The patch titled
lockdep: allow read_lock() recursion of same class
has been removed from the -mm tree. Its filename is
lockdep-allow-read_lock-recursion-of-same-class.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: lockdep: allow read_lock() recursion of same class
From: Ingo Molnar <mingo@xxxxxxx>
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@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/lockdep.c | 5 ++---
lib/locking-selftest.c | 8 ++++----
2 files changed, 6 insertions(+), 7 deletions(-)
diff -puN kernel/lockdep.c~lockdep-allow-read_lock-recursion-of-same-class kernel/lockdep.c
--- a/kernel/lockdep.c~lockdep-allow-read_lock-recursion-of-same-class
+++ a/kernel/lockdep.c
@@ -843,10 +843,9 @@ check_deadlock(struct task_struct *curr,
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 -puN lib/locking-selftest.c~lockdep-allow-read_lock-recursion-of-same-class lib/locking-selftest.c
--- a/lib/locking-selftest.c~lockdep-allow-read_lock-recursion-of-same-class
+++ a/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");
_
Patches currently in -mm which might be from mingo@xxxxxxx are
origin.patch
disable-debugging-version-of-write_lock.patch
lock-validator-fix-ns83820c-irq-flags-bug.patch
revert-gregkh-pci-pci-test-that-drivers-properly-call-pci_set_master.patch
my-name-is-ingo-molnar-you-killed-my-make-allyesconfig-prepare-to-die.patch
sched-fix-bug-in-__migrate_task.patch
small-kernel-schedc-cleanup.patch
x86-re-enable-generic-numa.patch
sched-add-above-background-load-function.patch
mm-implement-swap-prefetching.patch
sched-cleanup-remove-task_t-convert-to-struct-task_struct-prefetch.patch
genirq-convert-the-x86_64-architecture-to-irq-chips.patch
genirq-convert-the-i386-architecture-to-irq-chips.patch
genirq-irq-convert-the-move_irq-flag-from-a-32bit-word-to-a-single-bit.patch
genirq-irq-add-moved_masked_irq.patch
genirq-x86_64-irq-reenable-migrating-irqs-to-other-cpus.patch
genirq-msi-simplify-msi-enable-and-disable.patch
genirq-msi-make-the-msi-boolean-tests-return-either-0-or-1.patch
genirq-msi-implement-helper-functions-read_msi_msg-and-write_msi_msg.patch
genirq-msi-refactor-the-msi_ops.patch
genirq-msi-simplify-the-msi-irq-limit-policy.patch
genirq-irq-add-a-dynamic-irq-creation-api.patch
genirq-ia64-irq-dynamic-irq-support.patch
genirq-i386-irq-dynamic-irq-support.patch
genirq-x86_64-irq-dynamic-irq-support.patch
genirq-msi-make-the-msi-code-irq-based-and-not-vector-based.patch
genirq-x86_64-irq-move-msi-message-composition-into-io_apicc.patch
genirq-i386-irq-move-msi-message-composition-into-io_apicc.patch
genirq-msi-only-build-msi-apicc-on-ia64.patch
genirq-x86_64-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-i386-irq-remove-the-msi-assumption-that-irq-==-vector.patch
genirq-irq-remove-msi-hacks.patch
genirq-irq-generalize-the-check-for-hardirq_bits.patch
genirq-x86_64-irq-make-the-external-irq-handlers-report-their-vector-not-the-irq-number.patch
genirq-x86_64-irq-make-vector_irq-per-cpu.patch
genirq-x86_64-irq-kill-gsi_irq_sharing.patch
genirq-x86_64-irq-kill-irq-compression.patch
detect-atomic-counter-underflows.patch
debug-shared-irqs.patch
make-frame_pointer-default=y.patch
mutex-subsystem-synchro-test-module.patch
vdso-print-fatal-signals.patch
vdso-improve-print_fatal_signals-support-by-adding-memory-maps.patch
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