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locking/rwsem, security/apparmor: Replace homebrew use of write_can_lock() with lockdep 

The lockdep subsystem provides a robust way to assert that a lock is
held, so use that instead of write_can_lock, which can give incorrect
results for qrwlocks.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: John Johansen <john.johansen@canonical.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1507055129-12300-1-git-send-email-will.deacon@arm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Will Deacon 2017-10-03 19:25:26 +01:00 committed by Ingo Molnar
parent 0dc208b5d5
commit 26c4eb192c
2 changed files with 4 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

11
security/apparmor/include/lib.h
View File

@ -19,17 +19,6 @@
#include "match.h" #include "match.h"
/* Provide our own test for whether a write lock is held for asserts
* this is because on none SMP systems write_can_lock will always
* resolve to true, which is what you want for code making decisions
* based on it, but wrong for asserts checking that the lock is held
*/
#ifdef CONFIG_SMP
#define write_is_locked(X) !write_can_lock(X)
#else
#define write_is_locked(X) (1)
#endif /* CONFIG_SMP */
/* /*
* DEBUG remains global (no per profile flag) since it is mostly used in sysctl * DEBUG remains global (no per profile flag) since it is mostly used in sysctl
* which is not related to profile accesses. * which is not related to profile accesses.

8
security/apparmor/label.c
View File

@ -80,7 +80,7 @@ void __aa_proxy_redirect(struct aa_label *orig, struct aa_label *new)
AA_BUG(!orig); AA_BUG(!orig);
AA_BUG(!new); AA_BUG(!new);
AA_BUG(!write_is_locked(&labels_set(orig)->lock)); lockdep_assert_held_exclusive(&labels_set(orig)->lock);
tmp = rcu_dereference_protected(orig->proxy->label, tmp = rcu_dereference_protected(orig->proxy->label,
&labels_ns(orig)->lock); &labels_ns(orig)->lock);
@ -571,7 +571,7 @@ static bool __label_remove(struct aa_label *label, struct aa_label *new)
AA_BUG(!ls); AA_BUG(!ls);
AA_BUG(!label); AA_BUG(!label);
AA_BUG(!write_is_locked(&ls->lock)); lockdep_assert_held_exclusive(&ls->lock);
if (new) if (new)
__aa_proxy_redirect(label, new); __aa_proxy_redirect(label, new);
@ -608,7 +608,7 @@ static bool __label_replace(struct aa_label *old, struct aa_label *new)
AA_BUG(!ls); AA_BUG(!ls);
AA_BUG(!old); AA_BUG(!old);
AA_BUG(!new); AA_BUG(!new);
AA_BUG(!write_is_locked(&ls->lock)); lockdep_assert_held_exclusive(&ls->lock);
AA_BUG(new->flags & FLAG_IN_TREE); AA_BUG(new->flags & FLAG_IN_TREE);
if (!label_is_stale(old)) if (!label_is_stale(old))
@ -645,7 +645,7 @@ static struct aa_label *__label_insert(struct aa_labelset *ls,
AA_BUG(!ls); AA_BUG(!ls);
AA_BUG(!label); AA_BUG(!label);
AA_BUG(labels_set(label) != ls); AA_BUG(labels_set(label) != ls);
AA_BUG(!write_is_locked(&ls->lock)); lockdep_assert_held_exclusive(&ls->lock);
AA_BUG(label->flags & FLAG_IN_TREE); AA_BUG(label->flags & FLAG_IN_TREE);
/* Figure out where to put new node */ /* Figure out where to put new node */