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Reduce false positives from Static Analyzers

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Both Clang's Static Analyzer and Synopsys' Coverity would ignore
assertions. Following Clang's advice, we annotate our assertions:

https://clang-analyzer.llvm.org/annotations.html#custom_assertions

This makes both Clang's Static Analyzer and Coverity properly identify
assertions. This change reduced Clang's reported defects from 246 to
180. It also reduced the false positives reported by Coverityi by 10,
while enabling Coverity to find 9 more defects that previously were
false negatives.

A couple examples of this would be CID-1524417 and CID-1524423. After
submitting a build to coverity with the modified assertions, CID-1524417
disappeared while the report for CID-1524423 no longer claimed that the
assertion tripped.

Coincidentally, it turns out that it is possible to more accurately
annotate our headers than the Coverity modelling file permits in the
case of format strings. Since we can do that and this patch annotates
headers whenever `__coverity_panic__()` would have been used in the
model file, we drop all models that use `__coverity_panic__()` from the
model file.

Upon seeing the success in eliminating false positives involving
assertions, it occurred to me that we could also modify our headers to
eliminate coverity's false positives involving byte swaps. We now have
coverity specific byteswap macros, that do nothing, to disable
Coverity's false positives when we do byte swaps. This allowed us to
also drop the byteswap definitions from the model file.

Lastly, a model file update has been done beyond the mentioned
deletions:

 * The definitions of `umem_alloc_aligned()`, `umem_alloc()` andi
   `umem_zalloc()` were originally implemented in a way that was
   intended to inform coverity that when KM_SLEEP has been passed these
   functions, they do not return NULL. A small error in how this was
   done was found, so we correct it.

 * Definitions for umem_cache_alloc() and umem_cache_free() have been
   added.

In practice, no false positives were avoided by making these changes,
but in the interest of correctness from future coverity builds, we make
them anyway.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Reviewed-by: Ryan Moeller <ryan@iXsystems.com>
Signed-off-by: Richard Yao <richard.yao@alumni.stonybrook.edu>
Closes #13902
This commit is contained in:
Richard Yao
2022-09-30 18:30:12 -04:00
committed by GitHub
parent dee8934e8f
commit 55d7afa4ad
19 changed files with 170 additions and 131 deletions
Download Patch File Download Diff File Expand all files Collapse all files
include/os/linux/spl/sys/byteorder.h
+15
View File
@@ -36,11 +36,26 @@
#include <sys/isa_defs.h>
#ifdef __COVERITY__
/*
* Coverity's taint warnings from byteswapping are false positives for us.
* Suppress them by hiding byteswapping from Coverity.
*/
#define BSWAP_8(x) ((x) & 0xff)
#define BSWAP_16(x) ((x) & 0xffff)
#define BSWAP_32(x) ((x) & 0xffffffff)
#define BSWAP_64(x) (x)
#else /* __COVERITY__ */
#define BSWAP_8(x) ((x) & 0xff)
#define BSWAP_16(x) ((BSWAP_8(x) << 8) | BSWAP_8((x) >> 8))
#define BSWAP_32(x) ((BSWAP_16(x) << 16) | BSWAP_16((x) >> 16))
#define BSWAP_64(x) ((BSWAP_32(x) << 32) | BSWAP_32((x) >> 32))
#endif /* __COVERITY__ */
#define LE_16(x) cpu_to_le16(x)
#define LE_32(x) cpu_to_le32(x)
#define LE_64(x) cpu_to_le64(x)
include/os/linux/spl/sys/cmn_err.h
+1 -1
View File
@@ -41,7 +41,7 @@ extern void cmn_err(int, const char *, ...)
extern void vcmn_err(int, const char *, va_list)
__attribute__((format(printf, 2, 0)));
extern void vpanic(const char *, va_list)
__attribute__((format(printf, 1, 0)));
__attribute__((format(printf, 1, 0), __noreturn__));
#define fm_panic panic
include/os/linux/spl/sys/debug.h
+18 -11
View File
@@ -54,17 +54,24 @@
#define __maybe_unused __attribute__((unused))
#endif
int spl_panic(const char *file, const char *func, int line,
const char *fmt, ...);
void spl_dumpstack(void);
extern void spl_panic(const char *file, const char *func, int line,
const char *fmt, ...) __attribute__((__noreturn__));
extern void spl_dumpstack(void);
static inline int
spl_assert(const char *buf, const char *file, const char *func, int line)
{
spl_panic(file, func, line, "%s", buf);
return (0);
}
#define PANIC(fmt, a...) \
spl_panic(__FILE__, __FUNCTION__, __LINE__, fmt, ## a)
#define VERIFY(cond) \
(void) (unlikely(!(cond)) && \
spl_panic(__FILE__, __FUNCTION__, __LINE__, \
"%s", "VERIFY(" #cond ") failed\n"))
spl_assert("VERIFY(" #cond ") failed\n", \
__FILE__, __FUNCTION__, __LINE__))
#define VERIFY3B(LEFT, OP, RIGHT) do { \
const boolean_t _verify3_left = (boolean_t)(LEFT); \
@@ -152,13 +159,13 @@ void spl_dumpstack(void);
#define ASSERT0 VERIFY0
#define ASSERT VERIFY
#define IMPLY(A, B) \
((void)(likely((!(A)) || (B)) || \
spl_panic(__FILE__, __FUNCTION__, __LINE__, \
"(" #A ") implies (" #B ")")))
((void)(likely((!(A)) || (B)) || \
spl_assert("(" #A ") implies (" #B ")", \
__FILE__, __FUNCTION__, __LINE__)))
#define EQUIV(A, B) \
((void)(likely(!!(A) == !!(B)) || \
spl_panic(__FILE__, __FUNCTION__, __LINE__, \
"(" #A ") is equivalent to (" #B ")")))
((void)(likely(!!(A) == !!(B)) || \
spl_assert("(" #A ") is equivalent to (" #B ")", \
__FILE__, __FUNCTION__, __LINE__)))
#endif /* NDEBUG */
include/os/linux/spl/sys/kmem.h
+8 -4
View File
@@ -31,8 +31,10 @@
#include <linux/vmalloc.h>
extern int kmem_debugging(void);
extern char *kmem_vasprintf(const char *fmt, va_list ap);
extern char *kmem_asprintf(const char *fmt, ...);
extern char *kmem_vasprintf(const char *fmt, va_list ap)
__attribute__((format(printf, 1, 0)));
extern char *kmem_asprintf(const char *fmt, ...)
__attribute__((format(printf, 1, 2)));
extern char *kmem_strdup(const char *str);
extern void kmem_strfree(char *str);
@@ -179,8 +181,10 @@ extern unsigned int spl_kmem_alloc_max;
#define kmem_free(ptr, sz) spl_kmem_free((ptr), (sz))
#define kmem_cache_reap_active spl_kmem_cache_reap_active
extern void *spl_kmem_alloc(size_t sz, int fl, const char *func, int line);
extern void *spl_kmem_zalloc(size_t sz, int fl, const char *func, int line);
extern void *spl_kmem_alloc(size_t sz, int fl, const char *func, int line)
__attribute__((alloc_size(1)));
extern void *spl_kmem_zalloc(size_t sz, int fl, const char *func, int line)
__attribute__((alloc_size(1)));
extern void spl_kmem_free(const void *ptr, size_t sz);
/*