Messages in this thread | | | Date | Tue, 1 Jul 2008 10:15:16 +0200 | From | Ingo Molnar <> | Subject | Re: mmiotrace broken in linux-next (8-bit writes only) |
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* Pekka Paalanen <pq@iki.fi> wrote:
> The moment mmiotrace is enabled, I hit a NULL deref in: > > IP: [<ffffffff80256e71>] __trace_special+0x17c/0x23a > Call Trace: > [<ffffffff802573cc>] ftrace_special+0x6f/0x9a > [<ffffffff8023e3e4>] down+0x19/0x4a > [<ffffffff80228adc>] acquire_console_sem+0x42/0x58 > [<ffffffff8035d273>] con_flush_chars+0x28/0x43 > [<ffffffff80354a70>] write_chan+0x22e/0x334 > [<ffffffff802244e9>] ? default_wake_function+0x0/0xf > [<ffffffff8035236d>] tty_write+0x195/0x228 > [<ffffffff80354842>] ? write_chan+0x0/0x334 > [<ffffffff8027c23a>] vfs_write+0xae/0x137 > [<ffffffff8027c6e3>] sys_write+0x47/0x70 > [<ffffffff8020b1db>] system_call_after_swapgs+0x7b/0x80 > > which means 'entry' in __trace_special() is NULL.
> > - ftrace_special(sem->count, 0, __LINE__); > spin_lock_irqsave(&sem->lock, flags);
applied to tip/tracing/ftrace - thanks Pekka. This was a leftover line from semaphore debugging.
Ingo
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