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When strcmp-avx2.S is used as the default, elf/tst-valgrind-smoke fails with ==1272761== Conditional jump or move depends on uninitialised value(s) ==1272761== at 0x4022C98: strcmp (strcmp-avx2.S:462) ==1272761== by 0x400B05B: _dl_name_match_p (dl-misc.c:75) ==1272761== by 0x40085F3: _dl_map_object (dl-load.c:1966) ==1272761== by 0x401AEA4: map_doit (rtld.c:644) ==1272761== by 0x4001488: _dl_catch_exception (dl-catch.c:237) ==1272761== by 0x40015AE: _dl_catch_error (dl-catch.c:256) ==1272761== by 0x401B38F: do_preload (rtld.c:816) ==1272761== by 0x401C116: handle_preload_list (rtld.c:892) ==1272761== by 0x401EDF5: dl_main (rtld.c:1842) ==1272761== by 0x401A79E: _dl_sysdep_start (dl-sysdep.c:140) ==1272761== by 0x401BEEE: _dl_start_final (rtld.c:494) ==1272761== by 0x401BEEE: _dl_start (rtld.c:581) ==1272761== by 0x401AD87: ??? (in */elf/ld.so) The assembly codes are: 0x0000000004022c80 <+144>: vmovdqu 0x20(%rdi),%ymm0 0x0000000004022c85 <+149>: vpcmpeqb 0x20(%rsi),%ymm0,%ymm1 0x0000000004022c8a <+154>: vpcmpeqb %ymm0,%ymm15,%ymm2 0x0000000004022c8e <+158>: vpandn %ymm1,%ymm2,%ymm1 0x0000000004022c92 <+162>: vpmovmskb %ymm1,%ecx 0x0000000004022c96 <+166>: inc %ecx => 0x0000000004022c98 <+168>: jne 0x4022c32 <strcmp+66> strcmp-avx2.S has 32-byte vector loads of strings which are shorter than 32 bytes: (gdb) p (char *) ($rdi + 0x20) $6 = 0x1ffeffea20 "memcheck-amd64-linux.so" (gdb) p (char *) ($rsi + 0x20) $7 = 0x4832640 "core-amd64-linux.so" (gdb) call (int) strlen ((char *) ($rsi + 0x20)) $8 = 19 (gdb) call (int) strlen ((char *) ($rdi + 0x20)) $9 = 23 (gdb) It triggers the valgrind error. The above code is safe since the loads don't cross the page boundary. Update tst-valgrind-smoke.sh to accept an optional suppression file and pass a suppression file to valgrind when strcmp-avx2.S is the default implementation of strcmp. Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com> |
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