From: Tom Rix <trix@redhat.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: gregkh@linuxfoundation.org, acozzette@cs.hmc.edu,
linux-usb@vger.kernel.org, usb-storage@lists.one-eyed-alien.net,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] USB: realtek_cr: fix return check for dma functions
Date: Tue, 11 Aug 2020 10:29:29 -0700 [thread overview]
Message-ID: <1f7d5a64-f264-4fed-bf90-b64e2693652d@redhat.com> (raw)
In-Reply-To: <20200811160348.GD335280@rowland.harvard.edu>
On 8/11/20 9:03 AM, Alan Stern wrote:
> On Tue, Aug 11, 2020 at 08:15:05AM -0700, trix@redhat.com wrote:
>> From: Tom Rix <trix@redhat.com>
>>
>> clang static analysis reports this representative problem
>>
>> realtek_cr.c:639:3: warning: The left expression of the compound
>> assignment is an uninitialized value. The computed value will
>> also be garbage
>> SET_BIT(value, 2);
>> ^~~~~~~~~~~~~~~~~
>>
>> value is set by a successful call to rts51x_read_mem()
>>
>> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
>> if (retval < 0)
>> return -EIO;
>>
>> A successful call to rts51x_read_mem returns 0, failure can
>> return positive and negative values. This check is wrong
>> for a number of functions. Fix the retval check.
>>
>> Fixes: 065e60964e29 ("ums_realtek: do not use stack memory for DMA")
>> Signed-off-by: Tom Rix <trix@redhat.com>
>> ---
>> drivers/usb/storage/realtek_cr.c | 36 ++++++++++++++++----------------
>> 1 file changed, 18 insertions(+), 18 deletions(-)
>>
>> diff --git a/drivers/usb/storage/realtek_cr.c b/drivers/usb/storage/realtek_cr.c
>> index 3789698d9d3c..b983753e2368 100644
>> --- a/drivers/usb/storage/realtek_cr.c
>> +++ b/drivers/usb/storage/realtek_cr.c
>> @@ -481,16 +481,16 @@ static int enable_oscillator(struct us_data *us)
>> u8 value;
>>
>> retval = rts51x_read_mem(us, 0xFE77, &value, 1);
>> - if (retval < 0)
>> + if (retval != STATUS_SUCCESS)
>> return -EIO;
> Instead of changing all these call sites, wouldn't it be a lot easier
> just to change rts51x_read_mem() to make it always return a negative
> value (such as -EIO) when there's an error?
>
> Alan Stern
I thought about that but there was already existing (retval != STATUS_SUCCESS) checks for these calls.
Tom
>
next prev parent reply other threads:[~2020-08-11 17:29 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-11 15:15 [PATCH] USB: realtek_cr: fix return check for dma functions trix
2020-08-11 16:03 ` Alan Stern
2020-08-11 17:29 ` Tom Rix [this message]
2020-08-11 17:53 ` Alan Stern
2020-08-11 18:54 ` Tom Rix
2020-08-11 19:43 ` Alan Stern
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=1f7d5a64-f264-4fed-bf90-b64e2693652d@redhat.com \
--to=trix@redhat.com \
--cc=acozzette@cs.hmc.edu \
--cc=gregkh@linuxfoundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=stern@rowland.harvard.edu \
--cc=usb-storage@lists.one-eyed-alien.net \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).