syscall_emul: Corrected a bug on the syscall "read()" when reading EOF

Information
Submitter:	Nicolas Derumigny
Repository:	gem5
Branch:
Bugs:
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Description

syscall_emul: Corrected a bug on the syscall "read()".

Read() should not write anything when returning 0 (EOF).

This patch does not correct the same bug occuring for :
nbr_read=read(file, buf, nbytes) 
When nbr_read<nbytes, nbytes bytes are copied into the virtual

RAM instead of nbr_read. If buf is smaller than nbytes, a 

page fault occurs, even if buf is in fact bigger than nbr_read.

Testing Done

Works with CERE codelets (https://github.com/benchmark-subsetting/cere),
correcting the issue when replacing dumps in memory.

Issue Summary

Description	From	Last Updated	Status
I would drop this comment. It makes sense in the context of this patch (and is appropriate for the commit ...	Steve Reinhardt	Aug. 7, 2016, 9:10 a.m.	Resolved

LGTM, could you make sure that your description follows the fomatting guidelines (e.g., 65 char for the short description and 75 char per line in the long description). This makes it much easier for us to commit your patch :).

Nicolas Derumigny July 23, 2016, 6:16 a.m. (July 23, 2016, 6:16 a.m.)
```
I updated the description to fit the formatting requirements :).
```

Description:

		syscall_emu: Corrected a bug on the syscall "read()".
~		Read() should not write anything when returning 0 (EOF). This patch does not correct the same bug occuring for :
	~	Read() should not write anything when returning 0 (EOF).
	+	This patch does not correct the same bug occuring for :

		nbr_read=read(file, buf, nbytes)

~		When nbr_read<nbytes, nbytes bytes are copied into the virtual RAM instead of nbr_read. If buf is smaller than nbytes, a page fault occurs, even if buf is in fact bigger than nbr_read.
	~	When nbr_read<nbytes, nbytes bytes are copied into the virtual
	+	RAM instead of nbr_read. If buf is smaller than nbytes, a
	+	page fault occurs, even if buf is in fact bigger than nbr_read.

Testing Done:

~		Works with CERE codelets (https://github.com/benchmark-subsetting/cere), correcting the issue when replacing dumps in memory.
	~	Works with CERE codelets (https://github.com/benchmark-subsetting/cere),
	+	correcting the issue when replacing dumps in memory.

Ship It!

Ship It!

Thanks for the bug fix!

Note that the tag for the commit message is 'syscall_emul', not "syscall_emu'.

src/sim/syscall_emul.cc (Diff revision 1)

I would drop this comment. It makes sense in the context of this patch (and is appropriate for the commit message), but it is confusing when you don't know what the code used to look like. The fact that there used to be a bug here is irrelevant to people who look at this code in the future.

Show all issues

Change Summary:

Suppressed useless comment.

Summary:

-	syscall_emu: Corrected a bug on the syscall "read()" when reading EOF
+	syscall_emul: Corrected a bug on the syscall "read()" when reading EOF

Description:

~		syscall_emu: Corrected a bug on the syscall "read()".
	~	syscall_emul: Corrected a bug on the syscall "read()".
		Read() should not write anything when returning 0 (EOF).
		This patch does not correct the same bug occuring for :

		nbr_read=read(file, buf, nbytes)

		When nbr_read<nbytes, nbytes bytes are copied into the virtual
		RAM instead of nbr_read. If buf is smaller than nbytes, a
		page fault occurs, even if buf is in fact bigger than nbr_read.

Diff:

Revision 2 (+1 -1)

Show changes

src/sim/syscall_emul.cc

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Summary:

Description:

Diff:

Status: Closed (submitted)