Re: [Outreachy kernel] Trying to use Coccinelle

[Stefano Brivio <sbrivio@redhat.com>]

On Fri, 13 Mar 2020 10:40:46 +0100
Lourdes Pedrajas <lu@pplo.net> wrote:

> [...]
>
> Indeed, this is all the output: (this command is run in the sources root
> directory)
> 
> make coccicheck MODE=patch J=8 M=drivers/staging/android/
> 
> Please check for false positives in the output before submitting a patch.
> When using "patch" mode, carefully review the patch before submitting it.
> 
> coccicheck failed
> Makefile:1740: recipe for target 'coccicheck' failed
> make: *** [coccicheck] Error 255

Hah, I think I got the same issue on Debian. I installed coccinelle via
opam, then:

---
$ make coccicheck MODE=report M=drivers/staging/android/

Please check for false positives in the output before submitting a patch.
When using "patch" mode, carefully review the patch before submitting it.

coccicheck failed
make: *** [Makefile:1740: coccicheck] Error 255
---

Debugging: looking at makefiles, I thought about using V=1:

---
$ make V=1 coccicheck MODE=report M=drivers/staging/android/
bash ./scripts/coccicheck

Please check for false positives in the output before submitting a patch.
When using "patch" mode, carefully review the patch before submitting it.

Processing alloc_cast.cocci
with option(s) " --no-includes --include-headers"

Message example to submit a patch:
 Remove casting the values returned by memory allocation functions
 like kmalloc, kzalloc, kmem_cache_alloc, kmem_cache_zalloc etc.

 The semantic patch that makes this report is available
 in scripts/coccinelle/api/alloc/alloc_cast.cocci.

 More information about semantic patching is available at
 http://coccinelle.lip6.fr/

Semantic patch information:
 This makes an effort to find cases of casting of values returned by
 kmalloc, kzalloc, kcalloc, kmem_cache_alloc, kmem_cache_zalloc,
 kmem_cache_alloc_node, kmalloc_node and kzalloc_node and removes
 the casting as it is not required. The result in the patch case may
 need some reformatting.

Running (4 in parallel): /home/sbrivio/.opam/default/bin/spatch -D report --no-show-diff --very-quiet --cocci-file ./scripts/coccinelle/api/alloc/alloc_cast.cocci --no-includes --include-headers --patch . --dir drivers/staging/android/ -I ./arch/x86/include -I ./arch/x86/include/generated -I ./include -I ./arch/x86/include/uapi -I ./arch/x86/include/generated/uapi -I ./include/uapi -I ./include/generated/uapi --include ./include/linux/kconfig.h --jobs 4 --chunksize 1
coccicheck failed
make: *** [Makefile:1740: coccicheck] Error 255
---

so, yeah, spatch fails, but no error (see below) isn't propagated (even
with V=1)

Julia, do you think it's worth trying to fix this? Any quick idea?

Anyway, running the spatch command by itself:

---
$ /home/sbrivio/.opam/default/bin/spatch -D report --no-show-diff --very-quiet --cocci-file ./scripts/coccinelle/api/alloc/alloc_cast.cocci --no-includes --include-headers --patch . --dir drivers/staging/android/ -I ./arch/x86/include -I ./arch/x86/include/generated -I ./include -I ./arch/x86/include/uapi -I ./arch/x86/include/generated/uapi -I ./include/uapi -I ./include/generated/uapi --include ./include/linux/kconfig.h
Py.find_library: unable to find the Python library [libpython2.7m.so returned Library not found] [/usr/bin/../lib/libpython2.7m.so returned Library not found] [libpython2.7.so returned Library not found] [/usr/bin/../lib/libpython2.7.so returned Library not found]
---

I installed libpython2.7-dev, and everything works now.

-- 
Stefano