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author | Oleg Nesterov <oleg@redhat.com> | 2010-01-26 19:16:41 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2010-01-27 08:34:02 +0100 |
commit | 48d50674179981e41f432167b2441cec782d5484 (patch) | |
tree | 218bc15a2152a10d4b6e7bd412133121777cc182 /Documentation/keys.txt | |
parent | b04da8bfdfbbd79544cab2fadfdc12e87eb01600 (diff) | |
download | linux-48d50674179981e41f432167b2441cec782d5484.tar.gz linux-48d50674179981e41f432167b2441cec782d5484.tar.bz2 linux-48d50674179981e41f432167b2441cec782d5484.zip |
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 'Documentation/keys.txt')
0 files changed, 0 insertions, 0 deletions