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Commit Graph

171 Commits

Author SHA1 Message Date
Paul Eggert
dff8da6b3e Update copyright dates with scripts/update-copyrights 2024-01-01 10:53:40 -08:00
Adhemerval Zanella
6afce56c19 nptl: Decorate thread stack on pthread_create
Linux 4.5 removed thread stack annotations due to the complexity of
computing them [1], and Linux added PR_SET_VMA_ANON_NAME on 5.17
as a way to name anonymous virtual memory areas.

This patch adds decoration on the stack created and used by
pthread_create, for glibc crated thread stack the /proc/self/maps will
now show:

  [anon: glibc: pthread stack: <tid>]

And for user-provided stacks:

  [anon: glibc: pthread user stack: <tid>]

The guard page is not decorated, and the mapping name is cleared when
the thread finishes its execution (so the cached stack does not have any
name associated).

Checked on x86_64-linux-gnu aarch64 aarch64-linux-gnu.

[1] 65376df582

Co-authored-by: Ian Rogers <irogers@google.com>
Reviewed-by: DJ Delorie <dj@redhat.com>
2023-11-07 10:27:20 -03:00
Samuel Thibault
6333a6014f __call_tls_dtors: Use call_function_static_weak 2023-09-04 20:03:37 +02:00
Paul Pluzhnikov
7f0d9e61f4 Fix all the remaining misspellings -- BZ 25337 2023-06-02 01:39:48 +00:00
Joseph Myers
6d7e8eda9b Update copyright dates with scripts/update-copyrights 2023-01-06 21:14:39 +00:00
Adhemerval Zanella
3d8b5dde87 nptl: Fix pthread_create.c build with clang
clang complains that libc_hidden_data_def (__nptl_threads_events)
creates an invalid alias:

  pthread_create.c:50:1: error: alias must point to a defined variable or function
  libc_hidden_data_def (__nptl_threads_events)
  ^
  ../include/libc-symbols.h:621:37: note: expanded from macro
  'libc_hidden_data_def'

It seems that clang requires that a proper prototype is defined prior
the hidden alias creation.

Reviewed-by: Fangrui Song <maskray@google.com>
2022-11-01 09:51:10 -03:00
Wilco Dijkstra
22f4ab2d20 Use atomic_exchange_release/acquire
Rename atomic_exchange_rel/acq to use atomic_exchange_release/acquire
since these map to the standard C11 atomic builtins.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-09-26 16:58:08 +01:00
Wilco Dijkstra
4a07fbb689 Use C11 atomics instead of atomic_decrement_and_test
Replace atomic_decrement_and_test with atomic_fetch_add_relaxed.
These are simple counters which do not protect any shared data from
concurrent accesses. Also remove the unused file cond-perf.c.

Passes regress on AArch64.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-09-23 15:59:56 +01:00
Wilco Dijkstra
d1babeb32d Use C11 atomics instead of atomic_increment(_val)
Replace atomic_increment and atomic_increment_val with atomic_fetch_add_relaxed.
One case in sem_post.c uses release semantics (see comment above it).
The others are simple counters and do not protect any shared data from
concurrent accesses.

Passes regress on AArch64.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-09-23 15:59:56 +01:00
Wilco Dijkstra
8114b95cef Use C11 atomics instead of atomic_and/or
Remove the 4 uses of atomic_and and atomic_or with atomic_fetch_and_acquire
and atomic_fetch_or_acquire. This is preserves existing implied semantics,
however relaxed MO on FUTEX_OWNER_DIED accesses may be correct.

Passes regress on AArch64.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2022-09-23 15:59:56 +01:00
Wilco Dijkstra
a30e960328 Use relaxed atomics since there is no MO dependence
Replace the 3 uses of atomic_bit_set and atomic_bit_test_set with
atomic_fetch_or_relaxed.  Using relaxed MO is correct since the
atomics are used to ensure memory is released only once.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2022-09-13 11:58:07 +01:00
Wilco Dijkstra
a364a3a709 Use C11 atomics instead of atomic_decrement(_val)
Replace atomic_decrement and atomic_decrement_val with
atomic_fetch_add_relaxed.

Reviewed-by: DJ Delorie <dj@redhat.com>
2022-09-09 14:22:26 +01:00
Adhemerval Zanella
a1bdd81664 Refactor internal-signals.h
The main drive is to optimize the internal usage and required size
when sigset_t is embedded in other data structures.  On Linux, the
current supported signal set requires up to 8 bytes (16 on mips),
was lower than the user defined sigset_t (128 bytes).

A new internal type internal_sigset_t is added, along with the
functions to operate on it similar to the ones for sigset_t.  The
internal-signals.h is also refactored to remove unused functions

Besides small stack usage on some functions (posix_spawn, abort)
it lower the struct pthread by about 120 bytes (112 on mips).

Checked on x86_64-linux-gnu.

Reviewed-by: Arjun Shankar <arjun@redhat.com>
2022-06-30 14:56:21 -03:00
Adhemerval Zanella
baf2a265c7 misc: Optimize internal usage of __libc_single_threaded
By adding an internal alias to avoid the GOT indirection.
On some architecture, __libc_single_thread may be accessed through
copy relocations and thus it requires to update also the copies
default copy.

This is done by adding a new internal macro,
libc_hidden_data_{proto,def}, which has an addition argument that
specifies the alias name (instead of default __GI_ one).

Checked on x86_64-linux-gnu and i686-linux-gnu.

Reviewed-by: Fangrui Song <maskray@google.com>
2022-06-24 17:45:58 -03:00
Paul Eggert
581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00
Florian Weimer
a41c8e9235 nptl: rseq failure after registration on main thread is fatal
This simplifies the application programming model.

Browser sandboxes have already been fixed:

  Sandbox is incompatible with rseq registration
  <https://bugzilla.mozilla.org/show_bug.cgi?id=1651701>

  Allow rseq in the Linux sandboxes. r=gcp
  <https://hg.mozilla.org/mozilla-central/rev/042425712eb1>

  Sandbox needs to support rseq system call
  <https://bugs.chromium.org/p/chromium/issues/detail?id=1104160>

  Linux sandbox: Allow rseq(2)
  <https://chromium.googlesource.com/chromium/src.git/+/230675d9ac8f1>

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-12-09 09:49:32 +01:00
Florian Weimer
e3e589829d nptl: Add glibc.pthread.rseq tunable to control rseq registration
This tunable allows applications to register the rseq area instead
of glibc.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-12-09 09:49:32 +01:00
Florian Weimer
95e114a091 nptl: Add rseq registration
The rseq area is placed directly into struct pthread.  rseq
registration failure is not treated as an error, so it is possible
that threads run with inconsistent registration status.

<sys/rseq.h> is not yet installed as a public header.

Co-Authored-By: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-12-09 09:49:32 +01:00
Florian Weimer
e186fc5a31 nptl: Do not set signal mask on second setjmp return [BZ ]
__libc_signal_restore_set was in the wrong place: It also ran
when setjmp returned the second time (after pthread_exit or
pthread_cancel).  This is observable with blocked pending
signals during thread exit.

Fixes commit b3cae39dcb
("nptl: Start new threads with all signals blocked [BZ ]").

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-24 08:59:54 +01:00
Florian Weimer
2849e2f533 nptl: Avoid setxid deadlock with blocked signals in thread exit [BZ ]
As part of the fix for bug 12889, signals are blocked during
thread exit, so that application code cannot run on the thread that
is about to exit.  This would cause problems if the application
expected signals to be delivered after the signal handler revealed
the thread to still exist, despite pthread_kill can no longer be used
to send signals to it.  However, glibc internally uses the SIGSETXID
signal in a way that is incompatible with signal blocking, due to the
way the setxid handshake delays thread exit until the setxid operation
has completed.  With a blocked SIGSETXID, the handshake can never
complete, causing a deadlock.

As a band-aid, restore the previous handshake protocol by not blocking
SIGSETXID during thread exit.

The new test sysdeps/pthread/tst-pthread-setuid-loop.c is based on
a downstream test by Martin Osvald.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-09-23 09:56:07 +02:00
Florian Weimer
526c3cf11e nptl: Fix race between pthread_kill and thread exit (bug 12889)
A new thread exit lock and flag are introduced.  They are used to
detect that the thread is about to exit or has exited in
__pthread_kill_internal, and the signal is not sent in this case.

The test sysdeps/pthread/tst-pthread_cancel-select-loop.c is derived
from a downstream test originally written by Marek Polacek.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-09-13 11:06:08 +02:00
Siddhesh Poyarekar
30891f35fa Remove "Contributed by" lines
We stopped adding "Contributed by" or similar lines in sources in 2012
in favour of git logs and keeping the Contributors section of the
glibc manual up to date.  Removing these lines makes the license
header a bit more consistent across files and also removes the
possibility of error in attribution when license blocks or files are
copied across since the contributed-by lines don't actually reflect
reality in those cases.

Move all "Contributed by" and similar lines (Written by, Test by,
etc.) into a new file CONTRIBUTED-BY to retain record of these
contributions.  These contributors are also mentioned in
manual/contrib.texi, so we just maintain this additional record as a
courtesy to the earlier developers.

The following scripts were used to filter a list of files to edit in
place and to clean up the CONTRIBUTED-BY file respectively.  These
were not added to the glibc sources because they're not expected to be
of any use in future given that this is a one time task:

https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc
https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-09-03 22:06:44 +05:30
H.J. Lu
d8ea0d0168 Add an internal wrapper for clone, clone2 and clone3
The clone3 system call (since Linux 5.3) provides a superset of the
functionality of clone and clone2.  It also provides a number of API
improvements, including the ability to specify the size of the child's
stack area which can be used by kernel to compute the shadow stack size
when allocating the shadow stack.  Add:

extern int __clone_internal (struct clone_args *__cl_args,
			     int (*__func) (void *__arg), void *__arg);

to provide an abstract interface for clone, clone2 and clone3.

1. Simplify stack management for thread creation by passing both stack
base and size to create_thread.
2. Consolidate clone vs clone2 differences into a single file.
3. Call __clone3 if HAVE_CLONE3_WAPPER is defined.  If __clone3 returns
-1 with ENOSYS, fall back to clone or clone2.
4. Use only __clone_internal to clone a thread.  Since the stack size
argument for create_thread is now unconditional, always pass stack size
to create_thread.
5. Enable the public clone3 wrapper in the future after it has been
added to all targets.

NB: Sandbox will return ENOSYS on clone3 in both Chromium:

The following revision refers to this bug:
  218438259d

commit 218438259dd795456f0a48f67cbe5b4e520db88b
Author: Matthew Denton <mpdenton@chromium.org>
Date: Thu Jun 03 20:06:13 2021

Linux sandbox: return ENOSYS for clone3

Because clone3 uses a pointer argument rather than a flags argument, we
cannot examine the contents with seccomp, which is essential to
preventing sandboxed processes from starting other processes. So, we
won't be able to support clone3 in Chromium. This CL modifies the
BPF policy to return ENOSYS for clone3 so glibc always uses the fallback
to clone.

Bug: 1213452
Change-Id: I7c7c585a319e0264eac5b1ebee1a45be2d782303
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2936184
Reviewed-by: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Matthew Denton <mpdenton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#888980}

[modify] https://crrev.com/218438259dd795456f0a48f67cbe5b4e520db88b/sandbox/linux/seccomp-bpf-helpers/baseline_policy.cc

and Firefox:

https://hg.mozilla.org/integration/autoland/rev/ecb4011a0c76

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-07-14 06:33:58 -07:00
Florian Weimer
7c241325d6 Force building with -fno-common
As a result, is not necessary to specify __attribute__ ((nocommon))
on individual definitions.

GCC 10 defaults to -fno-common on all architectures except ARC,
but this change is compatible with older GCC versions and ARC, too.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-09 20:09:14 +02:00
Florian Weimer
fef400a2f9 nptl: Export libthread_db-used symbols under GLIBC_PRIVATE
This allows distributions to strip debugging information from
libc.so.6 without impacting the debugging experience.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-06-28 15:05:42 +02:00
Adhemerval Zanella
8fe503f74e nptl: Avoid async cancellation to wrongly update __nptl_nthreads (BZ )
The testcase provided on BZ#19366 may update __nptl_nthreads in a wrong
order, triggering an early process exit because the thread decrement
the value twice.

The issue is once the thread exits without acting on cancellation,
it decreaments '__nptl_nthreads' and then atomically set
 'cancelhandling' with EXITING_BIT (thus preventing further cancellation
handler to act).  The issue happens if a SIGCANCEL is received between
checking '__ntpl_nthreads' and setting EXITING_BIT.  To avoid it, the
'__nptl_nthreads' decrement is moved after EXITING_BIT.

It does fully follow the POSIX XSH 2.9.5 Thread Cancellation under
the heading Thread Cancellation Cleanup Handlers that states that
when a cancellation request is acted upon, or when a thread calls
pthread_exit(), the thread first disables cancellation by setting its
cancelability state to PTHREAD_CANCEL_DISABLE and its cancelability type
to PTHREAD_CANCEL_DEFERRED.  The issue is '__pthread_enable_asynccancel'
explicit enabled assynchrnous cancellation, so an interrupted syscall
within the cancellation cleanup handlers might see an invalid cancelling
type (a possible fix might be possible with my proposed solution to
BZ#12683).

Trying to come up with a test is quite hard since it requires to
mimic the timing issue described below, however I see that the
bug report reproducer does not early exit anymore.

Checked on x86_64-linux-gnu.
2021-06-09 15:16:45 -03:00
Adhemerval Zanella
41c7295617 nptl: Install cancellation handler on pthread_cancel
Now that cancellation is not used anymore to handle thread setup
creation failure, the sighandle can be installed only when
pthread_cancel is actually used.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
2021-06-09 15:16:45 -03:00
Adhemerval Zanella
02189e8fb0 nptl: Deallocate the thread stack on setup failure (BZ )
To setup either the thread scheduling parameters or affinity,
pthread_create enforce synchronization on created thread to wait until
its parent either release PD ownership or send a cancellation signal if
a failure occurs.

However, cancelling the thread does not deallocate the newly created
stack since cancellation expects that a pthread_join to deallocate any
allocated thread resouces (threads stack or TLS).

This patch changes on how the thread resource is deallocate in case of
failure to be synchronous, where the creating thread will signal the
created thread to exit early so it could be joined.  The creating thread
will be reponsible for the resource cleanup before returning to the
caller.

To signal the creating thread that a failure has occured, an unused
'struct pthread' member, parent_cancelhandling_unsed, now indicates
whether the setup has failed so creating thread can proper exit.

This strategy also simplifies by not using thread cancellation and
thus not running libgcc_so load in the signal handler (which is
avoided in thread cancellation since 'pthread_cancel' is the one
responsible to dlopen libgcc_s).  Another advantage is since the
early exit is move to first step at thread creation, the signal
mask is not already set and thus it can not act on change ID setxid
handler.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
2021-06-09 15:16:45 -03:00
Adhemerval Zanella
eaa53d0f77 nptl: Remove exit-thread.h
No function change.  The code is used only for Linux, besides
being included in generic code.
2021-06-04 09:52:28 -03:00
Adhemerval Zanella
42813c675d nptl: Move createthread to pthread_create
The 'create_thread' function is moved to pthread_create.c.  It removes
the START_THREAD_DEFN and START_THREAD_SELF macros and make the
lock usage more clear (no need to cross-reference multiple files).

No functional change.
2021-05-27 13:11:41 -03:00
Florian Weimer
76b0c59e33 nptl: Install SIGSETXID handler with SA_ONSTACK [BZ ]
The signal is sent to all threads, some of which may have switched
to very small stacks.  If they have also installed an alternate
signal stack, SA_ONSTACK makes this work.  The Go runtime needs this:

  runtime: C.setuid/C.setgid smashes Go stack
  <https://github.com/golang/go/issues/9400>

Doing this for SIGCANCEL is less obviously beneficial and needs further
testing.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-05-27 15:37:35 +02:00
Florian Weimer
f47f1d91af nptl: Move pthread_create, thrd_create into libc
The symbols were moved using scripts/move-symbol-to-libc.py.

The libpthread placeholder symbols need some changes because some
symbol versions have gone away completely.  But
__errno_location@@GLIBC_2.0 still exists, so the GLIBC_2.0 version
is still there.

The internal __pthread_create symbol now points to the correct
function, so the sysdeps/nptl/thrd_create.c override is no longer
necessary.

There was an issue how the hidden alias of pthread_getattr_default_np
was defined, so this commit cleans up that aspects and removes the
GLIBC_PRIVATE export altogether.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-21 22:35:00 +02:00
Florian Weimer
b8cdc3bba7 nptl: Move semi-public __pthread_get_minstack symbol into libc
No abilist updates here because it is a GLIBC_PRIVATE symbol.

It's also necessary to move nptl_version into pthread_create, so
that it still ends up in static binaries.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-21 22:35:00 +02:00
Florian Weimer
2f69522d46 nptl: Perform signal initialization upon pthread_create
Install signal handlers and unblock signals before pthread_create
creates the first thread.

create_thread in sysdeps/unix/sysv/linux/createthread.c can send
SIGCANCEL to the current thread, so the SIGCANCEL handler is currently
needed even if pthread_cancel is never called.  (The way timer_create
uses SIGCANCEL does not need a signal handler; both SIG_DFL and SIG_IGN
dispositions should work.)

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-21 22:35:00 +02:00
Florian Weimer
8fbb33b3f7 nptl: Move __free_tcb into libc
Under the name __nptl_free_tcb.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-11 11:24:36 +02:00
Florian Weimer
c79a31fb36 nptl: Move stack cache management, __libpthread_freeres into libc
This replaces the FREE_P macro with the __nptl_stack_in_use inline
function.  stack_list_del is renamed to __nptl_stack_list_del,
stack_list_add to __nptl_stack_list_add, __deallocate_stack to
__nptl_deallocate_stack, free_stacks to __nptl_free_stacks.

It is convenient to move __libpthread_freeres into libc at the
same time.  This removes the temporary __default_pthread_attr_freeres
export and restores full freeres coverage for __default_pthread_attr.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-11 11:22:33 +02:00
Florian Weimer
d2af73a348 nptl: Remove always-disabled debugging support
This removes the DEBUGGING_P macro and the __pthread_debug variable.
The __find_in_stack_list function is now unused and deleted as well.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-11 11:09:42 +02:00
Florian Weimer
ce0b7961ae nptl: Consolidate async cancel enable/disable implementation in libc
Previously, the source file nptl/cancellation.c was compiled multiple
times, for libc, libpthread, librt.  This commit switches to a single
implementation, with new __pthread_enable_asynccancel@@GLIBC_PRIVATE,
__pthread_disable_asynccancel@@GLIBC_PRIVATE exports.

The almost-unused CANCEL_ASYNC and CANCEL_RESET macros are replaced
by LIBC_CANCEL_ASYNC and LIBC_CANCEL_ASYNC macros.  They call the
__pthread_* functions unconditionally now.  The macros are still
needed because shared code uses them; Hurd has different definitions.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-05 17:19:32 +02:00
Florian Weimer
442e8a40da nptl: Move part of TCB initialization from libpthread to __tls_init_tp
This initalization should only happen once for the main thread's TCB.
At present, auditors can achieve this by not linking against
libpthread.  If libpthread becomes part of libc, doing this
initialization in libc would happen for every audit namespace,
or too late (if it happens from the main libc only).  That's why
moving this code into ld.so seems the right thing to do, right after
the TCB initialization.

For !__ASSUME_SET_ROBUST_LIST ports, this also moves the symbol
__set_robust_list_avail into ld.so, as __nptl_set_robust_list_avail.
It also turned into a proper boolean flag.

Inline the __pthread_initialize_pids function because it seems no
longer useful as a separate function.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-04-21 19:49:51 +02:00
Florian Weimer
2cfef0b042 nptl: Move __nptl_deallocate_tsd into libc
This prepares moving pthread_exit, and later the pthread_key_create
infrastructure.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-04-21 19:49:50 +02:00
Florian Weimer
43fe356d18 nptl: Move internal __nptl_nthreads variable into libc
Reviewed-by: Adhemerval Zanella   <adhemerval.zanella@linaro.org>
2021-04-21 19:49:50 +02:00
Florian Weimer
a64afc2252 nptl_db: Support different libpthread/ld.so load orders (bug 27744)
libthread_db is loaded once GDB encounters libpthread, and at this
point, ld.so may not have been processed by GDB yet. As a result,
_rtld_global cannot be accessed by regular means from libthread_db.
To make this work until GDB can be fixed, acess _rtld_global through
a pointer stored in libpthread.

The new test does not reproduce bug 27744 with
--disable-hardcoded-path-in-tests, but is still a valid smoke test.
With --enable-hardcoded-path-in-tests, it is necessary to avoid
add-symbol-file because this can tickle a GDB bug.

Fixes commit 1daccf403b ("nptl: Move
stack list variables into _rtld_global").

Tested-by: Emil Velikov <emil.velikov@collabora.com>
2021-04-21 11:50:43 +02:00
Paul Eggert
2b778ceb40 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 6694 files FOO.
I then removed trailing white space from benchtests/bench-pthread-locks.c
and iconvdata/tst-iconv-big5-hkscs-to-2ucs4.c, to work around this
diagnostic from Savannah:
remote: *** pre-commit check failed ...
remote: *** error: lines with trailing whitespace found
remote: error: hook declined to update refs/heads/master
2021-01-02 12:17:34 -08:00
Florian Weimer
1daccf403b nptl: Move stack list variables into _rtld_global
Now __thread_gscope_wait (the function behind THREAD_GSCOPE_WAIT,
formerly __wait_lookup_done) can be implemented directly in ld.so,
eliminating the unprotected GL (dl_wait_lookup_done) function
pointer.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2020-11-16 19:33:30 +01:00
Joseph Myers
2098d4034d Disable spurious -Wstringop-overflow for setjmp/longjmp (bug 26647)
Building glibc with GCC 11 fails with (among other warnings) spurious
-Wstringop-overflow warnings from calls to setjmp and longjmp with a
pointer to a pthread_unwind_buf that is smaller than jmp_buf.  As
discussed in bug 26647, the warning in libc-start.c is a false
positive, because setjmp and longjmp do not access anything (the
signal mask) beyond the common prefix of the two structures, so this
patch disables the warning for that call to setjmp, as well as for two
calls in NPTL code that produce the same warning and look like false
positives for the same reason.

Tested with build-many-glibcs.py for arm-linux-gnueabi, where this
allows the build to get further.

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-10-30 21:38:31 +00:00
Florian Weimer
efedd1ed3d Linux: Remove rseq support
The kernel ABI is not finalized, and there are now various proposals
to change the size of struct rseq, which would make the glibc ABI
dependent on the version of the kernels used for building glibc.
This is of course not acceptable.

This reverts commit 48699da1c4 ("elf:
Support at least 32-byte alignment in static dlopen"), commit
8f4632deb3 ("Linux: rseq registration
tests"), commit 6e29cb3f61 ("Linux: Use
rseq in sched_getcpu if available"), and commit
0c76fc3c2b ("Linux: Perform rseq
registration at C startup and thread creation"), resolving the conflicts
introduced by the ARC port and the TLS static surplus changes.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2020-07-16 17:55:35 +02:00
Florian Weimer
706ad1e7af Add the __libc_single_threaded variable
The variable is placed in libc.so, and it can be true only in
an outer libc, not libcs loaded via dlmopen or static dlopen.
Since thread creation from inner namespaces does not work,
pthread_create can update __libc_single_threaded directly.

Using __libc_early_init and its initial flag, implementation of this
variable is very straightforward.  A future version may reset the flag
during fork (but not in an inner namespace), or after joining all
threads except one.

Reviewed-by: DJ Delorie <dj@redhat.com>
2020-07-06 11:15:58 +02:00
Mathieu Desnoyers
0c76fc3c2b Linux: Perform rseq registration at C startup and thread creation
Register rseq TLS for each thread (including main), and unregister for
each thread (excluding main).  "rseq" stands for Restartable Sequences.

See the rseq(2) man page proposed here:
  https://lkml.org/lkml/2018/9/19/647

Those are based on glibc master branch commit 3ee1e0ec5c.
The rseq system call was merged into Linux 4.18.

The TLS_STATIC_SURPLUS define is increased to leave additional room for
dlopen'd initial-exec TLS, which keeps elf/tst-auditmany working.

The increase (76 bytes) is larger than 32 bytes because it has not been
increased in quite a while.  The cost in terms of additional TLS storage
is quite significant, but it will also obscure some initial-exec-related
dlopen failures.
2020-07-06 10:21:16 +02:00
Szabolcs Nagy
087942251f nptl: Don't madvise user provided stack
User provided stack should not be released nor madvised at
thread exit because it's owned by the user.

If the memory is shared or file based then MADV_DONTNEED
can have unwanted effects. With memory tagging on aarch64
linux the tags are dropped and thus it may invalidate
pointers.

Tested on aarch64-linux-gnu with MTE, it fixes

FAIL: nptl/tst-stack3
FAIL: nptl/tst-stack3-mem
2020-06-25 14:19:16 +01:00
Florian Weimer
ec41af45a6 nptl: Add pthread_attr_setsigmask_np, pthread_attr_getsigmask_np
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2020-06-02 11:59:18 +02:00