diff options
Diffstat (limited to 'nptl-Handle-spurious-EINTR-when-thread-cancellation-.patch')
| -rw-r--r-- | nptl-Handle-spurious-EINTR-when-thread-cancellation-.patch | 869 |
1 files changed, 869 insertions, 0 deletions
diff --git a/nptl-Handle-spurious-EINTR-when-thread-cancellation-.patch b/nptl-Handle-spurious-EINTR-when-thread-cancellation-.patch new file mode 100644 index 0000000..1126181 --- /dev/null +++ b/nptl-Handle-spurious-EINTR-when-thread-cancellation-.patch @@ -0,0 +1,869 @@ +From 290db09546b260a30137d03ce97a857e6f15b648 Mon Sep 17 00:00:00 2001 +From: Adhemerval Zanella <adhemerval.zanella@linaro.org> +Date: Wed, 6 Apr 2022 12:24:42 -0300 +Subject: [PATCH] nptl: Handle spurious EINTR when thread cancellation is + disabled (BZ#29029) + +Some Linux interfaces never restart after being interrupted by a signal +handler, regardless of the use of SA_RESTART [1]. It means that for +pthread cancellation, if the target thread disables cancellation with +pthread_setcancelstate and calls such interfaces (like poll or select), +it should not see spurious EINTR failures due the internal SIGCANCEL. + +However recent changes made pthread_cancel to always sent the internal +signal, regardless of the target thread cancellation status or type. +To fix it, the previous semantic is restored, where the cancel signal +is only sent if the target thread has cancelation enabled in +asynchronous mode. + +The cancel state and cancel type is moved back to cancelhandling +and atomic operation are used to synchronize between threads. The +patch essentially revert the following commits: + + 8c1c0aae20 nptl: Move cancel type out of cancelhandling + 2b51742531 nptl: Move cancel state out of cancelhandling + 26cfbb7162 nptl: Remove CANCELING_BITMASK + +However I changed the atomic operation to follow the internal C11 +semantic and removed the MACRO usage, it simplifies a bit the +resulting code (and removes another usage of the old atomic macros). + +Checked on x86_64-linux-gnu, i686-linux-gnu, aarch64-linux-gnu, +and powerpc64-linux-gnu. + +[1] https://man7.org/linux/man-pages/man7/signal.7.html + +Reviewed-by: Florian Weimer <fweimer@redhat.com> +Tested-by: Aurelien Jarno <aurelien@aurel32.net> + +(cherry-picked from commit 404656009b459658138ed1bd18f3c6cf3863e6a6) +--- + NEWS | 2 + + manual/process.texi | 3 +- + nptl/allocatestack.c | 2 - + nptl/cancellation.c | 50 +++++++--- + nptl/cleanup_defer.c | 42 +++++++-- + nptl/descr.h | 41 +++++--- + nptl/libc-cleanup.c | 39 +++++++- + nptl/pthread_cancel.c | 110 ++++++++++++++++------ + nptl/pthread_join_common.c | 7 +- + nptl/pthread_setcancelstate.c | 26 +++++- + nptl/pthread_setcanceltype.c | 31 +++++- + nptl/pthread_testcancel.c | 9 +- + sysdeps/nptl/dl-tls_init_tp.c | 3 - + sysdeps/nptl/pthreadP.h | 2 +- + sysdeps/pthread/Makefile | 1 + + sysdeps/pthread/tst-cancel29.c | 207 +++++++++++++++++++++++++++++++++++++++++ + 16 files changed, 484 insertions(+), 91 deletions(-) + create mode 100644 sysdeps/pthread/tst-cancel29.c + +diff --git a/NEWS b/NEWS +index 96e0589..55aea24 100644 +--- a/NEWS ++++ b/NEWS +@@ -37,6 +37,8 @@ The following bugs are resolved with this release: + recvmsg() + [28865] linux: _SC_NPROCESSORS_CONF and _SC_NPROCESSORS_ONLN are inaccurate + without /sys and /proc ++ [29029] nptl: poll() spuriously returns EINTR during thread ++ cancellation and with cancellation disabled + + + Version 2.34 +diff --git a/manual/process.texi b/manual/process.texi +index 28c9531..9307379 100644 +--- a/manual/process.texi ++++ b/manual/process.texi +@@ -68,8 +68,7 @@ until the subprogram terminates before you can do anything else. + @c CLEANUP_HANDLER @ascuplugin @ascuheap @acsmem + @c libc_cleanup_region_start @ascuplugin @ascuheap @acsmem + @c pthread_cleanup_push_defer @ascuplugin @ascuheap @acsmem +-@c __pthread_testcancel @ascuplugin @ascuheap @acsmem +-@c CANCEL_ENABLED_AND_CANCELED ok ++@c cancel_enabled_and_canceled @ascuplugin @ascuheap @acsmem + @c do_cancel @ascuplugin @ascuheap @acsmem + @c cancel_handler ok + @c kill syscall ok +diff --git a/nptl/allocatestack.c b/nptl/allocatestack.c +index 554a721..9610175 100644 +--- a/nptl/allocatestack.c ++++ b/nptl/allocatestack.c +@@ -120,8 +120,6 @@ get_cached_stack (size_t *sizep, void **memp) + + /* Cancellation handling is back to the default. */ + result->cancelhandling = 0; +- result->cancelstate = PTHREAD_CANCEL_ENABLE; +- result->canceltype = PTHREAD_CANCEL_DEFERRED; + result->cleanup = NULL; + result->setup_failed = 0; + +diff --git a/nptl/cancellation.c b/nptl/cancellation.c +index 0596278..e97d56f 100644 +--- a/nptl/cancellation.c ++++ b/nptl/cancellation.c +@@ -31,19 +31,26 @@ int + __pthread_enable_asynccancel (void) + { + struct pthread *self = THREAD_SELF; ++ int oldval = atomic_load_relaxed (&self->cancelhandling); + +- int oldval = THREAD_GETMEM (self, canceltype); +- THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_ASYNCHRONOUS); ++ while (1) ++ { ++ int newval = oldval | CANCELTYPE_BITMASK; + +- int ch = THREAD_GETMEM (self, cancelhandling); ++ if (newval == oldval) ++ break; + +- if (self->cancelstate == PTHREAD_CANCEL_ENABLE +- && (ch & CANCELED_BITMASK) +- && !(ch & EXITING_BITMASK) +- && !(ch & TERMINATED_BITMASK)) +- { +- THREAD_SETMEM (self, result, PTHREAD_CANCELED); +- __do_cancel (); ++ if (atomic_compare_exchange_weak_acquire (&self->cancelhandling, ++ &oldval, newval)) ++ { ++ if (cancel_enabled_and_canceled_and_async (newval)) ++ { ++ self->result = PTHREAD_CANCELED; ++ __do_cancel (); ++ } ++ ++ break; ++ } + } + + return oldval; +@@ -57,10 +64,29 @@ __pthread_disable_asynccancel (int oldtype) + { + /* If asynchronous cancellation was enabled before we do not have + anything to do. */ +- if (oldtype == PTHREAD_CANCEL_ASYNCHRONOUS) ++ if (oldtype & CANCELTYPE_BITMASK) + return; + + struct pthread *self = THREAD_SELF; +- self->canceltype = PTHREAD_CANCEL_DEFERRED; ++ int newval; ++ int oldval = atomic_load_relaxed (&self->cancelhandling); ++ do ++ { ++ newval = oldval & ~CANCELTYPE_BITMASK; ++ } ++ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling, ++ &oldval, newval)); ++ ++ /* We cannot return when we are being canceled. Upon return the ++ thread might be things which would have to be undone. The ++ following loop should loop until the cancellation signal is ++ delivered. */ ++ while (__glibc_unlikely ((newval & (CANCELING_BITMASK | CANCELED_BITMASK)) ++ == CANCELING_BITMASK)) ++ { ++ futex_wait_simple ((unsigned int *) &self->cancelhandling, newval, ++ FUTEX_PRIVATE); ++ newval = atomic_load_relaxed (&self->cancelhandling); ++ } + } + libc_hidden_def (__pthread_disable_asynccancel) +diff --git a/nptl/cleanup_defer.c b/nptl/cleanup_defer.c +index 7e858d0..35ba40f 100644 +--- a/nptl/cleanup_defer.c ++++ b/nptl/cleanup_defer.c +@@ -31,9 +31,22 @@ ___pthread_register_cancel_defer (__pthread_unwind_buf_t *buf) + ibuf->priv.data.prev = THREAD_GETMEM (self, cleanup_jmp_buf); + ibuf->priv.data.cleanup = THREAD_GETMEM (self, cleanup); + +- /* Disable asynchronous cancellation for now. */ +- ibuf->priv.data.canceltype = THREAD_GETMEM (self, canceltype); +- THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED); ++ int cancelhandling = atomic_load_relaxed (&self->cancelhandling); ++ if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK)) ++ { ++ int newval; ++ do ++ { ++ newval = cancelhandling & ~CANCELTYPE_BITMASK; ++ } ++ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling, ++ &cancelhandling, ++ newval)); ++ } ++ ++ ibuf->priv.data.canceltype = (cancelhandling & CANCELTYPE_BITMASK ++ ? PTHREAD_CANCEL_ASYNCHRONOUS ++ : PTHREAD_CANCEL_DEFERRED); + + /* Store the new cleanup handler info. */ + THREAD_SETMEM (self, cleanup_jmp_buf, (struct pthread_unwind_buf *) buf); +@@ -55,9 +68,26 @@ ___pthread_unregister_cancel_restore (__pthread_unwind_buf_t *buf) + + THREAD_SETMEM (self, cleanup_jmp_buf, ibuf->priv.data.prev); + +- THREAD_SETMEM (self, canceltype, ibuf->priv.data.canceltype); +- if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_ASYNCHRONOUS) +- __pthread_testcancel (); ++ if (ibuf->priv.data.canceltype == PTHREAD_CANCEL_DEFERRED) ++ return; ++ ++ int cancelhandling = atomic_load_relaxed (&self->cancelhandling); ++ if (cancelhandling & CANCELTYPE_BITMASK) ++ { ++ int newval; ++ do ++ { ++ newval = cancelhandling | CANCELTYPE_BITMASK; ++ } ++ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling, ++ &cancelhandling, newval)); ++ ++ if (cancel_enabled_and_canceled (cancelhandling)) ++ { ++ self->result = PTHREAD_CANCELED; ++ __do_cancel (); ++ } ++ } + } + versioned_symbol (libc, ___pthread_unregister_cancel_restore, + __pthread_unregister_cancel_restore, GLIBC_2_34); +diff --git a/nptl/descr.h b/nptl/descr.h +index 4de8413..03a4358 100644 +--- a/nptl/descr.h ++++ b/nptl/descr.h +@@ -277,18 +277,27 @@ struct pthread + + /* Flags determining processing of cancellation. */ + int cancelhandling; ++ /* Bit set if cancellation is disabled. */ ++#define CANCELSTATE_BIT 0 ++#define CANCELSTATE_BITMASK (1 << CANCELSTATE_BIT) ++ /* Bit set if asynchronous cancellation mode is selected. */ ++#define CANCELTYPE_BIT 1 ++#define CANCELTYPE_BITMASK (1 << CANCELTYPE_BIT) ++ /* Bit set if canceling has been initiated. */ ++#define CANCELING_BIT 2 ++#define CANCELING_BITMASK (1 << CANCELING_BIT) + /* Bit set if canceled. */ + #define CANCELED_BIT 3 +-#define CANCELED_BITMASK (0x01 << CANCELED_BIT) ++#define CANCELED_BITMASK (1 << CANCELED_BIT) + /* Bit set if thread is exiting. */ + #define EXITING_BIT 4 +-#define EXITING_BITMASK (0x01 << EXITING_BIT) ++#define EXITING_BITMASK (1 << EXITING_BIT) + /* Bit set if thread terminated and TCB is freed. */ + #define TERMINATED_BIT 5 +-#define TERMINATED_BITMASK (0x01 << TERMINATED_BIT) ++#define TERMINATED_BITMASK (1 << TERMINATED_BIT) + /* Bit set if thread is supposed to change XID. */ + #define SETXID_BIT 6 +-#define SETXID_BITMASK (0x01 << SETXID_BIT) ++#define SETXID_BITMASK (1 << SETXID_BIT) + + /* Flags. Including those copied from the thread attribute. */ + int flags; +@@ -388,14 +397,6 @@ struct pthread + /* Indicates whether is a C11 thread created by thrd_creat. */ + bool c11; + +- /* Thread cancel state (PTHREAD_CANCEL_ENABLE or +- PTHREAD_CANCEL_DISABLE). */ +- unsigned char cancelstate; +- +- /* Thread cancel type (PTHREAD_CANCEL_DEFERRED or +- PTHREAD_CANCEL_ASYNCHRONOUS). */ +- unsigned char canceltype; +- + /* Used in __pthread_kill_internal to detected a thread that has + exited or is about to exit. exit_lock must only be acquired + after blocking signals. */ +@@ -412,6 +413,22 @@ struct pthread + (sizeof (struct pthread) - offsetof (struct pthread, end_padding)) + } __attribute ((aligned (TCB_ALIGNMENT))); + ++static inline bool ++cancel_enabled_and_canceled (int value) ++{ ++ return (value & (CANCELSTATE_BITMASK | CANCELED_BITMASK | EXITING_BITMASK ++ | TERMINATED_BITMASK)) ++ == CANCELED_BITMASK; ++} ++ ++static inline bool ++cancel_enabled_and_canceled_and_async (int value) ++{ ++ return ((value) & (CANCELSTATE_BITMASK | CANCELTYPE_BITMASK | CANCELED_BITMASK ++ | EXITING_BITMASK | TERMINATED_BITMASK)) ++ == (CANCELTYPE_BITMASK | CANCELED_BITMASK); ++} ++ + /* This yields the pointer that TLS support code calls the thread pointer. */ + #if TLS_TCB_AT_TP + # define TLS_TPADJ(pd) (pd) +diff --git a/nptl/libc-cleanup.c b/nptl/libc-cleanup.c +index 180d15b..fccb1ab 100644 +--- a/nptl/libc-cleanup.c ++++ b/nptl/libc-cleanup.c +@@ -27,9 +27,24 @@ __libc_cleanup_push_defer (struct _pthread_cleanup_buffer *buffer) + + buffer->__prev = THREAD_GETMEM (self, cleanup); + ++ int cancelhandling = atomic_load_relaxed (&self->cancelhandling); ++ + /* Disable asynchronous cancellation for now. */ +- buffer->__canceltype = THREAD_GETMEM (self, canceltype); +- THREAD_SETMEM (self, canceltype, PTHREAD_CANCEL_DEFERRED); ++ if (__glibc_unlikely (cancelhandling & CANCELTYPE_BITMASK)) ++ { ++ int newval; ++ do ++ { ++ newval = cancelhandling & ~CANCELTYPE_BITMASK; ++ } ++ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling, ++ &cancelhandling, ++ newval)); ++ } ++ ++ buffer->__canceltype = (cancelhandling & CANCELTYPE_BITMASK ++ ? PTHREAD_CANCEL_ASYNCHRONOUS ++ : PTHREAD_CANCEL_DEFERRED); + + 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); +- if (buffer->__canceltype == PTHREAD_CANCEL_ASYNCHRONOUS) +- __pthread_testcancel (); ++ int cancelhandling = atomic_load_relaxed (&self->cancelhandling); ++ if (cancelhandling & CANCELTYPE_BITMASK) ++ { ++ int newval; ++ do ++ { ++ newval = cancelhandling | CANCELTYPE_BITMASK; ++ } ++ while (!atomic_compare_exchange_weak_acquire (&self->cancelhandling, ++ &cancelhandling, newval)); ++ ++ if (cancel_enabled_and_canceled (cancelhandling)) ++ { ++ self->result = PTHREAD_CANCELED; ++ __do_cancel (); ++ } ++ } + } + libc_hidden_def (__libc_cleanup_pop_restore) +diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c +index 9bac6e3..2680b55 100644 +--- a/nptl/pthread_cancel.c ++++ b/nptl/pthread_cancel.c +@@ -43,18 +43,29 @@ sigcancel_handler (int sig, siginfo_t *si, void *ctx) + + 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 7303069..617056e 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 7e2b6e4..cb567be 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 e7b24ae..e08ff7b 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 31185d8..2523021 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 ca494dd..c2054f8 100644 +--- a/sysdeps/nptl/dl-tls_init_tp.c ++++ b/sysdeps/nptl/dl-tls_init_tp.c +@@ -94,7 +94,4 @@ __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 374657a..b968afc 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 c657101..00419c4 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 0000000..4f0d99e +--- /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> +-- +1.8.3.1 + |