linux/scripts/coccinelle/iterators/for_each_child.cocci
Sumera Priyadarsini 82c2d81361 coccinelle: iterators: Add for_each_child.cocci script
While iterating over child nodes with the for_each functions, if
control is transferred from the middle of the loop, as in the case
of a break or return or goto, there is no decrement in the
reference counter thus ultimately resulting in a memory leak.

Add this script to detect potential memory leaks caused by
the absence of of_node_put() before break, goto, or, return
statements which transfer control outside the loop.

Signed-off-by: Sumera Priyadarsini <sylphrenadin@gmail.com>
Signed-off-by: Julia Lawall <julia.lawall@inria.fr>
2020-10-15 22:28:10 +02:00

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// SPDX-License-Identifier: GPL-2.0-only
// Adds missing of_node_put() before return/break/goto statement within a for_each iterator for child nodes.
//# False positives can be due to function calls within the for_each
//# loop that may encapsulate an of_node_put.
///
// Confidence: High
// Copyright: (C) 2020 Sumera Priyadarsini
// URL: http://coccinelle.lip6.fr
// Options: --no-includes --include-headers
virtual patch
virtual context
virtual org
virtual report
@r@
local idexpression n;
expression e1,e2;
iterator name for_each_node_by_name, for_each_node_by_type,
for_each_compatible_node, for_each_matching_node,
for_each_matching_node_and_match, for_each_child_of_node,
for_each_available_child_of_node, for_each_node_with_property;
iterator i;
statement S;
expression list [n1] es;
@@
(
(
for_each_node_by_name(n,e1) S
|
for_each_node_by_type(n,e1) S
|
for_each_compatible_node(n,e1,e2) S
|
for_each_matching_node(n,e1) S
|
for_each_matching_node_and_match(n,e1,e2) S
|
for_each_child_of_node(e1,n) S
|
for_each_available_child_of_node(e1,n) S
|
for_each_node_with_property(n,e1) S
)
&
i(es,n,...) S
)
@ruleone depends on patch && !context && !org && !report@
local idexpression r.n;
iterator r.i,i1;
expression e;
expression list [r.n1] es;
statement S;
@@
i(es,n,...) {
...
(
of_node_put(n);
|
e = n
|
return n;
|
i1(...,n,...) S
|
- return of_node_get(n);
+ return n;
|
+ of_node_put(n);
? return ...;
)
... when any
}
@ruletwo depends on patch && !context && !org && !report@
local idexpression r.n;
iterator r.i,i1,i2;
expression e,e1;
expression list [r.n1] es;
statement S,S2;
@@
i(es,n,...) {
...
(
of_node_put(n);
|
e = n
|
i1(...,n,...) S
|
+ of_node_put(n);
? break;
)
... when any
}
... when != n
when strict
when forall
(
n = e1;
|
?i2(...,n,...) S2
)
@rulethree depends on patch && !context && !org && !report exists@
local idexpression r.n;
iterator r.i,i1,i2;
expression e,e1;
identifier l;
expression list [r.n1] es;
statement S,S2;
@@
i(es,n,...) {
...
(
of_node_put(n);
|
e = n
|
i1(...,n,...) S
|
+ of_node_put(n);
? goto l;
)
... when any
}
... when exists
l: ... when != n
when strict
when forall
(
n = e1;
|
?i2(...,n,...) S2
)
// ----------------------------------------------------------------------------
@ruleone_context depends on !patch && (context || org || report) exists@
statement S;
expression e;
expression list[r.n1] es;
iterator r.i, i1;
local idexpression r.n;
position j0, j1;
@@
i@j0(es,n,...) {
...
(
of_node_put(n);
|
e = n
|
return n;
|
i1(...,n,...) S
|
return @j1 ...;
)
... when any
}
@ruleone_disj depends on !patch && (context || org || report)@
expression list[r.n1] es;
iterator r.i;
local idexpression r.n;
position ruleone_context.j0, ruleone_context.j1;
@@
* i@j0(es,n,...) {
...
*return @j1...;
... when any
}
@ruletwo_context depends on !patch && (context || org || report) exists@
statement S, S2;
expression e, e1;
expression list[r.n1] es;
iterator r.i, i1, i2;
local idexpression r.n;
position j0, j2;
@@
i@j0(es,n,...) {
...
(
of_node_put(n);
|
e = n
|
i1(...,n,...) S
|
break@j2;
)
... when any
}
... when != n
when strict
when forall
(
n = e1;
|
?i2(...,n,...) S2
)
@ruletwo_disj depends on !patch && (context || org || report)@
statement S2;
expression e1;
expression list[r.n1] es;
iterator r.i, i2;
local idexpression r.n;
position ruletwo_context.j0, ruletwo_context.j2;
@@
* i@j0(es,n,...) {
...
*break @j2;
... when any
}
... when != n
when strict
when forall
(
n = e1;
|
?i2(...,n,...) S2
)
@rulethree_context depends on !patch && (context || org || report) exists@
identifier l;
statement S,S2;
expression e, e1;
expression list[r.n1] es;
iterator r.i, i1, i2;
local idexpression r.n;
position j0, j3;
@@
i@j0(es,n,...) {
...
(
of_node_put(n);
|
e = n
|
i1(...,n,...) S
|
goto l@j3;
)
... when any
}
... when exists
l:
... when != n
when strict
when forall
(
n = e1;
|
?i2(...,n,...) S2
)
@rulethree_disj depends on !patch && (context || org || report) exists@
identifier l;
statement S2;
expression e1;
expression list[r.n1] es;
iterator r.i, i2;
local idexpression r.n;
position rulethree_context.j0, rulethree_context.j3;
@@
* i@j0(es,n,...) {
...
*goto l@j3;
... when any
}
... when exists
l:
... when != n
when strict
when forall
(
n = e1;
|
?i2(...,n,...) S2
)
// ----------------------------------------------------------------------------
@script:python ruleone_org depends on org@
i << r.i;
j0 << ruleone_context.j0;
j1 << ruleone_context. j1;
@@
msg = "WARNING: Function \"%s\" should have of_node_put() before return " % (i)
coccilib.org.print_safe_todo(j0[0], msg)
coccilib.org.print_link(j1[0], "")
@script:python ruletwo_org depends on org@
i << r.i;
j0 << ruletwo_context.j0;
j2 << ruletwo_context.j2;
@@
msg = "WARNING: Function \"%s\" should have of_node_put() before break " % (i)
coccilib.org.print_safe_todo(j0[0], msg)
coccilib.org.print_link(j2[0], "")
@script:python rulethree_org depends on org@
i << r.i;
j0 << rulethree_context.j0;
j3 << rulethree_context.j3;
@@
msg = "WARNING: Function \"%s\" should have of_node_put() before goto " % (i)
coccilib.org.print_safe_todo(j0[0], msg)
coccilib.org.print_link(j3[0], "")
// ----------------------------------------------------------------------------
@script:python ruleone_report depends on report@
i << r.i;
j0 << ruleone_context.j0;
j1 << ruleone_context.j1;
@@
msg = "WARNING: Function \"%s\" should have of_node_put() before return around line %s." % (i, j1[0].line)
coccilib.report.print_report(j0[0], msg)
@script:python ruletwo_report depends on report@
i << r.i;
j0 << ruletwo_context.j0;
j2 << ruletwo_context.j2;
@@
msg = "WARNING: Function \"%s\" should have of_node_put() before break around line %s." % (i,j2[0].line)
coccilib.report.print_report(j0[0], msg)
@script:python rulethree_report depends on report@
i << r.i;
j0 << rulethree_context.j0;
j3 << rulethree_context.j3;
@@
msg = "WARNING: Function \"%s\" should have of_node_put() before goto around lines %s." % (i,j3[0].line)
coccilib.report.print_report(j0[0], msg)