From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E8AEE2E9730 for ; Mon, 24 Nov 2025 21:33:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764020015; cv=none; b=jjbSLbcwagq7h14hWP2sNlSPMtovbSFPPDR0r0cr1qQk60OdekH2yPZ2ANnxnWTI8uqjdWBSKHRJN5Tm09MPdvMXmpSx+LmUdzf2ixSiSFj8RXAP7optOw12N3PFJzFyDv3Eo2u46A5+93dd7BDpfq6dRwz/Baokg12+RMJkdVI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764020015; c=relaxed/simple; bh=kHwsV9soQ/hYe3IL7knzV2l3BAqMV0Gy8Vvl2bznYxY=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=BH7rSiLGArWS08JSqE23eu49HYt2OQUWMwrS1y2ggGGa8T9ABl8Rhtl1fkI8gpNLTtBYD81fLTluRfZ8WSWH2lxkZjFfSb67IAuu47Sq6mSOEViXV/0u25WABQ7/Mc/PUz0TVnSeB4dJxqaO4krY3XlkbkVvWWWr2ixJUhy2OHs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=hDCd49wn; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="hDCd49wn" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F2C7CC19421; Mon, 24 Nov 2025 21:33:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1764020013; bh=kHwsV9soQ/hYe3IL7knzV2l3BAqMV0Gy8Vvl2bznYxY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=hDCd49wnR/71YN6o0bYbgd3sVa76lbd48mi3Xb+lJ7FrGGxsT9c3y5PUjcfghAgNT lIH44d9ulbVG3N47oQK4S0P8IPrfe3dNsNp/DTXM9hTaggkglJn6iC+4UVMnFJfZfG R32/QfPYGOaeDxJ99Mbr1x5dwY7cukUwQsCSb8HZqZ5NMSjZLUJRjukYvsF46hP0Gf ooerXpOxbyy4YRS35gYO6+OUrYHnyvZF18wA9hsOuHt/km55+Qp96gJtzAAHJEyHuG dG5FHqjGrfqx2D4l1Q96e22JZp6inM/uhilyGoEusGVlyI1xaYhEWk2kSozIyhZu1A +cjwoajBvHzxA== From: Sasha Levin To: stable@vger.kernel.org Cc: Vlastimil Babka , kernel test robot , Christoph Hellwig , Sasha Levin Subject: [PATCH 5.15.y 2/2] mm/mempool: fix poisoning order>0 pages with HIGHMEM Date: Mon, 24 Nov 2025 16:33:30 -0500 Message-ID: <20251124213330.39729-2-sashal@kernel.org> X-Mailer: git-send-email 2.51.0 In-Reply-To: <20251124213330.39729-1-sashal@kernel.org> References: <2025112436-unabashed-tacky-b8b3@gregkh> <20251124213330.39729-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Vlastimil Babka [ Upstream commit ec33b59542d96830e3c89845ff833cf7b25ef172 ] The kernel test has reported: BUG: unable to handle page fault for address: fffba000 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page *pde = 03171067 *pte = 00000000 Oops: Oops: 0002 [#1] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Tainted: G T 6.18.0-rc2-00031-gec7f31b2a2d3 #1 NONE a1d066dfe789f54bc7645c7989957d2bdee593ca Tainted: [T]=RANDSTRUCT Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 EIP: memset (arch/x86/include/asm/string_32.h:168 arch/x86/lib/memcpy_32.c:17) Code: a5 8b 4d f4 83 e1 03 74 02 f3 a4 83 c4 04 5e 5f 5d 2e e9 73 41 01 00 90 90 90 3e 8d 74 26 00 55 89 e5 57 56 89 c6 89 d0 89 f7 aa 89 f0 5e 5f 5d 2e e9 53 41 01 00 cc cc cc 55 89 e5 53 57 56 EAX: 0000006b EBX: 00000015 ECX: 001fefff EDX: 0000006b ESI: fffb9000 EDI: fffba000 EBP: c611fbf0 ESP: c611fbe8 DS: 007b ES: 007b FS: 0000 GS: 0000 SS: 0068 EFLAGS: 00010287 CR0: 80050033 CR2: fffba000 CR3: 0316e000 CR4: 00040690 Call Trace: poison_element (mm/mempool.c:83 mm/mempool.c:102) mempool_init_node (mm/mempool.c:142 mm/mempool.c:226) mempool_init_noprof (mm/mempool.c:250 (discriminator 1)) ? mempool_alloc_pages (mm/mempool.c:640) bio_integrity_initfn (block/bio-integrity.c:483 (discriminator 8)) ? mempool_alloc_pages (mm/mempool.c:640) do_one_initcall (init/main.c:1283) Christoph found out this is due to the poisoning code not dealing properly with CONFIG_HIGHMEM because only the first page is mapped but then the whole potentially high-order page is accessed. We could give up on HIGHMEM here, but it's straightforward to fix this with a loop that's mapping, poisoning or checking and unmapping individual pages. Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-lkp/202511111411.9ebfa1ba-lkp@intel.com Analyzed-by: Christoph Hellwig Fixes: bdfedb76f4f5 ("mm, mempool: poison elements backed by slab allocator") Cc: stable@vger.kernel.org Tested-by: kernel test robot Reviewed-by: Christoph Hellwig Link: https://patch.msgid.link/20251113-mempool-poison-v1-1-233b3ef984c3@suse.cz Signed-off-by: Vlastimil Babka Signed-off-by: Sasha Levin --- mm/mempool.c | 32 ++++++++++++++++++++++++++------ 1 file changed, 26 insertions(+), 6 deletions(-) diff --git a/mm/mempool.c b/mm/mempool.c index 802ca5db52696..5d3f0f67e6c15 100644 --- a/mm/mempool.c +++ b/mm/mempool.c @@ -63,10 +63,20 @@ static void check_element(mempool_t *pool, void *element) } else if (pool->free == mempool_free_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __check_element(pool, addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __check_element(pool, addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __check_element(pool, addr, PAGE_SIZE << order); +#endif } } @@ -86,10 +96,20 @@ static void poison_element(mempool_t *pool, void *element) } else if (pool->alloc == mempool_alloc_pages) { /* Mempools backed by page allocator */ int order = (int)(long)pool->pool_data; - void *addr = kmap_local_page((struct page *)element); - __poison_element(addr, 1UL << (PAGE_SHIFT + order)); - kunmap_local(addr); +#ifdef CONFIG_HIGHMEM + for (int i = 0; i < (1 << order); i++) { + struct page *page = (struct page *)element; + void *addr = kmap_local_page(page + i); + + __poison_element(addr, PAGE_SIZE); + kunmap_local(addr); + } +#else + void *addr = page_address((struct page *)element); + + __poison_element(addr, PAGE_SIZE << order); +#endif } } #else /* CONFIG_DEBUG_SLAB || CONFIG_SLUB_DEBUG_ON */ -- 2.51.0