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835 lines
27 KiB
835 lines
27 KiB
2 years ago
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commit 290db09546b260a30137d03ce97a857e6f15b648
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Author: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Wed Apr 6 12:24:42 2022 -0300
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nptl: Handle spurious EINTR when thread cancellation is disabled (BZ#29029)
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Some Linux interfaces never restart after being interrupted by a signal
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handler, regardless of the use of SA_RESTART [1]. It means that for
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pthread cancellation, if the target thread disables cancellation with
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pthread_setcancelstate and calls such interfaces (like poll or select),
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it should not see spurious EINTR failures due the internal SIGCANCEL.
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However recent changes made pthread_cancel to always sent the internal
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signal, regardless of the target thread cancellation status or type.
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To fix it, the previous semantic is restored, where the cancel signal
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is only sent if the target thread has cancelation enabled in
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asynchronous mode.
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The cancel state and cancel type is moved back to cancelhandling
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and atomic operation are used to synchronize between threads. The
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patch essentially revert the following commits:
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8c1c0aae20 nptl: Move cancel type out of cancelhandling
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2b51742531 nptl: Move cancel state out of cancelhandling
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26cfbb7162 nptl: Remove CANCELING_BITMASK
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However I changed the atomic operation to follow the internal C11
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semantic and removed the MACRO usage, it simplifies a bit the
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resulting code (and removes another usage of the old atomic macros).
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Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu,
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and powerpc64-linux-gnu.
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[1] https://man7.org/linux/man-pages/man7/signal.7.html
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Reviewed-by: Florian Weimer <fweimer@redhat.com>
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Tested-by: Aurelien Jarno <aurelien@aurel32.net>
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(cherry-picked from commit 404656009b459658138ed1bd18f3c6cf3863e6a6)
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diff --git a/manual/process.texi b/manual/process.texi
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index 28c9531f4294f56e..9307379194c6f666 100644
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--- a/manual/process.texi
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+++ b/manual/process.texi
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@@ -68,8 +68,7 @@ until the subprogram terminates before you can do anything else.
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@c CLEANUP_HANDLER @ascuplugin @ascuheap @acsmem
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@c libc_cleanup_region_start @ascuplugin @ascuheap @acsmem
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@c pthread_cleanup_push_defer @ascuplugin @ascuheap @acsmem
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-@c __pthread_testcancel @ascuplugin @ascuheap @acsmem
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-@c CANCEL_ENABLED_AND_CANCELED ok
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+@c cancel_enabled_and_canceled @ascuplugin @ascuheap @acsmem
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@c do_cancel @ascuplugin @ascuheap @acsmem
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@c cancel_handler ok
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@c kill syscall ok
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diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c
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index 554a721f814b53c4..96101753ec2f4323 100644
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--- a/nptl/allocatestack.c
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+++ b/nptl/allocatestack.c
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@@ -120,8 +120,6 @@ get_cached_stack (size_t *sizep, void **memp)
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/* Cancellation handling is back to the default. */
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result->cancelhandling = 0;
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- result->cancelstate = PTHREAD_CANCEL_ENABLE;
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- result->canceltype = PTHREAD_CANCEL_DEFERRED;
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result->cleanup = NULL;
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result->setup_failed = 0;
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diff --git a/nptl/cancellation.c b/nptl/cancellation.c
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index 05962784d51fb98b..e97d56f97d7a5698 100644
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--- a/nptl/cancellation.c
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+++ b/nptl/cancellation.c
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@@ -31,19 +31,26 @@ int
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__pthread_enable_asynccancel (void)
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{
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struct pthread *self = THREAD_SELF;
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+ int oldval = atomic_load_relaxed (&self->cancelhandling);
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- int oldval = THREAD_GETMEM (self, canceltype);
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- THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_ASYNCHRONOUS);
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+ while (1)
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+ {
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+ int newval = oldval | CANCELTYPE_BITMASK;
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- int ch = THREAD_GETMEM (self, cancelhandling);
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+ if (newval == oldval)
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+ break;
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- if (self->cancelstate == PTHREAD_CANCEL_ENABLE
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- && (ch & CANCELED_BITMASK)
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- && !(ch & EXITING_BITMASK)
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- && !(ch & TERMINATED_BITMASK))
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- {
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- THREAD_SETMEM (self, result, PTHREAD_CANCELED);
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- __do_cancel ();
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+ if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
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+ &oldval, newval))
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+ {
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+ if (cancel_enabled_and_canceled_and_async (newval))
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+ {
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+ self->result = PTHREAD_CANCELED;
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+ __do_cancel ();
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+ }
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+
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+ break;
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+ }
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}
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return oldval;
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@@ -57,10 +64,29 @@ __pthread_disable_asynccancel (int oldtype)
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{
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/* If asynchronous cancellation was enabled before we do not have
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anything to do. */
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- if (oldtype == PTHREAD_CANCEL_ASYNCHRONOUS)
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+ if (oldtype & CANCELTYPE_BITMASK)
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return;
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struct pthread *self = THREAD_SELF;
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- self->canceltype = PTHREAD_CANCEL_DEFERRED;
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+ int newval;
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+ int oldval = atomic_load_relaxed (&self->cancelhandling);
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+ do
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+ {
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+ newval = oldval & ~CANCELTYPE_BITMASK;
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+ }
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+ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
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+ &oldval, newval));
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+
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+ /* We cannot return when we are being canceled. Upon return the
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+ thread might be things which would have to be undone. The
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+ following loop should loop until the cancellation signal is
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+ delivered. */
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+ while (__glibc_unlikely ((newval & (CANCELING_BITMASK | CANCELED_BITMASK))
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+ == CANCELING_BITMASK))
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+ {
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+ futex_wait_simple ((unsigned int *) &self->cancelhandling, newval,
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+ FUTEX_PRIVATE);
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+ newval = atomic_load_relaxed (&self->cancelhandling);
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+ }
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}
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libc_hidden_def (__pthread_disable_asynccancel)
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diff --git a/nptl/cleanup_defer.c b/nptl/cleanup_defer.c
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index 7e858d0df068276b..35ba40fb0247c7cc 100644
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--- a/nptl/cleanup_defer.c
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+++ b/nptl/cleanup_defer.c
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@@ -31,9 +31,22 @@ ___pthread_register_cancel_defer (__pthread_unwind_buf_t *buf)
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ibuf->priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf);
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ibuf->priv.data.cleanup = THREAD_GETMEM (self, cleanup);
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- /* Disable asynchronous cancellation for now. */
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- ibuf->priv.data.canceltype = THREAD_GETMEM (self, canceltype);
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- THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED);
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+ int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
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+ if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
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+ {
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+ int newval;
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+ do
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+ {
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+ newval = cancelhandling & ~CANCELTYPE_BITMASK;
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+ }
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+ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
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+ &cancelhandling,
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+ newval));
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+ }
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+
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+ ibuf->priv.data.canceltype = (cancelhandling & CANCELTYPE_BITMASK
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+ ? PTHREAD_CANCEL_ASYNCHRONOUS
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+ : PTHREAD_CANCEL_DEFERRED);
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/* Store the new cleanup handler info. */
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THREAD_SETMEM (self, cleanup_jmp_buf, (struct pthread_unwind_buf *) buf);
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@@ -55,9 +68,26 @@ ___pthread_unregister_cancel_restore (__pthread_unwind_buf_t *buf)
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THREAD_SETMEM (self, cleanup_jmp_buf, ibuf->priv.data.prev);
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- THREAD_SETMEM (self, canceltype, ibuf->priv.data.canceltype);
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- if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
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- __pthread_testcancel ();
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+ if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_DEFERRED)
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+ return;
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+
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+ int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
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+ if (cancelhandling & CANCELTYPE_BITMASK)
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+ {
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+ int newval;
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+ do
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+ {
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+ newval = cancelhandling | CANCELTYPE_BITMASK;
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+ }
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+ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
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+ &cancelhandling, newval));
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+
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+ if (cancel_enabled_and_canceled (cancelhandling))
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+ {
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+ self->result = PTHREAD_CANCELED;
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+ __do_cancel ();
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+ }
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+ }
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}
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versioned_symbol (libc, ___pthread_unregister_cancel_restore,
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__pthread_unregister_cancel_restore, GLIBC_2_34);
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diff --git a/nptl/descr.h b/nptl/descr.h
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index dabf980e29615db3..dfef9c4bda075d13 100644
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--- a/nptl/descr.h
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+++ b/nptl/descr.h
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@@ -280,18 +280,27 @@ struct pthread
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/* Flags determining processing of cancellation. */
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int cancelhandling;
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+ /* Bit set if cancellation is disabled. */
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+#define CANCELSTATE_BIT 0
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+#define CANCELSTATE_BITMASK (1 << CANCELSTATE_BIT)
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+ /* Bit set if asynchronous cancellation mode is selected. */
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+#define CANCELTYPE_BIT 1
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+#define CANCELTYPE_BITMASK (1 << CANCELTYPE_BIT)
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+ /* Bit set if canceling has been initiated. */
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+#define CANCELING_BIT 2
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+#define CANCELING_BITMASK (1 << CANCELING_BIT)
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/* Bit set if canceled. */
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#define CANCELED_BIT 3
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-#define CANCELED_BITMASK (0x01 << CANCELED_BIT)
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+#define CANCELED_BITMASK (1 << CANCELED_BIT)
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/* Bit set if thread is exiting. */
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#define EXITING_BIT 4
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-#define EXITING_BITMASK (0x01 << EXITING_BIT)
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+#define EXITING_BITMASK (1 << EXITING_BIT)
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/* Bit set if thread terminated and TCB is freed. */
|
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#define TERMINATED_BIT 5
|
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|
-#define TERMINATED_BITMASK (0x01 << TERMINATED_BIT)
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|
+#define TERMINATED_BITMASK (1 << TERMINATED_BIT)
|
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|
/* Bit set if thread is supposed to change XID. */
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|
#define SETXID_BIT 6
|
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|
-#define SETXID_BITMASK (0x01 << SETXID_BIT)
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+#define SETXID_BITMASK (1 << SETXID_BIT)
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|
|
||
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/* Flags. Including those copied from the thread attribute. */
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int flags;
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@@ -391,14 +400,6 @@ struct pthread
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/* Indicates whether is a C11 thread created by thrd_creat. */
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bool c11;
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|
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- /* Thread cancel state (PTHREAD_CANCEL_ENABLE or
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- PTHREAD_CANCEL_DISABLE). */
|
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- unsigned char cancelstate;
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|
-
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- /* Thread cancel type (PTHREAD_CANCEL_DEFERRED or
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- PTHREAD_CANCEL_ASYNCHRONOUS). */
|
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- unsigned char canceltype;
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|
-
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/* Used in __pthread_kill_internal to detected a thread that has
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exited or is about to exit. exit_lock must only be acquired
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after blocking signals. */
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@@ -418,6 +419,22 @@ struct pthread
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(sizeof (struct pthread) - offsetof (struct pthread, end_padding))
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} __attribute ((aligned (TCB_ALIGNMENT)));
|
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|
|
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|
+static inline bool
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+cancel_enabled_and_canceled (int value)
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|
+{
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+ return (value & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK
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+ | TERMINATED_BITMASK))
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+ == CANCELED_BITMASK;
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+}
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|
+
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+static inline bool
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+cancel_enabled_and_canceled_and_async (int value)
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+{
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+ return ((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK
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+ | EXITING_BITMASK | TERMINATED_BITMASK))
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+ == (CANCELTYPE_BITMASK | CANCELED_BITMASK);
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+}
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+
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/* This yields the pointer that TLS support code calls the thread pointer. */
|
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#if TLS_TCB_AT_TP
|
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# define TLS_TPADJ(pd) (pd)
|
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|
diff --git a/nptl/libc-cleanup.c b/nptl/libc-cleanup.c
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index 180d15bc9e9a8368..fccb1abe69aa693c 100644
|
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--- a/nptl/libc-cleanup.c
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+++ b/nptl/libc-cleanup.c
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|
@@ -27,9 +27,24 @@ __libc_cleanup_push_defer (struct _pthread_cleanup_buffer *buffer)
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|
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buffer->__prev = THREAD_GETMEM (self, cleanup);
|
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|
|
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+ int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
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|
+
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/* Disable asynchronous cancellation for now. */
|
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- buffer->__canceltype = THREAD_GETMEM (self, canceltype);
|
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- THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED);
|
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+ if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK))
|
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|
+ {
|
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|
+ int newval;
|
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|
+ do
|
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|
+ {
|
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|
+ newval = cancelhandling & ~CANCELTYPE_BITMASK;
|
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|
+ }
|
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|
+ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
|
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|
+ &cancelhandling,
|
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|
+ newval));
|
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|
+ }
|
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|
+
|
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|
+ buffer->__canceltype = (cancelhandling & CANCELTYPE_BITMASK
|
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|
+ ? PTHREAD_CANCEL_ASYNCHRONOUS
|
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|
+ : PTHREAD_CANCEL_DEFERRED);
|
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|
|
||
|
THREAD_SETMEM (self, cleanup, buffer);
|
||
|
}
|
||
|
@@ -42,8 +57,22 @@ __libc_cleanup_pop_restore (struct _pthread_cleanup_buffer *buffer)
|
||
|
|
||
|
THREAD_SETMEM (self, cleanup, buffer->__prev);
|
||
|
|
||
|
- THREAD_SETMEM (self, canceltype, buffer->__canceltype);
|
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|
- if (buffer->__canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
|
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|
- __pthread_testcancel ();
|
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|
+ int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
|
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|
+ if (cancelhandling & CANCELTYPE_BITMASK)
|
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|
+ {
|
||
|
+ int newval;
|
||
|
+ do
|
||
|
+ {
|
||
|
+ newval = cancelhandling | CANCELTYPE_BITMASK;
|
||
|
+ }
|
||
|
+ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling,
|
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|
+ &cancelhandling, newval));
|
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|
+
|
||
|
+ if (cancel_enabled_and_canceled (cancelhandling))
|
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|
+ {
|
||
|
+ self->result = PTHREAD_CANCELED;
|
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|
+ __do_cancel ();
|
||
|
+ }
|
||
|
+ }
|
||
|
}
|
||
|
libc_hidden_def (__libc_cleanup_pop_restore)
|
||
|
diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c
|
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|
index 9bac6e3b76a20312..2680b55586e035fe 100644
|
||
|
--- a/nptl/pthread_cancel.c
|
||
|
+++ b/nptl/pthread_cancel.c
|
||
|
@@ -43,18 +43,29 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx)
|
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|
|
||
|
struct pthread *self = THREAD_SELF;
|
||
|
|
||
|
- int ch = atomic_load_relaxed (&self->cancelhandling);
|
||
|
- /* Cancelation not enabled, not cancelled, or already exitting. */
|
||
|
- if (self->cancelstate == PTHREAD_CANCEL_DISABLE
|
||
|
- || (ch & CANCELED_BITMASK) == 0
|
||
|
- || (ch & EXITING_BITMASK) != 0)
|
||
|
- return;
|
||
|
-
|
||
|
- /* Set the return value. */
|
||
|
- THREAD_SETMEM (self, result, PTHREAD_CANCELED);
|
||
|
- /* Make sure asynchronous cancellation is still enabled. */
|
||
|
- if (self->canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
|
||
|
- __do_cancel ();
|
||
|
+ int oldval = atomic_load_relaxed (&self->cancelhandling);
|
||
|
+ while (1)
|
||
|
+ {
|
||
|
+ /* We are canceled now. When canceled by another thread this flag
|
||
|
+ is already set but if the signal is directly send (internally or
|
||
|
+ from another process) is has to be done here. */
|
||
|
+ int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
|
||
|
+
|
||
|
+ if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
|
||
|
+ /* Already canceled or exiting. */
|
||
|
+ break;
|
||
|
+
|
||
|
+ if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
|
||
|
+ &oldval, newval))
|
||
|
+ {
|
||
|
+ self->result = PTHREAD_CANCELED;
|
||
|
+
|
||
|
+ /* Make sure asynchronous cancellation is still enabled. */
|
||
|
+ if ((oldval & CANCELTYPE_BITMASK) != 0)
|
||
|
+ /* Run the registered destructors and terminate the thread. */
|
||
|
+ __do_cancel ();
|
||
|
+ }
|
||
|
+ }
|
||
|
}
|
||
|
|
||
|
int
|
||
|
@@ -93,29 +104,70 @@ __pthread_cancel (pthread_t th)
|
||
|
}
|
||
|
#endif
|
||
|
|
||
|
- int oldch = atomic_fetch_or_acquire (&pd->cancelhandling, CANCELED_BITMASK);
|
||
|
- if ((oldch & CANCELED_BITMASK) != 0)
|
||
|
- return 0;
|
||
|
-
|
||
|
- if (pd == THREAD_SELF)
|
||
|
+ /* Some syscalls are never restarted after being interrupted by a signal
|
||
|
+ handler, regardless of the use of SA_RESTART (they always fail with
|
||
|
+ EINTR). So pthread_cancel cannot send SIGCANCEL unless the cancellation
|
||
|
+ is enabled and set as asynchronous (in this case the cancellation will
|
||
|
+ be acted in the cancellation handler instead by the syscall wrapper).
|
||
|
+ Otherwise the target thread is set as 'cancelling' (CANCELING_BITMASK)
|
||
|
+ by atomically setting 'cancelhandling' and the cancelation will be acted
|
||
|
+ upon on next cancellation entrypoing in the target thread.
|
||
|
+
|
||
|
+ It also requires to atomically check if cancellation is enabled and
|
||
|
+ asynchronous, so both cancellation state and type are tracked on
|
||
|
+ 'cancelhandling'. */
|
||
|
+
|
||
|
+ int result = 0;
|
||
|
+ int oldval = atomic_load_relaxed (&pd->cancelhandling);
|
||
|
+ int newval;
|
||
|
+ do
|
||
|
{
|
||
|
- /* A single-threaded process should be able to kill itself, since there
|
||
|
- is nothing in the POSIX specification that says that it cannot. So
|
||
|
- we set multiple_threads to true so that cancellation points get
|
||
|
- executed. */
|
||
|
- THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
|
||
|
+ newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
|
||
|
+ if (oldval == newval)
|
||
|
+ break;
|
||
|
+
|
||
|
+ /* If the cancellation is handled asynchronously just send a
|
||
|
+ signal. We avoid this if possible since it's more
|
||
|
+ expensive. */
|
||
|
+ if (cancel_enabled_and_canceled_and_async (newval))
|
||
|
+ {
|
||
|
+ /* Mark the cancellation as "in progress". */
|
||
|
+ int newval2 = oldval | CANCELING_BITMASK;
|
||
|
+ if (!atomic_compare_exchange_weak_acquire (&pd->cancelhandling,
|
||
|
+ &oldval, newval2))
|
||
|
+ continue;
|
||
|
+
|
||
|
+ if (pd == THREAD_SELF)
|
||
|
+ /* This is not merely an optimization: An application may
|
||
|
+ call pthread_cancel (pthread_self ()) without calling
|
||
|
+ pthread_create, so the signal handler may not have been
|
||
|
+ set up for a self-cancel. */
|
||
|
+ {
|
||
|
+ pd->result = PTHREAD_CANCELED;
|
||
|
+ if ((newval & CANCELTYPE_BITMASK) != 0)
|
||
|
+ __do_cancel ();
|
||
|
+ }
|
||
|
+ else
|
||
|
+ /* The cancellation handler will take care of marking the
|
||
|
+ thread as canceled. */
|
||
|
+ result = __pthread_kill_internal (th, SIGCANCEL);
|
||
|
+
|
||
|
+ break;
|
||
|
+ }
|
||
|
+
|
||
|
+ /* A single-threaded process should be able to kill itself, since
|
||
|
+ there is nothing in the POSIX specification that says that it
|
||
|
+ cannot. So we set multiple_threads to true so that cancellation
|
||
|
+ points get executed. */
|
||
|
+ THREAD_SETMEM (THREAD_SELF, header.multiple_threads, 1);
|
||
|
#ifndef TLS_MULTIPLE_THREADS_IN_TCB
|
||
|
__libc_multiple_threads = 1;
|
||
|
#endif
|
||
|
-
|
||
|
- THREAD_SETMEM (pd, result, PTHREAD_CANCELED);
|
||
|
- if (pd->cancelstate == PTHREAD_CANCEL_ENABLE
|
||
|
- && pd->canceltype == PTHREAD_CANCEL_ASYNCHRONOUS)
|
||
|
- __do_cancel ();
|
||
|
- return 0;
|
||
|
}
|
||
|
+ while (!atomic_compare_exchange_weak_acquire (&pd->cancelhandling, &oldval,
|
||
|
+ newval));
|
||
|
|
||
|
- return __pthread_kill_internal (th, SIGCANCEL);
|
||
|
+ return result;
|
||
|
}
|
||
|
versioned_symbol (libc, __pthread_cancel, pthread_cancel, GLIBC_2_34);
|
||
|
|
||
|
diff --git a/nptl/pthread_join_common.c b/nptl/pthread_join_common.c
|
||
|
index 7303069316caef13..617056ef10671607 100644
|
||
|
--- a/nptl/pthread_join_common.c
|
||
|
+++ b/nptl/pthread_join_common.c
|
||
|
@@ -57,12 +57,9 @@ __pthread_clockjoin_ex (pthread_t threadid, void **thread_return,
|
||
|
if ((pd == self
|
||
|
|| (self->joinid == pd
|
||
|
&& (pd->cancelhandling
|
||
|
- & (CANCELED_BITMASK | EXITING_BITMASK
|
||
|
+ & (CANCELING_BITMASK | CANCELED_BITMASK | EXITING_BITMASK
|
||
|
| TERMINATED_BITMASK)) == 0))
|
||
|
- && !(self->cancelstate == PTHREAD_CANCEL_ENABLE
|
||
|
- && (pd->cancelhandling & (CANCELED_BITMASK | EXITING_BITMASK
|
||
|
- | TERMINATED_BITMASK))
|
||
|
- == CANCELED_BITMASK))
|
||
|
+ && !cancel_enabled_and_canceled (self->cancelhandling))
|
||
|
/* This is a deadlock situation. The threads are waiting for each
|
||
|
other to finish. Note that this is a "may" error. To be 100%
|
||
|
sure we catch this error we would have to lock the data
|
||
|
diff --git a/nptl/pthread_setcancelstate.c b/nptl/pthread_setcancelstate.c
|
||
|
index 7e2b6e4974bd58bd..cb567be5926816f1 100644
|
||
|
--- a/nptl/pthread_setcancelstate.c
|
||
|
+++ b/nptl/pthread_setcancelstate.c
|
||
|
@@ -31,9 +31,29 @@ __pthread_setcancelstate (int state, int *oldstate)
|
||
|
|
||
|
self = THREAD_SELF;
|
||
|
|
||
|
- if (oldstate != NULL)
|
||
|
- *oldstate = self->cancelstate;
|
||
|
- self->cancelstate = state;
|
||
|
+ int oldval = atomic_load_relaxed (&self->cancelhandling);
|
||
|
+ while (1)
|
||
|
+ {
|
||
|
+ int newval = (state == PTHREAD_CANCEL_DISABLE
|
||
|
+ ? oldval | CANCELSTATE_BITMASK
|
||
|
+ : oldval & ~CANCELSTATE_BITMASK);
|
||
|
+
|
||
|
+ if (oldstate != NULL)
|
||
|
+ *oldstate = ((oldval & CANCELSTATE_BITMASK)
|
||
|
+ ? PTHREAD_CANCEL_DISABLE : PTHREAD_CANCEL_ENABLE);
|
||
|
+
|
||
|
+ if (oldval == newval)
|
||
|
+ break;
|
||
|
+
|
||
|
+ if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
|
||
|
+ &oldval, newval))
|
||
|
+ {
|
||
|
+ if (cancel_enabled_and_canceled_and_async (newval))
|
||
|
+ __do_cancel ();
|
||
|
+
|
||
|
+ break;
|
||
|
+ }
|
||
|
+ }
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
diff --git a/nptl/pthread_setcanceltype.c b/nptl/pthread_setcanceltype.c
|
||
|
index e7b24ae733dcc0f2..e08ff7b141f904f1 100644
|
||
|
--- a/nptl/pthread_setcanceltype.c
|
||
|
+++ b/nptl/pthread_setcanceltype.c
|
||
|
@@ -29,11 +29,32 @@ __pthread_setcanceltype (int type, int *oldtype)
|
||
|
|
||
|
volatile struct pthread *self = THREAD_SELF;
|
||
|
|
||
|
- if (oldtype != NULL)
|
||
|
- *oldtype = self->canceltype;
|
||
|
- self->canceltype = type;
|
||
|
- if (type == PTHREAD_CANCEL_ASYNCHRONOUS)
|
||
|
- __pthread_testcancel ();
|
||
|
+ int oldval = atomic_load_relaxed (&self->cancelhandling);
|
||
|
+ while (1)
|
||
|
+ {
|
||
|
+ int newval = (type == PTHREAD_CANCEL_ASYNCHRONOUS
|
||
|
+ ? oldval | CANCELTYPE_BITMASK
|
||
|
+ : oldval & ~CANCELTYPE_BITMASK);
|
||
|
+
|
||
|
+ if (oldtype != NULL)
|
||
|
+ *oldtype = ((oldval & CANCELTYPE_BITMASK)
|
||
|
+ ? PTHREAD_CANCEL_ASYNCHRONOUS : PTHREAD_CANCEL_DEFERRED);
|
||
|
+
|
||
|
+ if (oldval == newval)
|
||
|
+ break;
|
||
|
+
|
||
|
+ if (atomic_compare_exchange_weak_acquire (&self->cancelhandling,
|
||
|
+ &oldval, newval))
|
||
|
+ {
|
||
|
+ if (cancel_enabled_and_canceled_and_async (newval))
|
||
|
+ {
|
||
|
+ THREAD_SETMEM (self, result, PTHREAD_CANCELED);
|
||
|
+ __do_cancel ();
|
||
|
+ }
|
||
|
+
|
||
|
+ break;
|
||
|
+ }
|
||
|
+ }
|
||
|
|
||
|
return 0;
|
||
|
}
|
||
|
diff --git a/nptl/pthread_testcancel.c b/nptl/pthread_testcancel.c
|
||
|
index 31185d89f2ab84c6..25230215fd607e8b 100644
|
||
|
--- a/nptl/pthread_testcancel.c
|
||
|
+++ b/nptl/pthread_testcancel.c
|
||
|
@@ -24,13 +24,10 @@ void
|
||
|
___pthread_testcancel (void)
|
||
|
{
|
||
|
struct pthread *self = THREAD_SELF;
|
||
|
- int cancelhandling = THREAD_GETMEM (self, cancelhandling);
|
||
|
- if (self->cancelstate == PTHREAD_CANCEL_ENABLE
|
||
|
- && (cancelhandling & CANCELED_BITMASK)
|
||
|
- && !(cancelhandling & EXITING_BITMASK)
|
||
|
- && !(cancelhandling & TERMINATED_BITMASK))
|
||
|
+ int cancelhandling = atomic_load_relaxed (&self->cancelhandling);
|
||
|
+ if (cancel_enabled_and_canceled (cancelhandling))
|
||
|
{
|
||
|
- THREAD_SETMEM (self, result, PTHREAD_CANCELED);
|
||
|
+ self->result = PTHREAD_CANCELED;
|
||
|
__do_cancel ();
|
||
|
}
|
||
|
}
|
||
|
diff --git a/sysdeps/nptl/dl-tls_init_tp.c b/sysdeps/nptl/dl-tls_init_tp.c
|
||
|
index b39dfbff2c6678d5..23aa4cfc0b784dfc 100644
|
||
|
--- a/sysdeps/nptl/dl-tls_init_tp.c
|
||
|
+++ b/sysdeps/nptl/dl-tls_init_tp.c
|
||
|
@@ -107,7 +107,4 @@ __tls_init_tp (void)
|
||
|
It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
|
||
|
purposes this is good enough. */
|
||
|
THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
|
||
|
-
|
||
|
- THREAD_SETMEM (pd, cancelstate, PTHREAD_CANCEL_ENABLE);
|
||
|
- THREAD_SETMEM (pd, canceltype, PTHREAD_CANCEL_DEFERRED);
|
||
|
}
|
||
|
diff --git a/sysdeps/nptl/pthreadP.h b/sysdeps/nptl/pthreadP.h
|
||
|
index 374657a2fd0ee19a..b968afc4c6b61b92 100644
|
||
|
--- a/sysdeps/nptl/pthreadP.h
|
||
|
+++ b/sysdeps/nptl/pthreadP.h
|
||
|
@@ -276,7 +276,7 @@ __do_cancel (void)
|
||
|
struct pthread *self = THREAD_SELF;
|
||
|
|
||
|
/* Make sure we get no more cancellations. */
|
||
|
- THREAD_ATOMIC_BIT_SET (self, cancelhandling, EXITING_BIT);
|
||
|
+ atomic_bit_set (&self->cancelhandling, EXITING_BIT);
|
||
|
|
||
|
__pthread_unwind ((__pthread_unwind_buf_t *)
|
||
|
THREAD_GETMEM (self, cleanup_jmp_buf));
|
||
|
diff --git a/sysdeps/pthread/Makefile b/sysdeps/pthread/Makefile
|
||
|
index c65710169697ad95..00419c4d199df912 100644
|
||
|
--- a/sysdeps/pthread/Makefile
|
||
|
+++ b/sysdeps/pthread/Makefile
|
||
|
@@ -69,6 +69,7 @@ tests += tst-cnd-basic tst-mtx-trylock tst-cnd-broadcast \
|
||
|
tst-cancel12 tst-cancel13 tst-cancel14 tst-cancel15 tst-cancel16 \
|
||
|
tst-cancel18 tst-cancel19 tst-cancel20 tst-cancel21 \
|
||
|
tst-cancel22 tst-cancel23 tst-cancel26 tst-cancel27 tst-cancel28 \
|
||
|
+ tst-cancel29 \
|
||
|
tst-cleanup0 tst-cleanup1 tst-cleanup2 tst-cleanup3 \
|
||
|
tst-clock1 \
|
||
|
tst-cond-except \
|
||
|
diff --git a/sysdeps/pthread/tst-cancel29.c b/sysdeps/pthread/tst-cancel29.c
|
||
|
new file mode 100644
|
||
|
index 0000000000000000..4f0d99e002883be4
|
||
|
--- /dev/null
|
||
|
+++ b/sysdeps/pthread/tst-cancel29.c
|
||
|
@@ -0,0 +1,207 @@
|
||
|
+/* Check if a thread that disables cancellation and which call functions
|
||
|
+ that might be interrupted by a signal do not see the internal SIGCANCEL.
|
||
|
+
|
||
|
+ Copyright (C) 2022 Free Software Foundation, Inc.
|
||
|
+ This file is part of the GNU C Library.
|
||
|
+
|
||
|
+ The GNU C Library is free software; you can redistribute it and/or
|
||
|
+ modify it under the terms of the GNU Lesser General Public
|
||
|
+ License as published by the Free Software Foundation; either
|
||
|
+ version 2.1 of the License, or (at your option) any later version.
|
||
|
+
|
||
|
+ The GNU C Library is distributed in the hope that it will be useful,
|
||
|
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||
|
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||
|
+ Lesser General Public License for more details.
|
||
|
+
|
||
|
+ You should have received a copy of the GNU Lesser General Public
|
||
|
+ License along with the GNU C Library; if not, see
|
||
|
+ <https://www.gnu.org/licenses/>. */
|
||
|
+
|
||
|
+#include <array_length.h>
|
||
|
+#include <errno.h>
|
||
|
+#include <inttypes.h>
|
||
|
+#include <poll.h>
|
||
|
+#include <support/check.h>
|
||
|
+#include <support/support.h>
|
||
|
+#include <support/temp_file.h>
|
||
|
+#include <support/xthread.h>
|
||
|
+#include <sys/socket.h>
|
||
|
+#include <signal.h>
|
||
|
+#include <stdio.h>
|
||
|
+#include <unistd.h>
|
||
|
+
|
||
|
+/* On Linux some interfaces are never restarted after being interrupted by
|
||
|
+ a signal handler, regardless of the use of SA_RESTART. It means that
|
||
|
+ if asynchronous cancellation is not enabled, the pthread_cancel can not
|
||
|
+ set the internal SIGCANCEL otherwise the interface might see a spurious
|
||
|
+ EINTR failure. */
|
||
|
+
|
||
|
+static pthread_barrier_t b;
|
||
|
+
|
||
|
+/* Cleanup handling test. */
|
||
|
+static int cl_called;
|
||
|
+static void
|
||
|
+cl (void *arg)
|
||
|
+{
|
||
|
+ ++cl_called;
|
||
|
+}
|
||
|
+
|
||
|
+static void *
|
||
|
+tf_sigtimedwait (void *arg)
|
||
|
+{
|
||
|
+ pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, NULL);
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ int r;
|
||
|
+ pthread_cleanup_push (cl, NULL);
|
||
|
+
|
||
|
+ sigset_t mask;
|
||
|
+ sigemptyset (&mask);
|
||
|
+ r = sigtimedwait (&mask, NULL, &(struct timespec) { 0, 250000000 });
|
||
|
+ if (r != -1)
|
||
|
+ return (void*) -1;
|
||
|
+ if (errno != EAGAIN)
|
||
|
+ return (void*) -2;
|
||
|
+
|
||
|
+ pthread_cleanup_pop (0);
|
||
|
+ return NULL;
|
||
|
+}
|
||
|
+
|
||
|
+static void *
|
||
|
+tf_poll (void *arg)
|
||
|
+{
|
||
|
+ pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, NULL);
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ int r;
|
||
|
+ pthread_cleanup_push (cl, NULL);
|
||
|
+
|
||
|
+ r = poll (NULL, 0, 250);
|
||
|
+ if (r != 0)
|
||
|
+ return (void*) -1;
|
||
|
+
|
||
|
+ pthread_cleanup_pop (0);
|
||
|
+ return NULL;
|
||
|
+}
|
||
|
+
|
||
|
+static void *
|
||
|
+tf_ppoll (void *arg)
|
||
|
+{
|
||
|
+ pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, NULL);
|
||
|
+
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ int r;
|
||
|
+ pthread_cleanup_push (cl, NULL);
|
||
|
+
|
||
|
+ r = ppoll (NULL, 0, &(struct timespec) { 0, 250000000 }, NULL);
|
||
|
+ if (r != 0)
|
||
|
+ return (void*) -1;
|
||
|
+
|
||
|
+ pthread_cleanup_pop (0);
|
||
|
+ return NULL;
|
||
|
+}
|
||
|
+
|
||
|
+static void *
|
||
|
+tf_select (void *arg)
|
||
|
+{
|
||
|
+ pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, NULL);
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ int r;
|
||
|
+ pthread_cleanup_push (cl, NULL);
|
||
|
+
|
||
|
+ r = select (0, NULL, NULL, NULL, &(struct timeval) { 0, 250000 });
|
||
|
+ if (r != 0)
|
||
|
+ return (void*) -1;
|
||
|
+
|
||
|
+ pthread_cleanup_pop (0);
|
||
|
+ return NULL;
|
||
|
+}
|
||
|
+
|
||
|
+static void *
|
||
|
+tf_pselect (void *arg)
|
||
|
+{
|
||
|
+ pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, NULL);
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ int r;
|
||
|
+ pthread_cleanup_push (cl, NULL);
|
||
|
+
|
||
|
+ r = pselect (0, NULL, NULL, NULL, &(struct timespec) { 0, 250000000 }, NULL);
|
||
|
+ if (r != 0)
|
||
|
+ return (void*) -1;
|
||
|
+
|
||
|
+ pthread_cleanup_pop (0);
|
||
|
+ return NULL;
|
||
|
+}
|
||
|
+
|
||
|
+static void *
|
||
|
+tf_clock_nanosleep (void *arg)
|
||
|
+{
|
||
|
+ pthread_setcancelstate (PTHREAD_CANCEL_DISABLE, NULL);
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ int r;
|
||
|
+ pthread_cleanup_push (cl, NULL);
|
||
|
+
|
||
|
+ r = clock_nanosleep (CLOCK_REALTIME, 0, &(struct timespec) { 0, 250000000 },
|
||
|
+ NULL);
|
||
|
+ if (r != 0)
|
||
|
+ return (void*) -1;
|
||
|
+
|
||
|
+ pthread_cleanup_pop (0);
|
||
|
+ return NULL;
|
||
|
+}
|
||
|
+
|
||
|
+struct cancel_test_t
|
||
|
+{
|
||
|
+ const char *name;
|
||
|
+ void * (*cf) (void *);
|
||
|
+} tests[] =
|
||
|
+{
|
||
|
+ { "sigtimedwait", tf_sigtimedwait, },
|
||
|
+ { "poll", tf_poll, },
|
||
|
+ { "ppoll", tf_ppoll, },
|
||
|
+ { "select", tf_select, },
|
||
|
+ { "pselect", tf_pselect , },
|
||
|
+ { "clock_nanosleep", tf_clock_nanosleep, },
|
||
|
+};
|
||
|
+
|
||
|
+static int
|
||
|
+do_test (void)
|
||
|
+{
|
||
|
+ for (int i = 0; i < array_length (tests); i++)
|
||
|
+ {
|
||
|
+ xpthread_barrier_init (&b, NULL, 2);
|
||
|
+
|
||
|
+ cl_called = 0;
|
||
|
+
|
||
|
+ pthread_t th = xpthread_create (NULL, tests[i].cf, NULL);
|
||
|
+
|
||
|
+ xpthread_barrier_wait (&b);
|
||
|
+
|
||
|
+ struct timespec ts = { .tv_sec = 0, .tv_nsec = 100000000 };
|
||
|
+ while (nanosleep (&ts, &ts) != 0)
|
||
|
+ continue;
|
||
|
+
|
||
|
+ xpthread_cancel (th);
|
||
|
+
|
||
|
+ void *status = xpthread_join (th);
|
||
|
+ if (status != NULL)
|
||
|
+ printf ("test '%s' failed: %" PRIdPTR "\n", tests[i].name,
|
||
|
+ (intptr_t) status);
|
||
|
+ TEST_VERIFY (status == NULL);
|
||
|
+
|
||
|
+ xpthread_barrier_destroy (&b);
|
||
|
+
|
||
|
+ TEST_COMPARE (cl_called, 0);
|
||
|
+
|
||
|
+ printf ("in-time cancel test of '%s' successful\n", tests[i].name);
|
||
|
+ }
|
||
|
+
|
||
|
+ return 0;
|
||
|
+}
|
||
|
+
|
||
|
+#include <support/test-driver.c>
|