On Tue, Dec 22, 2015 at 09:44:01PM +0100, Mickaël Salaün wrote: > Fix a pointer cast typo introduced in v4.4-rc5 especially visible for > the i386 subarchitecture where it results in a kernel crash.
Why the hell bother casting it at all? _Any_ pointer will quietly convert to void *, no typecasts needed. The second argument of copy_from_user is const void __user *; sc is struct sigcontext __user *sc, so &sb->oldmask is either __u32 __user * or __u64 __user *, for 32bit and 64bit builds resp. Either is assignment-compatible with const void __user *. Basically, cast is telling the typechecking logics "sod off, I know better". And here it's not needed at all. Moreover, the bug you are fixing here is precisely that this code did *not* know better - if not for that cast, compiler would've immediately pointed to the problem. > - if (copy_from_user(&set.sig[0], (void *)sc->oldmask, > sizeof(set.sig[0])) || > + if (copy_from_user(&set.sig[0], (void *)&sc->oldmask, > sizeof(set.sig[0])) || Please, remove the cast completely. Simply pass it &sc->oldmask and be done with that. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
