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
| ||
|
Date: Thu, 19 Nov 2020 15:26:50 -0800 From: si-wei liu <si-wei.liu@...cle.com> To: mst@...hat.com CC: Jason Wang <jasowang@...hat.com>, lingshan.zhu@...el.com, joao.m.martins@...cle.com, boris.ostrovsky@...cle.com, linux-kernel@...r.kernel.org, virtualization@...ts.linux-foundation.org Subject: Re: [PATCH v3] vhost-vdpa: fix page pinning leakage in error path (rework) A gentle reminder. Any chance this patch will get picked soon? Thanks, -Siwei On 11/9/2020 7:28 PM, Jason Wang wrote: > > On 2020/11/6 上午7:26, Si-Wei Liu wrote: >> Pinned pages are not properly accounted particularly when >> mapping error occurs on IOTLB update. Clean up dangling >> pinned pages for the error path. >> >> The memory usage for bookkeeping pinned pages is reverted >> to what it was before: only one single free page is needed. >> This helps reduce the host memory demand for VM with a large >> amount of memory, or in the situation where host is running >> short of free memory. >> >> Fixes: 4c8cf31885f6 ("vhost: introduce vDPA-based backend") >> Signed-off-by: Si-Wei Liu <si-wei.liu@...cle.com> >> --- >> Changes in v3: >> - Turn explicit last_pfn check to a WARN_ON() (Jason) >> >> Changes in v2: >> - Drop the reversion patch >> - Fix unhandled page leak towards the end of page_list > > > Acked-by: Jason Wang <jasowang@...hat.com> > > Thanks > > >> >> drivers/vhost/vdpa.c | 80 >> ++++++++++++++++++++++++++++++++++++++++------------ >> 1 file changed, 62 insertions(+), 18 deletions(-) >> >> diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c >> index b6d9016..5b13dfd 100644 >> --- a/drivers/vhost/vdpa.c >> +++ b/drivers/vhost/vdpa.c >> @@ -560,6 +560,8 @@ static int vhost_vdpa_map(struct vhost_vdpa *v, >> if (r) >> vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1); >> + else >> + atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm); >> return r; >> } >> @@ -591,14 +593,16 @@ static int >> vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, >> unsigned long list_size = PAGE_SIZE / sizeof(struct page *); >> unsigned int gup_flags = FOLL_LONGTERM; >> unsigned long npages, cur_base, map_pfn, last_pfn = 0; >> - unsigned long locked, lock_limit, pinned, i; >> + unsigned long lock_limit, sz2pin, nchunks, i; >> u64 iova = msg->iova; >> + long pinned; >> int ret = 0; >> if (vhost_iotlb_itree_first(iotlb, msg->iova, >> msg->iova + msg->size - 1)) >> return -EEXIST; >> + /* Limit the use of memory for bookkeeping */ >> page_list = (struct page **) __get_free_page(GFP_KERNEL); >> if (!page_list) >> return -ENOMEM; >> @@ -607,52 +611,75 @@ static int >> vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, >> gup_flags |= FOLL_WRITE; >> npages = PAGE_ALIGN(msg->size + (iova & ~PAGE_MASK)) >> >> PAGE_SHIFT; >> - if (!npages) >> - return -EINVAL; >> + if (!npages) { >> + ret = -EINVAL; >> + goto free; >> + } >> mmap_read_lock(dev->mm); >> - locked = atomic64_add_return(npages, &dev->mm->pinned_vm); >> lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; >> - >> - if (locked > lock_limit) { >> + if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) { >> ret = -ENOMEM; >> - goto out; >> + goto unlock; >> } >> cur_base = msg->uaddr & PAGE_MASK; >> iova &= PAGE_MASK; >> + nchunks = 0; >> while (npages) { >> - pinned = min_t(unsigned long, npages, list_size); >> - ret = pin_user_pages(cur_base, pinned, >> - gup_flags, page_list, NULL); >> - if (ret != pinned) >> + sz2pin = min_t(unsigned long, npages, list_size); >> + pinned = pin_user_pages(cur_base, sz2pin, >> + gup_flags, page_list, NULL); >> + if (sz2pin != pinned) { >> + if (pinned < 0) { >> + ret = pinned; >> + } else { >> + unpin_user_pages(page_list, pinned); >> + ret = -ENOMEM; >> + } >> goto out; >> + } >> + nchunks++; >> if (!last_pfn) >> map_pfn = page_to_pfn(page_list[0]); >> - for (i = 0; i < ret; i++) { >> + for (i = 0; i < pinned; i++) { >> unsigned long this_pfn = page_to_pfn(page_list[i]); >> u64 csize; >> if (last_pfn && (this_pfn != last_pfn + 1)) { >> /* Pin a contiguous chunk of memory */ >> csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT; >> - if (vhost_vdpa_map(v, iova, csize, >> - map_pfn << PAGE_SHIFT, >> - msg->perm)) >> + ret = vhost_vdpa_map(v, iova, csize, >> + map_pfn << PAGE_SHIFT, >> + msg->perm); >> + if (ret) { >> + /* >> + * Unpin the pages that are left unmapped >> + * from this point on in the current >> + * page_list. The remaining outstanding >> + * ones which may stride across several >> + * chunks will be covered in the common >> + * error path subsequently. >> + */ >> + unpin_user_pages(&page_list[i], >> + pinned - i); >> goto out; >> + } >> + >> map_pfn = this_pfn; >> iova += csize; >> + nchunks = 0; >> } >> last_pfn = this_pfn; >> } >> - cur_base += ret << PAGE_SHIFT; >> - npages -= ret; >> + cur_base += pinned << PAGE_SHIFT; >> + npages -= pinned; >> } >> /* Pin the rest chunk */ >> @@ -660,10 +687,27 @@ static int >> vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v, >> map_pfn << PAGE_SHIFT, msg->perm); >> out: >> if (ret) { >> + if (nchunks) { >> + unsigned long pfn; >> + >> + /* >> + * Unpin the outstanding pages which are yet to be >> + * mapped but haven't due to vdpa_map() or >> + * pin_user_pages() failure. >> + * >> + * Mapped pages are accounted in vdpa_map(), hence >> + * the corresponding unpinning will be handled by >> + * vdpa_unmap(). >> + */ >> + WARN_ON(!last_pfn); >> + for (pfn = map_pfn; pfn <= last_pfn; pfn++) >> + unpin_user_page(pfn_to_page(pfn)); >> + } >> vhost_vdpa_unmap(v, msg->iova, msg->size); >> - atomic64_sub(npages, &dev->mm->pinned_vm); >> } >> +unlock: >> mmap_read_unlock(dev->mm); >> +free: >> free_page((unsigned long)page_list); >> return ret; >> } >
Powered by blists - more mailing lists