Re: [Patch] net: fix an array index overflow

From: Cong Wang
Date: Thu Dec 03 2009 - 03:27:46 EST


Dan Carpenter wrote:
On Tue, Dec 01, 2009 at 03:26:02AM -0500, Amerigo Wang wrote:
Don't use the address of an out-of-boundary element.

Maybe this is not harmful at runtime, but it is still
good to improve it.

Signed-off-by: WANG Cong <amwang@xxxxxxxxxx>
Cc: David S. Miller <davem@xxxxxxxxxxxxx>


It may be coincidence but my static checker smatch also complains about the code you modified.

It's the wrong idea to fix code to please a checker. You end up
doing things like adding an extra "return -ENOTREACHED" to silence
warnings. Then the next person who writes a checker has to figure
out how to seperate the unreachable code which was added to suppress
gcc warnings from bits which are unreachable because of typos.

Really any code that a human can read, a static checker should also
be able to read. Computer programs are just state machines. At the function level they are quite small state machines. It's all
logic and math which computers are very good at. So it should be fairly easy to fix the checker. ;)


Well, in some cases smatch seems really wrong, but not in this
case I think, or at least, smatch is suggesting us to improve
this code.

Please check Eric's reply in this thread, his patch looks nice
for me.

Thanks.

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