Bugs found by musl

(originally created for slcon 2013)

Bugs found and reported

Bugs relevant to musl

Unreported bugs

linux procfs and writev
posix: usage of the cx option in unistd.h
broken bre support in tre
broken random in all bsd libc and glibc (bad seed, ub signed int arithmetics)
search.h implementation bugs in bsd libc and glibc (stack overflow, hsearch crashes on glibc)
several libm bugs in glibc, fdlibm (freebsd, openbsd, bionic,..)
gcc fldpi, fldl2e,.. even with -frounding-math
gcc -fPIC -Os generates GOT for single 32bit consts instead of using immediate value (for float on i386)
llvm signal handler bug (not async-signal-safe, invalid use of c++, racy unmasking) in Support/Unix/Signals.inc
llvm exit bug (destructor calls exit)
llvm: invalid use of the address of stdin/stdout/stderr in Support/DynamicLibrary.cpp
address sanitizer: various problems: stack detection, include files, ifdef, non-portable code,..
various c++ projects: depend on constructor order of different tu (gcc 46770)
various projects: assume large thread stack size without setting it up (firefox,..)
various projects: query the base pointer of the stack to do pointer arithmetics with it (libgc, firefox,…)
calling dlopen from the constructor of global static object (firefox)
incorrect usage of feature test macros and configure results (lots of projects)
usage of obsolete wrong headers (sys/foo.h instead of foo.h and vice-versa, many projects)
glibc has some missing posix symbols (found by libc-test)
glibc has broken vfork on mips
glibc integer overflows in time/tz code
linux headers invoke ub by using (1 << 31) eg. MS_NOUSER in include/uapi/linux/fs.h
strace: broken handling of vfork
bionic: posix namespace violation, +gratuitous interface breaking
bionic: broken checks in wchar.cpp mbrtowc
gnutls: O_CLOEXEC
arp: posix namespace collision (tm_)
util-linux: cpuset.h __cpumask, etc, sys/ttydefaults.h, __sighandler_t
f() instead of (f)() in configure scripts (or #undef)
bionic/wchar.cpp ‘if (n == 0)’ is wrong, should be ‘if (s == NULL)’ and later ‘if (n == 0) return -2’
gcc vs c99 annex f issues
gcc dl_iterate_phdr configure check (hard coded solaris header check + glibc/bionic/bsd ifdef + config.host overrides)
posix: can syslog set errno (when it fails)?
isoc: fputc(‘c’,stdin) should be explicitly ub
posix: pow “For y < 0, if x is zero, .. +-HUGE_VAL” should be “if x is +-0” to match +-
isoc: underflow omission in annex f with FLT_EVAL_METHOD!=0 (comp.lang.c discussion)
glibc: fegetenv/fesetenv does not save/restore sse exception flags on i386
gcc: peephole optimization on i386 (i64 &= -1ULL<<32; turns into “andl \$-1,4(%esp); movl \$0,(%esp)”)
gcc: optimization for fmod loop: superfluous fldl/fstpl in loop
glibc, gnulib: invalid ld80 on i386 printf’d incorrectly, gnulib tests this case, but not correctly
glibc: -lxnet fails (posix requirement)
glibc vs linux: on microblaze struct elf_prpsinfo does not match the in-kernel definition.
gcc: generates usless .globl directive when referencing libgcc math function
gcc: libgcc symbol references has .globl but not .type directive so the assembler considers the symbol reference as object breaking eg -Bsymbolic-functions
gcc: definitions in libgcc.a should be .hidden (default visibility breaks usage in shared libraries)
gcc: (long long)ptr sign extends the pointer value, this eg breaks syscall arg passing on x32
glibc: alloca, strdupa, strndupa, should be declared with __attribute__((deprecated))
gcc, clang: mm_malloc.h pollutes global namespace, broken if libc posix_memalign is macro, gcc proto is wrong
gcc, __builtin_constant_p does not evaluate to an integer-constant-expression
linux: on 32bit mips linux uses -1U/2 as RLIM_INFINITY (which is in the middle of the valid range) but limits are not always compared accordingly: eg one can set inifine limit even if rlim_max is finite and >-1U/2