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From: Rui Miguel Silva <rui.silva@linaro.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Stern <stern@rowland.harvard.edu>
Cc: linux-usb@vger.kernel.org, Rui Miguel Silva <rui.silva@linaro.org>
Subject: [PATCH 4/5] usb: isp1760: do not shift in uninitialized slot
Date: Thu, 19 Aug 2021 19:09:28 +0100	[thread overview]
Message-ID: <20210819180929.1327349-5-rui.silva@linaro.org> (raw)
In-Reply-To: <20210819180929.1327349-1-rui.silva@linaro.org>

Even though it is not expected, and would trigger a WARN_ON, killing a
transfer in a uninitialized slot this sequence is warned by clang
analyzer, twice:

drivers/usb/isp1760/isp1760-hcd.c:1976:18: warning: The result of the left shift is undefined because the right operand is negative [clang-analyzer-core.UndefinedBinaryOperatorResult]
                skip_map |= (1 << qh->slot);
drivers/usb/isp1760/isp1760-hcd.c:1983:18: warning: The result of the left shift is undefined because the right operand is negative [clang-analyzer-core.UndefinedBinaryOperatorResult]
                skip_map |= (1 << qh->slot);

Only set skip map if slot is active.

Signed-off-by: Rui Miguel Silva <rui.silva@linaro.org>
---
 drivers/usb/isp1760/isp1760-hcd.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/isp1760/isp1760-hcd.c b/drivers/usb/isp1760/isp1760-hcd.c
index aed2714ce0cf..bf8ab3fe2e5a 100644
--- a/drivers/usb/isp1760/isp1760-hcd.c
+++ b/drivers/usb/isp1760/isp1760-hcd.c
@@ -1974,16 +1974,20 @@ static void kill_transfer(struct usb_hcd *hcd, struct urb *urb,
 	/* We need to forcefully reclaim the slot since some transfers never
 	   return, e.g. interrupt transfers and NAKed bulk transfers. */
 	if (usb_pipecontrol(urb->pipe) || usb_pipebulk(urb->pipe)) {
-		skip_map = isp1760_hcd_read(hcd, HC_ATL_PTD_SKIPMAP);
-		skip_map |= (1 << qh->slot);
-		isp1760_hcd_write(hcd, HC_ATL_PTD_SKIPMAP, skip_map);
-		ndelay(100);
+		if (qh->slot != -1) {
+			skip_map = isp1760_hcd_read(hcd, HC_ATL_PTD_SKIPMAP);
+			skip_map |= (1 << qh->slot);
+			isp1760_hcd_write(hcd, HC_ATL_PTD_SKIPMAP, skip_map);
+			ndelay(100);
+		}
 		priv->atl_slots[qh->slot].qh = NULL;
 		priv->atl_slots[qh->slot].qtd = NULL;
 	} else {
-		skip_map = isp1760_hcd_read(hcd, HC_INT_PTD_SKIPMAP);
-		skip_map |= (1 << qh->slot);
-		isp1760_hcd_write(hcd, HC_INT_PTD_SKIPMAP, skip_map);
+		if (qh->slot != -1) {
+			skip_map = isp1760_hcd_read(hcd, HC_INT_PTD_SKIPMAP);
+			skip_map |= (1 << qh->slot);
+			isp1760_hcd_write(hcd, HC_INT_PTD_SKIPMAP, skip_map);
+		}
 		priv->int_slots[qh->slot].qh = NULL;
 		priv->int_slots[qh->slot].qtd = NULL;
 	}
-- 
2.33.0


  parent reply	other threads:[~2021-08-19 18:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-19 18:09 [PATCH 0/5] usb: isp1760: clang analyzer fixes Rui Miguel Silva
2021-08-19 18:09 ` [PATCH 1/5] usb: isp1760: ignore return value for bus change pattern Rui Miguel Silva
2021-08-19 18:09 ` [PATCH 2/5] usb: isp1760: check maxpacketsize before using it Rui Miguel Silva
2021-08-19 18:09 ` [PATCH 3/5] usb: isp1760: do not reset retval Rui Miguel Silva
2021-08-19 18:09 ` Rui Miguel Silva [this message]
2021-08-19 18:09 ` [PATCH 5/5] usb: isp1760: clean never read udc_enabled warning Rui Miguel Silva

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