From: Thomas Gleixner <tglx@kernel.org>
To: "Thomas Weißschuh" <thomas.weissschuh@linutronix.de>,
"Andy Lutomirski" <luto@kernel.org>,
"Vincenzo Frascino" <vincenzo.frascino@arm.com>,
"Christophe Leroy (CS GROUP)" <chleroy@kernel.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] vdso/datastore: Zero out newly allocated datastore pages
Date: Thu, 09 Apr 2026 22:21:36 +0200 [thread overview]
Message-ID: <87ik9z28bz.ffs@tglx> (raw)
In-Reply-To: <20260409131620-8b31cf24-e2da-4650-a3f6-97a35fdaeb36@linutronix.de>
On Thu, Apr 09 2026 at 13:17, Thomas Weißschuh wrote:
>> The data pages need to be zeroed initially, as garbage data can break
>> the vDSO userspace logic.
>>
>> Fixes: 05988dba1179 ("vdso/datastore: Allocate data pages dynamically")
>> Link: https://lore.kernel.org/lkml/aQjJNmwniQwwjeBR@finisterre.sirena.org.uk/
>> Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
>> ---
>> I messed up and dropped __GFP_ZERO again when switching from folio_alloc() to
>> alloc_pages() in v6 of "sparc64: vdso: Switch to the generic vDSO library"
>> Previously the missing __GFP_ZERO triggered boot-failures in -next, but
>> apparently with alloc_pages() we got "lucky" so far.
>
> ... I panicked a bit after looking at the code again and not seeing the
> explicit zeroing. The actually works fine, as the memcpy() from the static
> vdso_initdata will do the zeroing.
>
> Sorry for the noise.
Happens to all of us. Better safe than sorry six weeks down the road.
prev parent reply other threads:[~2026-04-09 20:21 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-09 11:14 [PATCH] vdso/datastore: Zero out newly allocated datastore pages Thomas Weißschuh
2026-04-09 11:17 ` Thomas Weißschuh
2026-04-09 20:21 ` Thomas Gleixner [this message]
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