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From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: keescook@chromium.org, gustavoars@kernel.org,
	Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	Vinod Koul <vkoul@kernel.org>
Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org
Subject: [PATCH 1/2] dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc()
Date: Sat,  7 Oct 2023 13:13:09 +0200	[thread overview]
Message-ID: <c8fc5563c9593c914fde41f0f7d1489a21b45a9a.1696676782.git.christophe.jaillet@wanadoo.fr> (raw)

If pxad_alloc_desc() fails on the first dma_pool_alloc() call, then
sw_desc->nb_desc is zero.
In such a case pxad_free_desc() is called and it will BUG_ON().

Remove this erroneous BUG_ON().

It is also useless, because if "sw_desc->nb_desc == 0", then, on the first
iteration of the for loop, i is -1 and the loop will not be executed.
(both i and sw_desc->nb_desc are 'int')

Fixes: a57e16cf0333 ("dmaengine: pxa: add pxa dmaengine driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/dma/pxa_dma.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index 3c574dc0613b..94cef2905940 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -722,7 +722,6 @@ static void pxad_free_desc(struct virt_dma_desc *vd)
 	dma_addr_t dma;
 	struct pxad_desc_sw *sw_desc = to_pxad_sw_desc(vd);
 
-	BUG_ON(sw_desc->nb_desc == 0);
 	for (i = sw_desc->nb_desc - 1; i >= 0; i--) {
 		if (i > 0)
 			dma = sw_desc->hw_desc[i - 1]->ddadr;
-- 
2.34.1


WARNING: multiple messages have this Message-ID (diff)
From: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
To: keescook@chromium.org, gustavoars@kernel.org,
	Daniel Mack <daniel@zonque.org>,
	Haojian Zhuang <haojian.zhuang@gmail.com>,
	Robert Jarzmik <robert.jarzmik@free.fr>,
	Vinod Koul <vkoul@kernel.org>
Cc: linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org,
	kernel-janitors@vger.kernel.org,
	Christophe JAILLET <christophe.jaillet@wanadoo.fr>,
	linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org
Subject: [PATCH 1/2] dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc()
Date: Sat,  7 Oct 2023 13:13:09 +0200	[thread overview]
Message-ID: <c8fc5563c9593c914fde41f0f7d1489a21b45a9a.1696676782.git.christophe.jaillet@wanadoo.fr> (raw)

If pxad_alloc_desc() fails on the first dma_pool_alloc() call, then
sw_desc->nb_desc is zero.
In such a case pxad_free_desc() is called and it will BUG_ON().

Remove this erroneous BUG_ON().

It is also useless, because if "sw_desc->nb_desc == 0", then, on the first
iteration of the for loop, i is -1 and the loop will not be executed.
(both i and sw_desc->nb_desc are 'int')

Fixes: a57e16cf0333 ("dmaengine: pxa: add pxa dmaengine driver")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
---
 drivers/dma/pxa_dma.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/drivers/dma/pxa_dma.c b/drivers/dma/pxa_dma.c
index 3c574dc0613b..94cef2905940 100644
--- a/drivers/dma/pxa_dma.c
+++ b/drivers/dma/pxa_dma.c
@@ -722,7 +722,6 @@ static void pxad_free_desc(struct virt_dma_desc *vd)
 	dma_addr_t dma;
 	struct pxad_desc_sw *sw_desc = to_pxad_sw_desc(vd);
 
-	BUG_ON(sw_desc->nb_desc == 0);
 	for (i = sw_desc->nb_desc - 1; i >= 0; i--) {
 		if (i > 0)
 			dma = sw_desc->hw_desc[i - 1]->ddadr;
-- 
2.34.1


_______________________________________________
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             reply	other threads:[~2023-10-07 11:21 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-10-07 11:13 Christophe JAILLET [this message]
2023-10-07 11:13 ` [PATCH 1/2] dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc() Christophe JAILLET
2023-10-07 11:13 ` [PATCH 2/2] dmaengine: pxa_dma: Annotate struct pxad_desc_sw with __counted_by Christophe JAILLET
2023-10-07 11:13   ` Christophe JAILLET
2023-10-08 21:05   ` Kees Cook
2023-10-08 21:05     ` Kees Cook
2023-10-08 21:03 ` [PATCH 1/2] dmaengine: pxa_dma: Remove an erroneous BUG_ON() in pxad_free_desc() Kees Cook
2023-10-08 21:03   ` Kees Cook
2023-10-09  6:12 ` Vinod Koul
2023-10-09  6:12   ` Vinod Koul

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