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The posix_spawn on sparc issues invalid sigprocmask calls:
rt_sigprocmask(0xffe5e15c /* SIG_??? */, ~[], 0xffe5e1dc, 8) = -1 EINVAL (Invalid argument)
Which make support/tst-support_capture_subprocess fails with random
output (due the child signal being wrongly captured by the parent).
Tracking the culprit it seems to be a wrong code generation in the
INTERNAL_SYSCALL due the automatic sigset_t used on
__libc_signal_block_all:
return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
set, _NSIG / 8);
Where SIGALL_SET is defined as:
((__sigset_t) { .__val = {[0 ... _SIGSET_NWORDS-1 ] = -1 } })
Building the expanded __libc_signal_block_all on sparc64 with recent
compiler (gcc 8.3.1 and 9.1.1):
#include <signal>
int
_libc_signal_block_all (sigset_t *set)
{
INTERNAL_SYSCALL_DECL (err);
return INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_BLOCK, &SIGALL_SET,
set, _NSIG / 8);
}
The first argument (SIG_BLOCK) is not correctly set on 'o0' register:
__libc_signal_block_all:
save %sp, -304, %sp
add %fp, 1919, %o0
mov 128, %o2
sethi %hi(.LC0), %o1
call memcpy, 0
or %o1, %lo(.LC0), %o1
add %fp, 1919, %o1
mov %i0, %o2
mov 8, %o3
mov 103, %g1
ta 0x6d;
bcc,pt %xcc, 1f
mov 0, %g1
sub %g0, %o0, %o0
mov 1, %g1
1: sra %o0, 0, %i0
return %i7+8
nop
Where if SIGALL_SET is defined a const object, gcc correctly sets the
expected kernel argument in correct register:
sethi %hi(.LC0), %o1
call memcpy, 0
or %o1, %lo(.LC0), %o1
-> mov 1, %o0
add %fp, 1919, %o1
Another possible fix is use a static const object. Although there
should not be a difference between a const compound literal and a static
const object, the gcc C99 status page [1] has a note stating that this
optimization is not implemented:
"const-qualified compound literals could share storage with each
other and with string literals, but currently don't.".
This patch fixes it by moving both sigset_t that represent the
signal sets to static const data object. It generates slight better
code where the object reference is used directly instead of a stack
allocation plus the content materialization.
Checked on x86_64-linux-gnu, i686-linux-gnu, and sparc64-linux-gnu.
[1] https://gcc.gnu.org/c99status.html
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Also, change sources.redhat.com to sourceware.org.
This patch was automatically generated by running the following shell
script, which uses GNU sed, and which avoids modifying files imported
from upstream:
sed -ri '
s,(http|ftp)(://(.*\.)?(gnu|fsf|sourceware)\.org($|[^.]|\.[^a-z])),https\2,g
s,(http|ftp)(://(.*\.)?)sources\.redhat\.com($|[^.]|\.[^a-z]),https\2sourceware.org\4,g
' \
$(find $(git ls-files) -prune -type f \
! -name '*.po' \
! -name 'ChangeLog*' \
! -path COPYING ! -path COPYING.LIB \
! -path manual/fdl-1.3.texi ! -path manual/lgpl-2.1.texi \
! -path manual/texinfo.tex ! -path scripts/config.guess \
! -path scripts/config.sub ! -path scripts/install-sh \
! -path scripts/mkinstalldirs ! -path scripts/move-if-change \
! -path INSTALL ! -path locale/programs/charmap-kw.h \
! -path po/libc.pot ! -path sysdeps/gnu/errlist.c \
! '(' -name configure \
-execdir test -f configure.ac -o -f configure.in ';' ')' \
! '(' -name preconfigure \
-execdir test -f preconfigure.ac ';' ')' \
-print)
and then by running 'make dist-prepare' to regenerate files built
from the altered files, and then executing the following to cleanup:
chmod a+x sysdeps/unix/sysv/linux/riscv/configure
# Omit irrelevant whitespace and comment-only changes,
# perhaps from a slightly-different Autoconf version.
git checkout -f \
sysdeps/csky/configure \
sysdeps/hppa/configure \
sysdeps/riscv/configure \
sysdeps/unix/sysv/linux/csky/configure
# Omit changes that caused a pre-commit check to fail like this:
# remote: *** error: sysdeps/powerpc/powerpc64/ppc-mcount.S: trailing lines
git checkout -f \
sysdeps/powerpc/powerpc64/ppc-mcount.S \
sysdeps/unix/sysv/linux/s390/s390-64/syscall.S
# Omit change that caused a pre-commit check to fail like this:
# remote: *** error: sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S: last line does not end in newline
git checkout -f sysdeps/sparc/sparc64/multiarch/memcpy-ultra3.S
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This patch filters out the internal NPTL signals (SIGCANCEL/SIGTIMER and
SIGSETXID) from signal functions. GLIBC on Linux requires both signals to
proper implement pthread cancellation, posix timers, and set*id posix
thread synchronization.
And not filtering out the internal signal is troublesome:
- A conformant program on a architecture that does not filter out the
signals might inadvertently disable pthread asynchronous cancellation,
set*id synchronization or posix timers.
- It might also to security issues if SIGSETXID is masked and set*id
functions are called (some threads might have effective user or group
id different from the rest).
The changes are basically:
- Change __is_internal_signal to bool and used on all signal function
that has a signal number as input. Also for signal function which accepts
signals sets (sigset_t) it assumes that canonical function were used to
add/remove signals which lead to some input simplification.
- Fix tst-sigset.c to avoid check for SIGCANCEL/SIGTIMER and SIGSETXID.
It is rewritten to check each signal indidually and to check realtime
signals using canonical macros.
- Add generic __clear_internal_signals and __is_internal_signal
version since both symbols are used on generic implementations.
- Remove superflous sysdeps/nptl/sigfillset.c.
- Remove superflous SIGTIMER handling on Linux __is_internal_signal
since it is the same of SIGCANCEL.
- Remove dangling define and obvious comment on nptl/sigaction.c.
Checked on x86_64-linux-gnu.
[BZ #22391]
* nptl/sigaction.c (__sigaction): Use __is_internal_signal to
check for internal nptl signals.
* nptl/sigaction.c (__sigaction): Likewise.
* signal/sigaddset.c (sigaddset): Likewise.
* signal/sigdelset.c (sigdelset): Likewise.
* sysdeps/posix/signal.c (__bsd_signal): Likewise.
* sysdeps/posix/sigset.c (sigset): Call and check sigaddset return
value.
* signal/sigfillset.c (sigfillset): User __clear_internal_signals
to filter out internal nptl signals.
* signal/tst-sigset.c (do_test): Check ech signal indidually and
also check realtime signals using standard macros.
* sysdeps/generic/internal-signals.h (__clear_internal_signals,
__is_internal_signal, __libc_signal_block_all,
__libc_signal_block_app, __libc_signal_restore_set): New functions.
* sysdeps/nptl/sigfillset.c: Remove file.
* sysdeps/unix/sysv/linux/internal-signals.h (__is_internal_signal):
Change return to bool.
(__clear_internal_signals): Remove SIGTIMER clean since it is
equal to SIGCANEL on Linux.
* sysdeps/unix/sysv/linux/sigtimedwait.c (__sigtimedwait): Assume
signal set was constructed using standard functions.
Reported-by: Yury Norov <ynorov@caviumnetworks.com>
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