LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Pavel Skripkin <paskripkin@gmail.com>
To: "gregkh@linuxfoundation.org" <gregkh@linuxfoundation.org>
Cc: David Laight <David.Laight@aculab.com>,
	"Larry.Finger@lwfinger.net" <Larry.Finger@lwfinger.net>,
	"phil@philpotter.co.uk" <phil@philpotter.co.uk>,
	"straube.linux@gmail.com" <straube.linux@gmail.com>,
	"fmdefrancesco@gmail.com" <fmdefrancesco@gmail.com>,
	"linux-staging@lists.linux.dev" <linux-staging@lists.linux.dev>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 5/6] staging: r8188eu: add error handling of rtw_read32
Date: Fri, 27 Aug 2021 10:16:57 +0300	[thread overview]
Message-ID: <014d213d-b038-f40f-80b0-f1d5adbdf947@gmail.com> (raw)
In-Reply-To: <YSiQXpzswaRhvD4P@kroah.com>

On 8/27/21 10:12 AM, gregkh@linuxfoundation.org wrote:
> On Thu, Aug 26, 2021 at 11:03:04PM +0300, Pavel Skripkin wrote:
>> On 8/26/21 1:59 PM, David Laight wrote:
>> > From: Pavel Skripkin
>> > > Sent: 26 August 2021 11:55
>> > > 
>> > > On 8/26/21 1:22 PM, David Laight wrote:
>> > > > From: Pavel Skripkin
>> > > >> Sent: 26 August 2021 10:28
>> > > >>
>> > > >> On 8/26/21 12:22 PM, Pavel Skripkin wrote:
>> > > >> > On Thu, 26 Aug 2021 08:51:23 +0000
>> > > >> > David Laight <David.Laight@ACULAB.COM> wrote:
>> > > > ...
>> > > >> >> ...
>> > > >> >> > -static u32 usb_read32(struct intf_hdl *pintfhdl, u32 addr)
>> > > >> >> > +static int usb_read32(struct intf_hdl *pintfhdl, u32 addr, u32
>> > > >> >> > *data) {
>> > > >> >> >  	u8 requesttype;
>> > > >> >> >  	u16 wvalue;
>> > > >> >> >  	u16 len;
>> > > >> >> > -	__le32 data;
>> > > >> >> > +	int res;
>> > > >> >> > +	__le32 tmp;
>> > > >> >> > +
>> > > >> >> > +	if (WARN_ON(unlikely(!data)))
>> > > >> >> > +		return -EINVAL;
>> > > >> >> >
>> > > >> >>
>> > > >> >> Kill the NULL check - it is a silly coding error.
>> > > >> >> An OOPS is just as easy to debug.
>> > > >> >>
>> > > >> >
>> > > >> >
>> > > >> > I don't think that one single driver should kill the whole system. It's
>> > > >> > 100% an error, but kernel can recover from it (for example disconnect
>> > > >> > the driver, since it's broken).
>> > > >> >
>> > > >> >
>> > > >> > AFIAK, Greg and Linus do not like BUG_ONs in recoverable state...
>> > > >> > Correct me, if I am wrong
>> > > >> >
>> > > >> Oops, I thought about BUG_ON() instead of WARN_ON(), sorry for
>> > > >> confusion. My point is "we should not let the box boom".
>> > > >
>> > > >
>> > > > There is no point checking for NULL that just can't happen.
>> > > > In this case all the callers will pass the address of a local.
>> > > > There really is no point checking.
>> > > >
>> > > 
>> > > We not always read in local variable, there are few places, where we
>> > > read into passed buffer.
>> > 
>> > It is still a very local coding bug.
>> > 
>> > 	David
>> > 
>> 
>> Sure, but is defensive programming so bad?
> 
> Yes it is, for when it is not needed.
> 
>> Greg, what your opinion about this NULL check?
> 
> Never check for things that you know are not going to happen.  Otherwise
> the kernel would just be full of pointless checks everywhere.
> 
> And why are you waiting for me to tell you this?  Why do you not believe
> David?
> 


Just wanted to hear more opinions on this check. I believe David, but 
opinions of other people are important too, IMO




With regards,
Pavel Skripkin

  reply	other threads:[~2021-08-27  7:17 UTC|newest]

Thread overview: 118+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-20 17:07 [PATCH RFC 0/3] staging: r8188eu: avoid uninit value bugs Pavel Skripkin
2021-08-20 17:07 ` [PATCH RFC 1/3] staging: r8188eu: add proper rtw_read* error handling Pavel Skripkin
2021-08-20 21:50   ` Pavel Skripkin
2021-08-20 23:41   ` Phillip Potter
2021-08-21  5:55   ` Fabio M. De Francesco
2021-08-21 10:35     ` Pavel Skripkin
2021-08-21 12:11       ` Fabio M. De Francesco
2021-08-20 17:07 ` [PATCH RFC 2/3] staging: r8188eu: add error handling to ReadFuse Pavel Skripkin
2021-08-20 23:51   ` Phillip Potter
2021-08-21  3:59     ` Fabio M. De Francesco
2021-08-20 17:07 ` [PATCH RFC 3/3] staging: r8188eu: add error argument to read_macreg Pavel Skripkin
2021-08-20 23:18   ` Phillip Potter
2021-08-21 10:38     ` Pavel Skripkin
2021-08-20 23:12 ` [PATCH RFC 0/3] staging: r8188eu: avoid uninit value bugs Phillip Potter
2021-08-21 10:42   ` Pavel Skripkin
2021-08-22  9:53 ` Fabio M. De Francesco
2021-08-22 10:09   ` Pavel Skripkin
2021-08-22 10:59     ` Fabio M. De Francesco
2021-08-22 11:34       ` Fabio M. De Francesco
2021-08-22 12:10       ` Pavel Skripkin
2021-08-22 12:39         ` Greg KH
2021-08-22 12:50           ` Pavel Skripkin
2021-08-22 13:06             ` Greg KH
2021-08-22 13:21           ` Fabio M. De Francesco
2021-08-22 13:30             ` Greg KH
2021-08-22 13:31             ` Pavel Skripkin
2021-08-22 14:35               ` [PATCH RFC v2 0/6] " Pavel Skripkin
2021-08-22 14:35                 ` [PATCH RFC v2 1/6] staging: r8188eu: remove {read,write}_macreg Pavel Skripkin
2021-08-22 14:35                 ` [PATCH RFC v2 2/6] staging: r8188eu: add helper macro for printing registers Pavel Skripkin
2021-08-22 14:35                 ` [PATCH RFC v2 3/6] staging: r8188eu: add error handling of rtw_read8 Pavel Skripkin
2021-08-22 14:35                 ` [PATCH RFC v2 4/6] staging: r8188eu: add error handling of rtw_read16 Pavel Skripkin
2021-08-22 14:36                 ` [PATCH RFC v2 5/6] staging: r8188eu: add error handling of rtw_read32 Pavel Skripkin
2021-08-23 23:33                   ` Phillip Potter
2021-08-24  0:10                     ` Fabio M. De Francesco
2021-08-24  6:40                       ` Pavel Skripkin
2021-08-24  8:38                         ` Fabio M. De Francesco
2021-08-24  8:47                           ` Pavel Skripkin
2021-08-24  8:53                             ` Pavel Skripkin
2021-08-24  9:46                               ` Fabio M. De Francesco
2021-08-24 22:10                               ` Phillip Potter
2021-08-24 22:07                             ` Phillip Potter
2021-08-24  6:53                     ` Pavel Skripkin
2021-08-24  7:25                     ` [PATCH v3 0/6] staging: r8188eu: avoid uninit value bugs Pavel Skripkin
2021-08-24  7:27                       ` [PATCH v3 1/6] staging: r8188eu: remove {read,write}_macreg Pavel Skripkin
2021-08-26 10:39                         ` Greg KH
2021-08-26 10:40                         ` Greg KH
2021-08-24  7:27                       ` [PATCH v3 2/6] staging: r8188eu: add helper macro for printing registers Pavel Skripkin
2021-08-26 10:37                         ` Greg KH
2021-08-24  7:27                       ` [PATCH v3 3/6] staging: r8188eu: add error handling of rtw_read8 Pavel Skripkin
2021-08-25 12:05                         ` kernel test robot
2021-08-25 12:17                           ` Pavel Skripkin
2021-08-25 12:51                             ` Dan Carpenter
2021-08-25 13:02                               ` Pavel Skripkin
2021-08-25 13:34                                 ` Dan Carpenter
2021-08-25 13:44                                   ` Pavel Skripkin
2021-08-25 17:11                                     ` Nick Desaulniers
2021-08-26 11:08                                       ` Dan Carpenter
2021-08-25 23:45                         ` Fabio M. De Francesco
2021-08-26  5:13                           ` Pavel Skripkin
2021-08-26  8:21                         ` David Laight
2021-08-26  8:27                           ` Pavel Skripkin
2021-08-26 10:19                             ` David Laight
2021-08-26 11:21                               ` Dan Carpenter
2021-08-27  8:14                                 ` David Laight
2021-08-27  8:22                                   ` Pavel Skripkin
2021-08-27  9:07                         ` Dan Carpenter
2021-08-27  9:16                           ` Pavel Skripkin
2021-08-27  9:23                             ` Dan Carpenter
2021-08-30 11:21                         ` kernel test robot
2021-08-24  7:27                       ` [PATCH v3 4/6] staging: r8188eu: add error handling of rtw_read16 Pavel Skripkin
2021-08-25  4:35                         ` Fabio M. De Francesco
2021-08-25  8:22                           ` Pavel Skripkin
2021-08-25  9:48                             ` Fabio M. De Francesco
2021-08-25  9:55                               ` Pavel Skripkin
2021-08-25 10:06                                 ` Dan Carpenter
2021-08-25 10:13                                   ` Pavel Skripkin
2021-08-25 10:38                                     ` Dan Carpenter
2021-08-25 10:41                                       ` Pavel Skripkin
2021-08-25 11:06                                       ` Fabio M. De Francesco
2021-08-25 11:11                                         ` Fabio M. De Francesco
2021-08-25 11:31                                         ` Dan Carpenter
2021-08-25 12:11                                           ` Fabio M. De Francesco
2021-08-25 10:51                                 ` Fabio M. De Francesco
2021-08-26 10:50                         ` Greg KH
2021-08-26 10:58                           ` Pavel Skripkin
2021-08-24  7:27                       ` [PATCH v3 5/6] staging: r8188eu: add error handling of rtw_read32 Pavel Skripkin
2021-08-25  4:40                         ` Fabio M. De Francesco
2021-08-26  8:51                         ` David Laight
2021-08-26  9:22                           ` Pavel Skripkin
2021-08-26  9:27                             ` Pavel Skripkin
2021-08-26 10:22                               ` David Laight
2021-08-26 10:55                                 ` Pavel Skripkin
2021-08-26 10:59                                   ` David Laight
2021-08-26 20:03                                     ` Pavel Skripkin
2021-08-27  7:12                                       ` gregkh
2021-08-27  7:16                                         ` Pavel Skripkin [this message]
2021-08-24  7:27                       ` [PATCH v3 6/6] staging: r8188eu: make ReadEFuse return an int Pavel Skripkin
2021-08-25 10:13                       ` [PATCH v3 0/6] staging: r8188eu: avoid uninit value bugs Fabio M. De Francesco
2021-08-27  7:49                       ` Kari Argillander
2021-08-27  7:52                         ` Pavel Skripkin
2021-08-24  6:58                   ` [PATCH RFC v2 5/6] staging: r8188eu: add error handling of rtw_read32 Dan Carpenter
2021-08-24  7:01                     ` Pavel Skripkin
2021-08-24 15:07                       ` Fabio M. De Francesco
2021-08-22 14:36                 ` [PATCH RFC v2 6/6] staging: r8188eu: make ReadEFuse return an int Pavel Skripkin
2021-08-22 15:30                 ` [PATCH RFC v2 0/6] staging: r8188eu: avoid uninit value bugs Pavel Skripkin
2021-08-22 16:05                   ` Michael Straube
2021-08-22 16:26                     ` Pavel Skripkin
2021-08-22 23:52                       ` Phillip Potter
2021-08-22 17:36                 ` Fabio M. De Francesco
2021-08-22 17:38                   ` Pavel Skripkin
2021-08-22 20:06                     ` Fabio M. De Francesco
2021-08-22 20:19                       ` Pavel Skripkin
2021-08-23  0:12                 ` Phillip Potter
2021-08-23  6:38                   ` Pavel Skripkin
2021-08-23  6:44                   ` Pavel Skripkin
2021-08-22 16:03               ` [PATCH RFC 0/3] " Fabio M. De Francesco
2021-08-22 16:15                 ` Pavel Skripkin
2021-08-22 15:04             ` Phillip Potter

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=014d213d-b038-f40f-80b0-f1d5adbdf947@gmail.com \
    --to=paskripkin@gmail.com \
    --cc=David.Laight@aculab.com \
    --cc=Larry.Finger@lwfinger.net \
    --cc=fmdefrancesco@gmail.com \
    --cc=gregkh@linuxfoundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-staging@lists.linux.dev \
    --cc=phil@philpotter.co.uk \
    --cc=straube.linux@gmail.com \
    --subject='Re: [PATCH v3 5/6] staging: r8188eu: add error handling of rtw_read32' \
    /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

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).