Messages in this thread | | | Date | Thu, 17 Feb 2022 22:01:19 -0800 | From | Ira Weiny <> | Subject | Re: [PATCH V8 26/44] x86/fault: Print PKS MSR on fault |
| |
On Tue, Feb 01, 2022 at 10:13:40AM -0800, Edgecombe, Rick P wrote: > On Thu, 2022-01-27 at 09:54 -0800, ira.weiny@intel.com wrote: > > + if (error_code & X86_PF_PK) > > + pks_dump_fault_info(regs); > > + > > If the kernel makes an errant accesses to a userspace address with PKU > enabled and the usersapce page marked AD, it should oops and get here, > but will the X86_PF_PK bit be set even if smap is the real cause? Per > the SDM, it sounds like it would: > " > For accesses to user-mode addresses, the flag is set if > (1) CR4.PKE = 1; > (2) the linear address has protection key i; and > (3) the PKRU register (see Section 4.6.2) is such that either > (a) ADi = 1; or > (b) the following all hold: > (i) WDi = 1; > (ii) the access is a write access; and > (iii) either CR0.WP = 1 or the access causing the > page-fault exception was a user-mode access. > " > > ...and then this somewhat confusingly dumps the pks register. Is that > the real behavior?
Are you suggesting the PKRU should be printed instead or in addition to the PKS?
AFAICS this really should not present a problem even if the fault is due to a user pkey violation. It is simply extra information.
Ira
| |