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    Subject[PATCH v8] coccinelle: api: add kfree_mismatch script
    Date
    Check that alloc and free types of functions match each other.

    Signed-off-by: Denis Efremov <efremov@linux.com>
    ---
    Changes in v2:
    - Lines are limited to 80 characters where possible
    - Confidence changed from High to Medium because of
    fs/btrfs/send.c:1119 false-positive
    - __vmalloc_area_node() explicitly excluded from analysis
    instead of !(file in "mm/vmalloc.c") condition
    Changes in v3:
    - prints style in org && report modes changed for python2
    Changes in v4:
    - missing msg argument to print_todo fixed
    Changes in v5:
    - fix position p in kfree rule
    - move @kok and @v positions in choice rule after the arguments
    - remove kvmalloc suggestions
    Changes in v6:
    - more asterisks added in context mode
    - second @kok added to the choice rule
    Changes in v7:
    - file renamed to kfree_mismatch.cocci
    - python function relevant() removed
    - additional rule for filtering free positions added
    - btrfs false-positive fixed
    - confidence level changed to high
    - kvfree_switch rule added
    - names for position variables changed to @a (alloc) and @f (free)
    Changes in v8:
    - kzfree() replaced with kfree_sensitive()
    - "position f != free.fok;" simplified to "position f;" in patch
    and kvfree_switch rules

    scripts/coccinelle/api/kfree_mismatch.cocci | 229 ++++++++++++++++++++
    1 file changed, 229 insertions(+)
    create mode 100644 scripts/coccinelle/api/kfree_mismatch.cocci

    diff --git a/scripts/coccinelle/api/kfree_mismatch.cocci b/scripts/coccinelle/api/kfree_mismatch.cocci
    new file mode 100644
    index 000000000000..843b794fac7b
    --- /dev/null
    +++ b/scripts/coccinelle/api/kfree_mismatch.cocci
    @@ -0,0 +1,229 @@
    +// SPDX-License-Identifier: GPL-2.0-only
    +///
    +/// Check that kvmalloc'ed memory is freed by kfree functions,
    +/// vmalloc'ed by vfree functions and kvmalloc'ed by kvfree
    +/// functions.
    +///
    +// Confidence: High
    +// Copyright: (C) 2020 Denis Efremov ISPRAS
    +// Options: --no-includes --include-headers
    +//
    +
    +virtual patch
    +virtual report
    +virtual org
    +virtual context
    +
    +@alloc@
    +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 == NULL) {
    + ...
    + E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
    + vzalloc_node\|vmalloc_exec\|vmalloc_32\|
    + vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
    + __vmalloc_node\)(...)@vok
    + ...
    + }
    +)
    +
    +@free@
    +expression E;
    +position fok;
    +@@
    +
    + E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
    + kvmalloc_array\)(...)
    + ...
    + kvfree(E)@fok
    +
    +@vfree depends on !patch@
    +expression E;
    +position a != alloc.kok;
    +position f != free.fok;
    +@@
    +
    +* E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
    +* kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
    +* kcalloc_node\)(...)@a
    + ... 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)@f
    +
    +@depends on patch exists@
    +expression E;
    +position a != alloc.kok;
    +position f != free.fok;
    +@@
    +
    + E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
    + kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
    + kcalloc_node\)(...)@a
    + ... 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)@f
    ++ kfree(E)
    +
    +@kfree depends on !patch@
    +expression E;
    +position a != alloc.vok;
    +position f != free.fok;
    +@@
    +
    +* E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
    +* vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
    +* __vmalloc_node_range\|__vmalloc_node\)(...)@a
    + ... when != is_vmalloc_addr(E)
    + when any
    +* \(kfree\|kfree_sensitive\|kvfree\)(E)@f
    +
    +@depends on patch exists@
    +expression E;
    +position a != alloc.vok;
    +position f != free.fok;
    +@@
    +
    + E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
    + vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
    + __vmalloc_node_range\|__vmalloc_node\)(...)@a
    + ... when != is_vmalloc_addr(E)
    + when any
    +- \(kfree\|kvfree\)(E)@f
    ++ vfree(E)
    +
    +@kvfree depends on !patch@
    +expression E;
    +position a, f;
    +@@
    +
    +* E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
    +* kvmalloc_array\)(...)@a
    + ... when != is_vmalloc_addr(E)
    + when any
    +* \(kfree\|kfree_sensitive\|vfree\|vfree_atomic\)(E)@f
    +
    +@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)
    +
    +@kvfree_switch depends on !patch@
    +expression alloc.E;
    +position f;
    +@@
    +
    + ... when != is_vmalloc_addr(E)
    + when any
    +* \(kfree\|kfree_sensitive\|vfree\|vfree_atomic\)(E)@f
    +
    +@depends on patch exists@
    +expression alloc.E;
    +position f;
    +@@
    +
    + ... when != is_vmalloc_addr(E)
    + when any
    +(
    +- \(kfree\|vfree\)(E)@f
    ++ kvfree(E)
    +|
    +- kfree_sensitive(E)@f
    ++ kvfree_sensitive(E)
    +)
    +
    +@script: python depends on report@
    +a << vfree.a;
    +f << vfree.f;
    +@@
    +
    +msg = "WARNING kmalloc is used to allocate this memory at line %s" % (a[0].line)
    +coccilib.report.print_report(f[0], msg)
    +
    +@script: python depends on org@
    +a << vfree.a;
    +f << vfree.f;
    +@@
    +
    +msg = "WARNING kmalloc is used to allocate this memory at line %s" % (a[0].line)
    +coccilib.org.print_todo(f[0], msg)
    +
    +@script: python depends on report@
    +a << kfree.a;
    +f << kfree.f;
    +@@
    +
    +msg = "WARNING vmalloc is used to allocate this memory at line %s" % (a[0].line)
    +coccilib.report.print_report(f[0], msg)
    +
    +@script: python depends on org@
    +a << kfree.a;
    +f << kfree.f;
    +@@
    +
    +msg = "WARNING vmalloc is used to allocate this memory at line %s" % (a[0].line)
    +coccilib.org.print_todo(f[0], msg)
    +
    +@script: python depends on report@
    +a << kvfree.a;
    +f << kvfree.f;
    +@@
    +
    +msg = "WARNING kvmalloc is used to allocate this memory at line %s" % (a[0].line)
    +coccilib.report.print_report(f[0], msg)
    +
    +@script: python depends on org@
    +a << kvfree.a;
    +f << kvfree.f;
    +@@
    +
    +msg = "WARNING kvmalloc is used to allocate this memory at line %s" % (a[0].line)
    +coccilib.org.print_todo(f[0], msg)
    +
    +@script: python depends on report@
    +ka << alloc.kok;
    +va << alloc.vok;
    +f << kvfree_switch.f;
    +@@
    +
    +msg = "WARNING kmalloc (line %s) && vmalloc (line %s) are used to allocate this memory" % (ka[0].line, va[0].line)
    +coccilib.report.print_report(f[0], msg)
    +
    +@script: python depends on org@
    +ka << alloc.kok;
    +va << alloc.vok;
    +f << kvfree_switch.f;
    +@@
    +
    +msg = "WARNING kmalloc (line %s) && vmalloc (line %s) are used to allocate this memory" % (ka[0].line, va[0].line)
    +coccilib.org.print_todo(f[0], msg)
    +
    --
    2.26.2
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