-
由 Oleg Nesterov 提交于
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: NOleg Nesterov <oleg@redhat.com> Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <20100126181641.GA10460@redhat.com> Signed-off-by: NIngo Molnar <mingo@elte.hu>
48d50674