linux-kernel - Re: [syzbot ci] Re: make vmalloc gfp flags usage more apparent

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] [day] [month] [year] [list]

Message-ID: <aRYNOIQ0A4g6BClW@milan>
Date: Thu, 13 Nov 2025 17:54:16 +0100
From: Uladzislau Rezki <urezki@...il.com>
To: "Vishal Moola (Oracle)" <vishal.moola@...il.com>
Cc: Uladzislau Rezki <urezki@...il.com>, akpm@...ux-foundation.org,
	bpf@...r.kernel.org, hch@...radead.org, hch@....de,
	linux-kernel@...r.kernel.org, linux-mm@...ck.org,
	syzbot@...ts.linux.dev, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot ci] Re: make vmalloc gfp flags usage more apparent

On Thu, Nov 13, 2025 at 08:48:41AM -0800, Vishal Moola (Oracle) wrote:
> On Thu, Nov 13, 2025 at 02:33:31PM +0100, Uladzislau Rezki wrote:
> > On Wed, Nov 12, 2025 at 11:41:37PM -0800, syzbot ci wrote:
> > > syzbot ci has tested the following series
> > > 
> > > [v2] make vmalloc gfp flags usage more apparent
> > > https://lore.kernel.org/all/20251112185834.32487-1-vishal.moola@gmail.com
> > > * [PATCH v2 1/4] mm/vmalloc: warn on invalid vmalloc gfp flags
> > > * [PATCH v2 2/4] mm/vmalloc: Add a helper to optimize vmalloc allocation gfps
> > > * [PATCH v2 3/4] mm/vmalloc: cleanup large_gfp in vm_area_alloc_pages()
> > > * [PATCH v2 4/4] mm/vmalloc: cleanup gfp flag use in new_vmap_block()
> > > 
> > > and found the following issue:
> > > WARNING: kmalloc bug in bpf_prog_alloc_no_stats
> > > 
> > > Full report is available here:
> > > https://ci.syzbot.org/series/46d6cb1a-188d-4ff5-8fab-9c58465d74d3
> > > 
> > > ***
> > > 
> > > WARNING: kmalloc bug in bpf_prog_alloc_no_stats
> > > 
> > > tree:      linux-next
> > > URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/next/linux-next
> > > base:      b179ce312bafcb8c68dc718e015aee79b7939ff0
> > > arch:      amd64
> > > compiler:  Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8
> > > config:    https://ci.syzbot.org/builds/3449e2a5-35e0-4eac-86c6-97ca0ec741d7/config
> > > 
> > > ------------[ cut here ]------------
> > > Unexpected gfp: 0x400000 (__GFP_ACCOUNT). Fixing up to gfp: 0xdc0 (GFP_KERNEL|__GFP_ZERO). Fix your code!
> > > WARNING: mm/vmalloc.c:3938 at vmalloc_fix_flags+0x9c/0xe0, CPU#1: syz-executor/6079
> > > Modules linked in:
> > >
> > Again bpf :)
> > 
> > GFP_KERNEL_ACCOUNT? I saw there have been __GFP_HARDWALL added already,
> > IMO it is worth to replace it by "high level flag", which is GFP_USER.
> 
> Yeah I'll replace __GFP_HARDWALL with GFP_USER, and add
> GFP_KERNEL_ACCOUNT. At this point I'll just add GFP_NOFS and GFP_NOIO
> as well so its easier to understand the mask.
>
Sounds good!

--
Uladzislau Rezki