Tencent/matrix · critical

out of memory

Error message

out of memory

What it means

handle_D_option() processes -D command-line defines for lemon. It reallocs the global azDefine array to grow by one entry, and if realloc returns NULL it prints 'out of memory' and exits(1). This is a fatal allocation failure while registering a -D macro name.

Solutions

1. Free memory / raise limits (ulimit -v, container memory) and rerun lemon.
2. Reduce the number of -D defines passed to lemon.
3. Verify the build script isn't expanding variables into thousands of duplicate -D flags.
4. Replace the realloc pattern to use a temporary pointer and report the requested size for diagnosability.
5. Run lemon under valgrind to rule out prior heap corruption causing realloc failure.

Example fix

// before
azDefine = realloc(azDefine, sizeof(azDefine[0])*nDefine);
if( azDefine==0 ){
  fprintf(stderr,"out of memory\n");
  exit(1);
}
// after
char **pazNew = realloc(azDefine, sizeof(azDefine[0])*nDefine);
if( pazNew==0 ){
  fprintf(stderr,"out of memory growing azDefine to %d entries\n", nDefine);
  exit(1);
}
azDefine = pazNew;

# validate memory headroom and the -D list size before invoking lemon
[ ${#DEFINES[@]} -lt 1000 ] || { echo "too many -D defines"; exit 1; }
free_kb=$(awk '/MemAvailable/{print $2}' /proc/meminfo); [ "$free_kb" -ge 65536 ] || exit 1

// library exits(1); guard at process level
if (system("lemon -DFOO grammar.y") != 0) { /* raise limits and retry */ }

When it happens

Trigger: realloc(azDefine, sizeof(char*)*nDefine) returns NULL at lemon.c:1374 when processing a -D option on the lemon command line, because the heap is exhausted (or in edge cases realloc fails on an oversized/zero-size request).

Common situations: Passing many -D flags on a constrained system; memory-capped CI containers; general system OOM at the moment lemon starts; broken builds invoking lemon with an enormous generated -D list.

Related errors

• Unable to allocate memory for a new configuration.
• Out of memory. Aborting...
• Exactly one filename argument is required.
• sdkVersion is absent in result.info.
• manufacturer is absent in result.info.

AI-assisted analysis of Tencent/matrix@3b8293bd65 (2026-09-08). Data as JSON: /api/errors/43e5bd514eea7703. Report an issue: GitHub.

Appendix: source

Thrown at matrix/matrix-android/matrix-sqlite-lint/src/lemon/lemon-gen/lemon.c:1374

** is used mostly by the "MemoryCheck" macro in struct.h
*/
void memory_error(){
  fprintf(stderr,"Out of memory.  Aborting...\n");
  exit(1);
}

static int nDefine = 0;      /* Number of -D options on the command line */
static char **azDefine = 0;  /* Name of the -D macros */

/* This routine is called with the argument to each -D command-line option.
** Add the macro defined to the azDefine array.
*/
static void handle_D_option(char *z){
  char **paz;
  nDefine++;
  azDefine = realloc(azDefine, sizeof(azDefine[0])*nDefine);
  if( azDefine==0 ){
    fprintf(stderr,"out of memory\n");
    exit(1);
  }
  paz = &azDefine[nDefine-1];
  *paz = malloc( strlen(z)+1 );
  if( *paz==0 ){
    fprintf(stderr,"out of memory\n");
    exit(1);
  }
  strcpy(*paz, z);
  for(z=*paz; *z && *z!='='; z++){}
  *z = 0;
}


/* The main program.  Parse the command line and do it... */
int main(argc,argv)
int argc;
char **argv;

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