003649100: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 ================================================================== --- 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