diff options
| author | Ingo Molnar <mingo@elte.hu> | 2006-07-03 00:24:51 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@g5.osdl.org> | 2006-07-03 15:27:04 -0700 |
| commit | 6c9076ec9cd448f43bbda871352a7067f456ee26 (patch) | |
| tree | 8691366aa511f20146eb9cfe942e0d94c4136e1a | |
| parent | fbb9ce9530fd9b66096d5187fa6a115d16d9746c (diff) | |
[PATCH] lockdep: allow read_lock() recursion of same class
From: Ingo Molnar <mingo@elte.hu>
lockdep so far only allowed read-recursion for the same lock instance.
This is enough in the overwhelming majority of cases, but a hostap case
triggered and reported by Miles Lane relies on same-class
different-instance recursion. So we relax the restriction on read-lock
recursion.
(This change does not allow rwsem read-recursion, which is still
forbidden.)
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
| -rw-r--r-- | kernel/lockdep.c | 5 | ||||
| -rw-r--r-- | lib/locking-selftest.c | 8 |
2 files changed, 6 insertions, 7 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c index dd0580910a9..f32ca78c198 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -843,10 +843,9 @@ check_deadlock(struct task_struct *curr, struct held_lock *next, continue; /* * Allow read-after-read recursion of the same - * lock instance (i.e. read_lock(lock)+read_lock(lock)): + * lock class (i.e. read_lock(lock)+read_lock(lock)): */ - if ((read == 2) && prev->read && - (prev->instance == next_instance)) + if ((read == 2) && prev->read) return 2; return print_deadlock_bug(curr, prev, next); } diff --git a/lib/locking-selftest.c b/lib/locking-selftest.c index 9bdc8d440b2..7945787f439 100644 --- a/lib/locking-selftest.c +++ b/lib/locking-selftest.c @@ -248,7 +248,7 @@ GENERATE_TESTCASE(AA_rsem) /* * Special-case for read-locking, they are - * allowed to recurse on the same lock instance: + * allowed to recurse on the same lock class: */ static void rlock_AA1(void) { @@ -259,7 +259,7 @@ static void rlock_AA1(void) static void rlock_AA1B(void) { RL(X1); - RL(X2); // this one should fail + RL(X2); // this one should NOT fail } static void rsem_AA1(void) @@ -1132,7 +1132,7 @@ void locking_selftest(void) init_shared_classes(); debug_locks_silent = !debug_locks_verbose; - DO_TESTCASE_6("A-A deadlock", AA); + DO_TESTCASE_6R("A-A deadlock", AA); DO_TESTCASE_6R("A-B-B-A deadlock", ABBA); DO_TESTCASE_6R("A-B-B-C-C-A deadlock", ABBCCA); DO_TESTCASE_6R("A-B-C-A-B-C deadlock", ABCABC); @@ -1153,7 +1153,7 @@ void locking_selftest(void) print_testname("recursive read-lock #2"); printk(" |"); - dotest(rlock_AA1B, FAILURE, LOCKTYPE_RWLOCK); + dotest(rlock_AA1B, SUCCESS, LOCKTYPE_RWLOCK); printk(" |"); dotest(rsem_AA1B, FAILURE, LOCKTYPE_RWSEM); printk("\n"); |