On 2015/2/11 23:40, Catalin Marinas wrote: > On Wed, Feb 11, 2015 at 07:22:08PM +0800, Bamvor Jian Zhang wrote: >> On 2015/2/10 20:27, Catalin Marinas wrote: >>> On Tue, Feb 10, 2015 at 10:10:11AM +0000, Zhang Jian(Bamvor) wrote: ... > The native sigval_t is also a union but on 64-bit big endian, the > sival_int overlaps with the most significant 32-bit of the sival_ptr. > So reading sival_int would always be 0. When the compat siginfo is > copied to user, arm64 reads the native sival_ptr (si_ptr) and converts > it to the compat one, getting the correct 32-bit value. However, other > architectures access sival_int (si_int) instead which breaks with your > get_compat_sigevent() changes. > >>> I think the correct fix is in the arm64 code: >> >> The following code could fix my issue. > > Without any parts of your patch? Yes. As you mentioned above, sival_int overlaps the most significant 32bit of the sival_ptr, it seems that your patch is right if sival_ptr is less than 32bit. > I think that's correct fix since in the SIGEV_THREAD mq_notify case, we > would not deliver a signal as notification, so the sival_int value is > irrelevant (it would be 0 for big-endian compat tasks because of the > sigval_t union on 64-bit). > > Your patch would work as well but you have to change all the other > architectures to use si_ptr when copying to a compat siginfo. Yeah, it seems that my patch is useful only if the sival_ptr is bigger than 32bit. It need the similar changes with following catalin's patch in the following 64bit architecture: x86: arch/x86/ia32/ia32_signal.c tile, s390: arch/xxx/kernel/compat_signal.c parisc, sparc, mips: arch/xxx/kernel/signal32.c powerpc: arch/xxx/kernel/signal_32.c cc these maintainers for input. regards bamvor >>> diff --git a/arch/arm64/kernel/signal32.c b/arch/arm64/kernel/signal32.c >>> index e299de396e9b..32601939a3c8 100644 >>> --- a/arch/arm64/kernel/signal32.c >>> +++ b/arch/arm64/kernel/signal32.c >>> @@ -154,8 +154,7 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) >>> case __SI_TIMER: >>> err |= __put_user(from->si_tid, &to->si_tid); >>> err |= __put_user(from->si_overrun, &to->si_overrun); >>> - err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, >>> - &to->si_ptr); >>> + err |= __put_user(from->si_int, &to->si_int); >>> break; >>> case __SI_POLL: >>> err |= __put_user(from->si_band, &to->si_band); >>> @@ -184,7 +183,7 @@ int copy_siginfo_to_user32(compat_siginfo_t __user *to, const siginfo_t *from) >>> case __SI_MESGQ: /* But this is */ >>> err |= __put_user(from->si_pid, &to->si_pid); >>> err |= __put_user(from->si_uid, &to->si_uid); >>> - err |= __put_user((compat_uptr_t)(unsigned long)from->si_ptr, &to->si_ptr); >>> + err |= __put_user(from->si_int, &to->si_int); >>> break; >>> case __SI_SYS: >>> err |= __put_user((compat_uptr_t)(unsigned long) > -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
