linux-kernel - [PATCH v5 2/6] dmaengine: sh: rz-dmac: Move all CHCTRL updates under spinlock

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]

Message-ID: <20251217135213.400280-3-claudiu.beznea.uj@bp.renesas.com>
Date: Wed, 17 Dec 2025 15:52:09 +0200
From: Claudiu <claudiu.beznea@...on.dev>
To: vkoul@...nel.org,
	fabrizio.castro.jz@...esas.com,
	biju.das.jz@...renesas.com,
	geert+renesas@...der.be,
	prabhakar.mahadev-lad.rj@...renesas.com
Cc: claudiu.beznea@...on.dev,
	dmaengine@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Claudiu Beznea <claudiu.beznea.uj@...renesas.com>,
	stable@...r.kernel.org
Subject: [PATCH v5 2/6] dmaengine: sh: rz-dmac: Move all CHCTRL updates under spinlock

From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

Both rz_dmac_disable_hw() and rz_dmac_irq_handle_channel() update the
CHCTRL registers. To avoid concurrency issues when updating these
registers, take the virtual channel lock. All other CHCTRL updates were
already protected by the same lock.

Previously, rz_dmac_disable_hw() disabled and re-enabled local IRQs, before
accessing CHCTRL registers but this does not ensure race-free access.
Remove the local IRQ disable/enable code as well.

Fixes: 5000d37042a6 ("dmaengine: sh: Add DMAC driver for RZ/G2L SoC")
Cc: stable@...r.kernel.org
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---

Changes in v5:
- none, this patch is new

 drivers/dma/sh/rz-dmac.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
index c8e3d9f77b8a..c013bf30fa5e 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -298,13 +298,10 @@ static void rz_dmac_disable_hw(struct rz_dmac_chan *channel)
 {
 	struct dma_chan *chan = &channel->vc.chan;
 	struct rz_dmac *dmac = to_rz_dmac(chan->device);
-	unsigned long flags;
 
 	dev_dbg(dmac->dev, "%s channel %d\n", __func__, channel->index);
 
-	local_irq_save(flags);
 	rz_dmac_ch_writel(channel, CHCTRL_DEFAULT, CHCTRL, 1);
-	local_irq_restore(flags);
 }
 
 static void rz_dmac_set_dmars_register(struct rz_dmac *dmac, int nr, u32 dmars)
@@ -569,8 +566,8 @@ static int rz_dmac_terminate_all(struct dma_chan *chan)
 	unsigned int i;
 	LIST_HEAD(head);
 
-	rz_dmac_disable_hw(channel);
 	spin_lock_irqsave(&channel->vc.lock, flags);
+	rz_dmac_disable_hw(channel);
 	for (i = 0; i < DMAC_NR_LMDESC; i++)
 		lmdesc[i].header = 0;
 
@@ -721,6 +718,8 @@ static irqreturn_t rz_dmac_irq_handler(int irq, void *dev_id)
 {
 	struct rz_dmac_chan *channel = dev_id;
 
+	guard(spinlock)(&channel->vc.lock);
+
 	if (channel) {
 		rz_dmac_irq_handle_channel(channel);
 		return IRQ_WAKE_THREAD;
-- 
2.43.0