linux-kernel - [PATCH v1] fs/proc/task_mmu: fix PAGE_IS_PFNZERO detection for the huge zero folio

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-ID: <20250617143532.2375383-1-david@redhat.com>
Date: Tue, 17 Jun 2025 16:35:32 +0200
From: David Hildenbrand <david@...hat.com>
To: linux-kernel@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org,
	David Hildenbrand <david@...hat.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Muhammad Usama Anjum <usama.anjum@...labora.com>
Subject: [PATCH v1] fs/proc/task_mmu: fix PAGE_IS_PFNZERO detection for the huge zero folio

is_zero_pfn() does not work for the huge zero folio. Fix it by using
is_huge_zero_pmd().

Found by code inspection.

Fixes: 52526ca7fdb9 ("fs/proc/task_mmu: implement IOCTL to get and optionally clear info about PTEs")
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Muhammad Usama Anjum <usama.anjum@...labora.com>
Signed-off-by: David Hildenbrand <david@...hat.com>
---

Probably we should Cc stable, thoughts?

We should also extend the pagemap_ioctl selftest to cover this case, but I
don't have time for that right now. @Muhammad ?

---
 fs/proc/task_mmu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 27972c0749e78..4be91eb6ea5ca 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -2182,7 +2182,7 @@ static unsigned long pagemap_thp_category(struct pagemap_scan_private *p,
 				categories |= PAGE_IS_FILE;
 		}
 
-		if (is_zero_pfn(pmd_pfn(pmd)))
+		if (is_huge_zero_pmd(pmd))
 			categories |= PAGE_IS_PFNZERO;
 		if (pmd_soft_dirty(pmd))
 			categories |= PAGE_IS_SOFT_DIRTY;
-- 
2.49.0