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Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code

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On Fri, 2016-02-05 at 21:44 +0000, Rainer Weikusat wrote:
> The present unix_stream_read_generic contains various code sequences of
> the form
> 
> err = -EDISASTER;
> if (<test>)
> 	goto out;
> 
> This has the unfortunate side effect of possibly causing the error code
> to bleed through to the final
> 
> out:
> 	return copied ? : err;
> 
> and then to be wrongly returned if no data was copied because the caller
> didn't supply a data buffer, as demonstrated by the program available at
> 
> http://pad.lv/1540731
> 
> Change it such that err is only set if an error condition was detected.


Well, if you replace the traditional flow

err = -XXXX;
if (test)
     goto out;

Then please add unlikely() to at least give a hint to the compiler.

if (unlikely(test)) {
    err = -XXX;
    goto out;
}

And please add a 'Fixes: .... ' tag for bug fixes.

Thanks.

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[V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream  receive code Joseph Salisbury <joseph.salisbury@canonical.com> - 2016-02-05 20:00 +0100
  Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-05 21:00 +0100
    Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in  stream receive code Joseph Salisbury <joseph.salisbury@canonical.com> - 2016-02-05 21:10 +0100
      Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-05 22:20 +0100
        Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-05 23:10 +0100
  Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-05 22:50 +0100
    Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in  stream receive code Eric Dumazet <eric.dumazet@gmail.com> - 2016-02-06 00:10 +0100
      Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-07 19:50 +0100
        Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-07 21:40 +0100
        Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in stream receive code Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-07 23:30 +0100
          Re: [V4.4-rc6 Regression] af_unix: Revert 'lock_interruptible' in  stream receive code Eric Dumazet <eric.dumazet@gmail.com> - 2016-02-08 04:40 +0100
  [PATCH] af_unix: Don't set err in unix_stream_read_generic unless there was an error Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-05 23:40 +0100
    Re: [PATCH] af_unix: Don't set err in unix_stream_read_generic unless there was an error Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-07 20:30 +0100
      [PATCH] af_unix: Don't set err in unix_stream_read_generic unless there was an error Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-08 16:40 +0100
        Re: [PATCH] af_unix: Don't set err in unix_stream_read_generic unless there was an error Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-08 19:10 +0100
          [PATCH] af_unix: Don't set err in unix_stream_read_generic unless there was an error Rainer Weikusat <rweikusat@mobileactivedefense.com> - 2016-02-08 19:50 +0100
        Re: [PATCH] af_unix: Don't set err in unix_stream_read_generic unless  there was an error Sergei Shtylyov <sergei.shtylyov@cogentembedded.com> - 2016-02-08 19:40 +0100

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