From a6c813d0ad0fd9830f2cd3c3d079af8d2aa50a1f Mon Sep 17 00:00:00 2001 From: Adhemerval Zanella Date: Mon, 7 Dec 2020 17:17:24 -0300 Subject: 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 db988e50a87f613cb6b9e98a2fc66a4848bc3546 fixed for pthread_join). Checked on x86_64-linux-gnu and aarch64-linux-gnu. --- nptl/pthreadP.h | 2 ++ nptl/pthread_cancel.c | 6 +----- nptl/pthread_kill.c | 18 ++++++++++++------ 3 files changed, 15 insertions(+), 11 deletions(-) (limited to 'nptl') diff --git a/nptl/pthreadP.h b/nptl/pthreadP.h index 618922f..675d1de 100644 --- a/nptl/pthreadP.h +++ b/nptl/pthreadP.h @@ -515,6 +515,8 @@ libc_hidden_proto (__pthread_detach) extern int __pthread_kill (pthread_t threadid, int signo); libc_hidden_proto (__pthread_kill) extern int __pthread_cancel (pthread_t th); +extern int __pthread_kill_internal (pthread_t threadid, int signo) + attribute_hidden; extern void __pthread_exit (void *value) __attribute__ ((__noreturn__)); libc_hidden_proto (__pthread_exit) extern int __pthread_join (pthread_t threadid, void **thread_return); diff --git a/nptl/pthread_cancel.c b/nptl/pthread_cancel.c index de4659a..0698cd2 100644 --- a/nptl/pthread_cancel.c +++ b/nptl/pthread_cancel.c @@ -110,11 +110,7 @@ __pthread_cancel (pthread_t th) return 0; } - pid_t pid = __getpid (); - int val = INTERNAL_SYSCALL_CALL (tgkill, pid, pd->tid, SIGCANCEL); - return INTERNAL_SYSCALL_ERROR_P (val) - ? INTERNAL_SYSCALL_ERRNO (val) - : 0; + return __pthread_kill_internal (th, SIGCANCEL); } versioned_symbol (libc, __pthread_cancel, pthread_cancel, GLIBC_2_34); diff --git a/nptl/pthread_kill.c b/nptl/pthread_kill.c index 8982011..f79a2b2 100644 --- a/nptl/pthread_kill.c +++ b/nptl/pthread_kill.c @@ -21,13 +21,8 @@ #include int -__pthread_kill (pthread_t threadid, int signo) +__pthread_kill_internal (pthread_t threadid, int signo) { - /* Disallow sending the signal we use for cancellation, timers, - for the setxid implementation. */ - if (__is_internal_signal (signo)) - return EINVAL; - pid_t tid; struct pthread *pd = (struct pthread *) threadid; @@ -55,6 +50,17 @@ __pthread_kill (pthread_t threadid, int signo) return val; } + +int +__pthread_kill (pthread_t threadid, int signo) +{ + /* Disallow sending the signal we use for cancellation, timers, + for the setxid implementation. */ + if (__is_internal_signal (signo)) + return EINVAL; + + return __pthread_kill_internal (threadid, signo); +} /* Some architectures (for instance arm) might pull raise through libgcc, so avoid the symbol version if it ends up being used on ld.so. */ #if !IS_IN(rtld) -- cgit v1.1