Re: [lwip-users] Crash in 'stats_display_memp()'

[Eric Koldeweij]

Gisle,

You have definitely a problem with your "mem" pointer. There are 3 items 
added to the front and 3 items missing at the end. I definitely never 
encountered this before and I suspect that something has changed the 
pointer in an incorrect way or a copy gone wrong - some memory 
management issue. I think I cannot be of much more help here right now - 
it is certainly not a known issue. If you have it running on host, run 
with valgrind and see where it goes wrong.

The reason I asked about traffic is that without anything the stats will 
not count. It was to investigate if the problem occurs during 
initialization or after that. I would say it's after the initialization.

Good luck in finding this!

Regards,

Eric.

On 12/7/24 08:29, Gisle Vanem via lwip-users wrote:
> Eric Koldeweij wrote:
>
> > Normally RAW_PCB is the first one in the list and there should not be 
> > anything before that. Do you have either LWIP_MALLOC_MEMPOOL or 
> > LWIP_PBUF_MEMPOOL defined in your code?
>
> No.
>
> > Do you use custom pools (MEMP_USE_CUSTOM_POOLS defined to
> > a nonzero value)? If so, please post your lwippools.h.
>
> No I use '-DMEMP_MEM_MALLOC=1 -DMEM_LIBC_MALLOC=1'.
>
> > The code creating the enum is in src/include/lwip/memp.h and it takes 
> > its items from src/include/lwip/priv/memp_std.h.
> >
> > try using "gcc -E" to see what the include file expands like when 
> > it's processed?
>
> Here is the relevant pre-processed output of
> 'clang-cl -E':
>
> typedef enum
> {
> # 1 ".//src/include/lwip/priv/memp_std.h" 1
> # 42 ".//src/include/lwip/priv/memp_std.h"
>   MEMP_RAW_PCB,
>   MEMP_UDP_PCB,
>   MEMP_TCP_PCB,
>   MEMP_TCP_PCB_LISTEN,
>   MEMP_TCP_SEG,
>   MEMP_ALTCP_PCB,
>   MEMP_REASSDATA,
>   MEMP_FRAG_PBUF,
>   MEMP_NETBUF,
>   MEMP_NETCONN,
>   MEMP_TCPIP_MSG_API,
> # 94 ".//src/include/lwip/priv/memp_std.h"
>   MEMP_ARP_QUEUE,
>   MEMP_IGMP_GROUP,
>   MEMP_SYS_TIMEOUT,
>   MEMP_NETDB,
>   MEMP_ND6_QUEUE,
>   MEMP_IP6_REASSDATA,
>   MEMP_MLD6_GROUP,
> # 133 ".//src/include/lwip/priv/memp_std.h"
>   MEMP_PBUF,
>   MEMP_PBUF_POOL,
> # 55 ".//src/include/lwip/memp.h" 2
>   MEMP_MAX
> } memp_t;
>
> ---------
>
> Looks OK to me; MEMP_RAW_PCB=0, but
> 'lwip_stats.memp[0] == NULL' even still. Even
> after a lot of traffic was sent/received.
>
> I wondered about your original statement:
>
> > Has any traffic already occurred?
>
> Is it so that such a RAW_PCB pool is not initialised before traffic
> occur? If so, the 'stats_display_memp()' fails to assume that.