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Message-ID: <505192e0d4a8d336ff0e934590c761de3a72e3a9.camel@huaweicloud.com>
Subject: Re: [PATCH] arch/x86/um: Disable UBSAN sanitization
From: Roberto Sassu <roberto.sassu@huaweicloud.com>
To: Johannes Berg <johannes@sipsolutions.net>, richard@nod.at, 
	anton.ivanov@cambridgegreys.com, tglx@linutronix.de, mingo@redhat.com, 
	bp@alien8.de, dave.hansen@linux.intel.com, hpa@zytor.com
Cc: x86@kernel.org, linux-um@lists.infradead.org,
 linux-kernel@vger.kernel.org,  zohar@linux.ibm.com,
 linux-integrity@vger.kernel.org, Roberto Sassu <roberto.sassu@huawei.com>
Date: Mon, 13 May 2024 15:16:55 +0200
In-Reply-To: <d4f9861effd64c155f93cc712d2c7660b1cf2e4a.camel@sipsolutions.net>
References: <20240513122754.1282833-1-roberto.sassu@huaweicloud.com>
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On Mon, 2024-05-13 at 15:08 +0200, Johannes Berg wrote:
> On Mon, 2024-05-13 at 14:58 +0200, Roberto Sassu wrote:
> > On Mon, 2024-05-13 at 14:52 +0200, Johannes Berg wrote:
> > > On Mon, 2024-05-13 at 14:42 +0200, Roberto Sassu wrote:
> > > > On Mon, 2024-05-13 at 14:29 +0200, Johannes Berg wrote:
> > > > > On Mon, 2024-05-13 at 14:27 +0200, Roberto Sassu wrote:
> > > > > > From: Roberto Sassu <roberto.sassu@huawei.com>
> > > > > >=20
> > > > > > Disable UBSAN sanitization on UML, since UML does not support i=
t.
> > > > > >=20
> > > > >=20
> > > > > Luckily, that isn't actually true, nor does it actually do this a=
t all.
> > > > > Please fix the commit message.
> > > >=20
> > > > Thanks, I was actually wondering. I based that statement based on
> > > > ARCH_HAS_UBSAN=3Dn.
> > > >=20
> > > > Any other solution would be ok.
> > >=20
> > > Not sure I get it. What you're doing in the patch is perfectly fine a=
nd
> > > almost certainly required, but you're definitely not disabling UBSAN =
on
> > > ARCH=3Dum as you described in the commit message?
> >=20
> > Ok, I guess the right word is instrumentation (got it from commit
> > d4be85d068b44). And the reason is that the vDSO is executing in user
> > space. Will fix it.
>=20
> No, UBSAN is fine, but you're only disabling it for the vDSO :) The
> commit message doesn't even mention the vDSO though.

You are right, the commit message was misleading without vDSO.

Thanks

Roberto