Messages in this thread Patch in this message | | | Date | Tue, 6 Feb 2007 10:31:18 -0500 (EST) | From | Alan Stern <> | Subject | [PATCH] USB: fix concurrent buffer access in the hub driver |
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This patch (as849) fixes a bug in the hub driver. A single pre-allocated buffer is used for all port status reads, but nothing guarantees exclusive use of the buffer. A mutex is added to provide this guarantee.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
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This patch should go into Greg's USB development tree and -mm as well as into the 2.6.20-stable queue (submitted separately). It fixes the "usb somehow broken (CONFIG_USB_SUSPEND)" bug reported by Prakash Punnoor.
Alan Stern
Index: usb-2.6/drivers/usb/core/hub.c =================================================================== --- usb-2.6.orig/drivers/usb/core/hub.c +++ usb-2.6/drivers/usb/core/hub.c @@ -44,6 +44,7 @@ struct usb_hub { struct usb_hub_status hub; struct usb_port_status port; } *status; /* buffer for status reports */ + struct mutex status_mutex; /* for the status buffer */ int error; /* last reported error */ int nerrors; /* track consecutive errors */ @@ -535,6 +536,7 @@ static int hub_hub_status(struct usb_hub { int ret; + mutex_lock(&hub->status_mutex); ret = get_hub_status(hub->hdev, &hub->status->hub); if (ret < 0) dev_err (hub->intfdev, @@ -544,6 +546,7 @@ static int hub_hub_status(struct usb_hub *change = le16_to_cpu(hub->status->hub.wHubChange); ret = 0; } + mutex_unlock(&hub->status_mutex); return ret; } @@ -617,6 +620,7 @@ static int hub_configure(struct usb_hub ret = -ENOMEM; goto fail; } + mutex_init(&hub->status_mutex); hub->descriptor = kmalloc(sizeof(*hub->descriptor), GFP_KERNEL); if (!hub->descriptor) { @@ -1394,6 +1398,7 @@ static int hub_port_status(struct usb_hu { int ret; + mutex_lock(&hub->status_mutex); ret = get_port_status(hub->hdev, port1, &hub->status->port); if (ret < 4) { dev_err (hub->intfdev, @@ -1405,6 +1410,7 @@ static int hub_port_status(struct usb_hu *change = le16_to_cpu(hub->status->port.wPortChange); ret = 0; } + mutex_unlock(&hub->status_mutex); return ret; } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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