From: Byungchul Park <byungchul.park@lge.com>
To: <peterz@infradead.org>, <mingo@kernel.org>
Cc: <tglx@linutronix.de>, <walken@google.com>, <boqun.feng@gmail.com>,
<kirill@shutemov.name>, <linux-kernel@vger.kernel.org>,
<linux-mm@kvack.org>, <iamjoonsoo.kim@lge.com>,
<akpm@linux-foundation.org>, <willy@infradead.org>,
<npiggin@gmail.com>, <kernel-team@lge.com>
Subject: [PATCH v6 04/15] lockdep: Make check_prev_add() able to handle external stack_trace
Date: Tue, 14 Mar 2017 17:18:51 +0900 [thread overview]
Message-ID: <1489479542-27030-5-git-send-email-byungchul.park@lge.com> (raw)
In-Reply-To: <1489479542-27030-1-git-send-email-byungchul.park@lge.com>
Currently, a space for stack_trace is pinned in check_prev_add(), that
makes us not able to use external stack_trace. The simplest way to
achieve it is to pass an external stack_trace as an argument.
A more suitable solution is to pass a callback additionally along with
a stack_trace so that callers can decide the way to save or whether to
save. Actually crossrelease needs to do other than saving a stack_trace.
So pass a stack_trace and callback to handle it, to check_prev_add().
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
kernel/locking/lockdep.c | 40 +++++++++++++++++++---------------------
1 file changed, 19 insertions(+), 21 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4709110..2847356 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1797,20 +1797,13 @@ static inline void inc_chains(void)
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance, int *stack_saved)
+ struct held_lock *next, int distance, struct stack_trace *trace,
+ int (*save)(struct stack_trace *trace))
{
struct lock_list *entry;
int ret;
struct lock_list this;
struct lock_list *uninitialized_var(target_entry);
- /*
- * Static variable, serialized by the graph_lock().
- *
- * We use this static variable to save the stack trace in case
- * we call into this function multiple times due to encountering
- * trylocks in the held lock stack.
- */
- static struct stack_trace trace;
/*
* Prove that the new <prev> -> <next> dependency would not
@@ -1858,11 +1851,8 @@ static inline void inc_chains(void)
}
}
- if (!*stack_saved) {
- if (!save_trace(&trace))
- return 0;
- *stack_saved = 1;
- }
+ if (save && !save(trace))
+ return 0;
/*
* Ok, all validations passed, add the new lock
@@ -1870,14 +1860,14 @@ static inline void inc_chains(void)
*/
ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
&hlock_class(prev)->locks_after,
- next->acquire_ip, distance, &trace);
+ next->acquire_ip, distance, trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
&hlock_class(next)->locks_before,
- next->acquire_ip, distance, &trace);
+ next->acquire_ip, distance, trace);
if (!ret)
return 0;
@@ -1885,8 +1875,6 @@ static inline void inc_chains(void)
* Debugging printouts:
*/
if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
- /* We drop graph lock, so another thread can overwrite trace. */
- *stack_saved = 0;
graph_unlock();
printk("\n new dependency: ");
print_lock_name(hlock_class(prev));
@@ -1910,8 +1898,9 @@ static inline void inc_chains(void)
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
int depth = curr->lockdep_depth;
- int stack_saved = 0;
struct held_lock *hlock;
+ struct stack_trace trace;
+ int (*save)(struct stack_trace *trace) = save_trace;
/*
* Debugging checks.
@@ -1936,9 +1925,18 @@ static inline void inc_chains(void)
* added:
*/
if (hlock->read != 2 && hlock->check) {
- if (!check_prev_add(curr, hlock, next,
- distance, &stack_saved))
+ int ret = check_prev_add(curr, hlock, next,
+ distance, &trace, save);
+ if (!ret)
return 0;
+
+ /*
+ * Stop saving stack_trace if save_trace() was
+ * called at least once:
+ */
+ if (save && ret == 2)
+ save = NULL;
+
/*
* Stop after the first non-trylock entry,
* as non-trylock entries have added their
--
1.9.1
next prev parent reply other threads:[~2017-03-14 8:23 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-14 8:18 [PATCH v6 00/15] lockdep: Implement crossrelease feature Byungchul Park
2017-03-14 8:18 ` [PATCH v6 01/15] lockdep: Refactor lookup_chain_cache() Byungchul Park
2017-03-14 8:18 ` [PATCH v6 02/15] lockdep: Add a function building a chain between two classes Byungchul Park
2017-03-14 8:18 ` [PATCH v6 03/15] lockdep: Change the meaning of check_prev_add()'s return value Byungchul Park
2017-03-14 8:18 ` Byungchul Park [this message]
2017-03-14 8:18 ` [PATCH v6 05/15] lockdep: Implement crossrelease feature Byungchul Park
2017-04-19 14:25 ` Peter Zijlstra
2017-04-24 5:11 ` Byungchul Park
2017-04-24 10:17 ` Peter Zijlstra
2017-04-25 5:40 ` Byungchul Park
2017-05-16 14:18 ` Peter Zijlstra
2017-05-18 6:22 ` Byungchul Park
2017-04-19 15:08 ` Peter Zijlstra
2017-04-24 4:36 ` Byungchul Park
2017-04-19 17:19 ` Peter Zijlstra
2017-04-24 3:04 ` Byungchul Park
2017-04-24 9:30 ` Peter Zijlstra
2017-04-25 6:59 ` Byungchul Park
2017-04-19 17:20 ` Peter Zijlstra
2017-04-24 3:13 ` Byungchul Park
2017-05-19 8:07 ` Byungchul Park
2017-05-19 10:30 ` Peter Zijlstra
2017-05-19 10:56 ` Byungchul Park
2017-03-14 8:18 ` [PATCH v6 06/15] lockdep: Handle non(or multi)-acquisition of a crosslock Byungchul Park
2017-03-14 8:18 ` [PATCH v6 07/15] lockdep: Avoid adding redundant direct links of crosslocks Byungchul Park
2017-03-14 8:18 ` [PATCH v6 08/15] lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS Byungchul Park
2017-03-14 8:18 ` [PATCH v6 09/15] lockdep: Make print_circular_bug() aware of crossrelease Byungchul Park
2017-03-14 8:18 ` [PATCH v6 10/15] lockdep: Apply crossrelease to completions Byungchul Park
2017-03-14 8:18 ` [PATCH v6 11/15] pagemap.h: Remove trailing white space Byungchul Park
2017-03-14 8:18 ` [PATCH v6 12/15] lockdep: Apply crossrelease to PG_locked locks Byungchul Park
2017-03-14 8:19 ` [PATCH v6 13/15] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park
2017-03-14 8:19 ` [PATCH v6 14/15] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2017-03-14 8:19 ` [PATCH v6 15/15] lockdep: Crossrelease feature documentation Byungchul Park
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