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authorTetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>2018-03-27 19:41:41 +0900
committerThomas Gleixner <tglx@linutronix.de>2018-03-29 14:41:40 +0200
commitb3c39758c8a6972f02b43f83dba7fe7a352371b9 (patch)
tree8aae08ed6abf7ab3127dcbaaf52d2f6536114d43
parentc28d62cf52d791ba5f6db7ce525ed06b86291c82 (diff)
lockdep: Make the lock debug output more useful
The lock debug output in print_lock() has a few shortcomings: - It prints the hlock->acquire_ip field in %px and %pS format. That's redundant information. - It lacks information about the lock object itself. The lock class is not helpful to identify a particular instance of a lock. Change the output so it prints: - hlock->instance to allow identification of a particular lock instance. - only the %pS format of hlock->ip_acquire which is sufficient to decode the actual code line with faddr2line. The resulting output is: 3 locks held by a.out/31106: #0: 00000000b0f753ba (&mm->mmap_sem){++++}, at: copy_process.part.41+0x10d5/0x1fe0 #1: 00000000ef64d539 (&mm->mmap_sem/1){+.+.}, at: copy_process.part.41+0x10fe/0x1fe0 #2: 00000000b41a282e (&mapping->i_mmap_rwsem){++++}, at: copy_process.part.41+0x12f2/0x1fe0 [ tglx: Massaged changelog ] Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Acked-by: Michal Hocko <mhocko@suse.com> Acked-by: David Rientjes <rientjes@google.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: linux-mm@kvack.org Cc: Borislav Petkov <bp@suse.de> Link: https://lkml.kernel.org/r/201803271941.GBE57310.tVSOJLQOFFOHFM@I-love.SAKURA.ne.jp
-rw-r--r--kernel/locking/lockdep.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 12a2805dd64a..023386338269 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -556,9 +556,9 @@ static void print_lock(struct held_lock *hlock)
return;
}
+ printk(KERN_CONT "%p", hlock->instance);
print_lock_name(lock_classes + class_idx - 1);
- printk(KERN_CONT ", at: [<%px>] %pS\n",
- (void *)hlock->acquire_ip, (void *)hlock->acquire_ip);
+ printk(KERN_CONT ", at: %pS\n", (void *)hlock->acquire_ip);
}
static void lockdep_print_held_locks(struct task_struct *curr)