Re: [PATCH 0/5] kstrdup optimization

Craig Milo Rogers
2015-01-14T00:17:20Z

> As kfree_const() has the exact same signature as kfree(), the risk of
> accidentally passing pointers returned from kstrdup_const() to kfree() seems
> high, which may lead to memory corruption if the pointer doesn't point to
> allocated memory.
...
>> To verify if the source is in .rodata function checks if the address is between
>> sentinels __start_rodata, __end_rodata. I guess it should work with all
>> architectures.

kfree() could also check if the region being freed is in .rodata, and
ignore the call; kfree_const() would not be needed. If making this check all
the time leads to a significant decrease in performance (numbers needed here),
another option is to keep kfree_const() but add a check to kfree(), when
compiled for debugging, that issues a suitable complaint if the region being
freed is in .rodata.

Craig Milo Rogers