Commit Graph

2767 Commits

Author SHA1 Message Date
John David Anglin
2bbc694df2 nptl: Fix cleanups for stack grows up [BZ# 28899]
_STACK_GROWS_DOWN is defined to 0 when the stack grows up.  The
code in unwind.c used `#ifdef _STACK_GROWS_DOWN' to selct the
stack grows down define for FRAME_LEFT.  As a result, the
_STACK_GROWS_DOWN define was always selected and cleanups were
incorrectly sequenced when the stack grows up.
2022-02-28 15:47:38 +00:00
Adhemerval Zanella
254d3d5aef elf: Fix initial-exec TLS access on audit modules (BZ #28096)
For audit modules and dependencies with initial-exec TLS, we can not
set the initial TLS image on default loader initialization because it
would already be set by the audit setup.  However, subsequent thread
creation would need to follow the default behaviour.

This patch fixes it by setting l_auditing link_map field not only
for the audit modules, but also for all its dependencies.  This is
used on _dl_allocate_tls_init to avoid the static TLS initialization
at load time.

Checked on x86_64-linux-gnu, i686-linux-gnu, and aarch64-linux-gnu.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2022-02-01 14:49:46 -03:00
Jangwoong Kim
6b8dbbd03a nptl: Effectively skip CAS in spinlock loop
The commit:
"Add LLL_MUTEX_READ_LOCK [BZ #28537]"
SHA1: d672a98a1a

introduced LLL_MUTEX_READ_LOCK, to skip CAS in spinlock loop
if atomic load fails. But, "continue" inside of do-while loop
does not skip the evaluation of escape expression, thus CAS
is not skipped.

Replace do-while with while and skip LLL_MUTEX_TRYLOCK if
LLL_MUTEX_READ_LOCK fails.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2022-01-20 05:05:09 -08:00
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
68007900be misc, nptl: Remove stray references to __condvar_load_64_relaxed
The function was renamed to __atomic_wide_counter_load_relaxed
in commit 8bd336a00a ("nptl: Extract
<bits/atomic_wide_counter.h> from pthread_cond_common.c").
2021-12-06 08:01:08 +01:00
Florian Weimer
23c77f6018 nptl: Increase default TCB alignment to 32
rseq support will use a 32-byte aligned field in struct pthread,
so the whole struct needs to have at least that alignment.

nptl/tst-tls3mod.c uses TCB_ALIGNMENT, therefore include <descr.h>
to obtain the fallback definition.

Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
2021-12-03 20:43:31 +01:00
Florian Weimer
e186fc5a31 nptl: Do not set signal mask on second setjmp return [BZ #28607]
__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 #25098]").

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-24 08:59:54 +01:00
Florian Weimer
8bd336a00a nptl: Extract <bits/atomic_wide_counter.h> from pthread_cond_common.c
And make it an installed header.  This addresses a few aliasing
violations (which do not seem to result in miscompilation due to
the use of atomics), and also enables use of wide counters in other
parts of the library.

The debug output in nptl/tst-cond22 has been adjusted to print
the 32-bit values instead because it avoids a big-endian/little-endian
difference.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-11-17 12:20:13 +01:00
H.J. Lu
120ac6d238 Move assignment out of the CAS condition
Update

commit 49302b8fdf
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Nov 11 06:54:01 2021 -0800

    Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]

    Replace boolean CAS with value CAS to avoid the extra load.

and

commit 0b82747dc4
Author: H.J. Lu <hjl.tools@gmail.com>
Date:   Thu Nov 11 06:31:51 2021 -0800

    Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]

    Replace boolean CAS with value CAS to avoid the extra load.

by moving assignment out of the CAS condition.
2021-11-15 05:50:56 -08:00
H.J. Lu
d672a98a1a Add LLL_MUTEX_READ_LOCK [BZ #28537]
CAS instruction is expensive.  From the x86 CPU's point of view, getting
a cache line for writing is more expensive than reading.  See Appendix
A.2 Spinlock in:

https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/xeon-lock-scaling-analysis-paper.pdf

The full compare and swap will grab the cache line exclusive and cause
excessive cache line bouncing.

Add LLL_MUTEX_READ_LOCK to do an atomic load and skip CAS in spinlock
loop if compare may fail to reduce cache line bouncing on contended locks.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-11-12 10:32:09 -08:00
H.J. Lu
49302b8fdf Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-11-12 10:31:31 -08:00
H.J. Lu
0b82747dc4 Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]
Replace boolean CAS with value CAS to avoid the extra load.

Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
2021-11-12 10:30:57 -08:00
Stafford Horne
06acd6d1d6 nptl: Fix tst-cancel7 and tst-cancelx7 pidfile race
The check for waiting for the pidfile to be created looks wrong.  At the
point when ACCESS is run the pid file will always be created and
accessible as it is created during DO_PREPARE.  This means that thread
cancellation may be performed before the pid is written to the pidfile.

This was found to be flaky when testing on my OpenRISC platform.

Fix this by using the semaphore to wait for pidfile pid write
completion.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
2021-10-18 13:30:10 -03:00
Florian Weimer
eae81d7057 nptl: pthread_kill must send signals to a specific thread [BZ #28407]
The choice between the kill vs tgkill system calls is not just about
the TID reuse race, but also about whether the signal is sent to the
whole process (and any thread in it) or to a specific thread.

This was caught by the openposix test suite:

  LTP: openposix test suite - FAIL: SIGUSR1 is member of new thread pendingset.
  <https://gitlab.com/cki-project/kernel-tests/-/issues/764>

Fixes commit 526c3cf11e ("nptl: Fix race
between pthread_kill and thread exit (bug 12889)").

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-10-01 18:16:41 +02:00
Adhemerval Zanella
2313ab153d nptl: Add CLOCK_MONOTONIC support for PI mutexes
Linux added FUTEX_LOCK_PI2 to support clock selection
(commit bf22a6976897977b0a3f1aeba6823c959fc4fdae).  With the new
flag we can now proper support CLOCK_MONOTONIC for
pthread_mutex_clocklock with Priority Inheritance.  If kernel
does not support, EINVAL is returned instead.

The difference is the futex operation will be issued and the kernel
will advertise the missing support (instead of hard-code error
return).

Checked on x86_64-linux-gnu and i686-linux-gnu on Linux 5.14, 5.11,
and 4.15.
2021-10-01 10:11:11 -03:00
Adhemerval Zanella
8352b6df37 nptl: Use FUTEX_LOCK_PI2 when available
This patch uses the new futex PI operation provided by Linux v5.14
when it is required.

The futex_lock_pi64() is moved to futex-internal.c (since it used on
two different places and its code size might be large depending of the
kernel configuration) and clockid is added as an argument.

Co-authored-by: Kurt Kanzenbach <kurt@linutronix.de>
2021-10-01 08:09:13 -03:00
Florian Weimer
2849e2f533 nptl: Avoid setxid deadlock with blocked signals in thread exit [BZ #28361]
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
95dba35bf0 nptl: pthread_kill needs to return ESRCH for old programs (bug 19193)
The fix for bug 19193 breaks some old applications which appear
to use pthread_kill to probe if a thread is still running, something
that is not supported by POSIX.
2021-09-20 14:56:08 +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
Florian Weimer
8af8456004 nptl: pthread_kill, pthread_cancel should not fail after exit (bug 19193)
This closes one remaining race condition related to bug 12889: if
the thread already exited on the kernel side, returning ESRCH
is not correct because that error is reserved for the thread IDs
(pthread_t values) whose lifetime has ended.  In case of a
kernel-side exit and a valid thread ID, no signal needs to be sent
and cancellation does not have an effect, so just return 0.

sysdeps/pthread/tst-kill4.c triggers undefined behavior and is
removed with this commit.

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
Adhemerval Zanella
6f4973c1a2 nptl: Fix tst-cancel7 and tst-cancelx7 race condition (BZ #14232)
A mapped temporary file and a semaphore is used to synchronize the
pid information on the created file, the semaphore is updated once
the file contents is flushed.

Checked on x86_64-linux-gnu.

Reviewed-by: Florian Weimer <fweimer@redhat.com>
2021-08-26 17:13:47 -03:00
Joseph Myers
2ee9b24f47 Fix build of nptl/tst-thread_local1.cc with GCC 12
The test nptl/tst-thread_local1.cc fails to build with GCC mainline
because of changes to what libstdc++ headers implicitly include what
other headers:

tst-thread_local1.cc: In function 'int do_test()':
tst-thread_local1.cc:177:5: error: variable 'std::array<std::pair<const char*, std::function<void(void* (*)(void*))> >, 2> do_thread_X' has initializer but incomplete type
  177 |     do_thread_X
      |     ^~~~~~~~~~~

Fix this by adding an explicit include of <array>.

Tested with build-many-glibcs.py for aarch64-linux-gnu.
2021-08-02 16:33:44 +00:00
Siddhesh Poyarekar
2d2d9f2b48 Move malloc hooks into a compat DSO
Remove all malloc hook uses from core malloc functions and move it
into a new library libc_malloc_debug.so.  With this, the hooks now no
longer have any effect on the core library.

libc_malloc_debug.so is a malloc interposer that needs to be preloaded
to get hooks functionality back so that the debugging features that
depend on the hooks, i.e. malloc-check, mcheck and mtrace work again.
Without the preloaded DSO these debugging features will be nops.
These features will be ported away from hooks in subsequent patches.

Similarly, legacy applications that need hooks functionality need to
preload libc_malloc_debug.so.

The symbols exported by libc_malloc_debug.so are maintained at exactly
the same version as libc.so.

Finally, static binaries will no longer be able to use malloc
debugging features since they cannot preload the debugging DSO.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-07-22 18:37:59 +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
aaacde11f2 Reduce <limits.h> pollution due to dynamic PTHREAD_STACK_MIN
<limits.h> used to be a header file with no declarations.
GCC's libgomp includes it in a #pragma GCC visibility hidden block.
Including <unistd.h> from <limits.h> (indirectly) declares everything
in <unistd.h> with hidden visibility, resulting in linker failures.

This commit avoids C declarations in assembler mode and only declares
__sysconf in <limits.h> (and not the entire contents of <unistd.h>).
The __sysconf symbol is already part of the ABI.  PTHREAD_STACK_MIN
is no longer defined for __USE_DYNAMIC_STACK_SIZE && __ASSEMBLER__
because there is no possible definition.

Additionally, PTHREAD_STACK_MIN is now defined by <pthread.h> for
__USE_MISC because this is what developers expect based on the macro
name.  It also helps to avoid libgomp linker failures in GCC because
libgomp includes <pthread.h> before its visibility hacks.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-12 18:43:32 +02:00
H.J. Lu
5d98a7dae9 Define PTHREAD_STACK_MIN to sysconf(_SC_THREAD_STACK_MIN)
The constant PTHREAD_STACK_MIN may be too small for some processors.
Rename _SC_SIGSTKSZ_SOURCE to _DYNAMIC_STACK_SIZE_SOURCE.  When
_DYNAMIC_STACK_SIZE_SOURCE or _GNU_SOURCE are defined, define
PTHREAD_STACK_MIN to sysconf(_SC_THREAD_STACK_MIN) which is changed
to MIN (PTHREAD_STACK_MIN, sysconf(_SC_MINSIGSTKSZ)).

Consolidate <bits/local_lim.h> with <bits/pthread_stack_min.h> to
provide a constant target specific PTHREAD_STACK_MIN value.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-07-09 15:10:35 -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
508ee037a3 nptl: Use out-of-line wake function in __libc_lock_unlock slow path
This slightly reduces code size, as can be seen below.
__libc_lock_unlock is usually used along with __libc_lock_lock in
the same function.  __libc_lock_lock already has an out-of-line
slow path, so this change should not introduce many additional
non-leaf functions.

This change also fixes a link failure in 32-bit Arm thumb mode
because commit 1f9c804fbd
("nptl: Use internal low-level lock type for !IS_IN (libc)")
introduced __libc_do_syscall calls outside of libc.

Before x86-64:

   text	   data	    bss	    dec	    hex	filename
1937748	  20456	  54896	2013100	 1eb7ac	libc.so.6
  25601	    856	  12768	  39225	   9939	nss/libnss_db.so.2
  40310	    952	  25144	  66406	  10366	nss/libnss_files.so.2

After x86-64:
   text	   data	    bss	    dec	    hex	filename
1935312	  20456	  54896	2010664	 1eae28	libc.so.6
  25559	    864	  12768	  39191	   9917	nss/libnss_db.so.2
  39764	    960	  25144	  65868	  1014c	nss/libnss_files.so.2

Before i686:

2110961	  11272	  39144	2161377	 20fae1	libc.so.6
  27243	    428	  12652	  40323	   9d83	nss/libnss_db.so.2
  43062	    476	  25028	  68566	  10bd6	nss/libnss_files.so.2

After i686:

2107347	  11272	  39144	2157763	 20ecc3	libc.so.6
  26929	    432	  12652	  40013	   9c4d	nss/libnss_db.so.2
  43132	    480	  25028	  68640	  10c20	nss/libnss_files.so.2

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-07-09 10:59:22 +02:00
Florian Weimer
ceda365fba nptl: Reduce the GLIBC_PRIVATE ABI
The remaining symbols are mostly used by libthread_db.
__pthread_get_minstack has to remain exported even though unused.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-07-07 08:41:21 +02:00
Florian Weimer
8ec022a037 nptl: Remove GLIBC_2.34 versions of __pthread_mutex_lock, __pthread_mutex_unlock
Now that there are no internal users anymore, these new symbol
versions can be removed from the public ABI.  The compatibility
symbols remain.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-07-07 08:41:17 +02:00
Florian Weimer
dd45734e32 nptl: Add glibc.pthread.stack_cache_size tunable
The valgrind/helgrind test suite needs a way to make stack dealloction
more prompt, and this feature seems to be generally useful.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
2021-06-28 16:41:58 +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
Florian Weimer
30639e79d3 Linux: Cleanups after librt move
librt.so is no longer installed for PTHREAD_IN_LIBC, and tests
are not linked against it.  $(librt) is introduced globally for
shared tests that need to be linked for both PTHREAD_IN_LIBC
and !PTHREAD_IN_LIBC.

GLIBC_PRIVATE symbols that were needed during the transition are
removed again.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-06-28 09:51:01 +02:00
Florian Weimer
d12506b2db Linux: Move aio_init from librt into libc
This commit also moves the aio_misc and aio_sigquue helper,
so GLIBC_PRIVATE exports need to be added.

The symbol was moved using scripts/move-symbol-to-libc.py.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-06-25 11:48:25 +02:00
Adhemerval Zanella
9f70985569 Consolidate pthread_atfork
The pthread_atfork is similar between Linux and Hurd, only the compat
version bits differs.  The generic version is place at sysdeps/pthread
with a common name.

It also fixes an issue with Hurd license, where the static-only object
did not use LGPL + exception.

Checked on x86_64-linux-gnu, i686-linux-gnu, and with a build for
i686-gnu.
2021-06-24 10:04:41 -03:00
Adhemerval Zanella
bf6749a7f8 nptl: Use SA_RESTART for SIGCANCEL handler
The usage of signals to implementation pthread cancellation is an
implementation detail and should not be visible through cancellation
entrypoints.

However now that pthread_cancel always send the SIGCANCEL, some
entrypoint might be interruptable and return EINTR to the caller
(for instance on sem_wait).

Using SA_RESTART hides this, since the cancellation handler should
either act uppon cancellation (if asynchronous cancellation is enable)
or ignore the cancellation internal signal.

Checked on x86_64-linux-gnu and i686-linux-gnu.
2021-06-23 13:45:13 -03:00
Andreas Schwab
e8d52b64a5 Remove unsused symbols from nptl/Versions
The (private) symbols __pthread_clock_gettime, __pthread_clock_settime and
__pthread_initialize_minimal haven't been defined by libpthread for some
time.
2021-06-22 18:12:48 +02:00
Adhemerval Zanella
b769b0a2cb linux: Only use 64-bit syscall if required for internal futex
For !__ASSUME_TIME64_SYSCALLS there is no need to issue a 64-bit syscall
if the provided timeout fits in a 32-bit one.  The 64-bit usage should
be rare since the timeout is a relative one.

Checked on i686-linux-gnu on a 4.15 kernel and on a 5.11 kernel
(with and without --enable-kernel=5.1) and on x86_64-linux-gnu.

Reviewed-by: Lukasz Majewski <lukma@denx.de>
2021-06-22 12:09:52 -03:00
Florian Weimer
3c79234c7a nptl: Move pthreadP.h into sysdeps directory
This mirrors the situation on Hurd.  These directories are on
the include search part, so #include <pthreadP.h> works after this
change on both Hurd and nptl.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-06-22 09:51:10 +02:00
Florian Weimer
aa9a7f6296 nptl: Export _pthread_cleanup_push, _pthread_cleanup_pop again
These were turned into compat symbols as part of the libpthread
move.  It turns out they are used by language run-time libraries
(e.g., the GCC D front end), so it makes to preserve them as
external symbols even though they are not declared in any header
file.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>
2021-06-15 21:19:16 +02:00
Adhemerval Zanella
088d3291ef y2038: Add test coverage
It is enabled through a new rule, tests-y2038, which is built only
when the ABI supports the comapt 64-bit time_t (defined by the
header time64-compat.h, which also enables the creation of the
symbol Version for Linux).  It means the tests are not built
for ABI which already provide default 64-bit time_t.

The new rule already adds the required LFS and 64-bit time_t
compiler flags.

The current coverage is:

  * libc:
    - adjtime                       tst-adjtime-time64
    - adjtimex                      tst-adjtimex-time64
    - clock_adjtime                 tst-clock_adjtime-time64
    - clock_getres                  tst-clock-time64, tst-cpuclock1-time64
    - clock_gettime                 tst-clock-time64, tst-clock2-time64,
				    tst-cpuclock1-time64
    - clock_nanosleep               tst-clock_nanosleep-time64,
				    tst-cpuclock1-time64
    - clock_settime                 tst-clock2-time64
    - cnd_timedwait                 tst-cnd-timedwait-time64
    - ctime                         tst-ctime-time64
    - ctime_r                       tst-ctime-time64
    - difftime                      tst-difftime-time64
    - fstat                         tst-stat-time64
    - fstatat                       tst-stat-time64
    - futimens                      tst-futimens-time64
    - futimes                       tst-futimes-time64
    - futimesat                     tst-futimesat-time64
    - fts_*                         tst-fts-time64
    - getitimer                     tst-itimer-timer64
    - getrusage
    - gettimeofday                  tst-clock_nanosleep-time64
    - glob / globfree               tst-gnuglob64-time64
    - gmtime                        tst-gmtime-time64
    - gmtime_r                      tst-gmtime-time64
    - lstat                         tst-stat-time64
    - localtime                     tst-y2039-time64
    - localtime_t                   tst-y2039-time64
    - lutimes                       tst-lutimes-time64
    - mktime                        tst-mktime4-time64
    - mq_timedreceive               tst-mqueue{1248}-time64
    - mq_timedsend                  tst-mqueue{1248}-time64
    - msgctl                        test-sysvmsg-time64
    - mtx_timedlock                 tst-mtx-timedlock-time64
    - nanosleep                     tst-cpuclock{12}-time64,
				    tst-mqueue8-time64, tst-clock-time64
    - nftw / ftw                    ftwtest-time64
    - ntp_adjtime                   tst-ntp_adjtime-time64
    - ntp_gettime                   tst-ntp_gettime-time64
    - ntp_gettimex                  tst-ntp_gettimex-time64
    - ppoll                         tst-ppoll-time64
    - pselect                       tst-pselect-time64
    - pthread_clockjoin_np          tst-join14-time64
    - pthread_cond_clockwait        tst-cond11-time64
    - pthread_cond_timedwait        tst-abstime-time64
    - pthread_mutex_clocklock       tst-abstime-time64
    - pthread_mutex_timedlock       tst-abstime-time64
    - pthread_rwlock_clockrdlock    tst-abstime-time64, tst-rwlock14-time64
    - pthread_rwlock_clockwrlock    tst-abstime-time64, tst-rwlock14-time64
    - pthread_rwlock_timedrdlock    tst-abstime-time64, tst-rwlock14-time64
    - pthread_rwlock_timedwrlock    tst-abstime-time64, tst-rwlock14-time64
    - pthread_timedjoin_np          tst-join14-time64
    - recvmmsg                      tst-cancel4_2-time64
    - sched_rr_get_interval         tst-sched_rr_get_interval-time64
    - select                        tst-select-time64
    - sem_clockwait                 tst-sem5-time64
    - sem_timedwait                 tst-sem5-time64
    - semctl                        test-sysvsem-time64
    - semtimedop                    test-sysvsem-time64
    - setitimer                     tst-mqueue2-time64, tst-itimer-timer64
    - settimeofday                  tst-settimeofday-time64
    - shmctl                        test-sysvshm-time64
    - sigtimedwait                  tst-sigtimedwait-time64
    - stat                          tst-stat-time64
    - thrd_sleep                    tst-thrd-sleep-time64
    - time                          tst-mqueue{1248}-time64
    - timegm                        tst-timegm-time64
    - timer_gettime                 tst-timer4-time64
    - timer_settime                 tst-timer4-time64
    - timerfd_gettime               tst-timerfd-time64
    - timerfd_settime               tst-timerfd-time64
    - timespec_get                  tst-timespec_get-time64
    - timespec_getres               tst-timespec_getres-time64
    - utime                         tst-utime-time64
    - utimensat                     tst-utimensat-time64
    - utimes                        tst-utimes-time64
    - wait3                         tst-wait3-time64
    - wait4                         tst-wait4-time64

  * librt:
    - aio_suspend                   tst-aio6-time64
    - mq_timedreceive               tst-mqueue{1248}-time64
    - mq_timedsend                  tst-mqueue{1248}-time64
    - timer_gettime                 tst-timer4-time64
    - timer_settime                 tst-timer4-time64

  * libanl:
    - gai_suspend

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-06-15 10:42:11 -03:00
Adhemerval Zanella
47f24c21ee y2038: Add support for 64-bit time on legacy ABIs
A new build flag, _TIME_BITS, enables the usage of the newer 64-bit
time symbols for legacy ABI (where 32-bit time_t is default).  The 64
bit time support is only enabled if LFS (_FILE_OFFSET_BITS=64) is
also used.

Different than LFS support, the y2038 symbols are added only for the
required ABIs (armhf, csky, hppa, i386, m68k, microblaze, mips32,
mips64-n32, nios2, powerpc32, sparc32, s390-32, and sh).  The ABIs with
64-bit time support are unchanged, both for symbol and types
redirection.

On Linux the full 64-bit time support requires a minimum of kernel
version v5.1.  Otherwise, the 32-bit fallbacks are used and might
results in error with overflow return code (EOVERFLOW).

The i686-gnu does not yet support 64-bit time.

This patch exports following rediretions to support 64-bit time:

  * libc:
    adjtime
    adjtimex
    clock_adjtime
    clock_getres
    clock_gettime
    clock_nanosleep
    clock_settime
    cnd_timedwait
    ctime
    ctime_r
    difftime
    fstat
    fstatat
    futimens
    futimes
    futimesat
    getitimer
    getrusage
    gettimeofday
    gmtime
    gmtime_r
    localtime
    localtime_r
    lstat_time
    lutimes
    mktime
    msgctl
    mtx_timedlock
    nanosleep
    nanosleep
    ntp_gettime
    ntp_gettimex
    ppoll
    pselec
    pselect
    pthread_clockjoin_np
    pthread_cond_clockwait
    pthread_cond_timedwait
    pthread_mutex_clocklock
    pthread_mutex_timedlock
    pthread_rwlock_clockrdlock
    pthread_rwlock_clockwrlock
    pthread_rwlock_timedrdlock
    pthread_rwlock_timedwrlock
    pthread_timedjoin_np
    recvmmsg
    sched_rr_get_interval
    select
    sem_clockwait
    semctl
    semtimedop
    sem_timedwait
    setitimer
    settimeofday
    shmctl
    sigtimedwait
    stat
    thrd_sleep
    time
    timegm
    timerfd_gettime
    timerfd_settime
    timespec_get
    utime
    utimensat
    utimes
    utimes
    wait3
    wait4

  * librt:
    aio_suspend
    mq_timedreceive
    mq_timedsend
    timer_gettime
    timer_settime

  * libanl:
    gai_suspend

Reviewed-by: Lukasz Majewski <lukma@denx.de>
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
2021-06-15 10:42:11 -03:00
Adhemerval Zanella
8fe503f74e nptl: Avoid async cancellation to wrongly update __nptl_nthreads (BZ #19366)
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
a6c813d0ad nptl: Use pthread_kill on pthread_cancel
It consolidates the tgkill call and it is the first step of making
pthread_cancel async-signal-safe.  It also fix a possible issue
where the 'struct pthread' tid is not read atomically, which might
send an invalid cancellation signal (similar to what
db988e50a8 fixed for pthread_join).

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
2021-06-09 15:16:45 -03:00
Adhemerval Zanella
f779b1efb3 nptl: Implement raise in terms of pthread_kill
Now that pthread_kill is provided by libc.so it is possible to
implement the generic POSIX implementation as
'pthread_kill(pthread_self(), sig)'.

For Linux implementation, pthread_kill read the targeting TID from
the TCB.  For raise, this it not possible because it would make raise
fail when issue after vfork (where creates the resulting process
has a different TID from the parent, but its TCB is not updated as
for pthread_create).  To make raise use pthread_kill, it is make
usable from vfork by getting the target thread id through gettid
syscall.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
2021-06-09 15:16:45 -03:00
Adhemerval Zanella
8c1c0aae20 nptl: Move cancel type out of cancelhandling
Now that the thread cancellation type is not accessed concurrently
anymore, it is possible to move it out the cancelhandling.

By removing the cancel state out of the internal thread cancel handling
state there is no need to check if cancelled bit was set in CAS
operation.

It allows simplifing the cancellation wrappers and the
CANCEL_CANCELED_AND_ASYNCHRONOUS is removed.

Checked on x86_64-linux-gnu and aarch64-linux-gnu.
2021-06-09 15:16:45 -03:00