From: Dan Williams <dan.j.williams@intel.com> To: akpm@linux-foundation.org Cc: "Ira Weiny" <ira.weiny@intel.com>, "Bjorn Helgaas" <bhelgaas@google.com>, "Logan Gunthorpe" <logang@deltatee.com>, "Christoph Hellwig" <hch@lst.de>, "Jérôme Glisse" <jglisse@redhat.com>, "Greg Kroah-Hartman" <gregkh@linuxfoundation.org>, "Rafael J. Wysocki" <rafael@kernel.org>, linux-mm@kvack.org, linux-pci@vger.kernel.org, linux-nvdimm@lists.01.org, linux-kernel@vger.kernel.org Subject: [PATCH 0/6] mm/devm_memremap_pages: Fix page release race Date: Fri, 29 Mar 2019 08:27:24 -0700 Message-ID: <155387324370.2443841.574715745262628837.stgit@dwillia2-desk3.amr.corp.intel.com> (raw) Logan audited the devm_memremap_pages() shutdown path and noticed that it was possible to proceed to arch_remove_memory() before all potential page references have been reaped. Introduce a new ->cleanup() callback to do the work of waiting for any straggling page references and then perform the percpu_ref_exit() in devm_memremap_pages_release() context. For p2pdma this involves some deeper reworks to reference count resources on a per-instance basis rather than a per pci-device basis. A modified genalloc api is introduced to convey a driver-private pointer through gen_pool_{alloc,free}() interfaces. Also, a devm_memunmap_pages() api is introduced since p2pdma does not auto-release resources on a setup failure. The dax and pmem changes pass the nvdimm unit tests, but the hmm and p2pdma changes are compile-tested only. Thoughts on the api changes? I'm targeting to land this through Andrew's tree. 0day has chewed on this for a day and reported no issues so far. --- Dan Williams (6): drivers/base/devres: Introduce devm_release_action() mm/devm_memremap_pages: Introduce devm_memunmap_pages pci/p2pdma: Fix the gen_pool_add_virt() failure path lib/genalloc: Introduce chunk owners pci/p2pdma: Track pgmap references per resource, not globally mm/devm_memremap_pages: Fix final page put race drivers/base/devres.c | 24 ++++++++ drivers/dax/device.c | 13 +---- drivers/nvdimm/pmem.c | 17 +++++- drivers/pci/p2pdma.c | 105 +++++++++++++++++++++++-------------- include/linux/device.h | 1 include/linux/genalloc.h | 55 +++++++++++++++++-- include/linux/memremap.h | 8 +++ kernel/memremap.c | 23 ++++++-- lib/genalloc.c | 51 +++++++++--------- mm/hmm.c | 14 +---- tools/testing/nvdimm/test/iomap.c | 2 + 11 files changed, 209 insertions(+), 104 deletions(-)
next reply index Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-03-29 15:27 Dan Williams [this message] 2019-03-29 15:27 ` [PATCH 1/6] drivers/base/devres: Introduce devm_release_action() Dan Williams 2019-03-29 15:27 ` [PATCH 2/6] mm/devm_memremap_pages: Introduce devm_memunmap_pages Dan Williams 2019-03-29 15:27 ` [PATCH 3/6] pci/p2pdma: Fix the gen_pool_add_virt() failure path Dan Williams 2019-03-29 17:24 ` Bjorn Helgaas 2019-03-29 15:27 ` [PATCH 4/6] lib/genalloc: Introduce chunk owners Dan Williams 2019-03-29 15:27 ` [PATCH 5/6] pci/p2pdma: Track pgmap references per resource, not globally Dan Williams 2019-03-29 17:50 ` Logan Gunthorpe 2019-03-29 19:32 ` Dan Williams 2019-03-29 15:27 ` [PATCH 6/6] mm/devm_memremap_pages: Fix final page put race Dan Williams 2019-03-29 9:46 ` Ira Weiny
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