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, npiggin@gmail.com
Subject: [PATCH v4 09/15] lockdep: Make print_circular_bug() crosslock-aware
Date: Fri, 9 Dec 2016 14:12:05 +0900 [thread overview]
Message-ID: <1481260331-360-10-git-send-email-byungchul.park@lge.com> (raw)
In-Reply-To: <1481260331-360-1-git-send-email-byungchul.park@lge.com>
Friends of print_circular_bug() reporting circular bug assumes that
target hlock is owned by the current. However, in crossrelease feature,
target hlock can be owned by any context.
In this case, the circular bug is caused by target hlock which cannot be
released since its dependent lock cannot be released. So the report
format needs to be changed to be aware of this.
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
kernel/locking/lockdep.c | 56 +++++++++++++++++++++++++++++++++---------------
1 file changed, 39 insertions(+), 17 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index fbd07ee..cb1a600 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1126,22 +1126,41 @@ print_circular_lock_scenario(struct held_lock *src,
printk("\n\n");
}
- printk(" Possible unsafe locking scenario:\n\n");
- printk(" CPU0 CPU1\n");
- printk(" ---- ----\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(parent);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(target);
- printk(");\n");
- printk(" lock(");
- __print_lock_name(source);
- printk(");\n");
- printk("\n *** DEADLOCK ***\n\n");
+ if (cross_class(target)) {
+ printk(" Possible unsafe locking scenario by crosslock:\n\n");
+ printk(" CPU0 CPU1\n");
+ printk(" ---- ----\n");
+ printk(" lock(");
+ __print_lock_name(parent);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(source);
+ printk(");\n");
+ printk(" unlock(");
+ __print_lock_name(target);
+ printk(");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+ } else {
+ printk(" Possible unsafe locking scenario:\n\n");
+ printk(" CPU0 CPU1\n");
+ printk(" ---- ----\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(parent);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(target);
+ printk(");\n");
+ printk(" lock(");
+ __print_lock_name(source);
+ printk(");\n");
+ printk("\n *** DEADLOCK ***\n\n");
+ }
}
/*
@@ -1166,7 +1185,10 @@ print_circular_bug_header(struct lock_list *entry, unsigned int depth,
printk("%s/%d is trying to acquire lock:\n",
curr->comm, task_pid_nr(curr));
print_lock(check_src);
- printk("\nbut task is already holding lock:\n");
+ if (cross_class(hlock_class(check_tgt)))
+ printk("\nbut now in the release context of lock:\n");
+ else
+ printk("\nbut task is already holding lock:\n");
print_lock(check_tgt);
printk("\nwhich lock already depends on the new lock.\n\n");
printk("\nthe existing dependency chain (in reverse order) is:\n");
--
1.9.1
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next prev parent reply other threads:[~2016-12-09 5:16 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-09 5:11 [PATCH v4 00/15] lockdep: Implement crossrelease feature Byungchul Park
2016-12-09 5:11 ` [PATCH v4 01/15] x86/dumpstack: Optimize save_stack_trace Byungchul Park
2016-12-09 5:11 ` [PATCH v4 02/15] x86/dumpstack: Add save_stack_trace()_fast() Byungchul Park
2016-12-09 5:11 ` [PATCH v4 03/15] lockdep: Refactor lookup_chain_cache() Byungchul Park
2016-12-09 5:12 ` [PATCH v4 04/15] lockdep: Add a function building a chain between two classes Byungchul Park
2017-01-10 21:00 ` Peter Zijlstra
2017-01-12 1:41 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 05/15] lockdep: Make check_prev_add can use a separate stack_trace Byungchul Park
2017-01-12 16:16 ` Peter Zijlstra
2017-01-13 2:45 ` Byungchul Park
2017-01-13 10:11 ` Byungchul Park
2017-01-17 15:54 ` Peter Zijlstra
2017-01-18 2:04 ` Byungchul Park
2017-01-18 15:10 ` Peter Zijlstra
2017-01-19 2:47 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 06/15] lockdep: Make save_trace can skip stack tracing of the current Byungchul Park
2017-01-12 16:37 ` Peter Zijlstra
2017-01-13 0:18 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 07/15] lockdep: Implement crossrelease feature Byungchul Park
2017-01-13 4:39 ` Lai Jiangshan
2017-01-13 5:02 ` Byungchul Park
2017-01-16 15:10 ` Peter Zijlstra
2017-01-17 2:05 ` Byungchul Park
2017-01-17 7:12 ` Peter Zijlstra
2017-01-17 7:49 ` Byungchul Park
2017-01-17 7:14 ` Peter Zijlstra
2017-01-17 7:45 ` Byungchul Park
2017-01-16 15:13 ` Peter Zijlstra
2017-01-17 2:33 ` Byungchul Park
2017-01-17 6:24 ` Boqun Feng
2017-01-17 7:43 ` Byungchul Park
2016-12-09 5:12 ` [PATCH v4 08/15] lockdep: Make crossrelease use save_stack_trace_fast() Byungchul Park
2016-12-09 5:12 ` Byungchul Park [this message]
2016-12-09 5:12 ` [PATCH v4 10/15] lockdep: Apply crossrelease to completion operation Byungchul Park
2016-12-09 5:12 ` [PATCH v4 11/15] pagemap.h: Remove trailing white space Byungchul Park
2016-12-09 5:12 ` [PATCH v4 12/15] lockdep: Apply crossrelease to PG_locked lock Byungchul Park
2016-12-09 5:12 ` [PATCH v4 13/15] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park
2016-12-09 5:12 ` [PATCH v4 14/15] lockdep: Move data used in CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2016-12-09 5:12 ` [PATCH v4 15/15] lockdep: Crossrelease feature documentation Byungchul Park
2017-01-10 20:08 ` Peter Zijlstra
2017-01-11 1:29 ` Byungchul Park
2017-01-18 6:42 ` Boqun Feng
2017-01-18 10:53 ` Byungchul Park
2017-01-18 11:03 ` Peter Zijlstra
2017-01-18 11:54 ` Byungchul Park
2017-01-18 12:07 ` Peter Zijlstra
2017-01-18 12:14 ` byungchul.park
2017-01-18 14:12 ` Peter Zijlstra
2017-01-19 1:54 ` Byungchul Park
2017-01-18 12:49 ` byungchul.park
2016-12-09 5:21 ` [FYI] Output of 'cat /proc/lockdep' after applying crossrelease Byungchul Park
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