Random lwIP Crashes in _POSIX_Mutex_Lock_support()

[Sebastian Huber]

On 20/10/15 16:02, Isaac Gutekunst wrote:
> Hi Devel,
>
> I'm pretty sure this is a devel question, not users.
>
>
> I'm working with a colleague at Vecna to port lwIP to the STM32F7 BSP 
> we've developed.
>
> We have a basic HTTP server that prints out the current list of tasks. 
> We refresh the page at a very high rate, and after about 1-30 minutes, 
> get a crash.
>
> Every time the exception is thrown after 
> _CORE_mutex_Check_dispatch_for_seize( wait )  on line 254 of 
> coremuteximpl.h. Every time this is inside a pthread_mutex_lock() call.
>
>
> Here is the full backtrace:
>
> stm32fxxxx_fatal_error_handler() at hal-fatal-error-handler.c:126 
> 0x800af92
> _User_extensions_Fatal_visitor() at userextiterate.c:123 0x803212c
> _User_extensions_Iterate() at userextiterate.c:166 0x80321c0
> _User_extensions_Fatal() at userextimpl.h:254 0x802a85e
> _Terminate() at interr.c:44 0x802a888
> _CORE_mutex_Seize_body() at coremuteximpl.h:255 0x8068df0
> _POSIX_Mutex_Lock_support() at mutexlocksupp.c:57 0x806907e
> pthread_mutex_lock() at mutexlock.c:40 0x8068bee
> sys_arch_sem_wait() at sys_arch.c:485 0x808da8a
> sys_arch_mbox_fetch() at sys_arch.c:357 0x808d804
> sys_timeouts_mbox_fetch() at timers.c:532 0x80883ce
> tcpip_thread() at tcpip.c:95 0x808c170
> _Thread_Handler() at threadhandler.c:102 0x806bbe8
> _User_extensions_Thread_exitted() at userextimpl.h:244 0x806bb60
> bsp_section_work_begin() at 0xc016a12c
>
>
> However, the lwip code calling pthread_mutex_lock varies, but is 
> consistently from lwIP.
>
>
> Does this ring any bells?

Normally you get this if you obtain a locked mutex in interrupt context, 
but your stack trace says you are not.

>
> As far as I can tell this would only occur if the caller of 
> pthread_mutex_lock was in a "bad" state. I don't believe it is in an 
> interrupt context, and don't know what other bad states could exist.

We have

#define _CORE_mutex_Check_dispatch_for_seize(_wait) \
   (!_Thread_Dispatch_is_enabled() \
     && (_wait) \
     && (_System_state_Get() >= SYSTEM_STATE_UP))

What is the thread dispatch disable level and the system state at this 
point?

In case the thread dispatch disable level is not zero, then something is 
probably broken in the operating system code which is difficult to find. 
Could be a general memory corruption problem too. Which RTEMS version do 
you use?

-- 
Sebastian Huber, embedded brains GmbH

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