From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail115-76.sinamail.sina.com.cn (mail115-76.sinamail.sina.com.cn [218.30.115.76]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DFA361D5CFD for ; Tue, 17 Dec 2024 10:33:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=218.30.115.76 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734431628; cv=none; b=h3ORDHUL+Nvf6Mhc00cJG8wxgRB+VRNQdphV1AHSfbjLZGuUuUtAD57itTc7FVmNs/ppz5Fu/MlCuN6rTOgJXSDEXbdQcHjHU+00NboxMBYFogxN+CO6jomwG3eqS0bMzF2b0r3nCv9jGHvzMyF3eZJ3uTG4qsugh6Su5bpTiAk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734431628; c=relaxed/simple; bh=MVCAZuOwLya1jdzSAEEq1H1F3q4QH9kw2z/DMiFFPYY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oSiBipHa5F9YOLovtmzfJeDzSgmyzbOmfyChbl1CGtCQx5PCpWmYmQQilKEGncH0ldKjWzXbAb2uWMfn4nGy/g4QDzCQInqKnupzjnbeRnL7w23Si1i+iJCSTt3errM1jHU2h/z6op6RcwaXjwSgYOq/1P3brONQcgzZ9Vw7BEQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; arc=none smtp.client-ip=218.30.115.76 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([113.118.70.172]) by sina.com (10.185.250.22) with ESMTP id 676152F000003381; Tue, 17 Dec 2024 18:31:15 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 1732467602696 X-SMAIL-UIID: BBA5687D96D940A399423D5BC1F64706-20241217-183115-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [mm?] general protection fault in find_lock_task_mm Date: Tue, 17 Dec 2024 18:31:04 +0800 Message-ID: <20241217103105.151-1-hdanton@sina.com> In-Reply-To: <67607c8c.050a0220.37aaf.013a.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Mon, 16 Dec 2024 11:16:28 -0800 > syzbot found the following issue on: > > HEAD commit: 231825b2e1ff Revert "unicode: Don't special case ignorable.. > git tree: upstream > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=102844f8580000 #syz test --- x/mm/oom_kill.c +++ y/mm/oom_kill.c @@ -137,7 +137,10 @@ struct task_struct *find_lock_task_mm(st rcu_read_lock(); for_each_thread(p, t) { + if (!tryget_task_struct(t)) + continue; task_lock(t); + put_task_struct(t); if (likely(t->mm)) goto found; task_unlock(t); --