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| author | H.J. Lu <hjl.tools@gmail.com> | 2024-02-25 16:03:26 -0800 |
|---|---|---|
| committer | H.J. Lu <hjl.tools@gmail.com> | 2024-02-28 13:40:55 -0800 |
| commit | a1735e0aa858f0c8b15e5ee9975bff4279423680 (patch) | |
| tree | ac5f95008a2ddf782df051bfd1b2b14b7e583c66 /sysdeps/x86_64 | |
| parent | 8c7c188d62d76acda1b273b0d4d9c3b32983b28d (diff) | |
| download | glibc-a1735e0aa858f0c8b15e5ee9975bff4279423680.zip glibc-a1735e0aa858f0c8b15e5ee9975bff4279423680.tar.gz glibc-a1735e0aa858f0c8b15e5ee9975bff4279423680.tar.bz2 | |
x86_64: Suppress false positive valgrind error
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>
Diffstat (limited to 'sysdeps/x86_64')
| -rw-r--r-- | sysdeps/x86_64/Makefile | 6 | ||||
| -rw-r--r-- | sysdeps/x86_64/tst-valgrind-smoke.supp | 17 |
2 files changed, 23 insertions, 0 deletions
diff --git a/sysdeps/x86_64/Makefile b/sysdeps/x86_64/Makefile index 9337e95..66b2195 100644 --- a/sysdeps/x86_64/Makefile +++ b/sysdeps/x86_64/Makefile @@ -211,6 +211,12 @@ tst-plt-rewrite2-ENV = GLIBC_TUNABLES=glibc.cpu.plt_rewrite=2 $(objpfx)tst-plt-rewrite2: $(objpfx)tst-plt-rewritemod2.so endif +# Check if ISA level is 3 or above. +ifneq (,$(filter $(have-x86-isa-level),$(x86-isa-level-3-or-above))) +valgrind-suppressions-tst-valgrind-smoke = \ + --suppressions=$(..)sysdeps/x86_64/tst-valgrind-smoke.supp +endif + endif # $(subdir) == elf ifeq ($(subdir),csu) diff --git a/sysdeps/x86_64/tst-valgrind-smoke.supp b/sysdeps/x86_64/tst-valgrind-smoke.supp new file mode 100644 index 0000000..533c2de --- /dev/null +++ b/sysdeps/x86_64/tst-valgrind-smoke.supp @@ -0,0 +1,17 @@ +{ + False positive at strcmp-avx2.S:462 + Memcheck:Cond + fun:strcmp + fun:_dl_name_match_p + fun:_dl_map_object + fun:map_doit + fun:_dl_catch_exception + fun:_dl_catch_error + fun:do_preload + fun:handle_preload_list + fun:dl_main + fun:_dl_sysdep_start + fun:_dl_start_final + fun:_dl_start + obj:*/elf/ld.so +} |