Unlike GCC, llvm always uses an integrated assembler, which attempts to
recognized all `asm` statements written in the C code. glibc uses some
syntactically invalid asm statements to emit constants into assembly that
are later extracted with a sed or AWK script.
This change fixes two such invalid `asm` statements by wrapping the
output in a `.ascii` directive.. This does not break the sed/AWK (the same
special sequence is output) but it makes the statement syntactically valid.
See cf8e3f8757 for a previous fix for the same issue.
+ Use DOT_MACHINE macro instead of ".machine" instruction.
+ Use __isinf and __isinff instead of builtin versions.
+ In s_logb, s_logbf and s_logbl functions, used float versions to
calculate "ret = x & 0x7f800000;" expression.
When compiled as mempcpy, the return value is the end of the destination
buffer, thus it cannot be used to refer to the start of it.
(cherry picked from commit 9aaaab7c6e)
On s390 (31bit) if glibc is build with -Os, pthread_join sometimes
blocks indefinitely. This is e.g. observable with
testcase intl/tst-gettext6.
pthread_join is calling lll_wait_tid(tid), which performs the futex-wait
syscall in a loop as long as tid != 0 (thread is alive).
On s390 (and build with -Os), tid is loaded from memory before
comparing against zero and then the tid is loaded a second time
in order to pass it to the futex-wait-syscall.
If the thread exits in between, then the futex-wait-syscall is
called with the value zero and it waits until a futex-wake occurs.
As the thread is already exited, there won't be a futex-wake.
In lll_wait_tid, the tid is stored to the local variable __tid,
which is then used as argument for the futex-wait-syscall.
But unfortunately the compiler is allowed to reload the value
from memory.
With this patch, the tid is loaded with atomic_load_acquire.
Then the compiler is not allowed to reload the value for __tid from memory.
ChangeLog:
[BZ #23137]
* sysdeps/nptl/lowlevellock.h (lll_wait_tid):
Use atomic_load_acquire to load __tid.
(cherry picked from commit 1660901840)
This patch adds the PTRACE_SECCOMP_GET_METADATA constant from Linux
4.16 to all relevant sys/ptrace.h files. A type struct
__ptrace_seccomp_metadata, analogous to other such types, is also
added.
Tested for x86_64, and with build-many-glibcs.py.
* sysdeps/unix/sysv/linux/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): New enum value and macro.
* sysdeps/unix/sysv/linux/bits/ptrace-shared.h
(struct __ptrace_seccomp_metadata): New type.
* sysdeps/unix/sysv/linux/aarch64/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/arm/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/ia64/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/powerpc/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/s390/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/sparc/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/tile/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
* sysdeps/unix/sysv/linux/x86/sys/ptrace.h
(PTRACE_SECCOMP_GET_METADATA): Likewise.
(cherry picked from commit 9320ca88a1)
When there is no login uid Linux sets /proc/self/loginid to the sentinel
value of, (uid_t) -1. If this is set we can return early and avoid
needlessly looking up the sentinel value in any configured nss
databases.
Checked on aarch64-linux-gnu.
* sysdeps/unix/sysv/linux/getlogin_r.c (__getlogin_r_loginuid): Return
early when linux sentinel value is set.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
(cherry picked from commit cc8a1620eb)
The RISC-V kernel doesn't define SA_RESTORER, hence the kernel version
of struct sigaction doesn't have the sa_restorer field. The default
kernel_sigaction.h therefore can't be used.
This patch adds a RISC-V specific version of kernel_sigaction.h to fix
the issue. This fixes for example the libnih testsuite.
Note that this patch is not needed in master as the bug has been fixed
by commit b4a5d26d88 ("linux: Consolidate sigaction implementation").
This patch fixes the i386 sa_restorer field initialization for sigaction
syscall for kernel with vDSO. As described in bug report, i386 Linux
(and compat on x86_64) interprets SA_RESTORER clear with nonzero
sa_restorer as a request for stack switching if the SS segment is 'funny'.
This means that anything that tries to mix glibc's signal handling with
segmentation (for instance through modify_ldt syscall) is randomly broken
depending on what values lands in sa_restorer.
The testcase added is based on Linux test tools/testing/selftests/x86/ldt_gdt.c,
more specifically in do_multicpu_tests function. The main changes are:
- C11 atomics instead of plain access.
- Remove x86_64 support which simplifies the syscall handling and fallbacks.
- Replicate only the test required to trigger the issue.
Checked on i686-linux-gnu.
[BZ #21269]
* sysdeps/unix/sysv/linux/i386/Makefile (tests): Add tst-bz21269.
* sysdeps/unix/sysv/linux/i386/sigaction.c (SET_SA_RESTORER): Clear
sa_restorer for vDSO case.
* sysdeps/unix/sysv/linux/i386/tst-bz21269.c: New file.
(cherry picked from commit 68448be208)
