The first attempt resulted in several "Free of address-of
expression (BAD_FREE)" issues, because of code which relies on the fact that
any pointer in the same page is ok to pass to unmap_domain_page()
Model this property to remove the issues.
Coverity IDs: 1135356 113536{0,1} 1401300 141809{0,1} 1438864
Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
CC: George Dunlap <George.Dunlap@eu.citrix.com>
CC: Ian Jackson <ian.jackson@citrix.com>
CC: Jan Beulich <JBeulich@suse.com>
CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <sstabellini@kernel.org>
CC: Wei Liu <wl@xen.org>
CC: Julien Grall <julien@xen.org>
As the only way of testing is to upload a new model, this change matches what
I've already done in Snapshot 182435.
---
misc/coverity/model.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)
diff --git a/misc/coverity/model.c b/misc/coverity/model.c
index bd62566a0d..1ec3fe8673 100644
--- a/misc/coverity/model.c
+++ b/misc/coverity/model.c
@@ -82,21 +82,31 @@ void xfree(void *va)
* allocation of exactly 1 page.
*
* map_domain_page() never fails. (It will BUG() before returning NULL)
- *
- * TODO: work out how to correctly model the behaviour that this function will
- * only ever return page aligned pointers.
*/
void *map_domain_page(unsigned long mfn)
{
- return __coverity_alloc__(PAGE_SIZE);
+ unsigned long ptr = (unsigned long)__coverity_alloc__(PAGE_SIZE);
+
+ /*
+ * Expressing the alignment of the memory allocation isn't possible. As a
+ * substitute, tell Coverity to ignore any path where ptr isn't page
+ * aligned.
+ */
+ if ( ptr & ~PAGE_MASK )
+ __coverity_panic__();
+
+ return (void *)ptr;
}
/*
- * unmap_domain_page() will unmap a page. Model it as a free().
+ * unmap_domain_page() will unmap a page. Model it as a free(). Any *va
+ * within the page is valid to pass.
*/
void unmap_domain_page(const void *va)
{
- __coverity_free__(va);
+ unsigned long ptr = (unsigned long)va & PAGE_MASK;
+
+ __coverity_free__((void *)ptr);
}
/*
--
2.11.0
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On 06.01.2020 14:28, Andrew Cooper wrote: > The first attempt resulted in several "Free of address-of > expression (BAD_FREE)" issues, because of code which relies on the fact that > any pointer in the same page is ok to pass to unmap_domain_page() > > Model this property to remove the issues. > > Coverity IDs: 1135356 113536{0,1} 1401300 141809{0,1} 1438864 > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> Acked-by: Jan Beulich <jbeulich@suse.com> _______________________________________________ Xen-devel mailing list Xen-devel@lists.xenproject.org https://lists.xenproject.org/mailman/listinfo/xen-devel
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