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Thu, 09 Oct 2025 14:38:28 +0800 From: "Huang, Ying" To: Yadong Qi Cc: akpm@linux-foundation.org, urezki@gmail.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: vmalloc: WARN_ON if mapping size is not PAGE_SIZE aligned In-Reply-To: <20251009061410.820-1-yadong.qi@linux.alibaba.com> (Yadong Qi's message of "Thu, 9 Oct 2025 14:14:10 +0800") References: <20251009061410.820-1-yadong.qi@linux.alibaba.com> Date: Thu, 09 Oct 2025 14:38:27 +0800 Message-ID: <87zfa0tw9o.fsf@DESKTOP-5N7EMDA> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii X-Stat-Signature: ze6e79kgf1pnk6aktixysrgp413hcyac X-Rspamd-Queue-Id: 3ED1140005 X-Rspamd-Server: rspam06 X-Rspam-User: X-HE-Tag: 1759991912-831681 X-HE-Meta: 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 eUIKJ3E6 buLWfFIhMSeXb5xLuF81j+QaBMJKMuTY5UuqRz/+qblYRT+Oe9yRee4SMyWPqoPjS8VmZ2v9FLw0B1NXfwbAl9+iV3SBPmE69jRjwxVQD7H8gRw7uD85+enPkTAOd0K8yYilJOFOu1K/TafGYyGfKwyM6JyDyh5OqCq+yS1uvznxKY5vUPGoqjWom0RYy/5suwjNFmx3qf8oNMC+OhdFZirMdv+YzRHtTbpdNnlGAdC32B8RnT0YFs+XaAvwFUfLO0c+yBrXyVmGS51jxi6FCzpRS8T3lM1hx8I+rB2Z652T3Fz5LWwHC+UITczoaX1OWBLgEy5iDVTFkfFCOOJbQu7ms2gIX5MS+gldDMi+5Yu86TjSGMRVrch1NAA== 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: Yadong Qi writes: > In mm/vmalloc.c, the function vmap_pte_range() assumes that the > mapping size is aligned to PAGE_SIZE. If this assumption is > violated, the loop will become infinite because the termination > condition (`addr != end`) will never be met. This can lead to > overwriting other VA ranges and/or random pages physically follow > the page table. > > It's the caller's responsibility to ensure that the mapping size > is aligned to PAGE_SIZE. However, the memory corruption is hard > to root cause. To identify the programming error in the caller > easier, check whether the mapping size is PAGE_SIZE aligned with > WARN_ON(). > > Signed-off-by: Yadong Qi > Reviewed-by: Huang Ying > --- > v1 -> v2: > * Use WARN_ON instead of BUG_ON > --- > mm/vmalloc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 5edd536ba9d2..2cad593e4677 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -100,6 +100,9 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end, > struct page *page; > unsigned long size = PAGE_SIZE; > > + if (WARN_ON(!PAGE_ALIGNED(end - addr))) > + return -ENOMEM; > + EINVAL? > pfn = phys_addr >> PAGE_SHIFT; > pte = pte_alloc_kernel_track(pmd, addr, mask); > if (!pte) --- Best Regards, Huang, Ying