source: libcfa/src/concurrency/coroutine.cfa@ feb999f

Last change on this file since feb999f was cce0807, checked in by caparson <caparson@…>, 22 months ago

Fixed non-local ehm memory leak that occurs when a coroutine is deleted while suspended in a catchresume handler
  • Property mode set to 100644
File size: 13.6 KB
Line 
1//
2// Cforall Version 1.0.0 Copyright (C) 2016 University of Waterloo
3//
4// The contents of this file are covered under the licence agreement in the
5// file "LICENCE" distributed with Cforall.
6//
7// coroutine.c --
8//
9// Author : Thierry Delisle
10// Created On : Mon Nov 28 12:27:26 2016
11// Last Modified By : Peter A. Buhr
12// Last Modified On : Mon Sep 18 21:47:12 2023
13// Update Count : 25
14//
15
16#define __cforall_thread__
17
18#include "coroutine.hfa"
19
20#include <stddef.h>
21#include <malloc.h>
22#include <errno.h>
23#include <string.h>
24#include <unistd.h>
25#include <sys/mman.h> // mprotect
26#include <unwind.h>
27
28#include "kernel/private.hfa"
29#include "exception.hfa"
30#include "exception.h"
31#include "math.hfa"
32
33#define CFA_COROUTINE_USE_MMAP 0
34
35#define __CFA_INVOKE_PRIVATE__
36#include "invoke.h"
37
38extern "C" {
39 void _CtxCoroutine_Unwind(struct _Unwind_Exception * storage, struct coroutine$ *) __attribute__ ((__noreturn__));
40 static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) __attribute__ ((__noreturn__));
41 static void _CtxCoroutine_UnwindCleanup(_Unwind_Reason_Code, struct _Unwind_Exception *) {
42 abort();
43 }
44
45 extern void CtxRet( struct __stack_context_t * to ) asm ("CtxRet") __attribute__ ((__noreturn__));
46}
47
48//-----------------------------------------------------------------------------
49forall(T &)
50void copy(CoroutineCancelled(T) * dst, CoroutineCancelled(T) * src) libcfa_public {
51 dst->virtual_table = src->virtual_table;
52 dst->the_coroutine = src->the_coroutine;
53 dst->the_exception = src->the_exception;
54}
55
56forall(T &)
57const char * msg(CoroutineCancelled(T) *) libcfa_public {
58 return "CoroutineCancelled(...)";
59}
60
61// This code should not be inlined. It is the error path on resume.
62forall(T & | is_coroutine(T))
63void __cfaehm_cancelled_coroutine(
64 T & cor, coroutine$ * desc, EHM_DEFAULT_VTABLE(CoroutineCancelled(T)) ) libcfa_public {
65 verify( desc->cancellation );
66 desc->state = Cancelled;
67 exception_t * except = __cfaehm_cancellation_exception( desc->cancellation );
68
69 // TODO: Remove explitate vtable set once trac#186 is fixed.
70 CoroutineCancelled(T) except;
71 except.virtual_table = &_default_vtable;
72 except.the_coroutine = &cor;
73 except.the_exception = except;
74 // Why does this need a cast?
75 throwResume (CoroutineCancelled(T) &)except;
76
77 except->virtual_table->free( except );
78 free( desc->cancellation );
79 desc->cancellation = 0p;
80}
81
82// helper for popping from coroutine's ehm buffer
83inline nonlocal_exception * pop_ehm_head( coroutine$ * this ) {
84 lock( this->ehm_state.buffer_lock __cfaabi_dbg_ctx2 );
85 nonlocal_exception * nl_ex = pop_head( this->ehm_state.ehm_buffer );
86 unlock( this->ehm_state.buffer_lock );
87 return nl_ex;
88}
89
90//-----------------------------------------------------------------------------
91// Global state variables
92
93// minimum feasible stack size in bytes
94static const size_t MinStackSize = 1000;
95extern size_t __page_size; // architecture pagesize HACK, should go in proper runtime singleton
96extern int __map_prot;
97
98void __stack_prepare( __stack_info_t * this, size_t create_size );
99static void __stack_clean ( __stack_info_t * this );
100
101//-----------------------------------------------------------------------------
102// Coroutine ctors and dtors
103void ?{}( __stack_info_t & this, void * storage, size_t storageSize ) {
104 this.storage = (__stack_t *)storage;
105
106 // Did we get a piece of storage ?
107 if (this.storage || storageSize != 0) {
108 // We either got a piece of storage or the user asked for a specific size
109 // Immediately create the stack
110 // (This is slightly unintuitive that non-default sized coroutines create are eagerly created
111 // but it avoids that all coroutines carry an unnecessary size)
112 verify( storageSize != 0 );
113 __stack_prepare( &this, storageSize );
114 }
115}
116
117void ^?{}(__stack_info_t & this) {
118 bool userStack = ((intptr_t)this.storage & 0x1) != 0;
119 if ( ! userStack && this.storage ) {
120 __stack_clean( &this );
121 }
122}
123
124void ?{}( coroutine$ & this, const char name[], void * storage, size_t storageSize ) libcfa_public with( this ) {
125 (this.context){0p, 0p};
126 (this.stack){storage, storageSize};
127 this.name = name;
128 state = Start;
129 starter = 0p;
130 last = 0p;
131 cancellation = 0p;
132 ehm_state.ehm_buffer{};
133 ehm_state.buffer_lock{};
134 ehm_state.ehm_enabled = false;
135}
136
137void ^?{}(coroutine$& this) libcfa_public {
138 // handle any leftover pending non-local exceptions
139 nonlocal_exception * nl_ex = pop_ehm_head( &this );
140 unsigned unhandled_ex = 0;
141
142 // if any leftover exceptions handle
143 while ( nl_ex != 0p ){
144 unhandled_ex++;
145 free( nl_ex->the_exception );
146 free( nl_ex );
147 nl_ex = pop_ehm_head( &this );
148 }
149
150 #ifdef __CFA_DEBUG__
151 if ( unhandled_ex > 0 )
152 printf( "Warning: Coroutine %p exited with %u pending nonlocal exceptions.\n", &this, unhandled_ex );
153 #endif
154
155 if(this.state != Halted && this.state != Start && this.state != Primed) {
156 coroutine$ * src = active_coroutine();
157 coroutine$ * dst = &this;
158
159 struct _Unwind_Exception storage;
160 storage.exception_class = -1;
161 storage.exception_cleanup = _CtxCoroutine_UnwindCleanup;
162 this.cancellation = &storage;
163 this.last = src;
164
165 // not resuming self ?
166 if ( src == dst ) {
167 abort( "Attempt by coroutine %.256s (%p) to terminate itself.\n", src->name, src );
168 }
169
170 $ctx_switch( src, dst );
171 }
172}
173
174// Part of the Public API
175// Not inline since only ever called once per coroutine
176forall(T & | is_coroutine(T) | { EHM_DEFAULT_VTABLE(CoroutineCancelled(T)); })
177void prime(T& cor) libcfa_public {
178 coroutine$* this = get_coroutine(cor);
179 assert(this->state == Start);
180
181 this->state = Primed;
182 resume(cor);
183}
184
185static [void *, size_t] __stack_alloc( size_t storageSize ) {
186 const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
187 assert(__page_size != 0l);
188 size_t size = libCeiling( storageSize, 16 ) + stack_data_size;
189 size = ceiling(size, __page_size);
190
191 // If we are running debug, we also need to allocate a guardpage to catch stack overflows.
192 void * storage;
193 #if CFA_COROUTINE_USE_MMAP
194 storage = mmap(0p, size + __page_size, PROT_EXEC | PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0);
195 if(storage == ((void*)-1)) {
196 abort( "coroutine stack creation : internal error, mmap failure, error(%d) %s.", errno, strerror( errno ) );
197 }
198 if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) {
199 abort( "coroutine stack creation : internal error, mprotect failure, error(%d) %s.", errno, strerror( errno ) );
200 } // if
201 storage = (void *)(((intptr_t)storage) + __page_size);
202 #else
203 __cfaabi_dbg_debug_do(
204 storage = memalign( __page_size, size + __page_size );
205 );
206 __cfaabi_dbg_no_debug_do(
207 storage = (void*)malloc(size);
208 );
209
210 __cfaabi_dbg_debug_do(
211 if ( mprotect( storage, __page_size, PROT_NONE ) == -1 ) {
212 abort( "__stack_alloc : internal error, mprotect failure, error(%d) %s.", (int)errno, strerror( (int)errno ) );
213 }
214 storage = (void *)(((intptr_t)storage) + __page_size);
215 );
216 #endif
217 __cfaabi_dbg_print_safe("Kernel : Created stack %p of size %zu\n", storage, size);
218
219 verify( ((intptr_t)storage & (libAlign() - 1)) == 0ul );
220 return [storage, size];
221}
222
223static void __stack_clean ( __stack_info_t * this ) {
224 void * storage = this->storage->limit;
225
226 #if CFA_COROUTINE_USE_MMAP
227 size_t size = ((intptr_t)this->storage->base) - ((intptr_t)this->storage->limit) + sizeof(__stack_t);
228 storage = (void *)(((intptr_t)storage) - __page_size);
229 if(munmap(storage, size + __page_size) == -1) {
230 abort( "coroutine stack destruction : internal error, munmap failure, error(%d) %s.", errno, strerror( errno ) );
231 }
232 #else
233 __cfaabi_dbg_debug_do(
234 storage = (char*)(storage) - __page_size;
235 if ( mprotect( storage, __page_size, __map_prot ) == -1 ) {
236 abort( "(coStack_t *)%p.^?{}() : internal error, mprotect failure, error(%d) %s.", &this, errno, strerror( errno ) );
237 }
238 );
239
240 free( storage );
241 #endif
242 __cfaabi_dbg_print_safe("Kernel : Deleting stack %p\n", storage);
243}
244
245void __stack_prepare( __stack_info_t * this, size_t create_size ) libcfa_public {
246 const size_t stack_data_size = libCeiling( sizeof(__stack_t), 16 ); // minimum alignment
247 bool userStack;
248 void * storage;
249 size_t size;
250 if ( !this->storage ) {
251 userStack = false;
252 [storage, size] = __stack_alloc( create_size );
253 } else {
254 userStack = true;
255 __cfaabi_dbg_print_safe("Kernel : stack obj %p using user stack %p(%zd bytes)\n", this, this->storage, (intptr_t)this->storage->limit - (intptr_t)this->storage->base);
256
257 // The stack must be aligned, advance the pointer to the next align data
258 storage = (void*)libCeiling( (intptr_t)this->storage, libAlign());
259
260 // The size needs to be shrinked to fit all the extra data structure and be aligned
261 ptrdiff_t diff = (intptr_t)storage - (intptr_t)this->storage;
262 size = libFloor(create_size - stack_data_size - diff, libAlign());
263 } // if
264 assertf( size >= MinStackSize, "Stack size %zd provides less than minimum of %zd bytes for a stack.", size, MinStackSize );
265
266 this->storage = (__stack_t *)((intptr_t)storage + size - sizeof(__stack_t));
267 this->storage->limit = storage;
268 this->storage->base = (void*)((intptr_t)storage + size - sizeof(__stack_t));
269 this->storage->exception_context.top_resume = 0p;
270 this->storage->exception_context.current_exception = 0p;
271 __attribute__((may_alias)) intptr_t * istorage = (intptr_t*)&this->storage;
272 *istorage |= userStack ? 0x1 : 0x0;
273}
274
275// We need to call suspend from invoke.c, so we expose this wrapper that
276// is not inline (We can't inline Cforall in C)
277extern "C" {
278 void __cfactx_cor_leave( struct coroutine$ * src ) {
279 coroutine$ * starter = src->cancellation != 0 ? src->last : src->starter;
280
281 src->state = Halted;
282
283 assertf( starter != 0,
284 "Attempt to suspend/leave coroutine \"%.256s\" (%p) that has never been resumed.\n"
285 "Possible cause is a suspend executed in a member called by a coroutine user rather than by the coroutine main.",
286 src->name, src );
287 assertf( starter->state != Halted,
288 "Attempt by coroutine \"%.256s\" (%p) to suspend/leave back to terminated coroutine \"%.256s\" (%p).\n"
289 "Possible cause is terminated coroutine's main routine has already returned.",
290 src->name, src, starter->name, starter );
291
292 $ctx_switch( src, starter );
293 }
294
295 struct coroutine$ * __cfactx_cor_finish(void) {
296 struct coroutine$ * cor = active_coroutine();
297
298 // get the active thread once
299 thread$ * athrd = active_thread();
300
301 /* paranoid */ verify( athrd->corctx_flag );
302 athrd->corctx_flag = false;
303
304 if(cor->state == Primed) {
305 __cfactx_suspend();
306 }
307
308 cor->state = Active;
309
310 return cor;
311 }
312}
313
314
315////////////////////////////////////////////////////////////////////////////////////////////////////
316// non local ehm routines
317
318void defaultResumeAtHandler( exception_t * except ) {
319 __cfaehm_allocate_exception( except );
320 __cfaehm_begin_unwind( (void(*)(exception_t *))defaultTerminationHandler );
321}
322
323struct ehm_cleanup {
324 exception_t * ex;
325};
326
327void ^?{}( ehm_cleanup & this ) { free( this.ex ); }
328
329bool poll( coroutine$ * cor ) libcfa_public {
330 nonlocal_exception * nl_ex = pop_ehm_head( cor );
331
332 // if no exceptions return false
333 if ( nl_ex == 0p ) return false;
334
335 // otherwise loop and throwResume all pending exceptions
336 while ( nl_ex != 0p ){
337 ehm_cleanup ex_holder{ nl_ex->the_exception };
338 free( nl_ex );
339 __cfaehm_throw_resume( ex_holder.ex , defaultResumeAtHandler );
340
341 nl_ex = pop_ehm_head( cor );
342 }
343
344 return true;
345}
346
347bool poll() libcfa_public { return poll( active_coroutine() ); }
348void enable_ehm() libcfa_public { active_coroutine()->ehm_state.ehm_enabled = true; }
349void disable_ehm() libcfa_public { active_coroutine()->ehm_state.ehm_enabled = false; }
350bool checked_poll() libcfa_public { return active_coroutine()->ehm_state.ehm_enabled ? poll( active_coroutine() ) : false; }
351coroutine$ * resumer() libcfa_public { return active_coroutine()->last; }
352coroutine$ * first_resumer() libcfa_public { return active_coroutine()->starter; }
353
354// user facing ehm operations
355forall(T & | is_coroutine(T)) {
356 // enable/disable non-local exceptions
357 void enable_ehm( T & cor ) libcfa_public { get_coroutine( cor )->ehm_state.ehm_enabled = true; }
358 void disable_ehm( T & cor ) libcfa_public { get_coroutine( cor )->ehm_state.ehm_enabled = false; }
359
360 // poll for non-local exceptions
361 bool poll( T & cor ) libcfa_public { return poll( get_coroutine( cor ) ); }
362
363 // poll iff nonlocal ehm is enabled
364 bool checked_poll( T & cor ) libcfa_public { return get_coroutine( cor )->ehm_state.ehm_enabled ? poll( cor ) : false; }
365
366 coroutine$ * resumer( T & cor ) libcfa_public { return get_coroutine( cor )->last; }
367 coroutine$ * first_resumer( T & cor ) libcfa_public { return get_coroutine( cor )->starter; }
368}
369
370// resume non local exception at receiver (i.e. enqueue in ehm buffer)
371forall(exceptT *, T & | ehm_resume_at( exceptT, T ))
372void resumeAt( T & receiver, exceptT & ex ) libcfa_public {
373 coroutine$ * cor = get_coroutine( receiver );
374 nonlocal_exception * nl_ex = alloc();
375 exceptT * ex_copy = alloc();
376 memcpy( ex_copy, &ex, sizeof(exceptT) );
377 (*nl_ex){ (exception_t *)ex_copy };
378 lock( cor->ehm_state.buffer_lock __cfaabi_dbg_ctx2 );
379 append( cor->ehm_state.ehm_buffer, nl_ex );
380 unlock( cor->ehm_state.buffer_lock );
381}
382
383forall(exceptT * | { void $throwResume(exceptT &); })
384void resumeAt( coroutine$ * receiver, exceptT & ex ) libcfa_public {
385 nonlocal_exception * nl_ex = alloc();
386 exceptT * ex_copy = alloc();
387 memcpy( ex_copy, &ex, sizeof(exceptT) );
388 (*nl_ex){ (exception_t *)ex_copy };
389 lock( receiver->ehm_state.buffer_lock __cfaabi_dbg_ctx2 );
390 append( receiver->ehm_state.ehm_buffer, nl_ex );
391 unlock( receiver->ehm_state.buffer_lock );
392}
393
394// Local Variables: //
395// mode: c //
396// tab-width: 4 //
397// End: //
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