On Wed, Sep 2, 2015 at 9:39 PM, Jeff Epler <jep...@unpythonic.net> wrote: > On Wed, Sep 02, 2015 at 08:32:15PM +0530, Muni Sekhar wrote: >> [ Please keep me in CC as I'm not subscribed to the list] >> >> Hello, >> >> >> I am getting protection faults in different kernel modules if I try to >> free a pointer "from the middle" for example, look at the following >> code: > [..] > > Most memory allocators require the pointer eventually passed to the > freeing function is the same pointer as the one returned from the > allocating function. This is true for libc malloc/free, for instance. > As far as I know, it is true for the Linux allocators such as kzalloc. > The bug lies in whatever part of linux makes the invalid kfree call. > > I have not found any documentation that kernel kzalloc/kfree allow > passing a pointer "from the middle". For instance, > These routines are used to dynamically request pointer-aligned chunks of > memory, like malloc and free do in userspace > https://www.kernel.org/doc/htmldocs/kernel-hacking/routines-kmalloc.html > > If the faulty code that you allude to is in the Linux source then please > say what it is so that developers can fix it. If it's an out of source > module or kernel patch then contact the supplier of that code.
The faulty code mentioned above is not in the Linux source, I noticed this behaviour during testing our own module. Thanks for the clarification Jeff. > > Jeff -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
