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* [PATCH] mailbox: pcc: fix channel calculation in get_pcc_channel()
@ 2015-12-10 17:28 Alexey Klimov
  2015-12-10 18:19 ` Ashwin Chaugule
  0 siblings, 1 reply; 9+ messages in thread
From: Alexey Klimov @ 2015-12-10 17:28 UTC (permalink / raw)
  To: jassisinghbrar, ashwin.chaugule; +Cc: alexey.klimov, sudeep.holla, linux-kernel

This patch fixes the calculation of pcc_chan for non-zero id.
After the compiler ignores the (unsigned long) cast the
pcc_mbox_channels pointer is type-cast and then the type-cast
offset is added which results in address outside of the range
leading to the kernel crashing.

We might add braces and make it:

pcc_chan = (struct mbox_chan *)
		((unsigned long) pcc_mbox_channels +
		(id * sizeof(*pcc_chan)));

but let's go with array approach here and use id as index.

Tested on Juno board.

Acked-by: Sudeep Holla <sudeep.holla@arm.com>
Signed-off-by: Alexey Klimov <alexey.klimov@arm.com>
---
 drivers/mailbox/pcc.c | 8 +-------
 1 file changed, 1 insertion(+), 7 deletions(-)

diff --git a/drivers/mailbox/pcc.c b/drivers/mailbox/pcc.c
index 45d85ae..8f779a1 100644
--- a/drivers/mailbox/pcc.c
+++ b/drivers/mailbox/pcc.c
@@ -81,16 +81,10 @@ static struct mbox_controller pcc_mbox_ctrl = {};
  */
 static struct mbox_chan *get_pcc_channel(int id)
 {
-	struct mbox_chan *pcc_chan;
-
 	if (id < 0 || id > pcc_mbox_ctrl.num_chans)
 		return ERR_PTR(-ENOENT);
 
-	pcc_chan = (struct mbox_chan *)
-		(unsigned long) pcc_mbox_channels +
-		(id * sizeof(*pcc_chan));
-
-	return pcc_chan;
+	return &pcc_mbox_channels[id];
 }
 
 /**
-- 
1.9.1


^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2016-02-03  1:21 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-12-10 17:28 [PATCH] mailbox: pcc: fix channel calculation in get_pcc_channel() Alexey Klimov
2015-12-10 18:19 ` Ashwin Chaugule
2016-01-15 18:20   ` Ashwin Chaugule
2016-01-15 18:22     ` Ashwin Chaugule
2016-02-01 15:19       ` Alexey Klimov
2016-02-01 15:43         ` Jassi Brar
2016-02-01 20:51           ` Rafael J. Wysocki
2016-02-02 11:12             ` Jassi Brar
2016-02-03  1:22               ` Rafael J. Wysocki

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