linux-kernel - [PATCHv4 10/12] dmapool: don't memset on free twice

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 for Android: free password hash cracker in your pocket

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

Date:   Thu, 26 Jan 2023 13:51:23 -0800
From:   Keith Busch <kbusch@...a.com>
To:     <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        <willy@...radead.org>, <hch@....de>, <tonyb@...ernetics.com>,
        <akpm@...ux-foundation.org>
CC:     <kernel-team@...a.com>, Keith Busch <kbusch@...nel.org>
Subject: [PATCHv4 10/12] dmapool: don't memset on free twice

From: Keith Busch <kbusch@...nel.org>

If debug is enabled, dmapool will poison the range, so no need to clear
it to 0 immediately before writing over it.

Signed-off-by: Keith Busch <kbusch@...nel.org>
Reviewed-by: Christoph Hellwig <hch@....de>
---
 mm/dmapool.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/dmapool.c b/mm/dmapool.c
index 4dea2a0dbd336..21e6d362c7264 100644
--- a/mm/dmapool.c
+++ b/mm/dmapool.c
@@ -160,6 +160,8 @@ static void pool_check_block(struct dma_pool *pool, void *retval,
 static bool pool_page_err(struct dma_pool *pool, struct dma_page *page,
 			  void *vaddr, dma_addr_t dma)
 {
+	if (want_init_on_free())
+		memset(vaddr, 0, pool->size);
 	return false;
 }
 
@@ -441,8 +443,6 @@ void dma_pool_free(struct dma_pool *pool, void *vaddr, dma_addr_t dma)
 		return;
 	}
 
-	if (want_init_on_free())
-		memset(vaddr, 0, pool->size);
 	if (pool_page_err(pool, page, vaddr, dma)) {
 		spin_unlock_irqrestore(&pool->lock, flags);
 		return;
-- 
2.30.2