From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-il1-f208.google.com (mail-il1-f208.google.com [209.85.166.208]) (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 E80652D46CE for ; Mon, 27 Oct 2025 05:54:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.208 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761544474; cv=none; b=NZUlss7vmvvIhDEd2H6dPpmb1HFeIG/tw92E+VD8Ljcci0HgKSGerZk908D4o0898iHumT/dWa5usM12WsYWtB0vWwENXH/93wafv8CEhTNYZYn23oaE7elif/I60HEh/s6OXq6xsKoraYTd172hJ6sKJS8GfbuIIKgcj0YCHMA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1761544474; c=relaxed/simple; bh=SNmai1IOLY+pup+5LYY/q0U2eZq7K8fuJB8K0RS7rxQ=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=Yg6b+Mov1jOivOf0qB0lswhSTMH3+itmjfoVA+yANpo9MRG7VF1P41nvYgn9WjRYwWSkrgGniJXaokP4VQBoo14j76SU2qwr28HhMyf8vFmiO0H/TEPiHRBaRCcDb/oSJPM7wXz6AOegJgvc8jqnTPznw4IzEYfTRQLFf+ZGe/c= 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=209.85.166.208 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-f208.google.com with SMTP id e9e14a558f8ab-430d4a4dea3so62208855ab.0 for ; Sun, 26 Oct 2025 22:54:32 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1761544472; x=1762149272; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=GKC11teTiEOM5vQjUmVTNkUGadJpuIO6RJHtwgVzfnQ=; b=pPPWr/pNoW7KL5qfS/2lq1lXUcAxefTfWTvhQKhTYx9IIdcqDZf3XvtnM+uP4jC9Qp 2Xs1lzyJiR+NinDGi0I+ez2nMKax65c3zGnbUbMeKjLhGAq6YNatnoPC+qcFV/Z4F2hO eiDFScAevKOOWOYSWKu9me9xwxPINh/AO0PPvNhMwI3eTgG6pO9PGloSWkJcvYwiC+eT KUYz7ao3PgRmQnpcmD+oIy0V1QYVHeIqESoqGXcDAn5844eK2rG7wQlI77XNmR1SwT86 d3tIdIntOd8l0eGu3vK8n8/lnElYBEHgjqvp0AEww7BK0zB4NS31Tq70aGRB7NYE1pYA Zmmg== X-Forwarded-Encrypted: i=1; AJvYcCVON5yLXRu+DwULvm/WZtpqkYZ6r/umbUAlw8liNSuvnA8SJMoGZJ5yGV9fm3fvDOK44o1qZOmz+6MzOCY=@vger.kernel.org X-Gm-Message-State: AOJu0YybIsw9JCnAaADOpnFa1Ha0M32fD+0x6P/zFfsQRE66hNp4zBjz xskBye3HIzKaUk03kKJnkS1bD5YvwhXW+jM1YAfcdL54sMRDC2e7SYwswgbJ6teHDIjcVX2oj3L n+o3afbtZxQUwLZEd70z4GmtNgWLWs6YdCmVI3+mnZTAktIqcfMP20H7gh7U= X-Google-Smtp-Source: AGHT+IFFxWhXZUUoFvo6paTouupqI4Adh7UBpqa2Z4tR45DaNuUz00lT2knpS82K/lGQvBIoUmrin3NOkRlmFo6fQYAfUcRqQ94U Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6e02:188f:b0:42f:8bdd:6e9c with SMTP id e9e14a558f8ab-431eb66bd70mr135622495ab.14.1761544472098; Sun, 26 Oct 2025 22:54:32 -0700 (PDT) Date: Sun, 26 Oct 2025 22:54:32 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <68ff0918.050a0220.3344a1.0287.GAE@google.com> Subject: [syzbot] [i2c?] WARNING: refcount bug in i2c_get_adapter From: syzbot To: linux-i2c@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, wsa+renesas@sang-engineering.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: 211ddde0823f Linux 6.18-rc2 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=156b4d42580000 kernel config: https://syzkaller.appspot.com/x/.config?x=216353986aa62c5d dashboard link: https://syzkaller.appspot.com/bug?extid=76501d32a94a432940a8 compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/07371cf02d4e/disk-211ddde0.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/27220c94ca08/vmlinux-211ddde0.xz kernel image: https://storage.googleapis.com/syzbot-assets/12abd01b8291/bzImage-211ddde0.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+76501d32a94a432940a8@syzkaller.appspotmail.com ------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 6572 at lib/refcount.c:25 refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 Modules linked in: CPU: 1 UID: 0 PID: 6572 Comm: syz.2.237 Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025 RIP: 0010:refcount_warn_saturate+0xfa/0x1d0 lib/refcount.c:25 Code: 00 00 e8 e9 f5 3d fd 5b 41 5e c3 cc cc cc cc cc e8 db f5 3d fd c6 05 b8 91 60 0a 01 90 48 c7 c7 a0 9a 3e 8b e8 e7 3d 02 fd 90 <0f> 0b 90 90 eb d7 e8 bb f5 3d fd c6 05 99 91 60 0a 01 90 48 c7 c7 RSP: 0018:ffffc9000cdef6d8 EFLAGS: 00010246 RAX: 07f404c01321b500 RBX: 0000000000000002 RCX: 0000000000080000 RDX: ffffc90005d09000 RSI: 00000000000008d8 RDI: 00000000000008d9 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffed101712487b R12: ffffffff8b995c88 R13: dffffc0000000000 R14: ffff88805dd48390 R15: dffffc0000000000 FS: 00007fd67c35e6c0(0000) GS:ffff888126cc2000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b3001eff8 CR3: 000000003a534000 CR4: 00000000003526f0 Call Trace: __refcount_add include/linux/refcount.h:-1 [inline] __refcount_inc include/linux/refcount.h:366 [inline] refcount_inc include/linux/refcount.h:383 [inline] kref_get include/linux/kref.h:45 [inline] kobject_get+0xfd/0x120 lib/kobject.c:643 i2c_get_adapter+0x6d/0xa0 drivers/i2c/i2c-core-base.c:2612 i2cdev_open+0x48/0x190 drivers/i2c/i2c-dev.c:604 chrdev_open+0x4cf/0x5e0 fs/char_dev.c:414 do_dentry_open+0x9b1/0x1350 fs/open.c:965 vfs_open+0x3b/0x350 fs/open.c:1097 do_open fs/namei.c:3975 [inline] path_openat+0x2ef1/0x3840 fs/namei.c:4134 do_filp_open+0x1fa/0x410 fs/namei.c:4161 do_sys_openat2+0x121/0x1c0 fs/open.c:1437 do_sys_open fs/open.c:1452 [inline] __do_sys_openat fs/open.c:1468 [inline] __se_sys_openat fs/open.c:1463 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1463 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fd67e0fd810 Code: 48 89 44 24 20 75 93 44 89 54 24 0c e8 69 95 02 00 44 8b 54 24 0c 89 da 48 89 ee 41 89 c0 bf 9c ff ff ff b8 01 01 00 00 0f 05 <48> 3d 00 f0 ff ff 77 38 44 89 c7 89 44 24 0c e8 bc 95 02 00 8b 44 RSP: 002b:00007fd67c35db70 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000002603 RCX: 00007fd67e0fd810 RDX: 0000000000002603 RSI: 00007fd67c35dc10 RDI: 00000000ffffff9c RBP: 00007fd67c35dc10 R08: 0000000000000000 R09: 00232d6332692f76 R10: 0000000000000000 R11: 0000000000000293 R12: cccccccccccccccd R13: 00007fd67e356038 R14: 00007fd67e355fa0 R15: 00007ffec547dee8 --- 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