Messages in this thread | | | From | Nam Cao <> | Date | Sat, 4 Feb 2023 15:01:14 +0100 | Subject | Re: [PATCH] USB: serial: whiteheat: use stack instead of heap memory |
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On Sat, Feb 4, 2023 at 2:55 PM Greg Kroah-Hartman <gregkh@linuxfoundation.org> wrote: > > On Sat, Feb 04, 2023 at 02:46:51PM +0100, Nam Cao wrote: > > Some buffers in whiteheat_attach() are small and only used locally. Move > > them to the stack to avoid complications with heap memory. > > > > Compile-tested only. > > And that's the problem, you can't just compile test these things, the > code will blow up if you make these changes :( > > All USB transfers need to come from memory that can be safely DMAed. > Stack memory is not that type of memory, you HAVE to allocate it > dynamically from the heap in order to have this guarantee. > > So no, this patch is not acceptable, sorry. You will see this pattern > in all USB drivers, all data must be dynamically allocated, even for 2 > byte commands. > > So yes, there was a reason we added this "complexity" to the driver, it > is required :)
Thanks for "the lecture", and sorry for the broken patch.
Best regards, Nam
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