Commit 5103068e authored by Nicolai Stange's avatar Nicolai Stange Committed by Greg Kroah-Hartman
Browse files

debugfs, coccinelle: check for obsolete DEFINE_SIMPLE_ATTRIBUTE() usage 



In order to protect against file removal races, debugfs files created via
debugfs_create_file() now get wrapped by a struct file_operations at their
opening.

If the original struct file_operations are known to be safe against removal
races by themselves already, the proxy creation may be bypassed by creating
the files through debugfs_create_file_unsafe().

In order to help debugfs users who use the common
  DEFINE_SIMPLE_ATTRIBUTE() + debugfs_create_file()
idiom to transition to removal safe struct file_operations, the helper
macro DEFINE_DEBUGFS_ATTRIBUTE() has been introduced.

Thus, the preferred strategy is to use
  DEFINE_DEBUGFS_ATTRIBUTE() + debugfs_create_file_unsafe()
now.

Introduce a Coccinelle script that searches for
DEFINE_SIMPLE_ATTRIBUTE()-defined struct file_operations handed into
debugfs_create_file(). Suggest to turn these usages into the
  DEFINE_DEBUGFS_ATTRIBUTE() + debugfs_create_file_unsafe()
pattern.

Signed-off-by: default avatarNicolai Stange <nicstange@gmail.com>
Acked-by: default avatarJulia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent c6468808

scripts/coccinelle/api/debugfs/debugfs_simple_attr.cocci

0 → 100644
+67 −0
Original line number Diff line number Diff line 
/// Use DEFINE_DEBUGFS_ATTRIBUTE rather than DEFINE_SIMPLE_ATTRIBUTE

/// for debugfs files.

///

//# Rationale: DEFINE_SIMPLE_ATTRIBUTE + debugfs_create_file()

//# imposes some significant overhead as compared to

//# DEFINE_DEBUGFS_ATTRIBUTE + debugfs_create_file_unsafe().

//

// Copyright (C): 2016 Nicolai Stange

// Options: --no-includes

//



virtual context

virtual patch

virtual org

virtual report



@dsa@

declarer name DEFINE_SIMPLE_ATTRIBUTE;

identifier dsa_fops;

expression dsa_get, dsa_set, dsa_fmt;

position p;

@@

DEFINE_SIMPLE_ATTRIBUTE@p(dsa_fops, dsa_get, dsa_set, dsa_fmt);



@dcf@

expression name, mode, parent, data;

identifier dsa.dsa_fops;

@@

debugfs_create_file(name, mode, parent, data, &dsa_fops)





@context_dsa depends on context && dcf@

declarer name DEFINE_DEBUGFS_ATTRIBUTE;

identifier dsa.dsa_fops;

expression dsa.dsa_get, dsa.dsa_set, dsa.dsa_fmt;

@@

* DEFINE_SIMPLE_ATTRIBUTE(dsa_fops, dsa_get, dsa_set, dsa_fmt);





@patch_dcf depends on patch expression@

expression name, mode, parent, data;

identifier dsa.dsa_fops;

@@

- debugfs_create_file(name, mode, parent, data, &dsa_fops)

+ debugfs_create_file_unsafe(name, mode, parent, data, &dsa_fops)



@patch_dsa depends on patch_dcf && patch@

identifier dsa.dsa_fops;

expression dsa.dsa_get, dsa.dsa_set, dsa.dsa_fmt;

@@

- DEFINE_SIMPLE_ATTRIBUTE(dsa_fops, dsa_get, dsa_set, dsa_fmt);

+ DEFINE_DEBUGFS_ATTRIBUTE(dsa_fops, dsa_get, dsa_set, dsa_fmt);





@script:python depends on org && dcf@

fops << dsa.dsa_fops;

p << dsa.p;

@@

msg="%s should be defined with DEFINE_DEBUGFS_ATTRIBUTE" % (fops)

coccilib.org.print_todo(p[0], msg)



@script:python depends on report && dcf@

fops << dsa.dsa_fops;

p << dsa.p;

@@

msg="WARNING: %s should be defined with DEFINE_DEBUGFS_ATTRIBUTE" % (fops)

coccilib.report.print_report(p[0], msg)

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