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authorOleg Nesterov <oleg@redhat.com>2010-01-26 19:16:41 +0100
committerIngo Molnar <mingo@elte.hu>2010-01-27 08:34:02 +0100
commit48d50674179981e41f432167b2441cec782d5484 (patch)
tree218bc15a2152a10d4b6e7bd412133121777cc182 /kernel/lockdep.c
parentb04da8bfdfbbd79544cab2fadfdc12e87eb01600 (diff)
downloadlinux-48d50674179981e41f432167b2441cec782d5484.tar.bz2
lockdep: Fix check_usage_backwards() error message
Lockdep has found the real bug, but the output doesn't look right to me: > ========================================================= > [ INFO: possible irq lock inversion dependency detected ] > 2.6.33-rc5 #77 > --------------------------------------------------------- > emacs/1609 just changed the state of lock: > (&(&tty->ctrl_lock)->rlock){+.....}, at: [<ffffffff8127c648>] tty_fasync+0xe8/0x190 > but this lock took another, HARDIRQ-unsafe lock in the past: > (&(&sighand->siglock)->rlock){-.....} "HARDIRQ-unsafe" and "this lock took another" looks wrong, afaics. > ... key at: [<ffffffff81c054a4>] __key.46539+0x0/0x8 > ... acquired at: > [<ffffffff81089af6>] __lock_acquire+0x1056/0x15a0 > [<ffffffff8108a0df>] lock_acquire+0x9f/0x120 > [<ffffffff81423012>] _raw_spin_lock_irqsave+0x52/0x90 > [<ffffffff8127c1be>] __proc_set_tty+0x3e/0x150 > [<ffffffff8127e01d>] tty_open+0x51d/0x5e0 The stack-trace shows that this lock (ctrl_lock) was taken under ->siglock (which is hopefully irq-safe). This is a clear typo in check_usage_backwards() where we tell the print a fancy routine we're forwards. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100126181641.GA10460@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/lockdep.c')
-rw-r--r--kernel/lockdep.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/lockdep.c b/kernel/lockdep.c
index 5feaddcdbe49..c62ec14609b9 100644
--- a/kernel/lockdep.c
+++ b/kernel/lockdep.c
@@ -2147,7 +2147,7 @@ check_usage_backwards(struct task_struct *curr, struct held_lock *this,
return ret;
return print_irq_inversion_bug(curr, &root, target_entry,
- this, 1, irqclass);
+ this, 0, irqclass);
}
void print_irqtrace_events(struct task_struct *curr)