This is needed for the next patch which updates copyright dates.
* elf/sprof.c:
* sysdeps/unix/sysv/linux/tst-pidfd_getinfo.c:
Remove trailing white space.
* misc/tst-atomic.c: Remove trailing empty line.
The intention of the call "xmalloc(256 * 1024)" in tst-decorate-maps is
to force malloc() to fall back to using mmap() since such an amount
won't be available from the main heap.
Post 321e1fc73f, on aarch64, the heap gets extended by default by at
least 2MB, thus the aforementioned call may get satisfied on the main
heap itself. Thus, increase the amount of memory requested to force the
mmap() path again.
Checked on aarch64-linux-gnu.
The setup_vdso assumes that vDSO will contain only one PT_LOAD segment
and that 0 is the sentinel for the start mapping address. Although
the kernel avoids adding more than one PT_LOAD to avoid compatibility
issues, there is no impending issue that prevents glibc from supporting
vDSO with multiple PT_LOAD (as some wrapper tools do [1]).
To support multiple PT_LOAD segments, replace the sentinel with a bool
to indicate that the VMA start has already been set.
Testing is really tricky, since the bug report does not indicate which
tool was used to trigger the issue, nor a runtime that provides a vDSO
with multiple PT_LOAD. I had to modify the qemu user with a custom
script to create 2 PT_LOAD sections, remove checks that prevent the
vDSO object from being created, and remove the load bias adjustment
in load_elf_vdso. I could not come up with an easy test case to
integrate with glibc.
The Linux kernel provides vDSO with only one PT_LOAD due to
compatibility reasons. For instance
* arch/arm64/kernel/vdso/vdso.lds.S
86 /*
87 * We must supply the ELF program headers explicitly to get just one
88 * PT_LOAD segment, and set the flags explicitly to make segments read-only.
89 /
90 PHDRS
91 {
92 text PT_LOAD FLAGS(5) FILEHDR PHDRS; / PF_R|PF_X /
93 dynamic PT_DYNAMIC FLAGS(4); / PF_R /
94 note PT_NOTE FLAGS(4); / PF_R */
95 }
* arch/x86/entry/vdso/vdso-layout.lds.S
95 /*
96 * We must supply the ELF program headers explicitly to get just one
97 * PT_LOAD segment, and set the flags explicitly to make segments read-only.
98 /
99 PHDRS
100 {
101 text PT_LOAD FLAGS(5) FILEHDR PHDRS; / PF_R|PF_X /
102 dynamic PT_DYNAMIC FLAGS(4); / PF_R /
103 note PT_NOTE FLAGS(4); / PF_R */
104 eh_frame_hdr PT_GNU_EH_FRAME;
105 }
Checked on aarch64-linux-gnu.
[1] https://sourceware.org/bugzilla/show_bug.cgi?id=32583#c2
Reviewed-by: Florian Weimer <fweimer@redhat.com>
clang generates internal calls for some _chk symbol, so add internal
aliases for them, and stub some with rtld-stubbed-symbols to avoid
ld.so linker issues.
Reviewed-by: Sam James <sam@gentoo.org>
The support for lock elision was already deprecated with glibc 2.42:
commit 77438db8cf
"Mark support for lock elision as deprecated."
See also discussions:
https://sourceware.org/pipermail/libc-alpha/2025-July/168492.html
This patch removes the architecture specific support for lock elision
for x86, powerpc and s390 by removing the elision-conf.h, elision-conf.c,
elision-lock.c, elision-timed.c, elision-unlock.c, elide.h, htm.h/hle.h files.
Those generic files are also removed.
The architecture specific structures are adjusted and the elision fields are
marked as unused. See struct_mutex.h files.
Furthermore in struct_rwlock.h, the leftover __rwelision was also removed.
Those were originally removed with commit 0377a7fde6
"nptl: Remove rwlock elision definitions"
and by chance reintroduced with commit 7df8af43ad
"nptl: Add struct_rwlock.h"
The common code (e.g. the pthread_mutex-files) are changed back to the time
before lock elision was introduced with the x86-support:
- commit 1cdbe57948
"Add the low level infrastructure for pthreads lock elision with TSX"
- commit b023e4ca99
"Add new internal mutex type flags for elision."
- commit 68cc29355f
"Add minimal test suite changes for elision enabled kernels"
- commit e8c659d74e
"Add elision to pthread_mutex_{try,timed,un}lock"
- commit 49186d21ef
"Disable elision for any pthread_mutexattr_settype call"
- commit 1717da59ae
"Add a configure option to enable lock elision and disable by default"
Elision is removed also from the tunables, the initialization part, the
pretty-printers and the manual.
Some extra handling in the testsuite is removed as well as the full tst-mutex10
testcase, which tested a race while enabling lock elision.
I've also searched the code for "elision", "elide", "transaction" and e.g.
cleaned some comments.
I've run the testsuite on x86_64 and s390x and run the build-many-glibcs.py
script.
Thanks to Sachin Monga, this patch is also tested on powerpc.
A NEWS entry also mentions the removal.
Reviewed-by: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
clang might generate an abort call when cleanup functions (set by
__attribute__ ((cleanup)) calls functions not marked as nothrow.
The hurd already provides abort for the loader at
sysdeps/mach/hurd/dl-sysdep.c, and adding it rtld-stubbed-symbols
triggers duplicate symbols.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Introduce the `DL_DEBUG_TLS` debug mask to enable detailed logging for
Thread-Local Storage (TLS) and Thread Control Block (TCB) management.
This change integrates a new `tls` option into the `LD_DEBUG`
environment variable, allowing developers to trace:
- TCB allocation, deallocation, and reuse events in `dl-tls.c`,
`nptl/allocatestack.c`, and `nptl/nptl-stack.c`.
- Thread startup events, including the TID and TCB address, in
`nptl/pthread_create.c`.
A new test, `tst-dl-debug-tid`, has been added to validate the
functionality of this new debug logging, ensuring that relevant messages
are correctly generated for both main and worker threads.
This enhances the debugging capabilities for diagnosing issues related
to TLS allocation and thread lifecycle within the dynamic linker.
Reviewed-by: DJ Delorie <dj@redhat.com>
The clang default to warning for missing fall-through and it does
not support all comment-like annotation that gcc does. Use C23
[[fallthrough]] annotation instead.
proper attribute instead.
Reviewed-by: Collin Funk <collin.funk1@gmail.com>
Recent clang version optimizes some loops contructions to strlen [1],
which might generate function calls when self-relocation is not
already done (on tunable parsing). Use an out-of-line function
with __attribute_optimization_barrier__ to avoid this.
[1] facd7dfc80
Reviewed-by: Sam James <sam@gentoo.org>
clang issues an warning adding 'const unsigned char' to a string
does not append to the string.
Use array indexes instead of string addition (it is simpler than
add a warning suppression).
Reviewed-by: Sam James <sam@gentoo.org>
When debugging library loading issues with `LD_DEBUG`, it can be
frustrating to see logs for files in a directory are searched, but the
target library is skipped over without any indication of why. Add
reporting to all paths which reject a library as `ENOENT`.
Originally created for minimum-OS version detection, but that has since
been removed in b46d250656 (Remove kernel version check, 2022-02-21).
The remaining codepaths are still useful.
Signed-off-by: Ben Boeckel <ben.boeckel@kitware.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Remove the odd atomic_forced_read which is neither atomic nor forced.
Some uses are completely redundant, so simply remove them. In other cases
the intended use is to force a memory ordering, so use acquire load for those.
In yet other cases their purpose is unclear, for example __nscd_cache_search
appears to allow concurrent accesses to the cache while it is being garbage
collected by another thread! Use relaxed atomic loads here to block spills
from accidentally reloading memory that is being changed.
Passes regress on AArch64, OK for commit?
The "unused" variable could be use unitialized, which is an issue if ldd
is ran with "-u". Fix that by defining the variable to an empty value,
just like it is already done for the bind_now, warn and verbose
variables.
Reported-by: Johan Palmqvist <johan.palmqvist@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>
Remove all unused atomics. Replace uses of catomic_increment and
catomic_decrement with atomic_fetch_add_relaxed which maps to a standard
compiler builtin. Relaxed memory ordering is correct for simple counters
since they only need atomicity.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Convert (some) tests to use 'xfclose' rather than using plain 'fclose'
call with no error checking or plain missing such a call.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Convert tests to use 'xfmemopen' rather than open-coding error checks
with 'fmemopen' or plain missing them, where 'fmemopen' itself is not
the scope of testing. Leave 'fmemopen' tests alone.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
This patch replaces _dl_stack_flags global variable by
_dl_stack_prot_flags.
The advantage is that any convertion from p_flags to final used mprotect
flags occurs at loading of p_flags. It avoids repeated spurious
convertions of _dl_stack_flags, for example in allocate_thread_stack.
This modification was suggested in:
https://sourceware.org/pipermail/libc-alpha/2025-March/165537.html
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Update tst-env-setuid.c to delete LD_DEBUG_OUTPUT output, instead of
leaving it behind.
This partially fixes BZ #33182.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Detect if ld.so not contiguous and handle that case in _dl_find_object.
Set l_find_object_processed even for initially loaded link maps,
otherwise dlopen of an initially loaded object adds it to
_dlfo_loaded_mappings (where maps are expected to be contiguous),
in addition to _dlfo_nodelete_mappings.
Test elf/tst-link-map-contiguous-ldso iterates over the loader
image, reading every word to make sure memory is actually mapped.
It only does that if the l_contiguous flag is set for the link map.
Otherwise, it finds gaps with mmap and checks that _dl_find_object
does not return the ld.so mapping for them.
The test elf/tst-link-map-contiguous-main does the same thing for
the libc.so shared object. This only works if the kernel loaded
the main program because the glibc dynamic loader may fill
the gaps with PROT_NONE mappings in some cases, making it contiguous,
but accesses to individual words may still fault.
Test elf/tst-link-map-contiguous-libc is again slightly different
because the dynamic loader always fills the gaps with PROT_NONE
mappings, so a different form of probing has to be used.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Remove historic binutils reference from comment and update
how this data is used by applications.
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
This ensures that the compiler will not inline it, so that
debuggers which do not use the Systemtap probes can reliably
set a breakpoint on it.
Reviewed-by: Andreas K. Huettel <dilfridge@gentoo.org>
Tested-by: Andreas K. Huettel <dilfridge@gentoo.org>
If SFrame is enable check if DLFO_FLAG_SFRAME is set (since sframe
support is added by default) and if dlfo_sframe has the expected
value.
Checked on aarch64-linux-gnu and x86_64-linux-gnu.
Reviewed-by: Sam James <sam@gentoo.org>
The _dl_read_only_area function in the uninitialized ld.so after
static dlopen is not able to find anything. Instead, we need to
redirect to the code from the statically linked main program.
Fixes commit d60fffe28a46b2a41fc308c1804ff02375d27408 ("debug:
Improve '%n' fortify detection (BZ 30932)").
Reviewed-by: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
The SFrame provides information to be able to do stack trace is now
well defined and implemented in Binutils 2.41. The format simply
contains enough information to be able to do stack trace given a
program counter (PC) value, the stack pointer, and the frame pointer.
The SFrame information is stored in a .sframe ELF section, which is
loaded into its own PT_GNU_SFRAME segment. We consider for this support
SFrame version 2.
This patch adds the bits to _dl_find_object to recognize and store in
struct dl_find_object the necessary info about SFrame section.
Signed-off-by: Claudiu Zissulescu <claudiu.zissulescu-ianculescu@oracle.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
The changes in commit a93d9e03a3
("Extend struct r_debug to support multiple namespaces [BZ #15971]")
break the dyninst dynamic instrumentation tool. It brings its
own definition of _r_debug (rather than a declaration).
Furthermore, it turns out it is rather hard to use the proposed
handshake for accessing _r_debug via DT_DEBUG. If applications want
to access _r_debug, they can do so directly if the relevant code has
been built as PIC. To protect against harm from accidental copy
relocations due to linker relaxations, this commit restores copy
relocation support by adjusting both copies if interposition or
copy relocations are in play. Therefore, it is possible to
use a hidden reference in ld.so to access _r_debug.
Only perform the copy relocation initialization if libc has been
loaded. Otherwise, the ld.so search scope can be empty, and the
lookup of the _r_debug symbol mail fail.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
It combines updating r_state with the debugger notification.
The second change to _dl_open introduces an additional debugger
notification for dlmopen, but debuggers are expected to ignore it.
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
It replaces the ns_debug member of the namespaces. Previously,
the base namespace had an unused ns_debug member.
This change also fixes a concurrency issue: Now _dl_debug_initialize
only updates r_next of the previous namespace's r_debug after the new
r_debug is initialized, so that only the initialized version is
observed. (Client code accessing _r_debug will benefit from load
dependency tracking in CPUs even without explicit barriers.)
Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
Add DL_ADDRESS_WITHOUT_RELOC to force an address into a general purpose
register to prevent loading it into a vector register directly before
run-time relocation. This is an updated fix for BZ #33088.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Update tst-gnu2-tls2 tests to set XMM0...XMM7 to all 1s in malloc to
verify that XMM registers are preserved when _dl_tlsdesc_dynamic is
called by clearing vectors with zeroed XMM registers before
_dl_tlsdesc_dynamic and using these XMM registers to clear vectors
after _dl_tlsdesc_dynamic. This improves the BZ #31372 test.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>
Compiler generates the following instruction sequence for dynamic TLS
access:
leal tls_var@tlsgd(,%ebx,1), %eax
call ___tls_get_addr@PLT
CALL instruction is transparent to compiler which assumes all registers,
except for EFLAGS, AX, CX, and DX, are unchanged after CALL. But
___tls_get_addr is a normal function which doesn't preserve any vector
registers.
1. Rename the generic __tls_get_addr function to ___tls_get_addr_internal.
2. Change ___tls_get_addr to a wrapper function with implementations for
FNSAVE, FXSAVE, XSAVE and XSAVEC to save and restore all vector registers.
3. dl-tlsdesc-dynamic.h has:
_dl_tlsdesc_dynamic:
/* Like all TLS resolvers, preserve call-clobbered registers.
We need two scratch regs anyway. */
subl $32, %esp
cfi_adjust_cfa_offset (32)
It is wrong to use
movl %ebx, -28(%esp)
movl %esp, %ebx
cfi_def_cfa_register(%ebx)
...
mov %ebx, %esp
cfi_def_cfa_register(%esp)
movl -28(%esp), %ebx
to preserve EBX on stack. Fix it with:
movl %ebx, 28(%esp)
movl %esp, %ebx
cfi_def_cfa_register(%ebx)
...
mov %ebx, %esp
cfi_def_cfa_register(%esp)
movl 28(%esp), %ebx
4. Update _dl_tlsdesc_dynamic to call ___tls_get_addr_internal directly.
5. Add have-test-mtls-traditional to compile tst-tls23-mod.c with
traditional TLS variant to verify the fix.
6. Define DL_RUNTIME_RESOLVE_REALIGN_STACK in sysdeps/x86/sysdep.h.
This fixes BZ #32996.
Co-Authored-By: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
rtld.c has
extern const ElfW(Ehdr) __ehdr_start attribute_hidden;
...
_dl_rtld_map.l_map_start = (ElfW(Addr)) &__ehdr_start;
_dl_rtld_map.l_map_end = (ElfW(Addr)) _end;
As
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120653
shows, compiler may generate run-time relocation on __ehdr_start with
movq .LC0(%rip), %xmm0
...
.section .data.rel.ro.local,"aw"
.align 8
.LC0:
.quad __ehdr_start
This won't work before run-time relocation is finished in rtld.c. Add
optimization barrier to prevent run-time relocations against __ehdr_start
and _end.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
Reviewed-by: Sam James <sam@gentoo.org>
Since
commit 53df2ce688
Author: Florian Weimer <fweimer@redhat.com>
Date: Fri Sep 8 13:02:06 2023 +0200
elf: Remove unused l_text_end field from struct link_map
removed the only reference to _etext, also remove the unused _etext
declaration.
Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
If paths with both $(objpfx)/ and $(objpfx) (which already includes
a trailing slash) appear during the build, this can trigger unexpected
rebuilds, or incorrect concurrent rebuilds.
On 32-bit architecture ubsan triggers:
UBSAN: Undefined behaviour in dl-load.c:1345:54 pointer index expression with base 0x00612508 overflowed to 0xf7c3a508
Use explicit uintptr_t operation instead.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Update the list of RISC-V relocations from the ELF psABI as of June 2024.
It removes binutils-internal only relocations that were never part of
actual object files. The GNU_VTINHERIT and GNU_VTENTRY relocations were
never used because the corresponding GCC option -fvtable-gc was never
supported on RISC-V.
__ptmalloc_init was called too early in __libc_early_init: it uses
__libc_initial which is not set yet. Fix this by moving initialization
to the end of __libc_early_init.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
And simplify the interface of support_capture_subprogram_self_sgid.
Use the existing framework for temporary directories (now with
mode 0700) and directory/file deletion. Handle all execution
errors within support_capture_subprogram_self_sgid. In particular,
this includes test failures because the invoked program did not
exit with exit status zero. Existing tests that expect exit
status 42 are adjusted to use zero instead.
In addition, fix callers not to call exit (0) with test failures
pending (which may mask them, especially when running with --direct).
Fixes commit 35fc356fa3
("elf: Fix subprocess status handling for tst-dlopen-sgid (bug 32987)").
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Check that LD_LIBRARY_PATH is ignored for AT_SECURE statically
linked binaries, using support_capture_subprogram_self_sgid.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Now we finally support modern GCC and binutils, it's time for a cleanup.
Use PAC and BTI instructions unconditionally and use proper assembler syntax.
Remove the PR target/94791 strip_pac workarounds for buggy GCCs. Remove the
PAC/BTI configure checks - always emit GNU property notes on assembly files.
Change cfi_window_save to the correct cfi_negate_ra_state unwind directive.
Reviewed-by: Matthieu Longo <matthieu.longo@arm.com>
