linux-kernel - [PATCH] mm: vmalloc: add optimization hint on page existence check

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>] [day] [month] [year] [list]

Message-Id: <20240814-fix_vmap_unlikely-v1-1-cd7954775f12@gmail.com>
Date: Wed, 14 Aug 2024 01:12:13 +0800
From: Miao Wang via B4 Relay <devnull+shankerwangmiao.gmail.com@...nel.org>
To: Andrew Morton <akpm@...ux-foundation.org>, 
 Uladzislau Rezki <urezki@...il.com>, Christoph Hellwig <hch@...radead.org>, 
 Hariom Panthi <hariom1.p@...sung.com>
Cc: linux-mm@...ck.org, linux-kernel@...r.kernel.org, 
 Miao Wang <shankerwangmiao@...il.com>
Subject: [PATCH] mm: vmalloc: add optimization hint on page existence check

From: Miao Wang <shankerwangmiao@...il.com>

In commit 21e516b913c1 ("mm: vmalloc: dump page owner info if page is
already mapped"), a BUG_ON macro was changed into an if statement, where
the compiler optimization hint introduced in the BUG_ON macro was removed
along with this change. This patch adds back the hint.

Fixes: 21e516b913c1 ("mm: vmalloc: dump page owner info if page is already mapped")
Signed-off-by: Miao Wang <shankerwangmiao@...il.com>
---
 mm/vmalloc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 6b783baf12a1..5d031fc83f04 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -105,7 +105,7 @@ static int vmap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
 	if (!pte)
 		return -ENOMEM;
 	do {
-		if (!pte_none(ptep_get(pte))) {
+		if (unlikely(!pte_none(ptep_get(pte)))) {
 			if (pfn_valid(pfn)) {
 				page = pfn_to_page(pfn);
 				dump_page(page, "remapping already mapped page");

---
base-commit: 7c626ce4bae1ac14f60076d00eafe71af30450ba
change-id: 20240814-fix_vmap_unlikely-2973d2cb904b

Best regards,
-- 
Miao Wang <shankerwangmiao@...il.com>