On Tue, 13 Jan 2015 16:10:57 -0800 Craig Milo Rogers <rogers@xxxxxxx> wrote: > > 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. > Adding overhead to kfree() would be a show-stopper - it's a real hotpath. kstrdup_const() is only used in a small number of places. Just don't screw it up. btw, I have vague memories that gcc used to put some strings into .text under some circumstances. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>