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From: Paolo Bonzini <pbonzini@redhat.com>
To: qemu-devel@nongnu.org
Subject: [PATCH 6/6] coverity-model: write models fully for non-array allocation functions
Date: Sat, 31 Jul 2021 08:27:41 +0200	[thread overview]
Message-ID: <20210731062741.301102-7-pbonzini@redhat.com> (raw)
In-Reply-To: <20210731062741.301102-1-pbonzini@redhat.com>

Coverity seems to have issues figuring out the properties of g_malloc0
and other non *_n functions.  While this was "fixed" by removing the
custom second argument to __coverity_mark_as_afm_allocated__, inline
the code from the array-based allocation functions to avoid future
issues.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 scripts/coverity-scan/model.c | 57 +++++++++++++++++++++++++++++++----
 1 file changed, 51 insertions(+), 6 deletions(-)

diff --git a/scripts/coverity-scan/model.c b/scripts/coverity-scan/model.c
index 028f13e9e3..9d4fba53d9 100644
--- a/scripts/coverity-scan/model.c
+++ b/scripts/coverity-scan/model.c
@@ -269,32 +269,77 @@ void *g_try_realloc_n(void *ptr, size_t nmemb, size_t size)
 
 void *g_malloc(size_t size)
 {
-    return g_malloc_n(1, size);
+    void *ptr;
+
+    __coverity_negative_sink__(size);
+    ptr = __coverity_alloc__(size);
+    if (!ptr) {
+        __coverity_panic__();
+    }
+    __coverity_mark_as_uninitialized_buffer__(ptr);
+    __coverity_mark_as_afm_allocated__(ptr, AFM_free);
+    return ptr;
 }
 
 void *g_malloc0(size_t size)
 {
-    return g_malloc0_n(1, size);
+    void *ptr;
+
+    __coverity_negative_sink__(size);
+    ptr = __coverity_alloc__(size);
+    if (!ptr) {
+        __coverity_panic__();
+    }
+    __coverity_writeall0__(ptr);
+    __coverity_mark_as_afm_allocated__(ptr, AFM_free);
+    return ptr;
 }
 
 void *g_realloc(void *ptr, size_t size)
 {
-    return g_realloc_n(ptr, 1, size);
+    __coverity_negative_sink__(size);
+    __coverity_escape__(ptr);
+    ptr = __coverity_alloc__(size);
+    if (!ptr) {
+        __coverity_panic__();
+    }
+    /*
+     * Memory beyond the old size isn't actually initialized.  Can't
+     * model that.  See Coverity's realloc() model
+     */
+    __coverity_writeall__(ptr);
+    __coverity_mark_as_afm_allocated__(ptr, AFM_free);
+    return ptr;
 }
 
 void *g_try_malloc(size_t size)
 {
-    return g_try_malloc_n(1, size);
+    int nomem;
+
+    if (nomem) {
+        return NULL;
+    }
+    return g_malloc(size);
 }
 
 void *g_try_malloc0(size_t size)
 {
-    return g_try_malloc0_n(1, size);
+    int nomem;
+
+    if (nomem) {
+        return NULL;
+    }
+    return g_malloc0(size);
 }
 
 void *g_try_realloc(void *ptr, size_t size)
 {
-    return g_try_realloc_n(ptr, 1, size);
+    int nomem;
+
+    if (nomem) {
+        return NULL;
+    }
+    return g_realloc(ptr, size);
 }
 
 /* Other glib functions */
-- 
2.31.1



  parent reply	other threads:[~2021-07-31  6:33 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-31  6:27 [PATCH 0/6] Updates for Coverity modeling file Paolo Bonzini
2021-07-31  6:27 ` [PATCH 1/6] coverity-model: update address_space_read/write models Paolo Bonzini
2021-08-02 12:31   ` Peter Maydell
2021-07-31  6:27 ` [PATCH 2/6] coverity-model: make g_free a synonym of free Paolo Bonzini
2021-08-02 12:32   ` Peter Maydell
2021-07-31  6:27 ` [PATCH 3/6] coverity-model: remove model for more allocation functions Paolo Bonzini
2021-08-02 12:34   ` Peter Maydell
2021-07-31  6:27 ` [PATCH 4/6] coverity-model: clean up the models for array " Paolo Bonzini
2021-08-02 12:36   ` Peter Maydell
2021-08-02 16:20     ` Paolo Bonzini
2021-08-04  8:35       ` Markus Armbruster
2021-08-04  8:43         ` Peter Maydell
2021-07-31  6:27 ` [PATCH 5/6] coverity-model: constrain g_malloc/g_malloc0/g_realloc as never returning NULL Paolo Bonzini
2021-08-02 12:37   ` Peter Maydell
2021-07-31  6:27 ` Paolo Bonzini [this message]
2021-08-02 12:38   ` [PATCH 6/6] coverity-model: write models fully for non-array allocation functions Peter Maydell
2021-08-02 12:46 ` [PATCH 0/6] Updates for Coverity modeling file Peter Maydell
2021-08-02 16:22   ` Paolo Bonzini
2021-08-03  6:04 ` Markus Armbruster

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