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 078AB3A1E70; Sun, 4 Jan 2026 17:59:05 +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=1767549548; cv=none; b=UYnme/USBsr+YwuKJ5k/GQ0xKkW7+DnGpircCAxxR/bJvMwzzbTvbBNpJFkMdGC/n6q2JutIyhP+oi2EPtuPKRJNgQpBrMpPwyea6bI3Q1ZH1S6B9QFXXERa1HBZyQH0QT2B3rZD2xxmUwlRxchAFNLzwzGkGlB8qM0In6Dt/QI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767549548; c=relaxed/simple; bh=0OZPDaxVwdoSeACdoaN1quQhyId1qv1e8mlXVzC1RvQ=; h=Date:To:From:Subject:Message-Id; b=exnLOZ+ptQvGfZ6rOU2J1CGBGljadCfIJYW7VPPwPA3ipOTei6pVhEuKZgO+1qK3m/fYuz+N//KCRmGL44DCTWRd1MWJM+vdSeBT4JLhFVcS4phfO4plvxzqRCl3iMLJVhvBohAKw2fCONTa7SB8tjaXfsEjDrg+WPtong9KdtE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=x0dEkahT; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="x0dEkahT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAFE4C19421; Sun, 4 Jan 2026 17:59:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1767549545; bh=0OZPDaxVwdoSeACdoaN1quQhyId1qv1e8mlXVzC1RvQ=; h=Date:To:From:Subject:From; b=x0dEkahT6hgSAyvVNETPNm1CXwE2zG7nFdZ/H3FuU9Xmio+uMV513Z7/eNbbNNkVc beUaaVyGKoIDYbFVBw61cXaVrH4k0UDSrKWwsYuIBIACrzXuPoYFRWTY2p8nUiQcp4 kjxCwWf7oPElyA1DJ9quYtKRqvrHAOlDIT+I9b0M= Date: Sun, 04 Jan 2026 09:59:05 -0800 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,glider@google.com,elver@google.com,dvyukov@google.com,ryan.roberts@arm.com,akpm@linux-foundation.org From: Andrew Morton Subject: + mm-kmsan-fix-poisoning-of-high-order-non-compound-pages.patch added to mm-hotfixes-unstable branch Message-Id: <20260104175905.AAFE4C19421@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: mm: kmsan: fix poisoning of high-order non-compound pages has been added to the -mm mm-hotfixes-unstable branch. Its filename is mm-kmsan-fix-poisoning-of-high-order-non-compound-pages.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-kmsan-fix-poisoning-of-high-order-non-compound-pages.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Ryan Roberts Subject: mm: kmsan: fix poisoning of high-order non-compound pages Date: Sun, 4 Jan 2026 13:43:47 +0000 kmsan_free_page() is called by the page allocator's free_pages_prepare() during page freeing. Its job is to poison all the memory covered by the page. It can be called with an order-0 page, a compound high-order page or a non-compound high-order page. But page_size() only works for order-0 and compound pages. For a non-compound high-order page it will incorrectly return PAGE_SIZE. The implication is that the tail pages of a high-order non-compound page do not get poisoned at free, so any invalid access while they are free could go unnoticed. It looks like the pages will be poisoned again at allocation time, so that would bookend the window. Fix this by using the order parameter to calculate the size. Link: https://lkml.kernel.org/r/20260104134348.3544298-1-ryan.roberts@arm.com Fixes: b073d7f8aee4 ("mm: kmsan: maintain KMSAN metadata for page operations") Signed-off-by: Ryan Roberts Cc: Alexander Potapenko Cc: Dmitriy Vyukov Cc: Dmitry Vyukov Cc: Marco Elver Cc: Ryan Roberts Cc: Signed-off-by: Andrew Morton --- mm/kmsan/shadow.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/kmsan/shadow.c~mm-kmsan-fix-poisoning-of-high-order-non-compound-pages +++ a/mm/kmsan/shadow.c @@ -207,7 +207,7 @@ void kmsan_free_page(struct page *page, if (!kmsan_enabled || kmsan_in_runtime()) return; kmsan_enter_runtime(); - kmsan_internal_poison_memory(page_address(page), page_size(page), + kmsan_internal_poison_memory(page_address(page), PAGE_SIZE << order, GFP_KERNEL & ~(__GFP_RECLAIM), KMSAN_POISON_CHECK | KMSAN_POISON_FREE); kmsan_leave_runtime(); _ Patches currently in -mm which might be from ryan.roberts@arm.com are mm-kmsan-fix-poisoning-of-high-order-non-compound-pages.patch