Hi Jeff, Thanks for chiming in! On Wed, Oct 30, 2024 at 03:01:53PM -0700, Jeff Xu wrote: > On Tue, Oct 29, 2024 at 7:46 AM Kevin Brodsky <kevin.brodsky@xxxxxxx> wrote: > > > > TL;DR: reset POR_EL0 to "allow all" before writing the signal frame, > > preventing spurious uaccess failures. [...] > > @@ -924,12 +982,14 @@ SYSCALL_DEFINE0(rt_sigreturn) > > if (!access_ok(frame, sizeof (*frame))) > > goto badframe; > > > > - if (restore_sigframe(regs, frame)) > > + if (restore_sigframe(regs, frame, &ua_state)) > > goto badframe; > > > > if (restore_altstack(&frame->uc.uc_stack)) > > goto badframe; > > > Do you need to move restore_altstack ahead of restore_sigframe? > similar as x86 change [1], > the discussion for this happened in [2] [3] > > [1] https://lore.kernel.org/lkml/20240802061318.2140081-5-aruna.ramakrishna@xxxxxxxxxx/ > [2] https://lore.kernel.org/lkml/20240425210540.3265342-1-jeffxu@xxxxxxxxxxxx/ > [3] https://lore.kernel.org/lkml/d0162c76c25bc8e1c876aebe8e243ff2e6862359.camel@xxxxxxxxx/ > > > + restore_user_access_state(&ua_state); The POR isn't restored until here ^^^, so I _think_ restore_altstack() is fine where it is. Kevin, can you confirm, please? Will
