On 2024-06-28 01:18, Stefano Stabellini wrote:
On Thu, 27 Jun 2024, Nicola Vetrini wrote:
The label 'out_unmap' is only reachable after ASSERT_UNREACHABLE,
so the code below is only executed upon erroneously reaching that
program point and calling domain_crash, thus resulting in the
for loop after 'out_unmap' to become unreachable in some
configurations.
This is a defensive coding measure to have a safe fallback that is
reachable in non-debug builds, and can thus be deviated with a
comment-based deviation.
No functional change.
Signed-off-by: Nicola Vetrini <nicola.vetr...@bugseng.com>
The patch needs rebasing as it doesn't apply to staging anymore
Other than that:
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
This is actually going help also in terms of identifying impossible
code
paths for coverage
Thanks, I just sent a rebased v2 version.
---
docs/misra/safe.json | 8 ++++++++
xen/arch/x86/mm/p2m-pod.c | 1 +
2 files changed, 9 insertions(+)
diff --git a/docs/misra/safe.json b/docs/misra/safe.json
index c213e0a0be3b..b114c9485c86 100644
--- a/docs/misra/safe.json
+++ b/docs/misra/safe.json
@@ -60,6 +60,14 @@
},
{
"id": "SAF-7-safe",
+ "analyser": {
+ "eclair": "MC3R1.R2.1"
+ },
+ "name": "MC3R1.R2.1: statement unreachable in some
configurations",
+ "text": "Every path that can reach this statement is
preceded by statements that make it unreachable in certain
configurations (e.g. ASSERT_UNREACHABLE). This is understood as a
means of defensive programming."
+ },
+ {
+ "id": "SAF-8-safe",
"analyser": {},
"name": "Sentinel",
"text": "Next ID to be used"
diff --git a/xen/arch/x86/mm/p2m-pod.c b/xen/arch/x86/mm/p2m-pod.c
index bd84fe9e27ee..5a96c46a2286 100644
--- a/xen/arch/x86/mm/p2m-pod.c
+++ b/xen/arch/x86/mm/p2m-pod.c
@@ -1040,6 +1040,7 @@ out_unmap:
* Something went wrong, probably crashing the domain. Unmap
* everything and return.
*/
+ /* SAF-7-safe Rule 2.1: defensive programming */
for ( i = 0; i < count; i++ )
if ( map[i] )
unmap_domain_page(map[i]);
--
2.34.1
--
Nicola Vetrini, BSc
Software Engineer, BUGSENG srl (https://bugseng.com)
