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
| ||
|
Date: Tue, 9 Aug 2022 21:01:55 +0000 From: Carlos Llamas <cmllamas@...gle.com> To: Liam Howlett <liam.howlett@...cle.com> Cc: "linux-mm@...ck.org" <linux-mm@...ck.org>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, syzbot <syzbot+a7b60a176ec13cafb793@...kaller.appspotmail.com>, Andrew Morton <akpm@...ux-foundation.org>, Ondrej Mosnacek <omosnace@...hat.com>, "syzkaller-bugs@...glegroups.com" <syzkaller-bugs@...glegroups.com>, Minchan Kim <minchan@...nel.org>, Christian Brauner <brauner@...nel.org>, Greg Kroah-Hartman <gregkh@...uxfoundation.org>, Hridya Valsaraju <hridya@...gle.com>, Joel Fernandes <joel@...lfernandes.org>, Martijn Coenen <maco@...roid.com>, Suren Baghdasaryan <surenb@...gle.com>, Todd Kjos <tkjos@...roid.com>, Matthew Wilcox <willy@...radead.org>, Arve Hjønnevåg <arve@...roid.com> Subject: Re: [PATCH] binder_alloc: Add missing mmap_lock calls when using the VMA On Tue, Aug 09, 2022 at 07:02:17PM +0000, Liam Howlett wrote: > > > > do we need to hold on to the lock while we loop through the pages here? > > I think we do? Holding this lock will ensure the pages don't go away, I > believe (looking at mm/rmap.c comments on locking at the top)? > > In any case, this function is called from print_binder_proc_stats() > which looks to be a debugfs/debugging call so I thought safer would be > better than faster and with a potential race. The pages are protected by alloc->mutex, so you could immediately release the mmap lock after binder_alloc_get_vma() call. I agree this is a debugging call so it would be nice to reduce contention.
Powered by blists - more mailing lists