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* Coverity Model UpdateRichard Yao2022-11-291-4/+6
| | | | | | | | | | | | | | | When reviewing Clang Static Analyzer reports against a branch that had experimental header changes based on the Coverity model file to inform it that KM_SLEEP allocations cannot return NULL, I found a report saying that a KM_PUSHPAGE allocation returned NULL. The actual implementation does not return NULL unless KM_NOSLEEP has been passed, so we backport the correction from the experimental header changes to the Coverity model. Reviewed-by: Brian Behlendorf <[email protected]> Reviewed-by: Ryan Moeller <[email protected]> Signed-off-by: Richard Yao <[email protected]> Closes #14210
* Coverity model file updateRichard Yao2022-10-181-48/+341
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Upon review, it was found that the model for malloc() was incorrect. In addition, several general purpose memory allocation functions were missing models: * kmem_vasprintf() * kmem_asprintf() * kmem_strdup() * kmem_strfree() * spl_vmem_alloc() * spl_vmem_zalloc() * spl_vmem_free() * calloc() As an experiment to try to find more bugs, some less than general purpose memory allocation functions were also given models: * zfsvfs_create() * zfsvfs_free() * nvlist_alloc() * nvlist_dup() * nvlist_free() * nvlist_pack() * nvlist_unpack() Finally, the models were improved using additional coverity primitives: * __coverity_negative_sink__() * __coverity_writeall0__() * __coverity_mark_as_uninitialized_buffer__() * __coverity_mark_as_afm_allocated__() In addition, an attempt to inform coverity that certain modelled functions read entire buffers was used by adding the following to certain models: int first = buf[0]; int last = buf[buflen-1]; It was inspired by the QEMU model file. No additional false positives were found by this, but it is believed that the more accurate model file will help to catch false positives in the future. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Richard Yao <[email protected]> Closes #14048
* Reduce false positives from Static AnalyzersRichard Yao2022-09-301-92/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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 <[email protected]> Reviewed-by: Ryan Moeller <[email protected]> Signed-off-by: Richard Yao <[email protected]> Closes #13902
* Update coverity modelRichard Yao2022-09-161-1/+16
| | | | | | | | | | | | `uu_panic()` needs to be modelled and the definition of `vpanic()` from the original coverity model was missing `__coverity_format_string_sink__()`. We also model `libspl_assertf()` as part of an attempt to eliminate false positives. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Richard Yao <[email protected]> Closes #13901
* Add coverity model to repositoryRichard Yao2022-09-151-0/+407
Other projects such as the python project include their coverity models in their repositories. This provides transparency, which is beneficial in open source projects. Therefore, it is a good idea to include the coverity model in our repository too. Reviewed-by: Brian Behlendorf <[email protected]> Signed-off-by: Richard Yao <[email protected]> Closes #13884