lkml.org 
[lkml]   [2021]   [Jun]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/4] locking/lockdep: Remove the unnecessary trace saving
Date
In print_bad_irq_dependency(), save_trace() is called to set the ->trace
for @prev_root as the current call trace, however @prev_root corresponds
to the the held lock, which may not be acquired in current call trace,
therefore it's wrong to use save_trace() to set ->trace of @prev_root.
Moreover, with our adjustment of printing backwards dependency path, the
->trace of @prev_root is unncessary, so remove it.

Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
kernel/locking/lockdep.c | 3 ---
1 file changed, 3 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 3b32cd9cdfd0..74d084a398be 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2550,9 +2550,6 @@ print_bad_irq_dependency(struct task_struct *curr,
lockdep_print_held_locks(curr);

pr_warn("\nthe dependencies between %s-irq-safe lock and the holding lock:\n", irqclass);
- prev_root->trace = save_trace();
- if (!prev_root->trace)
- return;
print_shortest_lock_dependencies_backwards(backwards_entry, prev_root);

pr_warn("\nthe dependencies between the lock to be acquired");
--
2.30.2
\
 
 \ /
  Last update: 2021-06-18 19:02    [W:0.097 / U:0.980 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site