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

On Wed, Dec 11, 2024 at 10:22 AM <devel-request(a)lists.crash-utility.osci.io&gt; wrote: > Date: Tue, 10 Dec 2024 20:18:43 +0800 > From: "Hou Wenlong" <houwenlong.hwl(a)antgroup.com&gt; > Subject: [Crash-utility] [PATCH] x86_64: Mark #VC stack unavailable > when CONFIG_AMD_MEM_ENCRYPT is not set > To: devel(a)lists.crash-utility.osci.io > Cc: Hou Wenlong <houwenlong.hwl(a)antgroup.com&gt; > Message-ID: <f1fca9918841de9a48f428d498f50964f1dab543.1733831073.git.h > ouwenlong.hwl(a)antgroup.com&gt; > > 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. > > Thank you for the fix, Hou. > 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] && > Can you help double check if the above condition is redundant in your case? Seems the check '!accessible(ms->stkinfo.ebase[c][i])' should be enough.