[Crash-utility] Re: [PATCH] x86_64: Mark #VC stack unavailable when CONFIG_AMD_MEM_ENCRYPT is not set

Date: Thu, 12 Dec 2024 12:53:08 +1300 From: Tao Liu <ltao(a)redhat.com&gt; Subject: [Crash-utility] Re: [PATCH] x86_64: Mark #VC stack unavailable when CONFIG_AMD_MEM_ENCRYPT is not set To: Hou Wenlong <houwenlong.hwl(a)antgroup.com&gt; Cc: devel(a)lists.crash-utility.osci.io Message-ID: <CAO7dBbWi06FCj36_UPMXN3cs_=xQZd-oM= hAZ7eZrVpTkVWLkA(a)mail.gmail.com&gt; Content-Type: text/plain; charset="UTF-8" Hi Hou, On Wed, Dec 11, 2024 at 2:36 PM Hou Wenlong <houwenlong.hwl(a)antgroup.com&gt; wrote: > > When 'CONFIG_AMD_MEM_ENCRYPT' is not set, the IDT handler for #VC is not > registered, but the address of the #VC IST stack is still set in > tss_setup_ist(). Therefore, the name of the associated exception stack > is "UNKNOWN" instead of "VC". Although the base of the exception stack > is not zero and is available, it is not accessible, which will cause the > backtrace to fail when attempting to access the #VC stack. To fix this, > remove the name check. > > Signe-off-by: Hou Wenlong <houwenlong.hwl(a)antgroup.com&gt; > --- > x86_64.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/x86_64.c b/x86_64.c > index e7f8fe25b31f..ee12ba095e6e 100644 > --- a/x86_64.c > +++ b/x86_64.c > @@ -1540,7 +1540,7 @@ x86_64_ist_init(void) > > ms->stkinfo.available[c][i] = TRUE; > /* VC stack can be unmapped if SEV-ES is disabled or not supported. */ > - if (STREQ(ms->stkinfo.exception_stacks[i], "VC") && > + if (ms->stkinfo.ebase[c][i] && > !accessible(ms->stkinfo.ebase[c][i])) I agree the ms->stkinfo.ebase[c][i] should always be checked for "accessible", not just for "VC" stacks, so removing the "VC" name checking is reasonable. The code LGTM, so ack.

Thanks, Tao Liu > ms->stkinfo.available[c][i] = FALSE; > } > > base-commit: f13853cef53f5c5463a51021edbc81977e2b1405 > -- > 2.31.1