I think I have found the problem with sympow. It is nothing to do with
elliptic curves. It is simply a malloc/free error.
In util.c there is a function free_data, which frees TACKS[0]. TACKS[0]
is meant to be allocated in disk.c, but there are circumstances when
TACKS[0] is not allocated.
See the attached patch.
I am not going to submit it as a trac ticket until I have heard from
others. In general, how to different OS's react to "free(NULL)"?
FreeBSD does nothing, but maybe other OS's crash. In that case, the
code in free_data will also need to be changed to something like "if
(TACKS[0]!=NULL) free(TACKS[0]);".
But also, maybe there are other errors like this in sympow. I caught
this one by chance.
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--- sympow-1.018.1.p11/src/disk.c-orig 2012-04-19 02:33:51.000000000 +0000
+++ sympow-1.018.1.p11/src/disk.c 2012-04-19 02:34:22.000000000 +0000
@@ -39,7 +39,7 @@
else if (((sp&3)==0) && CM_CASE) {if (2*ep==sp) S[3]='l'; else S[3]='h';}
else {if (2*ep==sp) S[3]='L'; else S[3]='H';}
if (HECKE && dv) {TACKS[which]=malloc(dv*sizeof(QD)); TACKON[which]=dv;}
- else if (dv<=sp/2) TACKON[which]=0;
+ else if (dv<=sp/2) {TACKS[which]=NULL; TACKON[which]=0;}
else {TACKS[which]=malloc((dv-sp/2)*sizeof(QD)); TACKON[which]=dv-sp/2;}
S[4]=0; F=fopen("datafiles/param_data","r"); strcpy(U,S);
if (ANAL_RANK) {if (dv>0) U[0]='A'; else U[0]='m';}
