On 21/02/12 06:28, Richard Henderson wrote: > On 02/20/12 00:20, Michael Cree wrote: >> I have noticed some user space problems (pulseaudio crashes in pthread >> code, glibc/nptl test suite failures, java compiler freezes on SMP alpha >> systems) that arise when using a 2.6.39 or later kernel on Alpha. >> Bisecting between 2.6.38 and 2.6.39 (using glibc/nptl test suite as >> criterion for good/bad kernel) eventually leads to: >> >> 8d7718aa082aaf30a0b4989e1f04858952f941bc is the first bad commit >> commit 8d7718aa082aaf30a0b4989e1f04858952f941bc >> Author: Michel Lespinasse <walken@xxxxxxxxxx> >> Date: Thu Mar 10 18:50:58 2011 -0800 >> >> futex: Sanitize futex ops argument types >> >> Change futex_atomic_op_inuser and futex_atomic_cmpxchg_inatomic >> prototypes to use u32 types for the futex as this is the data type the >> futex core code uses all over the place. > > > futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr, > u32 oldval, u32 newval) > ... > : "r"(uaddr), "r"((long)oldval), "r"(newval) > > > There is no 32-bit compare instruction. These are implemented by > consistently extending the values to a 64-bit type. Since the > load instruction sign-extends, we want to sign-extend the other > quantity as well (despite the fact it's logically unsigned). > > So: > > - : "r"(uaddr), "r"((long)oldval), "r"(newval) > + : "r"(uaddr), "r"((long)(int)oldval), "r"(newval) > > should do the trick. Thanks, that fixes it. Will you formally submit a patch with commit message or should I? You can have at least a Reviewed-by, or even an Acked-by: Phil Carmody <ext-phil.2.carmody@xxxxxxxxx> who correctly analysed the problem in response to when I suggested the fix on the debian-alpha email list without explanation. Cheers Michael. -- To unsubscribe from this list: send the line "unsubscribe linux-alpha" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
