diff mbox

[COMMITTED] Add __safe_fatal and use it in __pthread_unwind forwarder fallback.

Message ID 20140731210732.0AC5B2C39A3@topped-with-meat.com
State Committed
Headers show

Commit Message

Roland McGrath July 31, 2014, 9:07 p.m. UTC
This both removes a Linuxism from nptl/forward.c and makes the code
actually work.  The old code was a bogus attempt at a one-argument kill
system call, which means it actually attempted to send a random register
value as signal number, to PID 9.  The new code (for Linux) takes care to
make a getpid system call and then a proper kill system call.

Build-tested and eyeballed code on x86_64-linux-gnu and arm-linux-gnueabihf.


	* sysdeps/generic/safe-fatal.h: New file.
	* sysdeps/unix/sysv/linux/safe-fatal.h: New file.
	* nptl/forward.c: Include it.
	(__pthread_unwind): Use __safe_fatal as default action, rather
	than a bogus use of INTERNAL_SYSCALL that could never work.
diff mbox

Patch

--- a/nptl/forward.c
+++ b/nptl/forward.c
@@ -23,7 +23,7 @@ 
 
 #include <shlib-compat.h>
 #include <atomic.h>
-#include <sysdep.h>
+#include <safe-fatal.h>
 
 
 /* Pointers to the libc functions.  */
@@ -202,11 +202,8 @@  FORWARD (pthread_setcancelstate, (int state, int *oldstate), (state, oldstate),
 
 FORWARD (pthread_setcanceltype, (int type, int *oldtype), (type, oldtype), 0)
 
-FORWARD_NORETURN(__pthread_unwind,
-	 void attribute_hidden __attribute ((noreturn)) __cleanup_fct_attribute
-	 attribute_compat_text_section,
-	 (__pthread_unwind_buf_t *buf), (buf), {
-		       /* We cannot call abort() here.  */
-		       INTERNAL_SYSCALL_DECL (err);
-		       INTERNAL_SYSCALL (kill, err, 1, SIGKILL);
-		     })
+FORWARD_NORETURN (__pthread_unwind,
+                  void attribute_hidden __attribute ((noreturn))
+                  __cleanup_fct_attribute attribute_compat_text_section,
+                  (__pthread_unwind_buf_t *buf), (buf),
+                  __safe_fatal ())
--- /dev/null
+++ b/sysdeps/generic/safe-fatal.h
@@ -0,0 +1,37 @@ 
+/* Crash the process immediately, without possibility of deadlock.  Generic.
+   Copyright (C) 2014 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SAFE_FATAL_H
+#define _SAFE_FATAL_H   1
+
+#include <abort-instr.h>
+
+static inline void
+__safe_fatal (void)
+{
+#ifdef ABORT_INSTRUCTION
+  /* This is not guaranteed to be free from the possibility of deadlock,
+     since it might generate a signal that can be caught.  But it's better
+     than nothing.  */
+  ABORT_INSTRUCTION;
+#else
+# error Need an OS-specific or machine-specific safe-fatal.h
+#endif
+}
+
+#endif  /* safe-fatal.h */
--- /dev/null
+++ b/sysdeps/unix/sysv/linux/safe-fatal.h
@@ -0,0 +1,33 @@ 
+/* Crash the process immediately, without possibility of deadlock.  Linux.
+   Copyright (C) 2014 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
+   <http://www.gnu.org/licenses/>.  */
+
+#ifndef _SAFE_FATAL_H
+#define _SAFE_FATAL_H   1
+
+#include <sysdep.h>
+#include <unistd.h>
+
+static inline void
+__safe_fatal (void)
+{
+  INTERNAL_SYSCALL_DECL (err);
+  pid_t self = INTERNAL_SYSCALL (getpid, err, 0);
+  INTERNAL_SYSCALL (kill, err, 2, self, SIGKILL);
+}
+
+#endif  /* safe-fatal.h */