#9404 HIGH 1.5-F11: VIA FB driver locks up during init on newer GCC

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#9404: VIA FB driver locks up during init on newer GCC
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           Reporter:  dsaxena   |       Owner:  dsaxena      
               Type:  defect    |      Status:  assigned     
           Priority:  high      |   Milestone:  1.5-F11      
          Component:  kernel    |     Version:  not specified
         Resolution:            |    Keywords:               
        Next_action:  diagnose  |    Verified:  0            
Deployment_affected:            |   Blockedby:               
           Blocking:            |  
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Comment(by dsd):

 I assume it is hanging on the down() line, suggesting semaphore
 contention.

 Have you tried adding printks to log access to console_sem?
 The only places it is accessed are in printk.c, functions: zap_locks(),
 acquire_console_semaphore_for_printk(), suspend_console(),
 resume_console(), acquire_console_sem(), try_acquire_console_sem(),
 release_console_sem() and console_unblank(). You could use dump_stack() to
 determine who's using it before we hit this lockup.

 Have you tried lockdep? That might point something out.

 This does smell like memory corruption, so you could also add some printks
 to the point of hang. console_sem.count should be a low number. With
 CONFIG_DEBUG_SPINLOCK enabled, console_sem.lock.magic should have value
 0xdead4ead.

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Ticket URL: <http://dev.laptop.org/ticket/9404#comment:2>
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