linux-kernel - Re: [PATCH] x86/CPU/AMD: Prevent reset reasons from being retained among boots

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: <20251006214148.GKaOQ3nNAl0BsC85Hf@fat_crate.local>
Date: Mon, 6 Oct 2025 23:41:48 +0200
From: Borislav Petkov <bp@...en8.de>
To: Rong Zhang <i@...g.moe>
Cc: "Mario Limonciello (AMD) (kernel.org)" <superm1@...nel.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	Dave Hansen <dave.hansen@...ux.intel.com>, x86@...nel.org,
	"H. Peter Anvin" <hpa@...or.com>,
	Yazen Ghannam <yazen.ghannam@....com>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] x86/CPU/AMD: Prevent reset reasons from being retained
 among boots

On Tue, Oct 07, 2025 at 01:07:45AM +0800, Rong Zhang wrote:
> Perhaps we could improve the wording in the documentation? I.e., mentioning
> that non-listed bits have nothing to do with reboot reasons.

You don't need to document in that detail. That's in the code itself:
s5_reset_reason_txt is sparse and that already tells you that not every bit in
the corresponding register is a reboot reason. It could just as well be junk
for all we know...

> That said, I am OK to remove the debug message printing the cleared
> value. If we decide that it's better to remove it, I will send a [PATCH
> v2].

The fix should be to simply write back the value read before we return from
that function.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette