Hi! When running the libxslt testsuite under Valgrind, I see: ``` $ valgrind -q --leak-check=no --trace-children=yes --trace-children-skip=valgrind,make,ninja --trace-children-skip-by-arg=valgrind,make,ninja --exit-on-first-error=yes --error-exitcode=1 make heck-local make[2]: Entering directory '/var/tmp/portage/dev-libs/libxslt-1.1.43/work/libxslt-1.1.43-abi_x86_64.amd64-python3_10/python/tests' -- basic.py ==19822== Conditional jump or move depends on uninitialised value(s) ==19822== at 0x4D8FD2A: __wcscat_avx2 (strcat-strlen-avx2.h.S:68) ==19822== by 0x4A9DE98: ??? (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4A73F74: ??? (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4A782BB: ??? (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4A78EAA: ??? (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4A79BBF: Py_InitializeFromConfig (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4A9E4A1: ??? (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4A9F7CF: Py_BytesMain (in /usr/lib64/libpython3.10.so.1.0) ==19822== by 0x4C53DF4: (below main) (libc_start_call_main.h:58) ``` This is with `ld.so (Gentoo 2.41-r1 (patchset 2)) stable release version 2.41` on: ``` $ uname -a Linux sam-build 6.12.16-gentoo-dist-hardened #1 SMP PREEMPT_DYNAMIC Tue Mar 11 16:55:27 CDT 2025 x86_64 AMD EPYC 7R13 48-Core Processor AuthenticAMD GNU/Linux ```
Output with debugging symbols: ``` ==80104== Conditional jump or move depends on uninitialised value(s) ==80104== at 0x4D8FD2A: __wcscat_avx2 (strcat-strlen-avx2.h.S:68) ==80104== by 0x4A9DF18: wcscat (wchar2.h:124) ==80104== by 0x4A9DF18: calculate_module_search_path (getpath.c:1378) ==80104== by 0x4A9DF18: calculate_path (getpath.c:1537) ==80104== by 0x4A9DF18: _PyPathConfig_Calculate (getpath.c:1602) ==80104== by 0x4A74034: pathconfig_init (pathconfig.c:354) ==80104== by 0x4A74034: config_init_pathconfig (pathconfig.c:369) ==80104== by 0x4A74034: _PyConfig_InitPathConfig (pathconfig.c:438) ==80104== by 0x4A7837B: init_interp_main (pylifecycle.c:1082) ==80104== by 0x4A78F6A: pyinit_main (pylifecycle.c:1195) ==80104== by 0x4A78F6A: pyinit_main (pylifecycle.c:1184) ==80104== by 0x4A79C7F: Py_InitializeFromConfig (pylifecycle.c:1226) ==80104== by 0x4A79C7F: Py_InitializeFromConfig (pylifecycle.c:1204) ==80104== by 0x4A9E521: pymain_init (main.c:66) ==80104== by 0x4A9F84F: pymain_main (main.c:691) ==80104== by 0x4A9F84F: Py_BytesMain (main.c:724) ==80104== by 0x4C53DF4: (below main) (libc_start_call_main.h:58) ```
Can you provide the two strings that generate this error? On my PC with Fedora 41 wcscat is using __wcscat_evex. I don't know if that has the same problem. That's glibc 2.40.
Created attachment 179659 [details] First go at a fix, based on strcmp. Please could you test this patch?
(In reply to Paul Floyd from comment #2) > Can you provide the two strings that generate this error? > (gdb) bt #0 0x0000000004d8fd2a in ?? () from /usr/lib64/libc.so.6 #1 0x0000000004a9e02d in wcscat (__dest=0x50715a0 L"/usr/lib/python310.zip:/usr/lib/python3.10", __src=0x506fff0 L"") at /usr/include/bits/wchar2.h:124 #2 calculate_module_search_path (calculate=0x1ffefffa30, pathconfig=0x1ffefffc20) at ./Modules/getpath.c:1409 #3 calculate_path (calculate=0x1ffefffa30, pathconfig=0x1ffefffc20) at ./Modules/getpath.c:1537 #4 _PyPathConfig_Calculate (pathconfig=pathconfig@entry=0x1ffefffc20, config=config@entry=0x4f06370) at ./Modules/getpath.c:1602 #5 0x0000000004a74035 in pathconfig_init (pathconfig=0x1ffefffc20, config=0x4f06370, compute_path_config=1) at Python/pathconfig.c:354 #6 config_init_pathconfig (config=0x4f06370, compute_path_config=1) at Python/pathconfig.c:369 #7 _PyConfig_InitPathConfig (config=config@entry=0x4f06370, compute_path_config=compute_path_config@entry=1) at Python/pathconfig.c:438 #8 0x0000000004a7837c in init_interp_main (tstate=0x4f224a0) at Python/pylifecycle.c:1082 #9 0x0000000004a78f6b in pyinit_main (tstate=<optimized out>) at Python/pylifecycle.c:1195 #10 pyinit_main (tstate=<optimized out>) at Python/pylifecycle.c:1184 #11 0x0000000004a79c80 in Py_InitializeFromConfig (config=<optimized out>) at Python/pylifecycle.c:1226 #12 Py_InitializeFromConfig (config=config@entry=0x1ffeffff00) at Python/pylifecycle.c:1204 #13 0x0000000004a9e522 in pymain_init (args=args@entry=0x1fff0000d0) at Modules/main.c:66 #14 0x0000000004a9f850 in pymain_main (args=0x1fff0000d0) at Modules/main.c:691 #15 Py_BytesMain (argc=<optimized out>, argv=<optimized out>) at Modules/main.c:724 #16 0x0000000004c53df5 in ?? () from /usr/lib64/libc.so.6 #17 0x0000000004c53ea7 in __libc_start_main () from /usr/lib64/libc.so.6 #18 0x0000000000109081 in _start () And for good measure: ``` (gdb) frame 2 #2 calculate_module_search_path (calculate=0x1ffefffa30, pathconfig=0x1ffefffc20) at ./Modules/getpath.c:1409 1409 wcscat(buf, defpath); (gdb) p buf $1 = 0x50715a0 L"/usr/lib/python310.zip:/usr/lib/python3.10" (gdb) p defpath $2 = 0x506fff0 L"" ```
The second instance is: ``` Program received signal SIGTRAP, Trace/breakpoint trap. 0x0000000004d8fd2a in ?? () from /usr/lib64/libc.so.6 (gdb) bt #0 0x0000000004d8fd2a in ?? () from /usr/lib64/libc.so.6 #1 0x0000000004a9e03c in wcscat (__dest=0x50715a0 L"/usr/lib/python310.zip:/usr/lib/python3.10", __src=0x4b6c470 <delimiter> L":") at /usr/include/bits/wchar2.h:124 #2 calculate_module_search_path (calculate=0x1ffefffa30, pathconfig=0x1ffefffc20) at ./Modules/getpath.c:1414 #3 calculate_path (calculate=0x1ffefffa30, pathconfig=0x1ffefffc20) at ./Modules/getpath.c:1537 #4 _PyPathConfig_Calculate (pathconfig=pathconfig@entry=0x1ffefffc20, config=config@entry=0x4f06370) at ./Modules/getpath.c:1602 #5 0x0000000004a74035 in pathconfig_init (pathconfig=0x1ffefffc20, config=0x4f06370, compute_path_config=1) at Python/pathconfig.c:354 #6 config_init_pathconfig (config=0x4f06370, compute_path_config=1) at Python/pathconfig.c:369 #7 _PyConfig_InitPathConfig (config=config@entry=0x4f06370, compute_path_config=compute_path_config@entry=1) at Python/pathconfig.c:438 #8 0x0000000004a7837c in init_interp_main (tstate=0x4f224a0) at Python/pylifecycle.c:1082 #9 0x0000000004a78f6b in pyinit_main (tstate=<optimized out>) at Python/pylifecycle.c:1195 #10 pyinit_main (tstate=<optimized out>) at Python/pylifecycle.c:1184 #11 0x0000000004a79c80 in Py_InitializeFromConfig (config=<optimized out>) at Python/pylifecycle.c:1226 #12 Py_InitializeFromConfig (config=config@entry=0x1ffeffff00) at Python/pylifecycle.c:1204 #13 0x0000000004a9e522 in pymain_init (args=args@entry=0x1fff0000d0) at Modules/main.c:66 #14 0x0000000004a9f850 in pymain_main (args=0x1fff0000d0) at Modules/main.c:691 #15 Py_BytesMain (argc=<optimized out>, argv=<optimized out>) at Modules/main.c:724 #16 0x0000000004c53df5 in ?? () from /usr/lib64/libc.so.6 #17 0x0000000004c53ea7 in __libc_start_main () from /usr/lib64/libc.so.6 #18 0x0000000000109081 in _start () ``` Anyway, trying the patch - thanks!
(In reply to Paul Floyd from comment #3) > Created attachment 179659 [details] > First go at a fix, based on strcmp. > > Please could you test this patch? Thanks, that fixes it.
Thanks for the examples. I can reproduce the issue. I'll push a fix and test shortly.
commit f87c58e89c4a0e85c59f39a7ae01027686bfff73 (HEAD -> master, origin/master, origin/HEAD) Author: Paul Floyd <pjfloyd@wanadoo.fr> Date: Sun Mar 23 10:21:29 2025 +0100 Bug 501893 - Missing suppression for __wcscat_avx2 (strcat-strlen-avx2.h.S:68)?
Also put on the VALGRIND_3_24 branch as: commit f206268ad56899f935d420770088076671a6b014 Author: Paul Floyd <pjfloyd@wanadoo.fr> Date: Sun Mar 23 10:21:29 2025 +0100 Bug 501893 - Missing suppression for __wcscat_avx2 (strcat-strlen-avx2.h.S:68)? (cherry picked from commit f87c58e89c4a0e85c59f39a7ae01027686bfff73)