Fixes are available
APAR status
Closed as program error.
Error description
The problem is that the compiler is generating assembler code that crashes. ===== COMPILE COMMAND: $ cc_r -o test 157849.c ===== TESTCASE: $ cat 157849.c #include <strings.h> #include <stdio.h> #include <fcntl.h> #include <errno.h> #include <sys/types.h> #include <sys/mman.h> typedef unsigned char uchar; /* Calendar date/time structure. */ #define BASE_YEAR 1900 typedef struct _dt { uchar year; /* Years since BASE_YEAR (0 - 255). */ uchar mon; /* Month within year (1 - 12). */ uchar day; /* Day within month (1 - 31). */ uchar hour; /* Hours within day (0 - 23). */ uchar min; /* Minutes within hour (0 - 59). */ uchar sec; /* Seconds within minute (0 - 59). */ } DateTime; static int printDate( DateTime d ); int main( int argc, char *argv[] ) { int rc = 0; int i = 0; int fd = -1; int dateCount = 0; char *map = NULL; DateTime *dates = NULL; fd = open( argv[1], O_RDWR ); if ( fd > 0 ) { map = mmap( NULL, 4096, PROT_READ|PROT_WRITE, MAP_FILE|MAP_PRIVATE, fd, 0 ); if ( map != NULL ) { /* get the date count */ /* dateCount = *(int *)map; */ dateCount = 682; /* point to the array of dates, which begins immediately after the count */ dates = (DateTime *)(map + sizeof(int) ); /* iterate over the entire array and print out each date */ if ( dateCount > 4096/sizeof(DateTime) ) fprintf( stderr, "Count value of %d is too big.\n", dateCount ); else { for ( i=0; i<dateCount; i++ ) printDate( dates[i] ); /* << crashes when the last date is at << the end of the mmapped region */ } } } else { rc = errno; fprintf( stderr, "Error %d opening %s.\n", rc, argv[1] ); } if ( map != 0 ) munmap( map, 4096 ); return rc; } /* main */ static int printDate( DateTime d ) { fprintf( stdout, "%04d:%02d:%02d\n", d.year+BASE_YEAR, d.mon, d.day ); return 0; } /* printDate */ $ ===== ACTUAL OUTPUT: $ ./test 157849.dat . . . 1900:00:00 1900:00:00 1900:00:00 1900:00:00 1900:00:00 1900:00:00 Memory fault $ ===== EXPECTED OUTPUT: Should not crash at runtime
Local fix
N/A
Problem summary
USERS AFFECTED: Users who write code loading arguments ending at protected page boundary are affected by this issue PROBLEM DESCRIPTION: Users will experience a runtime memory error when loading arguments ending at protected page boundary
Problem conclusion
The compiler has been changed to force the load arguments ending at protected page boundary with the exact size to void memory fault.
Temporary fix
Comments
APAR Information
APAR number
IJ06072
Reported component name
XL C/C++ FOR AI
Reported component ID
5725C7200
Reported release
D13
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-05-02
Closed date
2018-08-01
Last modified date
2018-08-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
XL C FOR AIX
Fixed component ID
5725C7100
Applicable component levels
RD13 PSY
UP
[{"Line of Business":{"code":"LOB57","label":"Power"},"Business Unit":{"code":"BU058","label":"IBM Infrastructure w\/TPS"},"Product":{"code":"SSGH2K","label":"XL C for AIX"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"D13"}]
Document Information
Modified date:
24 August 2021