From: Dan Carpenter <dan.carpenter@oracle.com>
To: Linus Walleij <linus.walleij@stericsson.com>
Cc: Vinod Koul <vkoul@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
linux-arm-kernel@lists.infradead.org, dmaengine@vger.kernel.org,
Jia-Ju Bai <baijiaju1990@gmail.com>,
kernel-janitors@vger.kernel.org
Subject: [PATCH] dmaengine: coh901318: Fix a double lock bug in dma_tc_handle()
Date: Mon, 17 Feb 2020 17:40:50 +0300 [thread overview]
Message-ID: <20200217144050.3i4ymbytogod4ijn@kili.mountain> (raw)
The caller is already holding the lock so this will deadlock.
Fixes: 0b58828c923e ("DMAENGINE: COH 901 318 remove irq counting")
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
This is the second double lock bug found using static analysis. The
previous one was commit 627469e4445b ("dmaengine: coh901318: Fix a
double-lock bug").
The fact that this has been broken for ten years suggests that no one
has the hardware.
drivers/dma/coh901318.c | 4 ----
1 file changed, 4 deletions(-)
diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c
index e51d836afcc7..1092d4ce723e 100644
--- a/drivers/dma/coh901318.c
+++ b/drivers/dma/coh901318.c
@@ -1947,8 +1947,6 @@ static void dma_tc_handle(struct coh901318_chan *cohc)
return;
}
- spin_lock(&cohc->lock);
-
/*
* When we reach this point, at least one queue item
* should have been moved over from cohc->queue to
@@ -1969,8 +1967,6 @@ static void dma_tc_handle(struct coh901318_chan *cohc)
if (coh901318_queue_start(cohc) == NULL)
cohc->busy = 0;
- spin_unlock(&cohc->lock);
-
/*
* This tasklet will remove items from cohc->active
* and thus terminates them.
--
2.11.0
next reply other threads:[~2020-02-17 14:41 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-17 14:40 Dan Carpenter [this message]
2020-02-17 22:24 ` [PATCH] dmaengine: coh901318: Fix a double lock bug in dma_tc_handle() Geert Uytterhoeven
2020-02-19 9:17 ` Vinod Koul
2020-02-19 9:20 ` Geert Uytterhoeven
2020-02-19 9:27 ` Vinod Koul
2020-02-21 14:50 ` Linus Walleij
2020-02-24 16:30 ` Vinod Koul
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