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Message-ID: <BYAPR07MB5381D8455AF977200D503D15DD529@BYAPR07MB5381.namprd07.prod.outlook.com>
Date: Wed, 12 Jan 2022 13:13:10 +0000
From: Pawel Laszczak <pawell@...ence.com>
To: Peter Chen <peter.chen@...nel.org>
CC: "a-govindraju@...com" <a-govindraju@...com>,
"frank.li@....com" <frank.li@....com>,
"rogerq@...nel.org" <rogerq@...nel.org>,
"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"stable@...r.kernel.org" <stable@...r.kernel.org>
Subject: RE: [PATCH] usb: cdnsp: Fix segmentation fault in cdns_lost_power
function
>
>On 22-01-11 10:07:37, Pawel Laszczak wrote:
>> From: Pawel Laszczak <pawell@...ence.com>
>>
>> CDNSP driver read not initialized cdns->otg_v0_regs
>> which lead to segmentation fault. Patch fixes this issue.
>>
>> Fixes: 2cf2581cd229 ("usb: cdns3: add power lost support for system resume")
>> cc: <stable@...r.kernel.org>
>> Signed-off-by: Pawel Laszczak <pawell@...ence.com>
>> ---
>> drivers/usb/cdns3/drd.c | 6 +++---
>> 1 file changed, 3 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/usb/cdns3/drd.c b/drivers/usb/cdns3/drd.c
>> index 55c73b1d8704..d00ff98dffab 100644
>> --- a/drivers/usb/cdns3/drd.c
>> +++ b/drivers/usb/cdns3/drd.c
>> @@ -483,11 +483,11 @@ int cdns_drd_exit(struct cdns *cdns)
>> /* Indicate the cdns3 core was power lost before */
>> bool cdns_power_is_lost(struct cdns *cdns)
>> {
>> - if (cdns->version == CDNS3_CONTROLLER_V1) {
>> - if (!(readl(&cdns->otg_v1_regs->simulate) & BIT(0)))
>> + if (cdns->version == CDNS3_CONTROLLER_V0) {
>> + if (!(readl(&cdns->otg_v0_regs->simulate) & BIT(0)))
>> return true;
>> } else {
>> - if (!(readl(&cdns->otg_v0_regs->simulate) & BIT(0)))
>> + if (!(readl(&cdns->otg_v1_regs->simulate) & BIT(0)))
>> return true;
>> }
>> return false;
>> --
>
>Pawel, may this lead cdns driver segment fault?
>
Yes, we can observe such situation for CDNSP driver on simulation.
As you know, it is a common code and driver support two version of register map for DRD.
If cdns->version == CDNSP_CONTROLLER_V2 (for CNDSP) the cdns->otg_v0_regs is NULL.
It will cause segmentation fault.
I didn't analyze why this issue was not observed on my FPGA testing board.
Regards,
Pawel Laszczak
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