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| author | Warner Losh <imp@FreeBSD.org> | 2021-07-09 17:21:18 +0000 |
|---|---|---|
| committer | Warner Losh <imp@FreeBSD.org> | 2021-07-12 19:42:58 +0000 |
| commit | 9cd9a0c86924c350f83e5c8fbcadc84ee0d72e26 (patch) | |
| tree | f958f2b4858c723f67fa675afeabe1da6058ed01 | |
| parent | 940fae4082550e7a6a5040b573705d5cdf87d560 (diff) | |
| download | src-9cd9a0c86924c350f83e5c8fbcadc84ee0d72e26.tar.gz src-9cd9a0c86924c350f83e5c8fbcadc84ee0d72e26.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
(cherry picked from commit 72821668b039c276914569e9caa1cdfa4e4cb674)
| -rw-r--r-- | sys/sys/malloc.h | 17 |
1 files changed, 11 insertions, 6 deletions
diff --git a/sys/sys/malloc.h b/sys/sys/malloc.h index 52a17b5171bc..8982e534fc22 100644 --- a/sys/sys/malloc.h +++ b/sys/sys/malloc.h @@ -297,16 +297,20 @@ 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__) /* @@ -314,5 +318,6 @@ 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_ */ |