From: Logan Gunthorpe <logang@deltatee.com>
To: Leon Romanovsky <leon@kernel.org>,
Bjorn Helgaas <bhelgaas@google.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Jens Axboe <axboe@kernel.dk>, Alex Williamson <alex@shazbot.org>,
Ankit Agrawal <ankita@nvidia.com>, Jason Gunthorpe <jgg@ziepe.ca>,
Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
"Joerg Roedel (AMD)" <joro@8bytes.org>,
Will Deacon <will@kernel.org>,
Robin Murphy <robin.murphy@arm.com>
Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-doc@vger.kernel.org, iommu@lists.linux.dev,
Tushar Dave <tdave@nvidia.com>, Matt Evans <matt@ozlabs.org>
Subject: Re: [PATCH v4 02/18] PCI/P2PDMA: Wait for RCU readers before freeing state
Date: Fri, 21 Aug 2026 17:10:24 -0600 [thread overview]
Message-ID: <de397acb-c5c0-491e-9361-e39c4b385584@deltatee.com> (raw)
In-Reply-To: <20260821-fix-p2p-acs-v4-0-v4-2-94426b96de73@nvidia.com>
On 2026-08-21 13:38, Leon Romanovsky wrote:
> From: Leon Romanovsky <leonro@nvidia.com>
>
> pci_p2pmem_find_many() scans all PCI devices without locking or
> protection against driver unbind, including devices with poolless
> P2PDMA state. pci_has_p2pmem() may observe pdev->p2pdma just before
> driver unbind clears it, while pci_p2pdma_release() skips the grace
> period when no pool is present. This allows devres to free the object
> while it is still in use.
>
> Clear the pointer with RCU_INIT_POINTER() and always wait for pre-existing
> RCU readers before returning. The same grace period continues to protect
> gen_pool users for pool-backed providers.
>
> Tested-by: Tushar Dave <tdave@nvidia.com>
> Cc: Alex Williamson <alex@shazbot.org>
> Cc: Matt Evans <matt@ozlabs.org>
> Fixes: 372d6d1b8ae3 ("PCI/P2PDMA: Refactor to separate core P2P functionality from memory allocation")
> Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Sounds fine:
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
next prev parent reply other threads:[~2026-08-21 23:10 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-21 19:38 [PATCH v4 00/18] PCI/P2PDMA: Fix ACS egress control handling Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 01/18] PCI/P2PDMA: Do not tear down the allocate attribute on registration failure Leon Romanovsky
2026-08-21 23:08 ` Logan Gunthorpe
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-21 19:38 ` [PATCH v4 02/18] PCI/P2PDMA: Wait for RCU readers before freeing state Leon Romanovsky
2026-08-21 23:10 ` Logan Gunthorpe [this message]
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-21 19:38 ` [PATCH v4 03/18] PCI/P2PDMA: Restrict the p2pmem search to pool backed providers Leon Romanovsky
2026-08-21 23:14 ` Logan Gunthorpe
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-21 19:38 ` [PATCH v4 04/18] PCI/P2PDMA: Safely terminate ACS redirect lists Leon Romanovsky
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-21 19:38 ` [PATCH v4 05/18] PCI/P2PDMA: Document the pdev->p2pdma lifetime and RCU rules Leon Romanovsky
2026-08-24 20:29 ` I Logan Gunthorpe
2026-08-30 9:14 ` I Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 06/18] PCI/P2PDMA: Gate the host bridge whitelist warning on verbose Leon Romanovsky
2026-08-24 21:08 ` Logan Gunthorpe
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-21 19:38 ` [PATCH v4 07/18] PCI/P2PDMA: Document the Address Type assumption Leon Romanovsky
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-21 19:38 ` [PATCH v4 08/18] PCI: Account for Direct Translated P2P in ACS isolation checks Leon Romanovsky
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-25 15:59 ` Logan Gunthorpe
2026-08-21 19:38 ` [PATCH v4 09/18] PCI: Add ACS egress control vector accessor Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 10/18] PCI: Account for ACS egress control in isolation checks Leon Romanovsky
2026-08-24 23:22 ` Jason Gunthorpe
2026-08-30 9:20 ` Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 11/18] PCI/P2PDMA: Derive peer-to-peer routing from ACS control bits Leon Romanovsky
2026-08-25 19:17 ` Logan Gunthorpe
2026-08-21 19:38 ` [PATCH v4 12/18] PCI/P2PDMA: Honor ACS egress control vectors Leon Romanovsky
2026-08-25 19:25 ` Logan Gunthorpe
2026-08-21 19:38 ` [PATCH v4 13/18] PCI/P2PDMA: Document ACS egress control handling Leon Romanovsky
2026-08-25 19:52 ` Logan Gunthorpe
2026-08-21 19:38 ` [PATCH v4 14/18] PCI/P2PDMA: Extract pure ACS routing decision helpers Leon Romanovsky
2026-08-25 19:55 ` Logan Gunthorpe
2026-08-21 19:38 ` [PATCH v4 15/18] PCI/P2PDMA: Add KUnit tests for ACS routing decisions Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 16/18] PCI/P2PDMA: Add KUnit coverage for the ACS P2P routing walk Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 17/18] PCI: Add KUnit coverage for ACS isolation checks Leon Romanovsky
2026-08-21 19:38 ` [PATCH v4 18/18] PCI/P2PDMA: Log detailed ACS routing diagnostics Leon Romanovsky
2026-08-25 20:02 ` Logan Gunthorpe
2026-08-30 8:37 ` Leon Romanovsky
2026-08-24 23:22 ` [PATCH v4 00/18] PCI/P2PDMA: Fix ACS egress control handling Jason Gunthorpe
2026-08-30 9:02 ` Leon Romanovsky
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