The patch titled
lockdep: increase max allowed recursion depth
has been removed from the -mm tree. Its filename is
lockdep-increase-max-allowed-recursion-depth.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: lockdep: increase max allowed recursion depth
From: Ingo Molnar <mingo@xxxxxxx>
In general, lockdep warnings are intended to be non-fatal, so I have put in
various practical limits on internal data structure failure modes. We haven't
had a /single/ lockdep-internal crash ever since lockdep went upstream [the
unwinder crashes are outside of lockdep], and that's largely due to the good
internal checks it does.
Recursion within the dependency graph is currently limited to 20, that's
probably not enough on some many-CPU boxes - this patch doubles it to 40. I
have written the lockdep functions to have as small stackframes as possible,
so 40 should be OK too. (The practical recursion limit should be somewhere
between 100 and 200 entries. If we hit that then I'll change the algorithm to
be iteration-based. Graph walking logic is so easy to program via recursion,
so i'd like to keep recursion as long as possible.)
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxx>
---
kernel/lockdep.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff -puN kernel/lockdep.c~lockdep-increase-max-allowed-recursion-depth kernel/lockdep.c
--- a/kernel/lockdep.c~lockdep-increase-max-allowed-recursion-depth
+++ a/kernel/lockdep.c
@@ -575,6 +575,8 @@ static noinline int print_circular_bug_t
return 0;
}
+#define RECURSION_LIMIT 40
+
static int noinline print_infinite_recursion_bug(void)
{
__raw_spin_unlock(&hash_lock);
@@ -595,7 +597,7 @@ check_noncircular(struct lock_class *sou
debug_atomic_inc(&nr_cyclic_check_recursions);
if (depth > max_recursion_depth)
max_recursion_depth = depth;
- if (depth >= 20)
+ if (depth >= RECURSION_LIMIT)
return print_infinite_recursion_bug();
/*
* Check this lock's dependency list:
@@ -645,7 +647,7 @@ find_usage_forwards(struct lock_class *s
if (depth > max_recursion_depth)
max_recursion_depth = depth;
- if (depth >= 20)
+ if (depth >= RECURSION_LIMIT)
return print_infinite_recursion_bug();
debug_atomic_inc(&nr_find_usage_forwards_checks);
@@ -684,7 +686,7 @@ find_usage_backwards(struct lock_class *
if (depth > max_recursion_depth)
max_recursion_depth = depth;
- if (depth >= 20)
+ if (depth >= RECURSION_LIMIT)
return print_infinite_recursion_bug();
debug_atomic_inc(&nr_find_usage_backwards_checks);
_
Patches currently in -mm which might be from mingo@xxxxxxx are
origin.patch
bonding-lockdep-annotation.patch
unwinder-speedup.patch
unwinder-speedup-tweaks.patch
lockdep-annotate-nfs-nfsd-in-kernel-sockets.patch
lockdep-annotate-nfs-nfsd-in-kernel-sockets-tidy.patch
sysrq-x-show-blocked-tasks.patch
remove-the-old-bd_mutex-lockdep-annotation.patch
new-bd_mutex-lockdep-annotation.patch
remove-lock_key-approach-to-managing-nested-bd_mutex-locks.patch
simplify-some-aspects-of-bd_mutex-nesting.patch
use-mutex_lock_nested-for-bd_mutex-to-avoid-lockdep-warning.patch
avoid-lockdep-warning-in-md.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
gtod-exponential-update_wall_time.patch
gtod-persistent-clock-support-core.patch
gtod-persistent-clock-support-i386.patch
time-uninline-jiffiesh.patch
time-uninline-jiffiesh-fix.patch
time-fix-msecs_to_jiffies-bug.patch
time-fix-timeout-overflow.patch
cleanup-uninline-irq_enter-and-move-it-into-a-function.patch
dynticks-extend-next_timer_interrupt-to-use-a-reference-jiffie.patch
hrtimers-namespace-and-enum-cleanup.patch
hrtimers-clean-up-locking.patch
hrtimers-state-tracking.patch
hrtimers-clean-up-callback-tracking.patch
hrtimers-move-and-add-documentation.patch
clockevents-core.patch
clockevents-drivers-for-i386.patch
high-res-timers-core.patch
gtod-mark-tsc-unusable-for-highres-timers.patch
dynticks-core.patch
dynticks-add-nohz-stats-to-proc-stat.patch
dynticks-i386-arch-code.patch
high-res-timers-dynticks-enable-i386-support.patch
debugging-feature-timer-stats.patch
round_jiffies-infrastructure.patch
round_jiffies-infrastructure-fix.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
-
To unsubscribe from this list: send the line "unsubscribe mm-commits" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
