linux-kernel - Re: [PATCH v6] coccinelle: api: add kvfree script

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Message-ID: <alpine.DEB.2.22.394.2008022142550.2531@hadrien>
Date:   Sun, 2 Aug 2020 22:24:21 +0200 (CEST)
From:   Julia Lawall <julia.lawall@...ia.fr>
To:     Denis Efremov <efremov@...ux.com>
cc:     cocci@...teme.lip6.fr, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v6] coccinelle: api: add kvfree script

> +@...tialize:python@
> +@@
> +# low-level memory api
> +filter = frozenset(['__vmalloc_area_node'])
> +
> +def relevant(p):
> +    return not (filter & {el.current_element for el in p})

Is this used?

Otherwise, I think it would be good to not warn about a use of kvfree
if that use is reachable from a kvmalloc.  There seems to be such a false
positive in fs/btrfs/send.c, on line 1118.

It also seems that when there are both a kmalloc and a vmalloc, there is
no warning if kfree or vfree is used.  Is that intentional?

julia


> +
> +@...ice@
> +expression E, E1;
> +position kok, vok;
> +@@
> +
> +(
> +  if (...) {
> +    ...
> +    E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|
> +          kmalloc_node\|kzalloc_node\|kmalloc_array\|
> +          kmalloc_array_node\|kcalloc_node\)(...)@kok
> +    ...
> +  } else {
> +    ...
> +    E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
> +          vzalloc_node\|vmalloc_exec\|vmalloc_32\|
> +          vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
> +          __vmalloc_node\)(...)@vok
> +    ...
> +  }
> +|
> +  E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
> +        kmalloc_array\|kmalloc_array_node\|kcalloc_node\)(...)@kok
> +  ... when != E = E1
> +      when any
> +  if (\(!E\|E == NULL\)) {
> +    ...
> +    E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
> +          vzalloc_node\|vmalloc_exec\|vmalloc_32\|
> +          vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
> +          __vmalloc_node\)(...)@vok
> +    ...
> +  }
> +)
> +
> +@...ee depends on !patch@
> +expression E;
> +position k != choice.kok;
> +position p;
> +@@
> +
> +* E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
> +*       kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
> +*       kcalloc_node\)(...)@k
> +  ... when != if (...) { ... E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|__vmalloc_node\)(...); ... }
> +      when != is_vmalloc_addr(E)
> +      when any
> +* \(vfree\|vfree_atomic\|kvfree\)(E)@p
> +
> +@...ree depends on patch exists@
> +expression E;
> +position k != choice.kok;
> +@@
> +
> +  E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
> +        kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
> +        kcalloc_node\)(...)@k
> +  ... when != if (...) { ... E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|__vmalloc_node\)(...); ... }
> +      when != is_vmalloc_addr(E)
> +      when any
> +- \(vfree\|vfree_atomic\|kvfree\)(E)
> ++ kfree(E)
> +
> +@...ee depends on !patch@
> +expression E;
> +position v != choice.vok;
> +position p;
> +@@
> +
> +* E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
> +*       vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
> +*       __vmalloc_node_range\|__vmalloc_node\)(...)@v
> +  ... when != !is_vmalloc_addr(E)
> +      when any
> +* \(kfree\|kzfree\|kvfree\)(E)@p
> +
> +@...ree depends on patch exists@
> +expression E;
> +position v != choice.vok;
> +@@
> +
> +  E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
> +        vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
> +        __vmalloc_node_range\|__vmalloc_node\)(...)@v
> +  ... when != !is_vmalloc_addr(E)
> +      when any
> +- \(kfree\|kvfree\)(E)
> ++ vfree(E)
> +
> +@...ree depends on !patch@
> +expression E;
> +position p, k;
> +@@
> +
> +* E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
> +*       kvmalloc_array\)(...)@k
> +  ... when != is_vmalloc_addr(E)
> +      when any
> +* \(kfree\|kzfree\|vfree\|vfree_atomic\)(E)@p
> +
> +@...free depends on patch exists@
> +expression E;
> +@@
> +
> +  E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
> +        kvmalloc_array\)(...)
> +  ... when != is_vmalloc_addr(E)
> +      when any
> +- \(kfree\|vfree\)(E)
> ++ kvfree(E)
> +
> +@...ipt: python depends on report@
> +k << vfree.k;
> +p << vfree.p;
> +@@
> +
> +msg = "WARNING: kmalloc is used to allocate this memory at line %s" % (k[0].line)
> +coccilib.report.print_report(p[0], msg)
> +
> +@...ipt: python depends on org@
> +k << vfree.k;
> +p << vfree.p;
> +@@
> +
> +msg = "WARNING: kmalloc is used to allocate this memory at line %s" % (k[0].line)
> +coccilib.org.print_todo(p[0], msg)
> +
> +@...ipt: python depends on report@
> +v << kfree.v;
> +p << kfree.p;
> +@@
> +
> +msg = "WARNING: vmalloc is used to allocate this memory at line %s" % (v[0].line)
> +coccilib.report.print_report(p[0], msg)
> +
> +@...ipt: python depends on org@
> +v << kfree.v;
> +p << kfree.p;
> +@@
> +
> +msg = "WARNING: vmalloc is used to allocate this memory at line %s" % (v[0].line)
> +coccilib.org.print_todo(p[0], msg)
> +
> +@...ipt: python depends on report@
> +k << kvfree.k;
> +p << kvfree.p;
> +@@
> +
> +msg = "WARNING: kvmalloc is used to allocate this memory at line %s" % (k[0].line)
> +coccilib.report.print_report(p[0], msg)
> +
> +@...ipt: python depends on org@
> +k << kvfree.k;
> +p << kvfree.p;
> +@@
> +
> +msg = "WARNING: kvmalloc is used to allocate this memory at line %s" % (k[0].line)
> +coccilib.org.print_todo(p[0], msg)
> --
> 2.26.2
>
>