linux-kernel - Re: [syzbot] [kernel?] general protection fault in pcl818_ai

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250705123842.2616-1-hdanton@sina.com>
Date: Sat,  5 Jul 2025 20:38:41 +0800
From: Hillf Danton <hdanton@...a.com>
To: syzbot <syzbot+fce5d9d5bd067d6fbe9b@...kaller.appspotmail.com>
Cc: linux-kernel@...r.kernel.org,
	syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [kernel?] general protection fault in pcl818_ai_cancel

> Date: Sat, 05 Jul 2025 03:41:26 -0700
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    26ffb3d6f02c Add linux-next specific files for 20250704
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1304cf70580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=8c567bd5a036e49d
> dashboard link: https://syzkaller.appspot.com/bug?extid=fce5d9d5bd067d6fbe9b
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11022c8c580000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=1704cf70580000

#syz test

--- x/drivers/comedi/drivers/pcl818.c
+++ y/drivers/comedi/drivers/pcl818.c
@@ -759,12 +759,15 @@ static int pcl818_ai_cancel(struct comed
 {
 	struct pcl818_private *devpriv = dev->private;
 	struct comedi_isadma *dma = devpriv->dma;
-	struct comedi_cmd *cmd = &s->async->cmd;
 
 	if (!devpriv->ai_cmd_running)
 		return 0;
 
 	if (dma) {
+		struct comedi_cmd *cmd;
+		if (!s || !s->async)
+			return 0;
+		cmd = &s->async->cmd;
 		if (cmd->stop_src == TRIG_NONE ||
 		    (cmd->stop_src == TRIG_COUNT &&
 		     s->async->scans_done < cmd->stop_arg)) {
--