Re: [PATCH] mremap NULL pointer dereference fix

[Rajesh Venkatasubramanian]

> To trigger the bug you have to have _just_ the right memory usage, I
> suspect. You literally have to have the destination page directory
> allocation unmap the _exact_ source page (which has to be clean) for the
> bug to hit.
>

To trigger the bug, I have to run my test program in a "while true;"
loop for an hour or so.

> So I suspect the oops only triggers on the machine that the trigger
> program was written for.
>
> Your version of the patch saves a goto in the source, but results in an
> extra goto in the generated assembly unless the compiler is clever enough
> to notice the double test for NULL.
>
> Never mind, that's a micro-optimization, and your version is cleaner.
> Let's go with it if Rajesh can verify that it fixes the problem for him.

I will test the patch and report.

Thanks,
Rajesh


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