Re: Re [PATCH v5 4/5] x86/pkeys: Restore altstack before sigcontext

[Aruna Ramakrishna]

> On Jun 10, 2024, at 2:44 PM, jeffxu@xxxxxxxxxxxx wrote:
> 
> Can we we move this patch to the first of the series? this can be an
> independent patch, the problem not only affect PKRU, but also other
> scenarios, as Rick pointed out in [1]
> 
> [1] https://lore.kernel.org/lkml/d0162c76c25bc8e1c876aebe8e243ff2e6862359.camel@xxxxxxxxx/
> 
> -Jeff

For this patch set, the issue with rt_sigreturn() is only exposed after patch 3/5 - i.e., when
copy_fpregs_to_sigframe() calls update_pkru_in_sigframe() to update the PKRU value to
user-specified PKRU that might disable pkey 0 access, thus breaking restore_altstack().
So it seemed logical to me to have this fix as patch 4/5 of this series. I’m not strongly
opposed to moving this to patch 1/5, but this ordering is easier to understand (I think).
But if this patch needs to be broken out of this patchset and submitted independently
(for the other scenarios you mentioned) - I can do that.

Thanks,
Aruna