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Wed, 12 Apr 2023 07:53:04 -0700 (PDT) Date: Wed, 12 Apr 2023 16:52:59 +0200 Mime-Version: 1.0 X-Mailer: git-send-email 2.40.0.577.gac1e443424-goog Message-ID: <20230412145300.3651840-1-glider@google.com> Subject: [PATCH 1/2] mm: kmsan: handle alloc failures in kmsan_vmap_pages_range_noflush() From: Alexander Potapenko To: glider@google.com Cc: urezki@gmail.com, hch@infradead.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, akpm@linux-foundation.org, elver@google.com, dvyukov@google.com, kasan-dev@googlegroups.com, Dipanjan Das Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 784F520024 X-Stat-Signature: kao9o14owu14h8xfk9d9jarzyofk7j4q X-HE-Tag: 1681311185-394179 X-HE-Meta: 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 0sCBp789 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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: As reported by Dipanjan Das, when KMSAN is used together with kernel fault injection (or, generally, even without the latter), calls to kcalloc() or __vmap_pages_range_noflush() may fail, leaving the metadata mappings for the virtual mapping in an inconsistent state. When these metadata mappings are accessed later, the kernel crashes. To address the problem, we return a non-zero error code from kmsan_vmap_pages_range_noflush() in the case of any allocation/mapping failure inside it, and make vmap_pages_range_noflush() return an error if KMSAN fails to allocate the metadata. This patch also removes KMSAN_WARN_ON() from vmap_pages_range_noflush(), as these allocation failures are not fatal anymore. Reported-by: Dipanjan Das Link: https://lore.kernel.org/linux-mm/CANX2M5ZRrRA64k0hOif02TjmY9kbbO2aCBPyq79es34RXZ=cAw@mail.gmail.com/ Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations") Signed-off-by: Alexander Potapenko --- include/linux/kmsan.h | 19 ++++++++++--------- mm/kmsan/shadow.c | 27 ++++++++++++++++++--------- mm/vmalloc.c | 6 +++++- 3 files changed, 33 insertions(+), 19 deletions(-) diff --git a/include/linux/kmsan.h b/include/linux/kmsan.h index e38ae3c346184..a0769d4aad1c8 100644 --- a/include/linux/kmsan.h +++ b/include/linux/kmsan.h @@ -134,11 +134,12 @@ void kmsan_kfree_large(const void *ptr); * @page_shift: page_shift passed to vmap_range_noflush(). * * KMSAN maps shadow and origin pages of @pages into contiguous ranges in - * vmalloc metadata address range. + * vmalloc metadata address range. Returns 0 on success, callers must check + * for non-zero return value. */ -void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, - pgprot_t prot, struct page **pages, - unsigned int page_shift); +int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift); /** * kmsan_vunmap_kernel_range_noflush() - Notify KMSAN about a vunmap. @@ -281,11 +282,11 @@ static inline void kmsan_kfree_large(const void *ptr) { } -static inline void kmsan_vmap_pages_range_noflush(unsigned long start, - unsigned long end, - pgprot_t prot, - struct page **pages, - unsigned int page_shift) +static inline int kmsan_vmap_pages_range_noflush(unsigned long start, + unsigned long end, + pgprot_t prot, + struct page **pages, + unsigned int page_shift) { } diff --git a/mm/kmsan/shadow.c b/mm/kmsan/shadow.c index a787c04e9583c..b8bb95eea5e3d 100644 --- a/mm/kmsan/shadow.c +++ b/mm/kmsan/shadow.c @@ -216,27 +216,29 @@ void kmsan_free_page(struct page *page, unsigned int order) kmsan_leave_runtime(); } -void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, - pgprot_t prot, struct page **pages, - unsigned int page_shift) +int kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, + pgprot_t prot, struct page **pages, + unsigned int page_shift) { unsigned long shadow_start, origin_start, shadow_end, origin_end; struct page **s_pages, **o_pages; - int nr, mapped; + int nr, mapped, err = 0; if (!kmsan_enabled) - return; + return 0; shadow_start = vmalloc_meta((void *)start, KMSAN_META_SHADOW); shadow_end = vmalloc_meta((void *)end, KMSAN_META_SHADOW); if (!shadow_start) - return; + return 0; nr = (end - start) / PAGE_SIZE; s_pages = kcalloc(nr, sizeof(*s_pages), GFP_KERNEL); o_pages = kcalloc(nr, sizeof(*o_pages), GFP_KERNEL); - if (!s_pages || !o_pages) + if (!s_pages || !o_pages) { + err = -ENOMEM; goto ret; + } for (int i = 0; i < nr; i++) { s_pages[i] = shadow_page_for(pages[i]); o_pages[i] = origin_page_for(pages[i]); @@ -249,10 +251,16 @@ void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, kmsan_enter_runtime(); mapped = __vmap_pages_range_noflush(shadow_start, shadow_end, prot, s_pages, page_shift); - KMSAN_WARN_ON(mapped); + if (mapped) { + err = mapped; + goto ret; + } mapped = __vmap_pages_range_noflush(origin_start, origin_end, prot, o_pages, page_shift); - KMSAN_WARN_ON(mapped); + if (mapped) { + err = mapped; + goto ret; + } kmsan_leave_runtime(); flush_tlb_kernel_range(shadow_start, shadow_end); flush_tlb_kernel_range(origin_start, origin_end); @@ -262,6 +270,7 @@ void kmsan_vmap_pages_range_noflush(unsigned long start, unsigned long end, ret: kfree(s_pages); kfree(o_pages); + return err; } /* Allocate metadata for pages allocated at boot time. */ diff --git a/mm/vmalloc.c b/mm/vmalloc.c index a50072066221a..1355d95cce1ca 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -605,7 +605,11 @@ int __vmap_pages_range_noflush(unsigned long addr, unsigned long end, int vmap_pages_range_noflush(unsigned long addr, unsigned long end, pgprot_t prot, struct page **pages, unsigned int page_shift) { - kmsan_vmap_pages_range_noflush(addr, end, prot, pages, page_shift); + int ret = kmsan_vmap_pages_range_noflush(addr, end, prot, pages, + page_shift); + + if (ret) + return ret; return __vmap_pages_range_noflush(addr, end, prot, pages, page_shift); } -- 2.40.0.577.gac1e443424-goog