Hi, I'm trying to test Postgres code for any unaligned memory accesses. I used a hack shown at [1] and put it in exec_simple_query, then I'm seeing a SIGBUS error from SplitIdentifierString's strncpy, see [2]. It looks like the SIGBUS error occurs even if a simple memcpy(for testing purpose) is done in recomputeNamespacePath or SplitIdentifierString.
I'm not sure this is the right way. I would like to know whether there is a standard way of testing Postgres code for any unaligned memory accesses. Thanks. Any help would be appreciated. [1] - https://www.programmersought.com/article/17701994124/ +/* Enable Alignment Checking */ +#if defined(__GNUC__) +# if defined(__i386__) + /* Enable Alignment Checking on x86 */ + __asm__("pushf\norl $0x40000,(%esp)\npopf"); +# elif defined(__x86_64__) + /* Enable Alignment Checking on x86_64 */ + __asm__("pushf\norl $0x40000,(%rsp)\npopf"); +# endif +#endif [2] Program received signal SIGBUS, Bus error. 0x00007f5067188d36 in __strncpy_sse2_unaligned () from /lib64/libc.so.6 (gdb) bt #0 0x00007f5067188d36 in __strncpy_sse2_unaligned () from /lib64/libc.so.6 #1 0x0000000000ada740 in SplitIdentifierString (rawstring=0x1146620 "\"$user", separator=44 ',', namelist=0x7ffcdf1911d0) at varlena.c:3817 #2 0x00000000005d203b in recomputeNamespacePath () at namespace.c:3761 #3 0x00000000005cde11 in FuncnameGetCandidates (names=0x1145e08, nargs=2, argnames=0x0, expand_variadic=true, expand_defaults=true, missing_ok=false) at namespace.c:971 #4 0x0000000000647dcb in func_get_detail (funcname=0x1145e08, fargs=0x1146570, fargnames=0x0, nargs=2, argtypes=0x7ffcdf191540, expand_variadic=true, expand_defaults=true, funcid=0x7ffcdf1916d8, rettype=0x7ffcdf1916dc, retset=0x7ffcdf19152f, nvargs=0x7ffcdf191528, vatype=0x7ffcdf191524, true_typeids=0x7ffcdf191538, argdefaults=0x7ffcdf191530) at parse_func.c:1421 #5 0x0000000000645961 in ParseFuncOrColumn (pstate=0x11462e8, funcname=0x1145e08, fargs=0x1146570, last_srf=0x0, fn=0x1145f28, proc_call=false, location=14) at parse_func.c:265 With Regards, Bharath Rupireddy. EnterpriseDB: http://www.enterprisedb.com
