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authorWarner Losh <imp@FreeBSD.org>2021-07-09 17:21:18 +0000
committerWarner Losh <imp@FreeBSD.org>2021-07-09 17:21:18 +0000
commit72821668b039c276914569e9caa1cdfa4e4cb674 (patch)
treeec55ecf87098964b67321d85014b2885d6c5c192 /sys
parent1472117a1e1c40f10b9c3a48788fbf8355588ee8 (diff)
downloadsrc-72821668b039c276914569e9caa1cdfa4e4cb674.tar.gz
src-72821668b039c276914569e9caa1cdfa4e4cb674.zip
stand/kmem_zalloc: panic when a M_WAITOK allocation fails
Malloc() might return NULL, in which case we will panic with a NULL pointer deref. Make it panic when the allocation fails to preserve the postcondtion that we never return a non-NULL value. Reviewed by: tsoome PR: 249859 Sponsored by: Netflix Differential Revision: https://reviews.freebsd.org/D31106
Diffstat (limited to 'sys')
-rw-r--r--sys/sys/malloc.h17
1 files changed, 11 insertions, 6 deletions
diff --git a/sys/sys/malloc.h b/sys/sys/malloc.h
index 0c585c5a0dcf..b8c2788edd44 100644
--- a/sys/sys/malloc.h
+++ b/sys/sys/malloc.h
@@ -298,16 +298,20 @@ extern void *Malloc(size_t bytes, const char *file, int line);
* flags mean anything and there's no need declare malloc types.
* Define the simple alloc / free routines in terms of Malloc and
* Free. None of the kernel features that this stuff disables are needed.
- *
- * XXX we are setting ourselves up for a potential crash if we can't allocate
- * memory for a M_WAITOK call.
*/
-#define M_WAITOK 0
+#define M_WAITOK 1
#define M_ZERO 0
-#define M_NOWAIT 0
+#define M_NOWAIT 2
#define MALLOC_DECLARE(x)
-#define kmem_zalloc(size, flags) Malloc((size), __FILE__, __LINE__)
+#define kmem_zalloc(size, flags) ({ \
+ void *p = Malloc((size), __FILE__, __LINE__); \
+ if (p == NULL && (flags & M_WAITOK) != 0) \
+ panic("Could not malloc %zd bytes with M_WAITOK from %s line %d", \
+ (size_t)size, __FILE__, __LINE__); \
+ p; \
+})
+
#define kmem_free(p, size) Free(p, __FILE__, __LINE__)
/*
@@ -315,5 +319,6 @@ extern void *Malloc(size_t bytes, const char *file, int line);
* M_WAITOK. Given the above, it will also be a nop.
*/
#define KM_SLEEP M_WAITOK
+#define KM_NOSLEEP M_NOWAIT
#endif /* _STANDALONE */
#endif /* !_SYS_MALLOC_H_ */