DFSAN test failures with glibc 2.37

[mgorny]

I've just set up a testing container with glibc 2.37, and I'm seeing the following test failures:

Failed Tests (2):
  DataFlowSanitizer-x86_64 :: custom.cpp
  DataFlowSanitizer-x86_64 :: release_shadow_space.c

Details:

FAIL: DataFlowSanitizer-x86_64 :: release_shadow_space.c (2162 of 6438)
******************** TEST 'DataFlowSanitizer-x86_64 :: release_shadow_space.c' FAILED ********************
Script:
--
: 'RUN: at line 1';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  /var/t
mp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/release_shadow_space.c -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_
pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp &&  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/co
mpiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp
: 'RUN: at line 2';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  /var/t
mp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/release_shadow_space.c -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_
pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp &&  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/co
mpiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp
: 'RUN: at line 3';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  /var/t
mp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/release_shadow_space.c -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -o /var/tmp
/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp &&  /var/tmp/portage/sys-libs/c
ompiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp
: 'RUN: at line 4';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  /var/t
mp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/release_shadow_space.c -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -o /var/tmp
/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp &&  /var/tmp/portage/sys-libs/c
ompiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp
--
Exit Code: 134

Command Output (stderr):
--
+ : 'RUN: at line 1'
+ /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang -fsanitize=dataflow -m64 /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/release_shadow_space.c -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp
+ /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp
release_shadow_space.c.tmp: /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/release_shadow_space.c:29: size_t get_rss_kb(): Assertion `feof(f)' failed.
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.script: line 4: 142712 Aborted                 (core dumped) /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/release_shadow_space.c.tmp

--

********************
FAIL: DataFlowSanitizer-x86_64 :: custom.cpp (2180 of 6438)
******************** TEST 'DataFlowSanitizer-x86_64 :: custom.cpp' FAILED ********************
Script:
--
: 'RUN: at line 1';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/custom.cpp -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp && DFSAN_OPTIONS="strict_data_dependencies=0"  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp
: 'RUN: at line 2';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  -DSTRICT_DATA_DEPENDENCIES /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/custom.cpp -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp &&  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp
: 'RUN: at line 3';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -mllvm -dfsan-combine-pointer-labels-on-load=false -DSTRICT_DATA_DEPENDENCIES /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/custom.cpp -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp &&  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp
: 'RUN: at line 4';      /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang  -fsanitize=dataflow  -m64  -DORIGIN_TRACKING -mllvm -dfsan-track-origins=1 -mllvm -dfsan-combine-pointer-labels-on-load=false /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/custom.cpp -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp && DFSAN_OPTIONS="strict_data_dependencies=0"  /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp
--
Exit Code: 134

Command Output (stderr):
--
+ : 'RUN: at line 1'
+ /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/lib/llvm/17/bin/clang -fsanitize=dataflow -m64 /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/custom.cpp -o /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp
+ DFSAN_OPTIONS=strict_data_dependencies=0
+ /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp
custom.cpp.tmp: /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt/test/dfsan/custom.cpp:1858: void test_sprintf(): Assertion `strcmp(buf, "Hello world!") == 0' failed.
/var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.script: line 4: 141221 Aborted                 (core dumped) DFSAN_OPTIONS="strict_data_dependencies=0" /var/tmp/portage/sys-libs/compiler-rt-sanitizers-17.0.0_pre20230211/work/compiler-rt_build/test/dfsan/X86_64Config/Output/custom.cpp.tmp

--

********************

This is on 22fb66e.

[mgorny]

Proposed to mark it XFAIL via https://reviews.llvm.org/D148496.

[MaskRay]

When bufsz is too large and buffer+bufsz wraps around, snprintf printing a string without % will have the last char changed to NUL (https://sourceware.org/bugzilla/show_bug.cgi?id=30441). musl requires that bufsz cannot be larger than INT_MAX. I have a pending patch to update dfsan interceptor to work with glibc 2.37+ and musl.

% cat sn.c
#include <stdio.h>
#include <stdint.h>

int main() {
  char str[20];
  snprintf(str, SIZE_MAX, "Hello world!");
  puts(str);
}
% cc sn.c
% ./a.out
Hello world