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b=lK9b1UqhTljbAj4g+blMlhA4X1wMFgzDTctN7roiK34DP+Q4F5dYp+k8DBcyTuS1O D62+y0QfPeLpW7O/PUj+6nqJ34TRT0VtCHQ++HWTFpz2DRLasgNZkaj5Iijh8BUAmN qls33WbB8gcWz0h6A3kDgNIASFjWJNFh+nkvl4clVY5/KhpZbPzrHnNDj4Sxv0U/89 W6ALLRLzRzCSJxe5qdOCXeyK15JkvTYihBh9xu/+kcrRxnxlh1A/jOt8ozpxnB0NyW kIT2mGgK+Hh9pChYhYyFbfLjnPx91gOOYijmHZxI5z51Ho6cDHO1IckuBGbZxATfdi 1UCqld45GvkuA== Date: Fri, 12 Sep 2025 17:04:06 +0200 From: Helge Deller To: David Hildenbrand , Toke =?iso-8859-15?Q?H=F8iland-J=F8rgensen?= , Linux Memory Management List , Linux parisc List , Andrew Morton Subject: [PATCH] Fix 32-bit boot failure due inaccurate page_pool_page_is_pp() Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 6716540012 X-Stat-Signature: naiuqppnx1rtsy4aprc6u9ghhjcd4wyx X-HE-Tag: 1757689451-419204 X-HE-Meta: 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 npZsSvRc 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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: Commit ee62ce7a1d90 ("page_pool: Track DMA-mapped pages and unmap them when destroying the pool") changed PP_MAGIC_MASK from 0xFFFFFFFC to 0xc000007c on 32-bit platforms. The function page_pool_page_is_pp() uses PP_MAGIC_MASK to identify page pool pages, but the remaining bits are not sufficient to unambiguously identify such pages any longer. So page_pool_page_is_pp() now sometimes wrongly reports pages as page pool pages and as such triggers a kernel BUG as it believes it found a page pool leak. There are patches upcoming where page_pool_page_is_pp() will not depend on PP_MAGIC_MASK and instead use page flags to identify page pool pages. Until those patches are merged, the easiest temporary fix is to disable the check on 32-bit platforms. Cc: David Hildenbrand Cc: Toke Høiland-Jørgensen Cc: Linux Memory Management List Cc: Linux parisc List Cc: # v6.15+ Signed-off-by: Helge Deller Link: https://www.spinics.net/lists/kernel/msg5849623.html Fixes: ee62ce7a1d90 ("page_pool: Track DMA-mapped pages and unmap them when destroying the pool") diff --git a/include/linux/mm.h b/include/linux/mm.h index 1ae97a0b8ec7..f3822ae70a81 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -4190,7 +4190,7 @@ int arch_lock_shadow_stack_status(struct task_struct *t, unsigned long status); */ #define PP_MAGIC_MASK ~(PP_DMA_INDEX_MASK | 0x3UL) -#ifdef CONFIG_PAGE_POOL +#if defined(CONFIG_PAGE_POOL) && defined(CONFIG_64BIT) static inline bool page_pool_page_is_pp(const struct page *page) { treturn (page->pp_magic & PP_MAGIC_MASK) == PP_SIGNATURE;