* dcrt0.cc (child_info_fork::alloc_stack_hard_way): Change sense of guard test.
Increase size of stack reserved and increase size before the current stack pointer. Use pointers when doing arithmetic. (dll_crt0_1): Initialize exception handler when we notice we're the child of a fork from non-main thread. * fork.cc (frok::parent): Make argument volatile. (frok::child): Ditto. (lock_signals): New class. (lock_pthread): Ditto. (hold_everhthing): Ditto. (frok::parent): Move atforkprepare and atforkparent to lock_pthread class. (fork): Make ischild boolean. Use hold_everything variable within limited scope to set various mutexes in such a way as to avoid deadlocks. * thread.h (pthread_mutex::tid): New variable, active when debugging for tracking thread id of owner. (pthread_mutex::set_owner): Set tid when debugging. * thread.cc (pthread_mutex::pthread_mutex): Clear tid. (pthread_mutex::_unlock): Ditto when unlocking. (pthread_mutex::fixup_after_fork): Set tid to special value after forking since owner is unknown.
This commit is contained in:
Christopher Faylor
parent
bd8f891e8a
commit
39fc0d36ae
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@ -1,3 +1,28 @@
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2007-02-22 Christopher Faylor <me@cgf.cx>
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* dcrt0.cc (child_info_fork::alloc_stack_hard_way): Change sense of
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guard test. Increase size of stack reserved and increase size before
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the current stack pointer. Use pointers when doing arithmetic.
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(dll_crt0_1): Initialize exception handler when we notice we're the
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child of a fork from non-main thread.
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* fork.cc (frok::parent): Make argument volatile.
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(frok::child): Ditto.
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(lock_signals): New class.
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(lock_pthread): Ditto.
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(hold_everhthing): Ditto.
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(frok::parent): Move atforkprepare and atforkparent to lock_pthread
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class.
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(fork): Make ischild boolean. Use hold_everything variable within
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limited scope to set various mutexes in such a way as to avoid
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deadlocks.
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* thread.h (pthread_mutex::tid): New variable, active when debugging
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for tracking thread id of owner.
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(pthread_mutex::set_owner): Set tid when debugging.
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* thread.cc (pthread_mutex::pthread_mutex): Clear tid.
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(pthread_mutex::_unlock): Ditto when unlocking.
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(pthread_mutex::fixup_after_fork): Set tid to special value after
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forking since owner is unknown.
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2007-02-22 Corinna Vinschen <corinna@vinschen.de>
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Throughout replace all usage of wincap.shared with the constant
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@ -451,8 +451,7 @@ check_sanity_and_sync (per_process *p)
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child_info NO_COPY *child_proc_info = NULL;
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#define CYGWIN_GUARD ((wincap.has_page_guard ()) ? \
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PAGE_EXECUTE_READWRITE|PAGE_GUARD : PAGE_NOACCESS)
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#define CYGWIN_GUARD (PAGE_EXECUTE_READWRITE | PAGE_GUARD)
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void
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child_info_fork::alloc_stack_hard_way (volatile char *b)
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@ -461,7 +460,7 @@ child_info_fork::alloc_stack_hard_way (volatile char *b)
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MEMORY_BASIC_INFORMATION m;
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void *newbase;
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int newlen;
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bool noguard;
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bool guard;
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if (!VirtualQuery ((LPCVOID) &b, &m, sizeof m))
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api_fatal ("fork: couldn't get stack info, %E");
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@ -472,28 +471,29 @@ child_info_fork::alloc_stack_hard_way (volatile char *b)
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{
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newbase = curbot;
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newlen = (LPBYTE) stackbottom - (LPBYTE) curbot;
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noguard = 1;
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guard = false;
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}
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else
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{
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newbase = stacktop;
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newlen = (DWORD) stackbottom - (DWORD) stacktop;
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noguard = 0;
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newbase = (LPBYTE) stacktop - (128 * 1024);
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newlen = (LPBYTE) stackbottom - (LPBYTE) newbase;
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guard = true;
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}
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if (!VirtualAlloc (newbase, newlen, MEM_RESERVE, PAGE_NOACCESS))
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api_fatal ("fork: can't reserve memory for stack %p - %p, %E",
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stacktop, stackbottom);
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new_stack_pointer = (void *) ((LPBYTE) stackbottom - stacksize);
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new_stack_pointer = (void *) ((LPBYTE) stackbottom - (stacksize += 8192));
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if (!VirtualAlloc (new_stack_pointer, stacksize, MEM_COMMIT,
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PAGE_EXECUTE_READWRITE))
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api_fatal ("fork: can't commit memory for stack %p(%d), %E",
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new_stack_pointer, stacksize);
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if (!VirtualQuery ((LPCVOID) new_stack_pointer, &m, sizeof m))
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api_fatal ("fork: couldn't get new stack info, %E");
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if (!noguard)
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if (guard)
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{
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m.BaseAddress = (LPVOID) ((DWORD) m.BaseAddress - 1);
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m.BaseAddress = (LPBYTE) m.BaseAddress - 1;
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if (!VirtualAlloc ((LPVOID) m.BaseAddress, 1, MEM_COMMIT,
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CYGWIN_GUARD))
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api_fatal ("fork: couldn't allocate new stack guard page %p, %E",
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@ -826,7 +826,9 @@ dll_crt0_1 (void *)
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{
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_tlsbase = (char *) fork_info->stackbottom;
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_tlstop = (char *) fork_info->stacktop;
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_my_tls.init_exception_handler (_cygtls::handle_exceptions);
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}
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longjmp (fork_info->jmp, true);
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}
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@ -45,11 +45,87 @@ class frok
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const char *error;
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int child_pid;
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int this_errno;
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int __stdcall parent (void *esp);
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int __stdcall child (void *esp);
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int __stdcall parent (volatile char * volatile here);
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int __stdcall child (volatile char * volatile here);
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friend int fork ();
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};
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class lock_signals
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{
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bool worked;
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public:
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lock_signals ()
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{
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worked = sig_send (NULL, __SIGHOLD) == 0;
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}
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operator int () const
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{
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return worked;
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}
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void dont_bother ()
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{
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worked = false;
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}
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~lock_signals ()
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{
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if (worked)
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sig_send (NULL, __SIGNOHOLD);
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}
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};
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class lock_pthread
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{
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bool bother;
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public:
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lock_pthread (): bother (1)
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{
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pthread::atforkprepare ();
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}
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void dont_bother ()
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{
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bother = false;
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}
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~lock_pthread ()
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{
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if (bother)
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pthread::atforkparent ();
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}
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};
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class hold_everything
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{
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bool& ischild;
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/* Note the order of the locks below. It is important,
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to avoid races, that the lock order be preserved.
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pthread is first because it serves as a master lock
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against other forks being attempted while this one is active.
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signals is next to stop signal processing for the duration
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of the fork.
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process is last. If it is put before signals, then a deadlock
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could be introduced if the process attempts to exit due to a signal. */
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lock_pthread pthread;
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lock_signals signals;
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lock_process process;
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public:
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hold_everything (bool& x): ischild (x) {}
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operator int () const {return signals;}
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~hold_everything()
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{
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if (ischild)
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{
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pthread.dont_bother ();
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process.dont_bother ();
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signals.dont_bother ();
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}
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}
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};
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static void
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resume_child (HANDLE forker_finished)
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{
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@ -92,7 +168,7 @@ sync_with_parent (const char *s, bool hang_self)
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}
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int __stdcall
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frok::child (void *)
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frok::child (volatile char * volatile here)
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{
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HANDLE& hParent = ch.parent;
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extern void fixup_hooks_after_fork ();
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@ -213,7 +289,7 @@ slow_pid_reuse (HANDLE h)
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#endif
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int __stdcall
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frok::parent (void *stack_here)
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frok::parent (volatile char * volatile stack_here)
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{
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HANDLE forker_finished;
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DWORD rc;
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@ -224,8 +300,6 @@ frok::parent (void *stack_here)
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pinfo child;
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static char errbuf[256];
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pthread::atforkprepare ();
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int c_flags = GetPriorityClass (hMainProc);
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debug_printf ("priority class %d", c_flags);
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@ -271,7 +345,7 @@ frok::parent (void *stack_here)
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ch.forker_finished = forker_finished;
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ch.stackbottom = _tlsbase;
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ch.stacktop = stack_here;
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ch.stacktop = (void *) stack_here;
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ch.stacksize = (char *) ch.stackbottom - (char *) stack_here;
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debug_printf ("stack - bottom %p, top %p, size %d",
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ch.stackbottom, ch.stacktop, ch.stacksize);
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@ -492,7 +566,6 @@ frok::parent (void *stack_here)
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ForceCloseHandle (forker_finished);
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forker_finished = NULL;
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pthread::atforkparent ();
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return child_pid;
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@ -516,14 +589,13 @@ extern "C" int
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fork ()
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{
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frok grouped;
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MALLOC_CHECK;
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debug_printf ("entering");
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grouped.first_dll = NULL;
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grouped.load_dlls = 0;
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int res;
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int ischild;
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bool ischild = false;
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myself->set_has_pgid_children ();
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@ -535,30 +607,28 @@ fork ()
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return -1;
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}
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lock_process now;
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if (sig_send (NULL, __SIGHOLD))
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{
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if (exit_state)
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Sleep (INFINITE);
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set_errno (EAGAIN);
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return -1;
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}
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{
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hold_everything held_everything (ischild);
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ischild = setjmp (grouped.ch.jmp);
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if (!held_everything)
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{
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if (exit_state)
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Sleep (INFINITE);
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set_errno (EAGAIN);
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return -1;
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}
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void *esp;
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__asm__ volatile ("movl %%esp,%0": "=r" (esp));
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ischild = !!setjmp (grouped.ch.jmp);
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if (ischild)
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{
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res = grouped.child (esp);
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now.dont_bother ();
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}
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else
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{
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volatile char * volatile esp;
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__asm__ volatile ("movl %%esp,%0": "=r" (esp));
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if (!ischild)
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res = grouped.parent (esp);
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sig_send (NULL, __SIGNOHOLD);
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}
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else
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res = grouped.child (esp);
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}
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MALLOC_CHECK;
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if (ischild || res > 0)
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@ -1,9 +1,7 @@
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/* thread.cc: Locking and threading module functions
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Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007 Red Hat, Inc.
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Originally written by Marco Fuykschot <marco@ddi.nl>
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Substantialy enhanced by Robert Collins <rbtcollins@hotmail.com>
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Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005,
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2006, 2007 Red Hat, Inc.
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This file is part of Cygwin.
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@ -1599,7 +1597,11 @@ pthread_mutex::pthread_mutex (pthread_mutexattr *attr) :
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verifyable_object (PTHREAD_MUTEX_MAGIC),
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lock_counter (0),
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win32_obj_id (NULL), recursion_counter (0),
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condwaits (0), owner (NULL), type (PTHREAD_MUTEX_ERRORCHECK),
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condwaits (0), owner (NULL),
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#ifdef DEBUGGING
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tid (0),
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#endif
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type (PTHREAD_MUTEX_ERRORCHECK),
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pshared (PTHREAD_PROCESS_PRIVATE)
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{
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win32_obj_id = ::CreateSemaphore (&sec_none_nih, 0, LONG_MAX, NULL);
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@ -1680,6 +1682,9 @@ pthread_mutex::_unlock (pthread_t self)
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if (--recursion_counter == 0)
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{
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owner = NULL;
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#ifdef DEBUGGING
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tid = 0;
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#endif
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if (InterlockedDecrement ((long *)&lock_counter))
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// Another thread is waiting
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::ReleaseSemaphore (win32_obj_id, 1, NULL);
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@ -1713,11 +1718,21 @@ pthread_mutex::_fixup_after_fork ()
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api_fatal ("pthread_mutex::_fixup_after_fork () doesn'tunderstand PROCESS_SHARED mutex's");
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if (owner == NULL)
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/* mutex has no owner, reset to initial */
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lock_counter = 0;
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{
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/* mutex has no owner, reset to initial */
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lock_counter = 0;
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#ifdef DEBUGGING
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tid = 0;
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#endif
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}
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else if (lock_counter != 0)
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/* All waiting threads are gone after a fork */
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lock_counter = 1;
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{
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/* All waiting threads are gone after a fork */
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lock_counter = 1;
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#ifdef DEBUGGING
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tid = 0xffffffff; /* Don't know the tid after a fork */
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#endif
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}
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win32_obj_id = ::CreateSemaphore (&sec_none_nih, 0, LONG_MAX, NULL);
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if (!win32_obj_id)
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@ -1,9 +1,6 @@
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/* thread.h: Locking and threading module definitions
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Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2007 Red Hat, Inc.
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Written by Marco Fuykschot <marco@ddi.nl>
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Major update 2001 Robert Collins <rbtcollins@hotmail.com>
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Copyright 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007 Red Hat, Inc.
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This file is part of Cygwin.
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@ -45,7 +42,8 @@ void ReleaseResourceLock (int, int, const char *)
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__attribute__ ((regparm (3)));
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}
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DWORD cancelable_wait (HANDLE, DWORD, const cw_cancel_action = cw_cancel_self, const enum cw_sig_wait = cw_sig_nosig)
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DWORD cancelable_wait (HANDLE, DWORD, const cw_cancel_action = cw_cancel_self,
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const enum cw_sig_wait = cw_sig_nosig)
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__attribute__ ((regparm (3)));
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class fast_mutex
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@ -298,6 +296,9 @@ public:
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unsigned int recursion_counter;
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LONG condwaits;
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pthread_t owner;
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#ifdef DEBUGGING
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DWORD tid; /* the thread id of the owner */
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#endif
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int type;
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int pshared;
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@ -328,6 +329,9 @@ public:
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{
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recursion_counter = 1;
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owner = self;
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#ifdef DEBUGGING
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tid = GetCurrentThreadId ();
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#endif
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}
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int lock_recursive ()
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Loading…
Reference in New Issue