Florian Weimer [Fri, 7 Nov 2025 09:14:43 +0000 (10:14 +0100)]
malloc: Perform batched frees if tcache is full
Batched frees amortize the locking overhead once the tcache is full.
Previously, once the tcache slot was full, each free acquired the
arena lock. With this change, neighboring tcache allocations in the
same arena re-use an arena lock that already exists.
Pass the tcache pointer to __libc_free_batch so that it is not
necessary to reload the tcache pointer after the _int_free_chunk
calls.
Both ld.so and malloc track kernel THP mode and THP page size when THP
in ld.so is enabled by
GLIBC_TUNABLES=glibc.elf.thp=1
and THP in malloc is enabled by
GLIBC_TUNABLES=glibc.malloc.hugetlb=1
But DL_MAP_DEFAULT_THP_PAGESIZE and MALLOC_DEFAULT_THP_PAGESIZE may be
different when they are defined in <hugepages.h>.
If THP in ld.so is enabled, change malloc to use kernel THP mode from
ld.so, instead of calling __get_thp_mode, and use THP page size from
ld.so if it came from __get_thp_size. This avoids calling __get_thp_mode
and __get_thp_size again, which are quite expensive:
1. Initialize mp_.thp_mode and GL(dl_thp_mode) to thp_mode_unknown.
2. Set mp_.thp_mode to GL(dl_thp_mode) if GL(dl_thp_mode) isn't
thp_mode_unknown. Otherwise call __get_thp_mode to set mp_.thp_mode.
3. GL(dl_elf_thp_pagesize) is set to DL_MAP_DEFAULT_THP_PAGESIZE without
calling __get_thp_size and THP page size for malloc may be different from
THP page size for ld.so. Set mp_.thp_pagesize to GL(dl_elf_thp_pagesize)
if DL_MAP_DEFAULT_THP_PAGESIZE is defined. Otherwise call __get_thp_size
to set mp_.thp_pagesize.
4. THP page size in malloc is capped to MAX_THP_PAGESIZE. If THP page
size is above MAX_THP_PAGESIZE, THP in malloc is disabled.
These result in when glibc.elf.thp is set to 1, malloc uses the actual
kernel THP mode instead of defaulting to madvise mode and madvise_thp
will stop issuing MADV_HUGEPAGE if kernel THP mode is always.
When scanf parses special floating-point inputs like "nan", "inf", it
may read one extra character to check whether the input still matches
the expected word.
If that extra character does not match, the conversion should fail, but
the character has already been read from the stream. Some error paths
did not push it back before reporting the conversion error, so later input
started at the wrong position.
Fix this by keeping EOF and width errors separate from character mismatch
errors. Push the character back before calling conv_error for mismatch
errors.
Add narrow and wide scanf tests using the same test body. The test cases
focus on the paths changed by this patch: mismatches while matching "nan",
"nan(...)", "inf", and "infinity".
Tested on x86_64 Fedora 42.
The following tests passed without regressions:
make test t=stdio-common/tst-scanf-bz34208
make test t=stdio-common/tst-wscanf-bz34208
make subdirs="stdio-common libio" check
Michael Ford [Thu, 25 Jun 2026 09:21:16 +0000 (10:21 +0100)]
nss: Remove --enable-static-nss configure option
Since the NSS reorganization in glibc 2.33 the --enable-static-nss
option no longer changes the build: the files and dns services are built
into libc unconditionally, and there is no longer any mechanism to bake
the remaining services into libc.a. After removing the dead
-DSTATIC_NSS define and the <gnu/lib-names.h> include (commits 82b710c1900944ea122a3880f542215948fc023d and 21694014388ad278aa03241800d1f0c0a7127ad1), the option's only remaining
effect was to define DO_STATIC_NSS, which suppresses the static link
warnings on the NSS interface functions in libc.a.
With DO_STATIC_NSS gone, nss_interface_function emits the static link
warning unconditionally; static_nss and build-static-nss are removed
along with the configure option.
tst-nss-static, previously built only when build-static-nss was set, is
now added to tests-static unconditionally so the static NSS path retains
test coverage.
Signed-off-by: Michael Ford <fanquake@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Add a new section to the Dynamic Linker chapter describing the
STT_GNU_IFUNC mechanism: the resolver calling convention for each
supported architecture, when resolvers run, and the functionality
supported in resolvers (TLS access, stack protector, cross-object
references) along with the remaining restrictions, reflecting the
recent ordering fixes (BZ 20680, BZ 23240, BZ 28817, BZ 34164,
BZ 34170). Also cross-reference it from the hardening section.
Sachin Monga [Thu, 18 Jun 2026 10:34:04 +0000 (05:34 -0500)]
ppc64le: Restore optimized memchr for power10 [BZ #34300]
Restore the POWER10 memchr implementation reverted in commit a7877bb6685300f159fa095c9f50b22b112cddb8 [BZ #33059], addressing the
actual cause:
The non-volatile vector register v20 used as the
zero vector (M_VREG_ZERO) is replaced with the volatile register v17.
Additionally, the assembler workaround used earlier for the
instructions lxvp and vextractbm is replaced with actual
instructions.
The RISC-V libthread_db THREAD_SELF descriptor currently assumes 64-bit
general-register slots:
REGISTER (64, 64, 4 * 8, ...)
That is correct for RV64, where tp/x4 is at byte offset 4 * 8 in the
general register set. On RV32, general-register slots are 32-bit wide,
so tp/x4 is at byte offset 4 * 4.
Using the RV64 layout on RV32 makes libthread_db read the wrong thread
pointer value and prevents GDB from enabling pthread-aware thread
debugging.
Use a helper macro to pass the RISC-V register size into the
DB_THREAD_SELF definition.
Signed-off-by: Shengwen Cheng <shengwen1997.tw@gmail.com> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
H.J. Lu [Tue, 23 Jun 2026 00:10:05 +0000 (08:10 +0800)]
thp: Limit THP code padding to 2 * THP page size
Since R_ARC_S25W_PCREL range is limited, 32MB THP code padding leads to
relocation overflow:
.../support/libsupport_nonshared.a(support_test_main.oS):
in function `support_test_main':
.../support/support_test_main.c:396:(.text+0x650): relocation truncated to fit: R_ARC_S25W_PCREL_PLT against symbol `atexit' defined in .text section in
../glibc/libc_nonshared.a(atexit.oS)
.../install/compilers/arc-linux-gnu/arc-glibc-linux-gnu/bin/ld: final link failed
collect2: error: ld returned 1 exit status
Limit THP code padding to 2 * THP page size to avoid R_ARC_S25W_PCREL
relocation overflow.
Tested natively for Linux/x86-64 and Linux/i686 as well as with
build-many-glibcs.py for arc-linux-gnu.
This fixes BZ #34311
Signed-off-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
hppa: Fix missing call to __feraiseexcept (BZ 34306)
The feupdateenv function is supposed to raise exceptions after
installing the environment represented by its envp argument.
This was accidentally missed on hppa.
The failure to raise exceptions was noticed by the failure of
the math/test-narrowing-trap test.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Sergey Kolosov [Mon, 22 Jun 2026 18:15:44 +0000 (20:15 +0200)]
resolv: Add test for gethostbyname_r unaligned buffer [BZ #18287]
Add a test for the buffer overflow in gethostbyname_r (Bug 18287), which
occurs when alignment padding is not subtracted from the remaining buffer
length.
The test uses binary search to find the exact required buffer size
for a mocked DNS response. It then tests all pointer misalignments
(1-7 bytes) using a custom 0xAA guard region. This guarantees
deterministic detection of out-of-bounds writes, avoiding false
negatives caused by malloc chunk rounding.
Justus Winter [Thu, 15 Aug 2013 08:43:35 +0000 (10:43 +0200)]
Define _PATH_MOUNTED as "/etc/mtab"
Change the definition of _PATH_MOUNTED to "/etc/mtab". This is the
value used on Linux, and BSD also uses /etc/mtab.
The change is motivated by the fact that on Debian /etc/mtab is a
symbolic link to /proc/mounts. This patch adjusts the macro for
non-linux systems such as Hurd. Changing this using
sysdeps/mach/hurd/paths.h causes build problems because
/usr/include/hurd/paths.h is shadowed by this file. This change is
proposed in the hope that aligning the non-linux targets with the
glibc for Linux is perceived as a good thing while fixing this problem
on Debian/Hurd along the way.
The parse_tilde function previously used strndupa to allocate memory
for the parsed username on the stack, and since the input is
user-defined, this can lead to a stack overflow.
This patch fixes the issue by replacing strndupa with scratch_buffer,
by reusing the buffer used in the __getpwnam_r call.
The new “tst-wordexp-tilde.c” test is a test-container to avoid using
system-defined NSS modules.
Yao Zihong [Sun, 21 Jun 2026 03:54:22 +0000 (22:54 -0500)]
riscv: Add RVV memmove for both multiarch and non-multiarch builds
This patch adds an RVV-optimized implementation of memmove for RISC-V and
enables it for both multiarch (IFUNC) and non-multiarch builds.
The implementation integrates Hau Hsu's 2023 RVV work under a unified
ifunc-based framework. A vectorized version (__memmove_vector) is added
alongside the generic fallback (__memmove_generic). The runtime resolver
selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
support (RVV).
Currently, the resolver still selects the RVV variant even when the RVV
extension is disabled via prctl(). As a consequence, any process that
has RVV disabled via prctl() will receive SIGILL when calling memmove().
Co-authored-by: Hau Hsu <hau.hsu@sifive.com> Co-authored-by: Jerry Shih <jerry.shih@sifive.com> Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
H.J. Lu [Mon, 13 Apr 2026 00:23:05 +0000 (08:23 +0800)]
elf: Support THP segment load with madvise enabled THP
The current THP segment load approach works only when THP is enabled
with always in the kernel. If THP is enabled with madvise in the
kernel, to enable THP segment load in an application, madvise should
be called with MADV_HUGEPAGE on all THP eligible PT_LOAD segments:
1. Define DL_MAP_DEFAULT_THP_PAGESIZE in hugepages.h and default it to 0.
If DL_MAP_DEFAULT_THP_PAGESIZE is defined, assume kernel THP madvise mode.
If kernel THP mode is always or never, there is an extra madvise call
which has no impact. DL_MAP_DEFAULT_THP_PAGESIZE is defined for x86-64
and 64-bit loongarch.
2. Update _dl_map_segment_align to support madvise THP mode. This fixes
BZ #34079.
3. Call _dl_executable_postprocess in rtld_setup_main_map for dynamic
executables and in LIBC_START_MAIN for static executables, which calls
madvise with MADV_HUGEPAGE on all THP eligible PT_LOAD segments in
executable. This fixes BZ #34080 for both dynamic and static executables.
4. Call _dl_postprocess_loadcmd_extra in _dl_postprocess_loadcmd, which
calls madvise with MADV_HUGEPAGE on all THP eligible PT_LOAD segments
when loading an object after they have been mapped in. This fixes
BZ #34080 for shared objects.
5. Set the maximum page alignment on THP tests to THP page size as the
default maximum page alignment may be smaller than THP page size.
6. Add tests to verify that large executable PT_LOAD segments in
executables are mapped at addresses aligned to THP page size when the
kernel is configured to use THP in "always" mode or "madvise" mode by
inspecting /proc/self/maps to check that the mapping address is aligned
to THP page size reported by the kernel. Also verify that madvise is
called with MADV_HUGEPAGE when the glibc tunable glibc.elf.thp=1 is used
and madvise isn't called with MADV_HUGEPAGE when the glibc tunable
glibc.elf.thp=0 is used.
Skip these tests if THP page size cannot be determined or if THP is not
enabled in "always" mode nor "madvise" mode.
Quote WANG Rui <wangrui@loongson.cn>:
From benchmarking a clang build of the Linux kernel on x86_64 with
your patch in THP madvise mode, I observed that iTLB misses were
reduced, similar to what we see in THP always mode.
NB: Some THP tests fail on arm due to limitations of arm32 kABI:
Remove unused THREAD_SET_POINTER_GUARD and THREAD_COPY_POINTER_GUARD
Commit a5ec880f808ee7268d985bed4f961799bdc0a4bf ("Consolidate pointer
guard to use a relro variable instead of the TCB") moved the pointer
guard to the module-local relro variable __pointer_chk_guard_local and
dropped the THREAD_{SET,COPY}_POINTER_GUARD macros, which are no longer
defined by any target.
Florian Weimer [Fri, 19 Jun 2026 16:22:20 +0000 (18:22 +0200)]
resolv: Fix buffer overreads in ns_sprintrrf (CVE-2026-6238)
Check that the RDATA payload does not require more than RDATALEN
bytes while processing it. The fixes cover A6, LOC records.
(CERT, TKEY, TSIG were fixed before, by switching to the generic
formatter.)
A6 record handling was introduced in commit 91633816430e7ec5a19fe3ff510a7c4822a9557e ("* resolv/ns_print.c
(ns_sprintrrf): Handle ns_t_a6 and ns_t_opt."), which went into glibc
2.7.
This fixes bug 34069.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Florian Weimer [Fri, 19 Jun 2026 16:22:20 +0000 (18:22 +0200)]
resolv: Fix ns_sprintrrf formatting of class, type values (bug 34289)
The p_class and p_type results could overwrite each other if both
were unknown. Format unknown values with CLASS and TYPE prefixes,
as in RFC 3597. Handle A6 separately because it cannot be added
to __p_type_syms for ABI reasons.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Florian Weimer [Fri, 19 Jun 2026 16:22:20 +0000 (18:22 +0200)]
Update GLIBC-SA-2026-0012 to mention A6 records
It turns out there is a missing inner length check in it, too.
Also fix the vulnerable commit. It predates the glibc 2.0 release
because the old stream-based formatting code in resolv/res_debug.c had
the same bug in its LOC handling.
Reviewed-by: Carlos O'Donell <carlos@redhat.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
elf: Do not scrub AT_RANDOM to a constant when reseeding fails (BZ 34197)
_dl_reseed_random zeroed the AT_RANDOM bytes before refilling them with
getrandom (GRND_NONBLOCK). That call is best-effort and can write nothing
(e.g. before the kernel entropy pool is initialized early at boot), leaving
the 16 bytes as a constant zero.
Since the value is exposed through getauxval (AT_RANDOM), this traded a
potential guard leak for a guaranteed predictable value.
Drop the memset and overwrite the bytes in place instead. The generic
version now just drops the pointer (it is not used anywhere).
elf: Scrub and reseed the AT_RANDOM bytes after deriving the guards (BZ 34197)
Once the pointer and stack guards have been derived from AT_RANDOM, scrub
the bytes and refill them with new random data unrelated to the guards.
On Linux, it uses getrandom syscall (as for tcache_key_initialize), and
fallback to zero the memory if the syscall is not avaiable.
This keeps AT_RANDOM useful to applications while ensuring those bytes no
longer reveal the guards.
The work is done by _dl_reseed_random, called once the guards are in place
and before any ELF constructor can observe AT_RANDOM: in security_init for
the dynamic loader and in __libc_start_main for statically linked programs.
Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu.
Consolidate dl-osinfo.h into the generic implementation
The generic and the Linux _dl_setup_stack_chk_guard and
_dl_setup_pointer_guard are identical when the kernel provides the
AT_RANDOM auxiliary vector, which is always the case on the supported
Linux kernels; the generic version only adds a fallback for a missing
AT_RANDOM. Remove the Linux-specific dl-osinfo.h and use the generic
one for all targets.
The removed header pulled in <dl-sysdep.h>, which is what transitively
declared __libc_enable_secure for dl-parse_auxv.h; include <unistd.h>
there directly so it no longer relies on that. Include <string.h> in
the generic header so it is self-contained.
Consolidate the C pointer guard and align the assembly implementations
The per-architecture pointer_guard.h files all implemented some variant
of C PTR_MANGLE/PTR_DEMANGLE: the i386 and x86_64 versions did an
exclusive-or by the guard followed by a rotate left by
2 * sizeof (uintptr_t) + 1 bits (9 on 32-bit, 17 on 64-bit), while the
other targets did the exclusive-or only. The assembly macros likewise
rotated on i386 and x86_64 but not on the other targets.
Consolidate everything to use XOR + rotate uniformly: collapse the
per-architecture C headers into a single generic implementation, and
add the matching rotate to the assembly implementations that lacked it.
Targets with an assembly rotate instruction (aarch64, arm, loongarch,
powerpc, s390, csky) just add it. Those without one (alpha, sparc, sh)
synthesize the rotation: alpha and sparc with a shift/shift/or sequence,
which needs an extra scratch register added to the PTR_MANGLE/PTR_DEMANGLE
macros, sh with single-bit rotates, which needs no scratch. The s390
__longjmp and ____longjmp_chk demangle the return address and stack
pointer in C, so update those too.
Checked with setjmp, ptrguard and longjmp_chk tests for all supported
ABIs that can run under qemu (all but csky), and with builds for all
supported ABIs.
Remove the jmp_buf stack pointer demangle on ABIs that do not mangle it
arc, m68k, microblaze, mips, and riscv store the raw stack pointer in
setjmp, while their jmpbuf-unwind.h applies PTR_DEMANGLE to it in
_jmpbuf_sp. This is currently harmless because these ABIs use the
generic pointer_guard.h, where the C PTR_DEMANGLE is a no-op.
Move the assembly PTR_MANGLE/PTR_DEMANGLE definitions out of each
pointer_guard.h into a new sibling pointer_guard-asm.h, guarded by
__ASSEMBLER__. pointer_guard.h now includes pointer_guard-asm.h and
keeps only the C definitions.
No functional change: the .S and .c files still include pointer_guard.h
and get the same macros, and <pointer_guard-asm.h> resolves per-arch
through the usual sysdeps include path.
i386, powerpc, s390, sh and sparc fell back to the generic no-op
pointer_guard.h in ld.so, so the loader's own setjmp/longjmp and mangled
function pointers were left unprotected (the other targets already
mangle in rtld). ld.so is position-independent and sets up
__pointer_chk_guard_local early in dl_main, so the loader can reach it
the same way a statically linked program does:
- powerpc, s390, sh, sparc: select __pointer_chk_guard_local for
IS_IN (rtld) and reuse the existing PIC guard load.
- i386: load it via @GOTOFF off a GOT pointer set up with LOAD_PIC_REG
in the caller-provided scratch register
(ld.so does not keep the GOT in %ebx at the setjmp/longjmp entry).
- s390: drop the IS_IN (rtld) "#undef PTR_DEMANGLE" in __longjmp.c so
the loader's longjmp demangles to match its setjmp.
Checked on x86_64-linux-gnu, aarch64-linux-gnu, i686-linux-gnu, and
armv7a-linux-gnueabihf. I also run elf and setjmp checks on qemu
loongarch64, powerpc64, powerpc64le, and s390x systems.
Consolidate pointer guard to use a relro variable instead of the TCB
For the targets that still read the pointer guard from the thread
descriptor (i386, x86_64, powerpc, s390, sparc, and sh), mangle and
demangle pointers using the module-local __pointer_chk_guard_local (in
ld.so and static binaries) or the global __pointer_chk_guard provided by
the dynamic loader (in shared objects), matching the scheme already used
by aarch64, alpha, arm, csky and loongarch.
On i386 the guard is no longer reachable as a single %gs-relative memory
operand, so the assembly PTR_MANGLE/PTR_DEMANGLE PIC variants need a
register to hold the GOT pointer and the guard address.
This removes the dependency on the TCB pointer_guard slot: drop
THREAD_{GET,SET,COPY}_POINTER_GUARD and the POINTER_GUARD tcb-offset,
and point the POINTER_CHK_GUARD test macro at the relro variable. The
tcbhead_t slot is kept (renamed to an unused reserved field, except on
s390 which reused the stack guard) to preserve the ABI. s390 gains a
distinct pointer guard rather than aliasing the stack guard.
Checked on x86_64-linux-gnu, aarch64-linux-gnu, i686-linux-gnu, and
armv7a-linux-gnueabihf. I also run elf and setjmp checks on qemu
loongarch64, powerpc64, powerpc64le, and s390x systems.
elf: Propagate the pointer guard to ld.so loaded via static dlopen (BZ 34196)
The static-dlopen does not initialize the pointer guard for ABIs that
define THREAD_SET_POINTER_GUARD. Besides not properly guard the
pointer if a libc.so symbol is called, this can lead to setjmp
failures (a jmp_buf set up by the loaded libc.so.6 cannot be restored
by the static program's __longjmp, and vice versa).
Seed the just-mapped loader's __pointer_chk_guard from the program's
__pointer_chk_guard_local in __rtld_static_init, next to the other
runtime values copied there.
Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu.
It syncs with CORE-MATH commit 887cab6f. The new tests are from
the CORE-MATH acosh worst-cases inputs that trigger the FE_TOWARDZERO
issue with the previous implementation, along with the hard-to-round
cases from CORE-MATH commits 72febed6 and ce9e99f6.
Checked on x86_64-linux-gnu, x86_64-linux-gnu with --disable-multi-arch
(so soft FMA implementation is used), i686-linux-gnu (which uses its
own acosh implementation), aarch64-linux-gnu, and
armv7a-linux-gnueabihf.
Reviewed-by: Paul Zimmermann <Paul.Zimmermann@inria.fr>
Michael Ford [Wed, 10 Jun 2026 15:24:50 +0000 (17:24 +0200)]
inet: Remove unused STATIC_NSS define
The --enable-static-nss configuration adds -DSTATIC_NSS to CFLAGS for
the inet subdirectory, but no source file has referenced the STATIC_NSS
macro for quite some time. So remove the dead define.
Signed-off-by: Michael Ford <fanquake@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Michael Ford [Thu, 11 Jun 2026 13:58:04 +0000 (15:58 +0200)]
nss: Remove <gnu/lib-names.h> include from nsswitch.c
nsswitch.c no longer references any of the *_SO macros provided by
<gnu/lib-names.h>. The only consumer, __nss_shlib_revision, moved to
nss_module.c as part of the NSS reorganization in glibc 2.33 (and
nss_module.c includes the header unconditionally), but the guarded
include was left behind.
Signed-off-by: Michael Ford <fanquake@gmail.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
_dl_runtime_resolve and _dl_runtime_profile only preserved the integer
argument registers (r0-r3) across the inner call to _dl_fixup /
_dl_profile_fixup. Two related ABI requirements demand more:
* Under AAPCS-VFP, d0-d7 hold the caller's double arguments to the
function being resolved. Recent GCC emits VFP instructions inside
the fixup routines, clobbering them, so the resolved function sees
corrupted arguments (BZ 34144).
* Per RTABI32, the __aeabi_mem* helpers (and similar runtime helpers
reachable through the dynamic linker) must only corrupt integer
core registers. IFUNC resolvers, audit modules, and interposed
malloc invoked during symbol resolution may also use VFP, even on
softfp ABI builds (BZ 15792).
Save all call-clobbered VFP state -- d0-d15 unconditionally, d16-d31
when HWCAP_ARM_VFPD32 is set, and fpscr -- around the inner fixup
call. Whether VFP is usable is a property of the hardware, not of
the ABI glibc was built with, so the decision is gated on AT_HWCAP at
runtime in both hardfp and softfp builds; hardfp builds will always
find HWCAP_ARM_VFP set, while softfp builds running on a non-VFP CPU
correctly skip the save.
For _dl_runtime_profile the save area is slipped in just before the
bl to _dl_profile_fixup; the outgoing framesizep argument is
recomputed to account for the extra frame, and both the fast path
(no audit framesize) and the slow path (audit wraps with
pltenter/pltexit) traverse the restore before splitting.
aarch64: Fix static PIE CPU feature detection (BZ 34205)
ARCH_INIT_CPU_FEATURES is called from __libc_start_main before
_dl_relocate_static_pie, so any code it runs must not rely on
relocations being applied yet. Two issues break this under static PIE:
1. The cpu_list table held 'const char *name' members, whose
addresses are not link-time constants under PIE and thus require
base-relative relocations that are not yet in place. Replace the
array of structs with a flat NUL-separated name string and a
parallel midr array, removing the pointer relocations.
2. tunable_strcmp pulls in memcmp, which is an IFUNC and is likewise
unresolved at this point. Redirect memcmp to __memcmp_generic in
the aarch64 dl-symbol-redir-ifunc.h and include it from
csu/libc-start.c.
Sana Kazi [Mon, 15 Jun 2026 14:37:59 +0000 (16:37 +0200)]
nptl: open threads comm with O_WRONLY|O_CLOEXEC
pthread_setname_np opens the thread's comm file using O_RDWR, but the
function only ever writes to it. This causes two distinct problems:
1. Missing O_CLOEXEC: the file descriptor is not marked close-on-exec,
so it remains open across fork+exec. A child process that audits
its inherited file-descriptor set will encounter an unexpected /proc
fd it did not open and may treat this as a security violation and
abort.
2. Unnecessary O_RDWR: requesting read+write access when only write
access is needed can cause open() to fail under security policies
that permit writing to /proc/<tid>/comm but deny reading it.
Fix both issues by replacing O_RDWR with O_WRONLY|O_CLOEXEC
Similarly, updated pthread_getname_np to use O_CLOEXEC.
Yury Khrustalev [Tue, 26 May 2026 10:19:53 +0000 (11:19 +0100)]
malloc: aarch64: Add ifuncs for malloc functions
Introduce ifuncs and resolvers for functions pertinent to the
malloc interface on the AArch64 target: malloc, calloc, free,
realloc, memalign, valloc, pvalloc, posix_memalign, aligned_alloc,
free_sized, free_aligned_sized, malloc_usable_size.
A target can define the USE_MULTIARCH_MALLOC macro. In this case
it must provide alternative aliases for the malloc functions that
point to the ifuncs.
This implementation respects the --disable-multi-arch configure
flag. If multi-arch support is disabled, the generic aliases
are used on aarch64.
This patch contains aarch64-specific resolvers. At this moment they
return core implementations but in the future they can be changed
to support for features, e.g. to handle memory tagging.
Fabian Rast [Thu, 11 Jun 2026 12:30:37 +0000 (14:30 +0200)]
rtld: cache cpuid results on the stack for intel
dl_init_cacheinfo retrieves various information about cache
sizes, using the cpuid instruction on x86.
Previously, the same cpuid leaves were queried multiple times.
This behavior caused intel_check_word to prominently show up in
profiles of dynamic loader startup on the Intel(R) Xeon(R) Gold 6430.
The big performance impact could not be reproduced on other Intel cpus.
This patch reduces the number of cpuid queries on startup
by caching their results on the stack for reuse when searching for a
different cache size value.
This approach does not change the overall design of
the cache enumeration code (repeated calls to handle_* functions).
The values are cached on the stack instead of globally (e.g.
in the cpu_features global) because they are never needed after
early initialization.
The cache is only active for Intel cpus, because it has not yet
been shown through benchmarks that it meaningfully improves performance
for other processors.
Signed-off-by: Fabian Rast <fabian.rast@tum.de> Reviewed-by: Sunil K Pandey <skpgkp2@gmail.com>
Joseph Myers [Wed, 10 Jun 2026 18:49:53 +0000 (18:49 +0000)]
Fix -Wconstant-logical-operand error for Hurd
Building for Hurd with GCC mainline produces an error in pt-block.c
(here MSG_OPTIONS is a macro that may be defined before pt-block.c is
included by another source file):
In file included from ../sysdeps/mach/htl/pt-block-intr.c:6:
../sysdeps/mach/htl/pt-block.c: In function '__pthread_block_intr':
../sysdeps/mach/htl/pt-block.c:49:42: error: use of logical '&&' with constant operand '1024' [-Werror=constant-logical-operand]
49 | if ((MSG_OPTIONS & MACH_RCV_INTERRUPT) && err == MACH_RCV_INTERRUPTED)
| ^~
../sysdeps/mach/htl/pt-block.c:49:42: note: use '&' for bitwise operation
49 | if ((MSG_OPTIONS & MACH_RCV_INTERRUPT) && err == MACH_RCV_INTERRUPTED)
| ^~
| &
Fix this, and a similar error in pt-timedblock.c, with an explicit != 0.
Tested with build-many-glibcs.py (compilers and glibcs builds) for
i686-gnu and x86_64-gnu.
Joseph Myers [Wed, 10 Jun 2026 16:33:27 +0000 (16:33 +0000)]
Fix -Werror=constant-logical-operand errors in soft-fp
Building for sparc64-linux-gnu with GCC mainline produces a series of
-Werror=constant-logical-operand errors in soft-fp code, relating to
calls to _FP_TO_INT where rsigned is -1 not 0 or 1. Use explicit != 0
in the soft-fp code to avoid these errors.
Tested with build-many-glibcs.py (compilers and glibcs builds) for
sparc64-linux-gnu with GCC mainline.
Joseph Myers [Wed, 10 Jun 2026 14:01:34 +0000 (14:01 +0000)]
Fix -Wconstant-logical-operand error in tst-printf-format-skeleton.c
Building the glibc testsuite with GCC mainline fails with:
In file included from tst-printf-format-skeleton-double.c:33,
from tst-printf-format-p-double.c:20:
tst-printf-format-skeleton.c: In function 'do_test':
tst-printf-format-skeleton.c:308:12: error: use of logical '&&' with constant operand '53' [-Werror=constant-logical-operand]
308 | if (PREC && printf ("prec:%i\n", PREC) < 0)
| ^~
tst-printf-format-skeleton.c:308:12: note: use '&' for bitwise operation
308 | if (PREC && printf ("prec:%i\n", PREC) < 0)
| ^~
| &
cc1: all warnings being treated as errors
Fix this using an explicit "!= 0". Tested with build-many-glibcs.py
for aarch64-linux-gnu.
Zihong Yao [Tue, 9 Jun 2026 03:27:54 +0000 (03:27 +0000)]
riscv: Keep __memcmpeq alias with RVV memcmp
Commit 2efc702628 replaces the generic RISC-V memcmp, which also exports
__memcmpeq.
A dedicated RISC-V __memcmpeq implementation is expected in a later patch,
which is still under review. Keep the alias here so this patch does not
temporarily drop the existing __memcmpeq ABI.
Tested on a Muse-Pi board with GCC 15.2.0 using `--with-arch=rv64g_zca_zcd --with-abi=lp64d`
and `CFLAGS="-march=rv64g_zca_zcd -mabi=lp64d -O2"`. Full make check was
run for both multiarch and non-multiarch builds.
This also fixes the string/inl-tester link failure caused by the missing
__memcmpeq symbol.
In both runs, the only FAILs are the unchanged cospi/sinpi/tanpi math test
failures.
Signed-off-by: Zihong Yao <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Florian Weimer [Tue, 9 Jun 2026 05:28:02 +0000 (07:28 +0200)]
iconv: Suppress intermediate errors with //TRANSLIT (bug 34236)
When tentatively converting characters on behalf of
__gconv_transliterate, do not create a persistent error. Just
produce a local error, and rely on __gconv_transliterate to
produce the error if all transliteration options are exhausted.
This fixes transliteration of “½” to ASCII, which cannot use the
“ 1⁄2 ” alternative. Eventually, the “ 1/2 ” alternative is chosen,
but the error sticks. Therefore, iconv exited with status 1 before
this change.
Adjust iconv/tst-iconv_prog.sh to test both C and en_US.UTF-8 locales.
This requires changing the way the ICONV template is defined, so that
run_program_env is evaluated multiple times.
Josef Johansson [Mon, 8 Jun 2026 15:32:27 +0000 (17:32 +0200)]
nscd: Typo in comment
Fixes: https://sourceware.org/bugzilla/show_bug.cgi?id=34240 Signed-off-by: Josef Johansson <josef@oderland.se> Reviewed-by: Florian Weimer <fweimer@redhat.com>
Bug: https://bugs.gentoo.org/976773
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=31901
Bug: https://sourceware.org/bugzilla/show_bug.cgi?id=34210 Tested-by: Andreas K. Hüttel <dilfridge@gentoo.org> Reported-by: Eli Schwartz <eschwartz@gentoo.org> Reviewed-by: Andreas K. Hüttel <dilfridge@gentoo.org>
elf: Set up TLS slotinfo for dlopen'd modules before relocation (BZ 34170)
An IFUNC resolver in a DSO that is being loaded by dlopen is allowed
to read its own TLS storage during the resolver call. After af34b1376a3 ("elf: Initialize static TLS before relocation processing
(BZ 34164)") that works for the initial-exec model on every supported
architecture.
However, it does not work for the dynamic-TLS path (on both -mtls-dialect mode,
if the ABI supports both). Both lookup paths index the calling thread's
DTV by the new module's l_tls_modid and, on miss, walk
GL(dl_tls_dtv_slotinfo_list) to discover the module and lazily allocate
its TLS block. The just-loaded DSO is however not yet in that list when
its resolver fires, so the lookup faults inside dlopen. This is the
direct dlopen analog of BZ 34164.
The solution is to reorder dl_open_worker_begin so the slotinfo install
happens before the relocation pass. The new order is:
1. resize_scopes, resize_tls_slotinfo, add_to_global_resize
(unchanged, still recoverable).
2. update_tls_slotinfo: register the new modules in slotinfo, bump
dl_tls_generation, initialise their static TLS images.
3. Relocate the new objects. IFUNC resolvers can now read their
own DSO's __thread storage via any TLS model.
4. Demarcation point.
5. update_scopes, _dl_find_object_update.
Checked on aarch64-linux-gnu and x86_64-linux-gnu.
Simplify _int_free_chunk() and always lock if needed. Use
_int_free_merge_chunk() for cases that assume the arena has been locked
instead. Move the errno save/restore to _int_free_maybe_trim().
Yao Zihong [Fri, 5 Jun 2026 00:39:31 +0000 (19:39 -0500)]
riscv: Add RVV strrchr for both multiarch and non-multiarch builds
This patch adds an RVV-optimized implementation of strrchr for RISC-V and
enables it for both multiarch (IFUNC) and non-multiarch builds.
The implementation integrates Hau Hsu's 2023 RVV work under a unified
ifunc-based framework. A vectorized version (__strrchr_vector) is added
alongside the generic fallback (__strrchr_generic). The runtime resolver
selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
support (RVV).
Currently, the resolver still selects the RVV variant even when the RVV
extension is disabled via prctl(). As a consequence, any process that
has RVV disabled via prctl() will receive SIGILL when calling strrchr().
Co-authored-by: Hau Hsu <hau.hsu@sifive.com> Co-authored-by: Jerry Shih <jerry.shih@sifive.com> Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
Yao Zihong [Fri, 5 Jun 2026 00:37:35 +0000 (19:37 -0500)]
riscv: Add RVV strchr for both multiarch and non-multiarch builds
This patch adds an RVV-optimized implementation of strchr for RISC-V and
enables it for both multiarch (IFUNC) and non-multiarch builds.
The implementation integrates Hau Hsu's 2023 RVV work under a unified
ifunc-based framework. A vectorized version (__strchr_vector) is added
alongside the generic fallback (__strchr_generic). The runtime resolver
selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
support (RVV).
Currently, the resolver still selects the RVV variant even when the RVV
extension is disabled via prctl(). As a consequence, any process that
has RVV disabled via prctl() will receive SIGILL when calling strchr().
Co-authored-by: Hau Hsu <hau.hsu@sifive.com> Co-authored-by: Jerry Shih <jerry.shih@sifive.com> Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
Yao Zihong [Fri, 5 Jun 2026 00:34:33 +0000 (19:34 -0500)]
riscv: Add RVV memchr for both multiarch and non-multiarch builds
This patch adds an RVV-optimized implementation of memchr for RISC-V and
enables it for both multiarch (IFUNC) and non-multiarch builds.
The implementation integrates Hau Hsu's 2023 RVV work under a unified
ifunc-based framework. A vectorized version (__memchr_vector) is added
alongside the generic fallback (__memchr_generic). The runtime resolver
selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
support (RVV).
Currently, the resolver still selects the RVV variant even when the RVV
extension is disabled via prctl(). As a consequence, any process that
has RVV disabled via prctl() will receive SIGILL when calling memchr().
Co-authored-by: Hau Hsu <hau.hsu@sifive.com> Co-authored-by: Jerry Shih <jerry.shih@sifive.com> Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
Yao Zihong [Fri, 5 Jun 2026 00:25:00 +0000 (19:25 -0500)]
riscv: Add RVV memccpy for both multiarch and non-multiarch builds
This patch adds an RVV-optimized implementation of memccpy for RISC-V and
enables it for both multiarch (IFUNC) and non-multiarch builds.
The implementation integrates Hau Hsu's 2023 RVV work under a unified
ifunc-based framework. A vectorized version (__memccpy_vector) is added
alongside the generic fallback (__memccpy_generic). The runtime resolver
selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
support (RVV).
Currently, the resolver still selects the RVV variant even when the RVV
extension is disabled via prctl(). As a consequence, any process that
has RVV disabled via prctl() will receive SIGILL when calling memccpy().
Co-authored-by: Hau Hsu <hau.hsu@sifive.com> Co-authored-by: Jerry Shih <jerry.shih@sifive.com> Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
Yao Zihong [Thu, 4 Jun 2026 23:28:06 +0000 (18:28 -0500)]
riscv: Add RVV memcmp for both multiarch and non-multiarch builds
This patch adds an RVV-optimized implementation of memcmp for RISC-V and
enables it for both multiarch (IFUNC) and non-multiarch builds.
The implementation integrates Hau Hsu's 2023 RVV work under a unified
ifunc-based framework. A vectorized version (__memcmp_vector) is added
alongside the generic fallback (__memcmp_generic). The runtime resolver
selects the RVV variant when RISCV_HWPROBE_KEY_IMA_EXT_0 reports vector
support (RVV).
Currently, the resolver still selects the RVV variant even when the RVV
extension is disabled via prctl(). As a consequence, any process that
has RVV disabled via prctl() will receive SIGILL when calling memcmp().
Co-authored-by: Hau Hsu <hau.hsu@sifive.com> Co-authored-by: Jerry Shih <jerry.shih@sifive.com> Signed-off-by: Yao Zihong <zihong.plct@isrc.iscas.ac.cn> Reviewed-by: Peter Bergner <bergner@tenstorrent.com>
The default maximum arenas is 8 times the number of cores in a 64-bit system.
Since modern CPUs have many cores and big servers have 256 cores, this results
in excessive number of arenas, which wastes memory. Limit the number of arenas
to max (8, ncores) which is less extreme. In the future the limit should be
lowered further for large systems.
Adam Yi [Mon, 18 May 2026 03:21:47 +0000 (11:21 +0800)]
resolv: reset _u._ext.nscount in __res_iclose [BZ #34154]
__res_iclose, when called with FREE_ADDR=true, frees and NULLs every
statp->_u._ext.nsaddrs[ns] but does not reset statp->_u._ext.nscount.
This breaks the invariant relied on by __res_context_send's cache
validation loop in resolv/res_send.c:293-312: when _u._ext.nscount
is non-zero, every _u._ext.nsaddrs[ns] corresponding to
statp->nsaddr_list[ns].sin_family != 0 is expected to be non-NULL.
res_init unconditionally calls __res_iclose(&_res, true) before
__res_vinit, so any __res_vinit failure (for example,
fopen("/etc/resolv.conf") returning EMFILE under file-descriptor
exhaustion, or any allocation failure in __resolv_conf_load,
__resolv_conf_allocate, or __resolv_conf_attach before
update_from_conf runs) leaves _u._ext.nscount non-zero with all
_u._ext.nsaddrs[] NULL. The next name lookup walks the validation
loop and dereferences NULL in sock_eq. A DNS lookup may fail after
a failed res_init, but it should not segfault.
Reset _u._ext.nscount = 0 alongside the existing __resolv_conf_detach
call. The next __res_context_send call then re-enters its init
block (res_send.c:316-335) and repopulates _u._ext.nsaddrs[] from
statp->nsaddr_list[], which __res_iclose leaves untouched. This
also lets support/resolv_test.c drop its now-redundant manual reset
after __res_iclose(&_res, true).
Add a regression test that drops RLIMIT_NOFILE so fopen of
/etc/resolv.conf fails with EMFILE inside __res_vinit, then verifies
the subsequent gethostbyname does not crash.
Signed-off-by: Adam Yi <ayi@janestreet.com> Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Wilco Dijkstra [Tue, 10 Mar 2026 15:47:26 +0000 (15:47 +0000)]
malloc: Improve documentation of malloc tunables
Update default for tcache_count tunable. Remove existing documentation and
mention removal of fastbins in mxfast tunable. Improve wording of hugetlb
tunable, including default for AArch64.
Wilco Dijkstra [Tue, 2 Jun 2026 14:07:05 +0000 (14:07 +0000)]
malloc: Minor cleanups
Merge request2size into checked_request2size. Improve interface of
clear_memory. Fix incorrect use of __glibc_unlikely in __libc_calloc.
Fix missing tabs.
arm: Fix main-in-dso with non-BFD linkers (BZ 34098)
Commit c2d6afb4a010 changed the PIC && !SHARED path of start.S (used by
crt1.o and rcrt1.o) to load main via a R_ARM_REL32 data relocation. When
main is provided by a shared object, BFD ld synthesizes a canonical PLT
entry for it, but other linkers (e.g. mold) do not, producing a broken
binary that crashes at startup.
Follow the aarch64 approach and reference main through a local __wrap_main
that tail-calls it with a branch relocation, which every linker turns into
a PLT entry.
Checked on armv7a-linux-gnueabihf with and without --enable-default-pie.
elf: Fix tst-ifunc-tls-init with --disable-default-pie
The test failed with --disable-default-pie because its primary check read
the resolver's diagnostic side effect before the resolver had run.
In a non-PIE executable the references to the IFUNC (fptr and ifunc_tls)
are satisfied through a canonical IPLT entry in the executable itself.
Under the default lazy binding that IPLT is resolved on first use, not
during startup relocation, so the resolver had not yet run when
'check_sentinel' inspected that value. With a PIE executable
(or LD_BIND_NOW=1) the resolver runs eagerly at startup and the check
passed. The dlopen path was unaffected because dlopen resolves the
data relocation eagerly.
This is a test ordering issue: the resolver always reads the initial-exec
TLS correctly whenever it runs, so the BZ 34164 fix is not involved.
Reorder test_tls_ifunc so that fptr/ifunc_tls force the IFUNC to be
resolved before the last_seen_sentinel value is inspected.
Checked on x86_64-linux-gnu and i686-linux-gnu with --disable-default-pie.
Sachin Monga [Tue, 2 Jun 2026 05:44:41 +0000 (00:44 -0500)]
powerpc64le: Add optimized __memcmpeq for POWER10
__memcmpeq (added in glibc 2.35) was previously an alias to memcmp on
POWER10 via strong_alias. However, in the multiarch IFUNC path, this
caused __memcmpeq to resolve to the generic C memcmp.c implementation
rather than the optimized POWER10 memcmp.S, leaving a significant
performance gap.
Unlike memcmp, __memcmpeq only needs to return zero or nonzero with
no requirement on the sign or magnitude for unequal inputs, allowing
a simpler and faster implementation.
Performance on POWER10 :
1) __memcmpeq (generic) -> __memcmpeq_power10
The primary motivation - __memcmpeq was resolving to generic C
in the multiarch path.
- Small data (< 8B to < 512B) : ~52% - 82% improvement.
- Bulk (< 16MB to < 256MB) : ~25% - 32% improvement.
- Large (1GB) : ~33% improvement
2) memcmp_power10 (optimized .S) -> __memcmpeq_power10:
Comparing dedicated __memcmpeq against the optimized memcmp
it previously aliased to.
- Small data (< 8B to < 256B) : No improvement observed.
Real-world workloads predominantly operate on larger buffers
- >= 512B : ~9% improvement.
- 16MB - 128MB : ~25% - 32% improvement.
- 256MB : ~3% improvement.
- Large (1GB) : On par.
arm: Redirect memcpy to __memcpy_arm for loader/static init code
After "elf: Initialize TCB and stack-protector before static IFUNC
resolvers (BZ 20680, BZ 27582, BZ 28817)", early loader and static
initialization code may run before the IFUNC resolvers are processed.
The armv7-a supports memcpy, so add a dl-symbol-redir-ifunc.h to
redirect the memcpy to to __memcpy_arm implementation.
Yury Khrustalev [Thu, 21 May 2026 10:51:57 +0000 (11:51 +0100)]
malloc: aarch64: Remove broken memory tagging
Remove the --enable-memory-tagging configure option along with
all associated variables and macros.
Removing the glibc.mem.tagging tunable.
Remove the memory-tagging makefile variable.
Remove the USE_MTAG macro definition and code that is conditionally
compiled when this macro is defined.
As a result, we change 'mtag_mmap_flags' to 'extra_mmap_prot' that
is now always defined. Change of the name due to this being used
as part of PROT options in mmap syscalls rather than part of flags.
Remove 'mtag_enabled' that would become compile-time false. Also
remove any code that would never be compiled when 'mtag_enabled'
is false.
Remove AArch64-specific code pertinent to memory tagging, that is
currently broken, from the core malloc implementation. We keep
the assembly code, since we are going to need it in the future. to
preserve Git history.
math: Fix non-narrowing test build with arg-format conditions
auto-libm-test-in shares inputs between narrowing and non-narrowing
functions, and some carry arg-format conditions (e.g. "arg-ibm128").
When auto-libm-test-out-fma is regenerated, gen-libm-test.py turns these
into TEST_COND_arg_ibm128, which expands via ARG_MANT_DIG to ARG_PREFIX.
ARG_PREFIX is only defined for TEST_NARROW, so the non-narrowing fma test
failed to build with "ARG_PREFIX_MANT_DIG undeclared".
Define TEST_COND_arg_ibm128 to 0 when ARG_FLOAT is not defined, mirroring
the existing guard for TEST_COND_ibm128_libgcc; in the non-narrowing case
there is no separate argument format, so the condition is always false.
Muhammad Kamran [Thu, 28 May 2026 09:29:33 +0000 (09:29 +0000)]
aarch64: Use build attributes for asm feature marking
When the compiler defines __ARM_BUILDATTR64_FV, emit AArch64
feature-and-bits build attributes for BTI, PAC, and GCS from sysdep.h
instead of a GNU property note. Keep the GNU property note as the
fallback for older toolchains.
Mirror the same marking logic in elf/tst-asm-helper.h so custom test
DSOs and assembly tests that cannot include sysdep.h get consistent
feature marking.
Martin Coufal [Tue, 26 May 2026 11:15:27 +0000 (13:15 +0200)]
misc: add a new test for gethostname
Add a simple test that runs in a UTS namespace: checks gethostname
after various sethostname values (including empty and HOST_NAME_MAX),
verifies ENAMETOOLONG when the buffer is too small for a maximal name,
EINVAL when sethostname is given a name longer than HOST_NAME_MAX.
Frédéric Bérat [Tue, 26 May 2026 11:29:57 +0000 (13:29 +0200)]
test: Fix and stabilize tst-wcsmbs-clone-overflow test
The test tst-wcsmbs-clone-overflow was initially added to tests-static.
However, this causes the test to be unstable because gconv modules
dynamically load libc.so. Any discrepancy between the statically linked
version and the dynamically loaded one can lead to a crash.
By removing the test from tests-static, it relies on dynamic linking,
safely bypassing the dlopen crash. Since the test is now dynamically
linked, it cannot use the internal thread-local symbol
_NL_CURRENT_DATA(LC_CTYPE) because _nl_current_LC_CTYPE is hidden in
libc.so, leading to undefined references. Thus, the test now uses
newlocale and uselocale, safely extracting the locale data from the
returned locale_t object.
Furthermore, using newlocale requires the gconv-modules configuration to
be built and available so that the ISO8859-1.so module can be
dynamically loaded. Otherwise, glibc falls back to the built-in C locale
conversions, leaving __shlib_handle as NULL and silently bypassing the
reference counter increment.
A new Makefile fragment, gen-gconv-modules.mk, is introduced to ensure
the gconv-modules are built before the test runs, and an explicit check
for __shlib_handle != NULL is added to the test.
math: Fix fma alignment when exponent difference is exactly 64 (BZ 34183)
When d (the exponent difference between z and x*y) is exactly 64,
the alignment path shifts z left by 64 bits via (zhi = nz.m, zlo = 0)
and decrements d to 0, then takes the inner 'if (d < 64)' branch
which evaluates 'rhi << (64 - d)' with d == 0. A shift by 64 of a
64-bit value is UB in C.
Add the explicit 'if (d == 0)' empty branch (present in the
original musl implementation).
Checked on x86_64-linux-gnu with --disable-multi-arch and
arm-linux-gnueabihf.
support: Skip malloc hugetlb={1,2} variants when kernel cannot honor them
The malloc test variants run with GLIBC_TUNABLES=glibc.malloc.hugetlb=1
exercise transparent huge pages via MADV_HUGEPAGE, which is only
meaningful when /sys/kernel/mm/transparent_hugepage/enabled is set to
'madvise' ('always' makes the madvise redundant and 'never' makes it
ineffective). The hugetlb=2 variants rely on MAP_HUGETLB, which
requires a positive /proc/sys/vm/nr_hugepages. On systems that do not
satisfy these prerequisites - including any non-Linux target - those
runs only consume CPU time in this case.
Add support/support_check_hugetlb.{c,h} exposing:
- support_thp_is_madvise: true iff THP is in 'madvise' mode;
- support_hugepages_reserved: true iff nr_hugepages > 0;
- support_check_malloc_hugetlb: inspects GLIBC_TUNABLES and calls
FAIL_UNSUPPORTED when the requested hugetlb mode cannot be honored.
Gate the check at compile time so only the variant binaries pay for
it.
relocation loop (applies relocations to .tdata in DSO memory)
_dl_allocate_tls_init copies relocated .tdata -> main thread TLS
to a new order:
_dl_allocate_tls_init copies unrelocated .tdata -> main thread TLS
relocation loop (relocates .tdata in DSO memory, but the TLS block
has stale copies)
This broke file-scope thread-local initialised with the address of a
function (for instance the cache structs in libmpfr).
Fix it by splitting ELF_DYNAMIC_RELOCATE inside
_dl_relocate_object_no_relro into the non-IRELATIVE and IRELATIVE
sub-passes (similar as done on static-pie startup by b75ad99d45b)
and call _dl_init_static_tls between them. By the time the IFUNC
pass fires, .tdata is fully relocated.
Checked on x86_64-linux-gnu and aarch64-linux-gnu.
projects / thirdparty / glibc.git / log
