Minimal example: #include <string.h> int main(int argc, const char *argv[]) { char *p = ""; return strncasecmp(p, "", 1); } It seems the return value is corrupted as the compiled program crashes only when it is referenced. Crashes only on 32 bit and certain processors, might bet when SSE3 and SSE4 are in use, as this problem appeared in the newest glibc and there seems to be changes for it done: * Optimized strcasecmp and strncasecmp for SSSE3 and SSE4.2 on x86-32.
> Crashes only on 32 bit and certain processors Please tell *which* processor(s) it crashes on. A crash stack trace from GDB and "info registers" would be nice as well.
$ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 26 model name : Intel(R) Xeon(R) CPU W3530 @ 2.80GHz stepping : 5 cpu MHz : 2792.974 cache size : 6144 KB fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 5 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 constant_tsc up pni monitor ssse3 bogomips : 5585.94 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: $ cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 26 model name : Intel(R) Xeon(R) CPU W3530 @ 2.80GHz stepping : 5 cpu MHz : 2800.294 cache size : 8192 KB physical id : 0 siblings : 4 core id : 0 cpu cores : 4 apicid : 0 initial apicid : 0 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 11 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx rdtscp lm constant_tsc arch_perfmon pebs bts xtopology nonstop_tsc aperfmperf pni dtes64 monitor ds_cpl vmx est tm2 ssse3 cx16 xtpr pdcm dca sse4_1 sse4_2 popcnt lahf_lm ida dts tpr_shadow vnmi flexpriority ept vpid bogomips : 5600.58 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: # cat /proc/cpuinfo processor : 0 vendor_id : GenuineIntel cpu family : 6 model : 23 model name : Intel(R) Core(TM)2 Duo CPU E8400 @ 3.00GHz stepping : 10 microcode : 0xa07 cpu MHz : 2000.000 cache size : 6144 KB physical id : 0 siblings : 2 core id : 0 cpu cores : 2 apicid : 0 initial apicid : 0 fdiv_bug : no hlt_bug : no f00f_bug : no coma_bug : no fpu : yes fpu_exception : yes cpuid level : 13 wp : yes flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe nx lm constant_tsc arch_perfmon pebs bts aperfmperf pni dtes64 monitor ds_cpl vmx smx est tm2 ssse3 cx16 xtpr pdcm sse4_1 xsave lahf_lm dts tpr_shadow vnmi flexpriority bogomips : 5984.88 clflush size : 64 cache_alignment : 64 address sizes : 36 bits physical, 48 bits virtual power management: With dynamical debug libraries I seem to get every program to crash for now, here's a static stack trace: Program received signal SIGSEGV, Segmentation fault. 0x08055d98 in __strncasecmp_l_ssse3 () (gdb) bt #0 0x08055d98 in __strncasecmp_l_ssse3 () #1 0xbffff1d8 in ?? () (gdb) info registers eax 0x0 0 ecx 0x0 0 edx 0x80c3c28 135019560 ebx 0x0 0 esp 0xbffff1a8 0xbffff1a8 ebp 0x0 0x0 esi 0x0 0 edi 0x8049650 134518352 eip 0x8055d98 0x8055d98 <__strncasecmp_l_ssse3+10312> eflags 0x10246 [ PF ZF IF RF ] cs 0x73 115 ss 0x7b 123 ds 0x7b 123 es 0x7b 123 fs 0x0 0 gs 0x33 51
This issue is reproduced for core2 or atom machine (with SSSE3 support and without SSE42). Some bug exists in __strncasecmp_l_ssse3 but not in __strncasecmp_l_sse42. I will try to fix.
This issue is reproduced for core2 or atom machine (and any with SSSE3 support and without SSE42). Some bug exists in __strncasecmp_l_ssse3 but not in __strncasecmp_l_sse42. I will try to fix.
Thanks, fixed for glibc now.