[PATCH 0/2] Fix double allocation in swiotlb_alloc()

From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: kernel-team@android.com, Will Deacon <will@kernel.org>,
	iommu@lists.linux.dev, Christoph Hellwig <hch@lst.de>,
	Marek Szyprowski <m.szyprowski@samsung.com>,
	Robin Murphy <robin.murphy@arm.com>,
	Petr Tesarik <petr.tesarik1@huawei-partners.com>,
	Dexuan Cui <decui@microsoft.com>
Subject: [PATCH 0/2] Fix double allocation in swiotlb_alloc()
Date: Fri, 26 Jan 2024 15:19:54 +0000	[thread overview]
Message-ID: <20240126151956.10014-1-will@kernel.org> (raw)

Hi folks,

These two patches fix a nasty double allocation problem in swiotlb_alloc()
and add a diagnostic to help catch any similar issues in future. This was
a royal pain to track down and I've had to make a bit of a leap at the
correct alignment semantics (i.e. iotlb_align_mask vs alloc_align_mask).

Without these changes, we've been observing random vsock hangs when
communicating with virtual machines in Android.

Please have a look!

Cheers,

Will

Cc: iommu@lists.linux.dev
Cc: Christoph Hellwig <hch@lst.de>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Robin Murphy <robin.murphy@arm.com>
Cc: Petr Tesarik <petr.tesarik1@huawei-partners.com>
Cc: Dexuan Cui <decui@microsoft.com>

--->8

Will Deacon (2):
  swiotlb: Fix allocation alignment requirement when searching slots
  swiotlb: Enforce page alignment in swiotlb_alloc()

 kernel/dma/swiotlb.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

-- 
2.43.0.429.g432eaa2c6b-goog