linux-kernel - [PATCH 01/13] PCI/P2PDMA: Release the per-cpu ref of pgmap when vm_insert

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] [thread-next>] [day] [month] [year] [list]

Message-Id: <20251220040446.274991-2-houtao@huaweicloud.com>
Date: Sat, 20 Dec 2025 12:04:34 +0800
From: Hou Tao <houtao@...weicloud.com>
To: linux-kernel@...r.kernel.org
Cc: linux-pci@...r.kernel.org,
	linux-mm@...ck.org,
	linux-nvme@...ts.infradead.org,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	Logan Gunthorpe <logang@...tatee.com>,
	Alistair Popple <apopple@...dia.com>,
	Leon Romanovsky <leonro@...dia.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Tejun Heo <tj@...nel.org>,
	"Rafael J . Wysocki" <rafael@...nel.org>,
	Danilo Krummrich <dakr@...nel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	David Hildenbrand <david@...nel.org>,
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>,
	Keith Busch <kbusch@...nel.org>,
	Jens Axboe <axboe@...nel.dk>,
	Christoph Hellwig <hch@....de>,
	Sagi Grimberg <sagi@...mberg.me>,
	houtao1@...wei.com
Subject: [PATCH 01/13] PCI/P2PDMA: Release the per-cpu ref of pgmap when vm_insert_page() fails

From: Hou Tao <houtao1@...wei.com>

When vm_insert_page() fails in p2pmem_alloc_mmap(), p2pmem_alloc_mmap()
doesn't invoke percpu_ref_put() to free the per-cpu ref of pgmap
acquired after gen_pool_alloc_owner(), and memunmap_pages() will hang
forever when trying to remove the PCIe device.

Fix it by adding the missed percpu_ref_put().

Fixes: 7e9c7ef83d78 ("PCI/P2PDMA: Allow userspace VMA allocations through sysfs")
Signed-off-by: Hou Tao <houtao1@...wei.com>
---
 drivers/pci/p2pdma.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/pci/p2pdma.c b/drivers/pci/p2pdma.c
index 4a2fc7ab42c3..218c1f5252b6 100644
--- a/drivers/pci/p2pdma.c
+++ b/drivers/pci/p2pdma.c
@@ -152,6 +152,7 @@ static int p2pmem_alloc_mmap(struct file *filp, struct kobject *kobj,
 		ret = vm_insert_page(vma, vaddr, page);
 		if (ret) {
 			gen_pool_free(p2pdma->pool, (uintptr_t)kaddr, len);
+			percpu_ref_put(ref);
 			return ret;
 		}
 		percpu_ref_get(ref);
-- 
2.29.2