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From: Aneesh Kumar K.V <aneesh.kumar@kernel.org>
To: Jason Gunthorpe <jgg@ziepe.ca>
Cc: iommu@lists.linux.dev, linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org, linux-coco@lists.linux.dev,
	Robin Murphy <robin.murphy@arm.com>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Will Deacon <will@kernel.org>, Marc Zyngier <maz@kernel.org>,
	Steven Price <steven.price@arm.com>,
	Suzuki K Poulose <Suzuki.Poulose@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	Jiri Pirko <jiri@resnulli.us>,
	Mostafa Saleh <smostafa@google.com>,
	Petr Tesarik <ptesarik@suse.com>,
	Alexey Kardashevskiy <aik@amd.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Xu Yilun <yilun.xu@linux.intel.com>,
	linuxppc-dev@lists.ozlabs.org, linux-s390@vger.kernel.org,
	Madhavan Srinivasan <maddy@linux.ibm.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Nicholas Piggin <npiggin@gmail.com>,
	"Christophe Leroy (CS GROUP)" <chleroy@kernel.org>,
	Alexander Gordeev <agordeev@linux.ibm.com>,
	Gerald Schaefer <gerald.schaefer@linux.ibm.com>,
	Heiko Carstens <hca@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>,
	Christian Borntraeger <borntraeger@linux.ibm.com>,
	Sven Schnelle <svens@linux.ibm.com>, x86@kernel.org,
	Michael Kelley <mhklinux@outlook.com>
Subject: Re: [PATCH v7 02/22] dma-pool: fix page leak in
 atomic_pool_expand() cleanup
In-Reply-To: <20260713175433.GI3133966@ziepe.ca>
References: <20260701054926.825925-1-aneesh.kumar@kernel.org>
 <20260701054926.825925-3-aneesh.kumar@kernel.org>
 <20260713175433.GI3133966@ziepe.ca>
Date: Tue, 14 Jul 2026 09:05:25 +0530
Message-ID: <yq5azezumef6.fsf@kernel.org>
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Jason Gunthorpe <jgg@ziepe.ca> writes:

> On Wed, Jul 01, 2026 at 11:19:06AM +0530, Aneesh Kumar K.V (Arm) wrote:
>> @@ -115,8 +116,10 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
>>  	 */
>>  	ret = set_memory_decrypted((unsigned long)page_to_virt(page),
>>  				   1 << order);
>> -	if (ret)
>> +	if (ret) {
>> +		leak_pages = true;
>>  		goto remove_mapping;
>> +	}
>
> Truely these _set_memory_decrypted() things are an insane API. So a if
> it fails to decrypt it can be in any messy state?
>

Yes, we could possibly try to encrypt the page again and, if that
succeeds, avoid leaking it. We might want to do that tree-wide in a
separate patch.

>
>> @@ -130,14 +133,15 @@ static int atomic_pool_expand(struct gen_pool *pool, size_t pool_size,
>>  				   1 << order);
>>  	if (WARN_ON_ONCE(ret)) {
>>  		/* Decrypt succeeded but encrypt failed, purposely leak */
>> -		goto out;
>> +		leak_pages = true;
>
> At least this one makes some sense..
>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
>
> Jason

-aneesh