From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail3-166.sinamail.sina.com.cn (mail3-166.sinamail.sina.com.cn [202.108.3.166]) (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 B23F28003D for ; Wed, 11 Feb 2026 06:31:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=202.108.3.166 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770791494; cv=none; b=onEn3xNTYMguAXNeapm9I/Ko3eNvsdnxaTl6SMPUNJbMCjIYLwJNsOXF993PvYopJzRU5xdus5o6wIXE4s0MeCzHu2JRRavN8Ky0pSQ+XwitQV10PKmRsXxFwWCj/mbEpxoIYae97XT6a8jUn6jwN5EGClrYYTZNY05i3Wm3Rec= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1770791494; c=relaxed/simple; bh=JUL7RvH/c2hMYy4nFfDOzUg6EIblsYqj9TGpc1L7p4U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=LlOAkgg6BcXqUXVumVuevljks8I282/zUNNg4z7hVaqC2PShsHFf8ZvUCGrKWZLyaq04/l7xXlxv8v3058XmeCJT0bmh/JwHEA309RQY0Sm6ccQz172sl4UVo0c1Po4sGhlKz4tXqm02+B2m1kRPDVNqHNDMoL/ZshjFGI3fthU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=VTkSg5dS; arc=none smtp.client-ip=202.108.3.166 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="VTkSg5dS" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1770791490; bh=AKWZ+tUPwGQ19xA2phduQlA1NhwO5vWGDfIwpENlfZ8=; h=From:Subject:Date:Message-ID; b=VTkSg5dS3VDpWCSa1Th/rhSg8tVShmb+UvCJzYyH/qnYsZmmwkd88T41WM3Y4kWoA w4bqaqfjia+ybituYFE5hUlU1XuSssCqgjfDLRmV+UkB9JIOXfcnM8x1RD76fNC4IJ vjTIycB/OYkxbylbODksZDEoUOsM2aiDXlwnYsJw= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.62.144]) by sina.com (10.54.253.31) with ESMTP id 698C223B00006CFA; Wed, 11 Feb 2026 14:31:26 +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: 5881916816366 X-SMAIL-UIID: 91128DCB11A845F2854065202670AA4A-20260211-143126-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [kernel?] KASAN: slab-use-after-free Read in futex_unqueue Date: Wed, 11 Feb 2026 14:31:12 +0800 Message-ID: <20260211063113.2881-1-hdanton@sina.com> In-Reply-To: <698ba684.a70a0220.2c38d7.007c.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 > Date: Tue, 10 Feb 2026 13:43:32 -0800 [thread overview] > Hello, > > syzbot found the following issue on: > > HEAD commit: 72c395024dac Merge tag 'docs-7.0' of git://git.kernel.org/.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=137d9b22580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=bf83be18dae53c93 > dashboard link: https://syzkaller.appspot.com/bug?extid=6c1861115b4253e45969 > 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=169f8ae6580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=17f657fa580000 #syz test --- x/kernel/futex/core.c +++ y/kernel/futex/core.c @@ -1735,8 +1735,7 @@ void futex_hash_free(struct mm_struct *m free_percpu(mm->futex_ref); kvfree(mm->futex_phash_new); fph = rcu_dereference_raw(mm->futex_phash); - if (fph) - kvfree(fph); + kvfree_rcu(fph, rcu); } static bool futex_pivot_pending(struct mm_struct *mm) --- x/kernel/fork.c +++ y/kernel/fork.c @@ -1165,8 +1165,6 @@ EXPORT_SYMBOL_IF_KUNIT(mm_alloc); static inline void __mmput(struct mm_struct *mm) { - VM_BUG_ON(atomic_read(&mm->mm_users)); - uprobe_clear_state(mm); exit_aio(mm); ksm_exit(mm); --