linux-kernel - Re: [syzbot] [mm?] INFO: rcu detected stall in vms_complete_munmap

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: <967f3aa0-447a-4121-b80b-299c926a33f5@rowland.harvard.edu>
Date: Fri, 25 Oct 2024 11:13:33 -0400
From: Alan Stern <stern@...land.harvard.edu>
To: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Cc: syzbot <syzbot+0ca979b86eaec7337a89@...kaller.appspotmail.com>,
	Liam.Howlett@...cle.com, akpm@...ux-foundation.org,
	jannh@...gle.com, linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	linux-usb@...r.kernel.org, syzkaller-bugs@...glegroups.com,
	vbabka@...e.cz, Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [syzbot] [mm?] INFO: rcu detected stall in
 vms_complete_munmap_vmas

On Fri, Oct 25, 2024 at 12:37:36PM +0100, Lorenzo Stoakes wrote:
> On Fri, Oct 25, 2024 at 04:23:30AM -0700, syzbot wrote:
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    c6d9e43954bf Merge 6.12-rc4 into usb-next
> > git tree:       https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing
> > console output: https://syzkaller.appspot.com/x/log.txt?x=139f225f980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=4a2bb21f91d75c65
> > dashboard link: https://syzkaller.appspot.com/bug?extid=0ca979b86eaec7337a89
> > compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=179f225f980000
> >
> > Downloadable assets:
> > disk image: https://storage.googleapis.com/syzbot-assets/3bf4a453ec2f/disk-c6d9e439.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/e4a2db2a5d95/vmlinux-c6d9e439.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/8eb8e481b288/bzImage-c6d9e439.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+0ca979b86eaec7337a89@...kaller.appspotmail.com
> >
> 
> Isn't this just the same thing as [0]?
> 
> Again I think we're just happening to hit a stall in the unmap logic rather than
> this being an mm thing.
> 
> We retried that one a few times and it didn't hit any mm code after the
> first time.
> 
> Greg mentioned there was some weirdness with the dummy usb hcd controller
> in [1].

For what it's worth, that weirdness has been fixed in 6.12-rc4 by commit 
5189df7b8088 ("USB: gadget: dummy-hcd: Fix "task hung" problem").

Alan Stern