From d4c157c7b1a67a0844a904baaca9a840c196c103 Mon Sep 17 00:00:00 2001 From: Boqun Feng Date: Sat, 19 Jun 2021 01:01:08 +0800 Subject: [PATCH] locking/lockdep: Remove the unnecessary trace saving 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 Signed-off-by: Boqun Feng Signed-off-by: Peter Zijlstra (Intel) Link: https://lore.kernel.org/r/20210618170110.3699115-3-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");