Re: [Xen-devel] [xen-unstable-smoke test] 136291: regressions - FAIL

[Roger Pau Monné <roger.pau@xxxxxxxxxx>]

On Wed, May 15, 2019 at 10:24:44AM +0000, osstest service owner wrote:
> flight 136291 xen-unstable-smoke real [real]
> http://logs.test-lab.xenproject.org/osstest/logs/136291/
> 
> Regressions :-(
> 
> Tests which did not succeed and are blocking,
> including tests which could not be run:
>  build-amd64                   6 xen-build                fail REGR. vs. 
> 136179

The error is:

p2m.c: In function 'altp2m_get_effective_entry':
p2m.c:502:26: error: 'page_order' may be used uninitialized in this function 
[-Werror=maybe-uninitialized]
         if ( prepopulate && page_order != PAGE_ORDER_4K )

I think the above patch should solve it, AFAICT it's not a real
uninitialized usage.

---8<---
From fd12faf088ea679fdfb86b4758403692ee99e06b Mon Sep 17 00:00:00 2001
From: Roger Pau Monne <roger.pau@xxxxxxxxxx>
Date: Wed, 15 May 2019 12:32:38 +0200
Subject: [PATCH] altp2m: placate uninitialized variable error
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

gcc reports:

p2m.c: In function 'altp2m_get_effective_entry':
p2m.c:502:26: error: 'page_order' may be used uninitialized in this function 
[-Werror=maybe-uninitialized]
         if ( prepopulate && page_order != PAGE_ORDER_4K )

Placate the error by initializing page_order to 0.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
 xen/arch/x86/mm/p2m.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 57c5eeda91..133106962b 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -2352,7 +2352,7 @@ int altp2m_get_effective_entry(struct p2m_domain *ap2m, 
gfn_t gfn, mfn_t *mfn,
     if ( !mfn_valid(*mfn) && !p2m_is_hostp2m(ap2m) )
     {
         struct p2m_domain *hp2m = p2m_get_hostp2m(ap2m->domain);
-        unsigned int page_order;
+        unsigned int page_order = 0;
         int rc;
 
         *mfn = __get_gfn_type_access(hp2m, gfn_x(gfn), t, a,
-- 
2.17.2 (Apple Git-113)



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