From: Uladzislau Rezki <urezki@gmail.com>
To: "Vishal Moola (Oracle)" <vishal.moola@gmail.com>
Cc: Uladzislau Rezki <urezki@gmail.com>,
syzbot ci <syzbot+ci9989da8336cb2bc7@syzkaller.appspotmail.com>,
akpm@linux-foundation.org, hch@lst.de,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
vishal.moola@gmail.com, syzbot@lists.linux.dev,
syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot ci] Re: make vmalloc gfp flags usage more apparent
Date: Wed, 12 Nov 2025 13:02:03 +0100 [thread overview]
Message-ID: <aRR3O7l2Ewx-VRoE@milan> (raw)
In-Reply-To: <aRQyMck_MeVvvCdX@infradead.org>
On Tue, Nov 11, 2025 at 11:07:29PM -0800, Christoph Hellwig wrote:
> On Tue, Nov 11, 2025 at 09:21:06PM +0100, Uladzislau Rezki wrote:
> > > Unexpected gfp: 0x100000 (__GFP_HARDWALL). Fixing up to gfp: 0xdc0 (GFP_KERNEL|__GFP_ZERO). Fix your code!
> > >
> > It looks like we need to add __GFP_HARDWALL to the white-list-mask.
>
> __GFP_HARDWALL is part of GFP_USER. Doing GFP_USER vmalloc sounds like
> a bit of an odd idea to me, but there are a few users mostly in bpf
> and drm code (why do these always show up for odd API usage patterns?).
>
> So I guess yes, we'll need to allow it for now, but I'd like to start
> a discussion if it really makes much sense.
>
<snip>
/* plain bpf_prog allocation */
prog = bpf_prog_alloc(bpf_prog_size(attr->insn_cnt), GFP_USER);
if (!prog) {
<snip>
I assume that was the place that triggered the splat.
Vishal, will you send the patch adding GFP_USER to address the splat?
--
Uladzislau Rezki
next prev parent reply other threads:[~2025-11-12 12:02 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-10 16:04 [PATCH 0/4] " Vishal Moola (Oracle)
2025-11-10 16:04 ` [PATCH 1/4] mm/vmalloc: warn on invalid vmalloc gfp flags Vishal Moola (Oracle)
2025-11-10 16:04 ` [PATCH 2/4] mm/vmalloc: Add a helper to optimize vmalloc allocation gfps Vishal Moola (Oracle)
2025-11-10 16:04 ` [PATCH 3/4] mm/vmalloc: cleanup large_gfp in vm_area_alloc_pages() Vishal Moola (Oracle)
2025-11-10 16:04 ` [PATCH 4/4] mm/vmalloc: cleanup gfp flag use in new_vmap_block() Vishal Moola (Oracle)
2025-11-10 19:22 ` [syzbot ci] Re: make vmalloc gfp flags usage more apparent syzbot ci
2025-11-11 20:21 ` Uladzislau Rezki
2025-11-12 7:07 ` Christoph Hellwig
2025-11-12 12:02 ` Uladzislau Rezki [this message]
2025-11-12 18:38 ` Vishal Moola (Oracle)
2025-11-12 18:58 [PATCH v2 0/4] " Vishal Moola (Oracle)
2025-11-13 7:41 ` [syzbot ci] " syzbot ci
2025-11-13 13:33 ` Uladzislau Rezki
2025-11-13 16:48 ` Vishal Moola (Oracle)
2025-11-13 16:54 ` Uladzislau Rezki
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