The problem is visible with glibc 2.32 under valgrind: ==20== Invalid read of size 1 ==20== at 0x483DAB4: strcmp (vg_replace_strmem.c:847) ==20== by 0x109414: main (test-perror2.c:84) ==20== Address 0x4a1a3d0 is 0 bytes inside a block of size 17 free'd ==20== at 0x483A9F5: free (vg_replace_malloc.c:538) ==20== by 0x48E2134: strerror_l (in /usr/lib64/libc-2.32.so) ==20== by 0x109328: main (test-perror2.c:72) ==20== Block was alloc'd at ==20== at 0x4839809: malloc (vg_replace_malloc.c:307) ==20== by 0x48CA03F: __vasprintf_internal (in /usr/lib64/libc-2.32.so) ==20== by 0x48A46F9: asprintf (in /usr/lib64/libc-2.32.so) ==20== by 0x48E2184: strerror_l (in /usr/lib64/libc-2.32.so) ==20== by 0x1092E2: main (test-perror2.c:67) ==20== ==20== Invalid read of size 1 ==20== at 0x483DAC8: strcmp (vg_replace_strmem.c:847) ==20== by 0x109414: main (test-perror2.c:84) ==20== Address 0x4a1a3d1 is 1 bytes inside a block of size 17 free'd ==20== at 0x483A9F5: free (vg_replace_malloc.c:538) ==20== by 0x48E2134: strerror_l (in /usr/lib64/libc-2.32.so) ==20== by 0x109328: main (test-perror2.c:72) ==20== Block was alloc'd at ==20== at 0x4839809: malloc (vg_replace_malloc.c:307) ==20== by 0x48CA03F: __vasprintf_internal (in /usr/lib64/libc-2.32.so) ==20== by 0x48A46F9: asprintf (in /usr/lib64/libc-2.32.so) ==20== by 0x48E2184: strerror_l (in /usr/lib64/libc-2.32.so) ==20== by 0x1092E2: main (test-perror2.c:67)
I think it's the test that's invalid. This was reported as an actual grep test failure (without valgrind) on 32-bit Arm, where glibc malloc happens to return a different buffer address for the internal allocation (so that msg3 != msg4). test-strerror_r has the same issue. Thanks, Florian
