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AFNElJ+8e5Log7QkpJIvhmlLBYiIuyUcpoSefMwXnmcdqqjBghQtJkulDBk3wLf3HdwqL+DbjpOWpmjcFI5sGn8/S11+poKw8d4=@vger.kernel.org X-Gm-Message-State: AOJu0YwwyJp/x3p/q+SzOzKitiTdSWEzhoqblnMDrRurHe6XJSF0dwcm Y9uZWCujDhZLS6tNd65aUTcT27B6pzLBu0DVs9CJdOR1kF6TTTo/IfERUuHZRjKM4tR9f5jCHe/ uHgVW3JVHl+Ci3vlvTq5wGbheMaT65qcVJJpNNCjeXaa6Bbx70S0lPqEhNwc= Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:6411:b0:48f:a9f3:1c38 with SMTP id 5614622812f47-49216e3555amr7704047b6e.2.1782539040059; Fri, 26 Jun 2026 22:44:00 -0700 (PDT) Date: Fri, 26 Jun 2026 22:44:00 -0700 In-Reply-To: <790d4d56-4c24-4468-b588-722e6aa86ba1@I-love.SAKURA.ne.jp> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a3f6320.ac7367b4.6675.000a.GAE@google.com> Subject: Re: [syzbot] [tomoyo?] KMSAN: uninit-value in tomoyo_path_chown (3) From: syzbot To: penguin-kernel@i-love.sakura.ne.jp Cc: jmorris@namei.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-security-module@vger.kernel.org, paul@paul-moore.com, penguin-kernel@i-love.sakura.ne.jp, serge@hallyn.com, syzkaller-bugs@googlegroups.com, takedakn@nttdata.co.jp Content-Type: text/plain; charset="UTF-8" > On 2026/06/17 17:41, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: 2b414a95b8f7 Merge tag 's390-7.1-5' of git://git.kernel.or.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=12cff156580000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=a0ca3b8cb3875012 >> dashboard link: https://syzkaller.appspot.com/bug?extid=eaae8fa60ce81f1e4eeb >> compiler: Debian clang version 21.1.8 (++20251221033036+2078da43e25a-1~exp1~20251221153213.50), Debian LLD 21.1.8 >> >> Unfortunately, I don't have any reproducer for this issue yet. >> > > The AI's analysis > > In this case, `chown_common()` skips setting `newattrs.ia_vfsuid` and `newattrs.ia_vfsgid`. > > at https://syzkaller.appspot.com/ai_job?id=abea5dd9-2a6e-4669-a927-d87ef7833666 is wrong. > We always set newattrs.ia_vfsuid and newattrs.ia_vfsgid before checking for -1. > > retry_deleg: > newattrs.ia_vfsuid = INVALID_VFSUID; > newattrs.ia_vfsgid = INVALID_VFSGID; > newattrs.ia_valid = ATTR_CTIME; > if ((user != (uid_t)-1) && !setattr_vfsuid(&newattrs, uid)) > return -EINVAL; > if ((group != (gid_t)-1) && !setattr_vfsgid(&newattrs, gid)) > return -EINVAL; > > Therefore, unless VFS people find something that can cause this problem, > this would be a random memory corruption which confused KMSAN. > > #syz set subsystems: unclassified > > #syz set no-reminders > Command #1: The specified label value is incorrect. "unclassified" is not among the allowed values. Please use one of the supported label values. The following labels are suported: actionable, missing-backport, no-reminders, prio: {low, normal, high}, subsystems: {.. see below ..} The list of subsystems: https://syzkaller.appspot.com/upstream/subsystems?all=true