The mergesort removal from qsort implementation (commit 03bf8357e8)
had the side-effect of making sorting nonstable. Although neither
POSIX nor C standard specify that qsort should be stable, it seems
that it has become an instance of Hyrum's law where multiple programs
expect it.
Also, the resulting introsort implementation is not faster than
the previous mergesort (which makes the change even less appealing).
This patch restores the previous mergesort implementation, with the
exception of machinery that checks the resulting allocation against
the _SC_PHYS_PAGES (it only adds complexity and the heuristic not
always make sense depending on the system configuration and load).
The alloca usage was replaced with a fixed-size buffer.
For the fallback mechanism, the implementation uses heapsort. It is
simpler than quicksort, and it does not suffer from adversarial
inputs. With memory overcommit, it should be rarely triggered.
The drawback is mergesort requires O(n) extra space, and since it is
allocated with malloc the function is AS-signal-unsafe. It should be
feasible to change it to use mmap, although I am not sure how urgent
it is. The heapsort is also nonstable, so programs that require a
stable sort would still be subject to this latent issue.
The tst-qsort5 is removed since it will not create quicksort adversarial
inputs with the current qsort_r implementation.
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Systemd execution environment configuration may prohibit changing a memory
mapping to become executable:
MemoryDenyWriteExecute=
Takes a boolean argument. If set, attempts to create memory mappings
that are writable and executable at the same time, or to change existing
memory mappings to become executable, or mapping shared memory segments
as executable, are prohibited.
When it is set, systemd service stops working if PLT rewrite is enabled.
Check if mprotect works before rewriting PLT. This fixes BZ #31230.
This also works with SELinux when deny_execmem is on.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Ffsll function randomly regress by ~20%, depending on how code gets
aligned in memory. Ffsll function code size is 17 bytes. Since default
function alignment is 16 bytes, it can load on 16, 32, 48 or 64 bytes
aligned memory. When ffsll function load at 16, 32 or 64 bytes aligned
memory, entire code fits in single 64 bytes cache line. When ffsll
function load at 48 bytes aligned memory, it splits in two cache line,
hence random regression.
Ffsll function size reduction from 17 bytes to 12 bytes ensures that it
will always fit in single 64 bytes cache line.
This patch fixes ffsll function random performance regression.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
This patch referents the commit 374cef3 to add static-pie support. And
because the dummy link map is used when relocating ourselves, so need
not to set __global_pointer$ at this time.
It will also check whether toolchain supports to build static-pie.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
The 551101e824 change is incorrect for
alpha and sparc, since __NR_stat is defined by both kABI. Use
__NR_newfstat to check whether to fallback to __NR_fstat64 (similar
to what fstatat64 does).
Checked on sparc64-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Remove the error handling wrapper from exp10. This is very similar to
the changes done to exp and exp2, except that we also need to handle
pow10 and pow10l.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Increase benchmark iterations for math and vector math functions to improve
timing accuracy. Vector math benchmarks now take 1-3 seconds on a modern CPU.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Otherwise the warning message for the getwd symbol ends up being duplicated.
Signed-off-by: Frederic Cambus <fred@statdns.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
The __getrandom_nocancel function returns errors as negative values
instead of errno. This is inconsistent with other _nocancel functions
and it breaks "TEMP_FAILURE_RETRY (__getrandom_nocancel (p, n, 0))" in
__arc4random_buf. Use INLINE_SYSCALL_CALL instead of
INTERNAL_SYSCALL_CALL to fix this issue.
But __getrandom_nocancel has been avoiding from touching errno for a
reason, see BZ 29624. So add a __getrandom_nocancel_nostatus function
and use it in tcache_key_initialize.
Signed-off-by: Xi Ruoyao <xry111@xry111.site>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org>
CET feature bits in TCB, which are Linux specific, are used to check if
CET features are active. Move CET feature check to Linux/x86 directory.
Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
Starting with commit 40c0add7d4
"resolve: Remove __res_context_query alloca usage"
there is an endless loop in __res_context_query if
__res_context_mkquery fails e.g. if type is invalid. Then the
scratch buffer is resized to MAXPACKET size and it is retried again.
Before the mentioned commit, it was retried only once and with the
mentioned commit, there is no check and it retries in an endless loop.
This is observable with xtest resolv/tst-resolv-qtypes which times out
after 300s.
This patch retries mkquery only once as before the mentioned commit.
Furthermore, scratch_buffer_set_array_size is now only called with
nelem=2 if type is T_QUERY_A_AND_AAAA (also see mentioned commit).
The test tst-resolv-qtypes is also adjusted to verify that <func>
is really returning with -1 in case of an invalid type.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
After 78ca44da01
("elf: Relocate libc.so early during startup and dlmopen (bug 31083)")
we start seeing tst-nodeps2 failures when building the testsuite with
--enable-hard-coded-path-in-tests.
When building the testsuite with --enable-hard-coded-path-in-tests
the tst-nodeps2-mod.so is not built with the required DT_RUNPATH
values and the test escapes the test framework and loads the system
libraries and aborts. The fix is to use the existing
$(link-test-modules-rpath-link) variable to set DT_RUNPATH correctly.
No regressions on x86_64.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
1. Remove _dl_runtime_resolve_shstk and _dl_runtime_profile_shstk.
2. Move CET offsets from x86 cpu-features-offsets.sym to x86-64
features-offsets.sym.
3. Rename x86 cet-control.h to x86-64 feature-control.h since it is only
for x86-64 and also used for PLT rewrite.
4. Add x86-64 ldsodefs.h to include feature-control.h.
5. Change TUNABLE_CALLBACK (set_plt_rewrite) to x86-64 only.
6. Move x86 dl-procruntime.c to x86-64.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Move sysdeps/x86/libc-start.h to sysdeps/x86_64/libc-start.h and use
sysdeps/generic/libc-start.h for i386.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Running build-many-glibcs.py with Python 3.12 or later produces a
warning:
build-many-glibcs.py:566: DeprecationWarning: datetime.datetime.utcnow() is deprecated and scheduled for removal in a future version. Use timezone-aware objects to represent datetimes in UTC: datetime.datetime.now(datetime.UTC).
build_time = datetime.datetime.utcnow()
Replace with datetime.datetime.now(datetime.timezone.utc) (the
datetime.UTC constant is new in 3.11, so not suitable for use in this
script at present).
Running build-many-glibcs.py with Python 3.12 or later produces a
warning:
build-many-glibcs.py:173: SyntaxWarning: invalid escape sequence '\.'
m = re.fullmatch('([0-9]+)\.([0-9]+)[.0-9]*', l)
Use a raw string instead to avoid that warning. (Note: I haven't
checked whether any other Python scripts included with glibc might
have issues with newer Python versions.)
The feupdateenv tests added by 802aef27b2 do not restore the floating
point mask, which might keep some floating point exception enabled and
thus make the feupdateenv_single_test raise an unexpected signal.
Checked on x86_64-linux-gnu and aarch64-linux-gnu (on Apple M1 trapping
is supported).
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
On x86-64 machine with
[hjl@gnu-cfl-3 x86-glibc]$ ls -l /usr/include/asm/prctl.h sysdeps/unix/sysv/linux/x86_64/include/asm/prctl.h
-rw-r--r-- 1 hjl hjl 825 Jan 9 09:41 sysdeps/unix/sysv/linux/x86_64/include/asm/prctl.h
-rw-r--r-- 1 root root 1170 Nov 27 16:00 /usr/include/asm/prctl.h
[hjl@gnu-cfl-3 x86-glibc]$
glibc configured with --enable-cet build failed:
make[2]: Entering directory '/export/gnu/import/git/gitlab/x86-glibc/iconv'
../Makerules:327: update target
'/export/build/gnu/tools-build/glibc-cet-gitlab/build-x86_64-linux/gnu/lib-names-64.h'
due to: /export/build/gnu/tools-build/glibc-cet-gitlab/build-x86_64-linux/gnu/lib-names-64.stmp
:
../Makeconfig:1216: update target
'/export/build/gnu/tools-build/glibc-cet-gitlab/build-x86_64-linux/libc-modules.h'
due to: /export/build/gnu/tools-build/glibc-cet-gitlab/build-x86_64-linux/libc-modules.stmp
:
../Makerules:1126: update target '/usr/include/asm/prctl.h' due to:
../sysdeps/unix/sysv/linux/x86_64/64/../include/asm/prctl.h
force-install
/usr/bin/install -c -m 644
../sysdeps/unix/sysv/linux/x86_64/64/../include/asm/prctl.h
/usr/include/asm/prctl.h
/usr/bin/install: cannot remove '/usr/include/asm/prctl.h': Permission denied
make[2]: *** [../Makerules:1126: /usr/include/asm/prctl.h] Error 1
make[2]: Leaving directory '/export/gnu/import/git/gitlab/x86-glibc/iconv'
make[1]: *** [Makefile:484: iconv/subdir_lib] Error 2
make[1]: Leaving directory '/export/gnu/import/git/gitlab/x86-glibc'
make: *** [Makefile:9: all] Error 2
This is triggered by the rule in Makerules:
$(inst_includedir)/%.h: $(..)include/%.h $(+force)
$(do-install)
Since no files under include/ should be installed, remove it from
Makerules.
Tested it on x86-64. There are no differences in the installed header
files.
CET is only support for x86_64, this patch reverts:
- faaee1f07e x86: Support shadow stack pointer in setjmp/longjmp.
- be9ccd27c0 i386: Add _CET_ENDBR to indirect jump targets in
add_n.S/sub_n.S
- c02695d776 x86/CET: Update vfork to prevent child return
- 5d844e1b72 i386: Enable CET support in ucontext functions
- 124bcde683 x86: Add _CET_ENDBR to functions in crti.S
- 562837c002 x86: Add _CET_ENDBR to functions in dl-tlsdesc.S
- f753fa7dea x86: Support IBT and SHSTK in Intel CET [BZ #21598]
- 825b58f3fb i386-mcount.S: Add _CET_ENDBR to _mcount and __fentry__
- 7e119cd582 i386: Use _CET_NOTRACK in i686/memcmp.S
- 177824e232 i386: Use _CET_NOTRACK in memcmp-sse4.S
- 0a899af097 i386: Use _CET_NOTRACK in memcpy-ssse3-rep.S
- 7fb613361c i386: Use _CET_NOTRACK in memcpy-ssse3.S
- 77a8ae0948 i386: Use _CET_NOTRACK in memset-sse2-rep.S
- 00e7b76a8f i386: Use _CET_NOTRACK in memset-sse2.S
- 90d15dc577 i386: Use _CET_NOTRACK in strcat-sse2.S
- f1574581c7 i386: Use _CET_NOTRACK in strcpy-sse2.S
- 4031d7484a i386/sub_n.S: Add a missing _CET_ENDBR to indirect jump
- target
-
Checked on i686-linux-gnu.
The CET is only supported for x86_64 and there is no plan to add
kernel support for i386. Move the Makefile rules and files from the
generic x86 folder to x86_64 one.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Resolves: BZ # 31221
glibc can recognise its code, but does not have its data.
This patch remedies that.
Signed-off-by: Janet Blackquill <uhhadd@gmail.com>
