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Tsirkin" , Jason Wang , Xuan Zhuo , =?utf-8?q?Eugenio_P=C3=A9rez?= , Maxime Coquelin Subject: [PATCH RFT v2 1/4] vpda: try to fix the potential crash due to misusing __GFP_NOFAIL Date: Wed, 31 Jul 2024 12:01:52 +1200 Message-Id: <20240731000155.109583-2-21cnbao@gmail.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20240731000155.109583-1-21cnbao@gmail.com> References: <20240731000155.109583-1-21cnbao@gmail.com> MIME-Version: 1.0 X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 77B591C0015 X-Stat-Signature: pw471ftne7iwo34r9r4ghq6azrxw1gs6 X-HE-Tag: 1722384171-926928 X-HE-Meta: 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 0Aa/NmJy 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: From: Barry Song mm doesn't support non-blockable __GFP_NOFAIL allocation. Because __GFP_NOFAIL without direct reclamation may just result in a busy loop within non-sleepable contexts. static inline struct page * __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct alloc_context *ac) { ... /* * Make sure that __GFP_NOFAIL request doesn't leak out and make sure * we always retry */ if (gfp_mask & __GFP_NOFAIL) { /* * All existing users of the __GFP_NOFAIL are blockable, so warn * of any new users that actually require GFP_NOWAIT */ if (WARN_ON_ONCE_GFP(!can_direct_reclaim, gfp_mask)) goto fail; ... } ... fail: warn_alloc(gfp_mask, ac->nodemask, "page allocation failure: order:%u", order); got_pg: return page; } Let's move the memory allocation out of the atomic context and use the normal sleepable context to get pages. [RFT]: This has only been compile-tested; I'd prefer if the VDPA maintainers handles it. Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: Xuan Zhuo Cc: "Eugenio Pérez" Cc: Maxime Coquelin Signed-off-by: Barry Song --- drivers/vdpa/vdpa_user/iova_domain.c | 31 +++++++++++++++++++++++----- drivers/vdpa/vdpa_user/iova_domain.h | 5 ++++- drivers/vdpa/vdpa_user/vduse_dev.c | 4 +++- 3 files changed, 33 insertions(+), 7 deletions(-) diff --git a/drivers/vdpa/vdpa_user/iova_domain.c b/drivers/vdpa/vdpa_user/iova_domain.c index 791d38d6284c..9318f059a8b5 100644 --- a/drivers/vdpa/vdpa_user/iova_domain.c +++ b/drivers/vdpa/vdpa_user/iova_domain.c @@ -283,7 +283,23 @@ int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain, return ret; } -void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain) +struct page **vduse_domain_alloc_pages_to_remove_bounce(struct vduse_iova_domain *domain) +{ + struct page **pages; + unsigned long count, i; + + if (!domain->user_bounce_pages) + return NULL; + + count = domain->bounce_size >> PAGE_SHIFT; + pages = kmalloc_array(count, sizeof(*pages), GFP_KERNEL | __GFP_NOFAIL); + for (i = 0; i < count; i++) + pages[i] = alloc_page(GFP_KERNEL | __GFP_NOFAIL); + + return pages; +} + +void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain, struct page **pages) { struct vduse_bounce_map *map; unsigned long i, count; @@ -294,15 +310,16 @@ void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain) count = domain->bounce_size >> PAGE_SHIFT; for (i = 0; i < count; i++) { - struct page *page = NULL; + struct page *page = pages[i]; map = &domain->bounce_maps[i]; - if (WARN_ON(!map->bounce_page)) + if (WARN_ON(!map->bounce_page)) { + put_page(page); continue; + } /* Copy user page to kernel page if it's in use */ if (map->orig_phys != INVALID_PHYS_ADDR) { - page = alloc_page(GFP_ATOMIC | __GFP_NOFAIL); memcpy_from_page(page_address(page), map->bounce_page, 0, PAGE_SIZE); } @@ -310,6 +327,7 @@ void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain) map->bounce_page = page; } domain->user_bounce_pages = false; + kfree(pages); out: write_unlock(&domain->bounce_lock); } @@ -543,10 +561,13 @@ static int vduse_domain_mmap(struct file *file, struct vm_area_struct *vma) static int vduse_domain_release(struct inode *inode, struct file *file) { struct vduse_iova_domain *domain = file->private_data; + struct page **pages; + + pages = vduse_domain_alloc_pages_to_remove_bounce(domain); spin_lock(&domain->iotlb_lock); vduse_iotlb_del_range(domain, 0, ULLONG_MAX); - vduse_domain_remove_user_bounce_pages(domain); + vduse_domain_remove_user_bounce_pages(domain, pages); vduse_domain_free_kernel_bounce_pages(domain); spin_unlock(&domain->iotlb_lock); put_iova_domain(&domain->stream_iovad); diff --git a/drivers/vdpa/vdpa_user/iova_domain.h b/drivers/vdpa/vdpa_user/iova_domain.h index f92f22a7267d..17efa5555b3f 100644 --- a/drivers/vdpa/vdpa_user/iova_domain.h +++ b/drivers/vdpa/vdpa_user/iova_domain.h @@ -74,7 +74,10 @@ void vduse_domain_reset_bounce_map(struct vduse_iova_domain *domain); int vduse_domain_add_user_bounce_pages(struct vduse_iova_domain *domain, struct page **pages, int count); -void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain); +void vduse_domain_remove_user_bounce_pages(struct vduse_iova_domain *domain, + struct page **pages); + +struct page **vduse_domain_alloc_pages_to_remove_bounce(struct vduse_iova_domain *domain); void vduse_domain_destroy(struct vduse_iova_domain *domain); diff --git a/drivers/vdpa/vdpa_user/vduse_dev.c b/drivers/vdpa/vdpa_user/vduse_dev.c index 7ae99691efdf..5d8d5810df57 100644 --- a/drivers/vdpa/vdpa_user/vduse_dev.c +++ b/drivers/vdpa/vdpa_user/vduse_dev.c @@ -1030,6 +1030,7 @@ static int vduse_dev_queue_irq_work(struct vduse_dev *dev, static int vduse_dev_dereg_umem(struct vduse_dev *dev, u64 iova, u64 size) { + struct page **pages; int ret; mutex_lock(&dev->mem_lock); @@ -1044,7 +1045,8 @@ static int vduse_dev_dereg_umem(struct vduse_dev *dev, if (dev->umem->iova != iova || size != dev->domain->bounce_size) goto unlock; - vduse_domain_remove_user_bounce_pages(dev->domain); + pages = vduse_domain_alloc_pages_to_remove_bounce(dev->domain); + vduse_domain_remove_user_bounce_pages(dev->domain, pages); unpin_user_pages_dirty_lock(dev->umem->pages, dev->umem->npages, true); atomic64_sub(dev->umem->npages, &dev->umem->mm->pinned_vm);