Re: [lwip-users] pbuf_realloc in ip.c problem

[Simon Goldschmidt]

This was bug 27105, fixed in 1.3.1RC3 (was still included in RC1 and RC2).

Link to the bug:
http://cvs.savannah.gnu.org/viewvc/lwip/src/include/lwip/mem.h?revision=1.23&root=lwip&view=markup

This has nothing to do with ip.c or pbuf.c. Please check your mem.h file 
against the file in this link (which is the current and 1.3.1 version):

http://cvs.savannah.gnu.org/viewvc/lwip/src/include/lwip/mem.h?revision=1.23&root=lwip&view=markup

Especially these lines, which fix the bug:

>>>
#ifndef mem_realloc
static void *mem_realloc(void *mem, mem_size_t size)
{
  LWIP_UNUSED_ARG(size);
  return mem;
}
#endif
<<<

they were like this before:

>>>
#ifndef mem_realloc
#define mem_realloc realloc
#endif
<<<

I just checked the download link you gave and memp.h is fixed in the zip. 
Please re-check the version you are using is really 1.3.1 stable, not an RC.

You can either upgrade or change the memp.h file manually if upgrading is not 
an option.

Simon



> Hi,
> 
> I am using
> http://download.savannah.gnu.org/releases-noredirect/lwip/lwip-1.3.1.zip
> 
> md5
> af8c4bf938e3ca48af3d54e29d57ab54 *ip.c
> 1a1ec514a862fb1d931f4eb4c236cb21 *pbuf.c
> 
> Martin
> 
> 2009/9/1 Simon Goldschmidt <address@hidden>:
> > Which version of lwIP are you using? This was a bug in 1.3.0 that has
> been fixed in 1.3.1, if I remember correctly. Try upgrading to the latest
> version to fix this.
> >
> > Simon
> >
> >
> > -------- Original-Nachricht --------
> >> Datum: Tue, 1 Sep 2009 09:44:09 +0200
> >> Von: Martin Velek <address@hidden>
> >> An: address@hidden
> >> Betreff: [lwip-users] pbuf_realloc in ip.c problem
> >
> >> Hello,
> >>
> >> I am using lwip 1.3.1 with FreeRTOS and LM3S9B92. Because there is a
> >> memory manager in the OS I have defined
> >> #define MEM_LIBC_MALLOC                 1
> >> #define MEMP_MEM_MALLOC                 1
> >> #define MEM_USE_POOLS                   0
> >> with bget implementation of memory manager. All incomming packets are
> >> PBUF_RAM.
> >>
> >> The lwip running fine until a tcp packet to port 80 is received(http
> >> server by netconn). The lwip will cause a invalid memory  access.
> >>
> >> During debuging I have discovered that in file ip.c is called
> >> pbuf_realloc(p, iphdr_len) and inside this function is called
> >> mem_realloc(brel). Unfortunately bget reallocate memory by creating a
> >> new space and than will free the old memory.
> >> However this new memory is "lost" because the new pointer is not
> >> stored. (q = mem_realloc(q, (u8_t *)q->payload - (u8_t *)q +
> >> rem_len);) and q is not stored back to "p".
> >> So, p is still pointing to the deallocated memory.
> >> I have thought that the bget implementation is wrong but the standard
> >> C's realloc returns:
> >> "A pointer to the reallocated memory block, which may be either the
> >> same as the ptr argument or a new location.
> >> The type of this pointer is void*, which can be cast to the desired
> >> type of data pointer in order to be dereferenceable.
> >> If the function failed to allocate the requested block of memory, a
> >> NULL pointer is returned."
> >>
> >> Have anyone next similar problem?
> >>
> >> Thank you for your reply.
> >>
> >> Regards,
> >> Martin Velek
> >>
> >>
> >> _______________________________________________
> >> lwip-users mailing list
> >> address@hidden
> >> http://lists.nongnu.org/mailman/listinfo/lwip-users
> >
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> 
> 
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