From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: John Stultz <john.stultz@linaro.org>,
Vinod Koul <vkoul@kernel.org>, Sasha Levin <sashal@kernel.org>,
dmaengine@vger.kernel.org
Subject: [PATCH AUTOSEL 4.19 04/11] dmaengine: k3dma: Avoid null pointer traversal
Date: Fri, 10 Jan 2020 17:05:48 -0500 [thread overview]
Message-ID: <20200110220556.28505-3-sashal@kernel.org> (raw)
In-Reply-To: <20200110220556.28505-1-sashal@kernel.org>
From: John Stultz <john.stultz@linaro.org>
[ Upstream commit 2f42e05b942fe2fbfb9bbc6e34e1dd8c3ce4f3a4 ]
In some cases we seem to submit two transactions in a row, which
causes us to lose track of the first. If we then cancel the
request, we may still get an interrupt, which traverses a null
ds_run value.
So try to avoid starting a new transaction if the ds_run value
is set.
While this patch avoids the null pointer crash, I've had some
reports of the k3dma driver still getting confused, which
suggests the ds_run/ds_done value handling still isn't quite
right. However, I've not run into an issue recently with it
so I think this patch is worth pushing upstream to avoid the
crash.
Signed-off-by: John Stultz <john.stultz@linaro.org>
[add ss tag]
Link: https://lore.kernel.org/r/20191218190906.6641-1-john.stultz@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/dma/k3dma.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
diff --git a/drivers/dma/k3dma.c b/drivers/dma/k3dma.c
index 6bfa217ed6d0..ba3c3791f9dc 100644
--- a/drivers/dma/k3dma.c
+++ b/drivers/dma/k3dma.c
@@ -222,9 +222,11 @@ static irqreturn_t k3_dma_int_handler(int irq, void *dev_id)
c = p->vchan;
if (c && (tc1 & BIT(i))) {
spin_lock_irqsave(&c->vc.lock, flags);
- vchan_cookie_complete(&p->ds_run->vd);
- p->ds_done = p->ds_run;
- p->ds_run = NULL;
+ if (p->ds_run != NULL) {
+ vchan_cookie_complete(&p->ds_run->vd);
+ p->ds_done = p->ds_run;
+ p->ds_run = NULL;
+ }
spin_unlock_irqrestore(&c->vc.lock, flags);
}
if (c && (tc2 & BIT(i))) {
@@ -264,6 +266,10 @@ static int k3_dma_start_txd(struct k3_dma_chan *c)
if (BIT(c->phy->idx) & k3_dma_get_chan_stat(d))
return -EAGAIN;
+ /* Avoid losing track of ds_run if a transaction is in flight */
+ if (c->phy->ds_run)
+ return -EAGAIN;
+
if (vd) {
struct k3_dma_desc_sw *ds =
container_of(vd, struct k3_dma_desc_sw, vd);
--
2.20.1
next prev parent reply other threads:[~2020-01-10 22:06 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-10 22:05 [PATCH AUTOSEL 4.19 01/11] mips: cacheinfo: report shared CPU map Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 02/11] MIPS: Prevent link failure with kcov instrumentation Sasha Levin
2020-01-10 22:05 ` Sasha Levin [this message]
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 05/11] s390/qeth: fix false reporting of VNIC CHAR config failure Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 06/11] s390/qeth: Fix vnicc_is_in_use if rx_bcast not set Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 07/11] hsr: reset network header when supervision frame is created Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 08/11] ioat: ioat_alloc_ring() failure handling Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 09/11] hexagon: parenthesize registers in asm predicates Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 10/11] hexagon: work around compiler crash Sasha Levin
2020-01-10 22:05 ` [PATCH AUTOSEL 4.19 11/11] ocfs2: call journal flush to mark journal as empty after journal recovery when mount Sasha Levin
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