From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-io1-f70.google.com (mail-io1-f70.google.com [209.85.166.70]) (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 96D6E189902 for ; Mon, 30 Sep 2024 11:14:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.166.70 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727694895; cv=none; b=EtBHU7qWeE4o6QhjS4kGKcXpCnhvLb0pHm51wUhG0Duroa0Ei43mFrQVVos/uIrxG3r3u/1H/iu8Nr8JrKbRR4NP6lmL6UD5/sUbnvPb2UvPGxD03fWnLQ52IxLeWRti+DMJaRVHlgLO6gNne79jtYyN/E43b0G0AgbSdp8a3LY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1727694895; c=relaxed/simple; bh=Muj4u1jXspjCCD1s0hKhK51KRt9DDCkn/lFDY2vnQ4U=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=Au4zrPcXzgVaTequzDNgerAR0XZukaCWsgGZud8FPjYwqx48lw6wtXo3OMufffIcZhpWJQq/UTjvmX7bOFYoB9mcncd1D5TB+79i2vn+E/0gV0+yBGafjoFBM7T0JB7OyjpUQ02Q3eAp2WvldVjrbWoplkLVLy2M0XP6BALyZSI= 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=209.85.166.70 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-io1-f70.google.com with SMTP id ca18e2360f4ac-82cf147a566so335289039f.1 for ; Mon, 30 Sep 2024 04:14:53 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1727694893; x=1728299693; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=Dn8u8b4MNSgHRWmASvsbSPMzBxf6cvqbUY4zQ+OWk+w=; b=ekJj2zq/fP+NEaWOoKbAaiJ6f9zUI4EWJgkiJ15N+eAURR25H1XDEORW0OgwOW7HC5 6rayhGkpWDzIVuliKaXwuBBxTUsiyehLfW5w0GpLw/Eec/ioI3fbMrvH1wXHV0YyRwC3 qZeel0EPdO1hFw8QQDA6I3XLLWx2uTa9xr5ssCWxMqGFhcAG8XmQZn8OgSfrab7Qzovt LpCnnuwS5tIE9OMRJvmEjPX8ghMRGi+/PPXK2FJ7bwQP4EfIfCAwhox2KLOimdX2IzfN ki2kvbrf79D52GVp0IncnlmaeiNsnY6gkc++gzvVuUwD8t4zX5MKAQs+l/PLNYZFOEZZ Ja6w== X-Gm-Message-State: AOJu0YzY/r+YSj+N+c0BIOj2hplMiUZH+W5/QUsi82u1DQrTrhMzGIdF /u/yPqrDu2E75L5WzDOvDI7m7g566NwfL6HlaWTDMqkKkd7ixb29LZDdyeRvaBiW9uHxRW5/+nH FSnyX7TRta8nwGtYcmtrROQ3K9sxQ0pa6n1A3u/oadlldX6LXt+K41Uk= X-Google-Smtp-Source: AGHT+IGRyAFE76oIKij/VUq9Bv+xUQaUhdDtsHKlEHQ0jmBrbg/De03YldRTWeSn8pTwPwrhTNorgCTTQNZ/OsH9am5i7xV43nFP Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a92:c266:0:b0:3a1:a57a:40a1 with SMTP id e9e14a558f8ab-3a34515565emr77321885ab.5.1727694892663; Mon, 30 Sep 2024 04:14:52 -0700 (PDT) Date: Mon, 30 Sep 2024 04:14:52 -0700 In-Reply-To: <000000000000c848d3060cd1d16a@google.com> X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <66fa882c.050a0220.aab67.0030.GAE@google.com> Subject: Re: [syzbot] Re: [syzbot] [net?] KASAN: slab-use-after-free Read in advance_sched From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Content-Type: text/plain; charset="UTF-8" For archival purposes, forwarding an incoming command email to linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com. *** Subject: Re: [syzbot] [net?] KASAN: slab-use-after-free Read in advance_sched Author: dmantipov@yandex.ru #syz test: git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git d505d3593b52b6c43507f119572409087416ba28 >From 5450d2cda2e81d3fd79526e1efb76578472851fb Mon Sep 17 00:00:00 2001 From: Dmitry Antipov Date: Mon, 30 Sep 2024 13:25:01 +0300 Subject: [PATCH v6 1/2] net: sched: fix use-after-free in taprio_change() In 'taprio_change()', 'admin' pointer may become dangling due to sched switch / removal caused by 'advance_sched()', and critical section protected by 'q->current_entry_lock' is too small to prevent from such a scenario (which causes use-after-free detected by KASAN). Fix this by prefer 'rcu_replace_pointer()' over 'rcu_assign_pointer()' to update 'admin' immediately before an attempt to schedule freeing. Fixes: a3d43c0d56f1 ("taprio: Add support adding an admin schedule") Reported-by: syzbot+b65e0af58423fc8a73aa@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=b65e0af58423fc8a73aa Signed-off-by: Dmitry Antipov --- v6: adjust to match recent changes v5: unchanged since v4 but resend due to series change v4: adjust subject to target net tree v3: unchanged since v2 v2: unchanged since v1 --- net/sched/sch_taprio.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/sched/sch_taprio.c b/net/sched/sch_taprio.c index 8498d0606b24..9f4e004cdb8b 100644 --- a/net/sched/sch_taprio.c +++ b/net/sched/sch_taprio.c @@ -1965,7 +1965,8 @@ static int taprio_change(struct Qdisc *sch, struct nlattr *opt, taprio_start_sched(sch, start, new_admin); - rcu_assign_pointer(q->admin_sched, new_admin); + admin = rcu_replace_pointer(q->admin_sched, new_admin, + lockdep_rtnl_is_held()); if (admin) call_rcu(&admin->rcu, taprio_free_sched_cb); -- 2.46.2