linux-kernel - Re: Linux6.14-rc5 BUG: spinlock bad magic in z3fold_zpool

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: <CAKEwX=NbpaQcq_awoPKmAuPWL=D4C2W7o_9D3J_SuDFvtbo9Ag@mail.gmail.com>
Date: Wed, 26 Mar 2025 15:43:28 -0400
From: Nhat Pham <nphamcs@...il.com>
To: ffhgfv <xnxc22xnxc22@...com>
Cc: "vitaly.wool" <vitaly.wool@...sulko.com>, linmiaohe <linmiaohe@...wei.com>, 
	akpm <akpm@...ux-foundation.org>, linux-mm <linux-mm@...ck.org>, 
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: Re: Linux6.14-rc5 BUG: spinlock bad magic in z3fold_zpool_free

On Wed, Mar 26, 2025 at 10:32 AM Nhat Pham <nphamcs@...il.com> wrote:
>
> On Wed, Mar 26, 2025 at 10:11 AM ffhgfv <xnxc22xnxc22@...com> wrote:
> >
> > Hello, I found a bug titled " BUG: spinlock bad magic in z3fold_zpool_free   " with modified syzkaller in the Linux6.14-rc5.
> > If you fix this issue, please add the following tag to the commit:  Reported-by: Jianzhou Zhao <xnxc22xnxc22@...com>,    xingwei lee <xrivendell7@...il.com>, Zhizhuo Tang <strforexctzzchange@...mail.com>
>
> Please stop using z3fold :) We already removed it upstream.

To clarify a little bit - we've found that z3fold is buggy (for a very
long time), and does not outperform zsmalloc in many of the workloads
we test on (both microbenchmark and real production workloads). We've
deprecated it since 6.12:

https://github.com/torvalds/linux/commit/7a2369b74abf76cd3e54c45b30f6addb497f831b

and will remove it altogether:

https://lore.kernel.org/all/20250129180633.3501650-1-yosry.ahmed@linux.dev/

Perhaps Vitaly can fix the issue for stability's sake (or in case
there is a reason why you MUST use z3fold)? But I strongly recommend
you experiment with zsmalloc :)