add patch series

1 files changed, 586 insertions, 0 deletions

diff --git a/debian/patches/fix-locking0004-vm-fix-locking-issues.patch b/debian/patches/fix-locking0004-vm-fix-locking-issues.patch
new file mode 100644
index 0000000..0de9159
--- /dev/null
+++ b/debian/patches/fix-locking0004-vm-fix-locking-issues.patch
@@ -0,0 +1,586 @@
+From 76a4bcc276ef16e01dced9a5b947f87a286d419c Mon Sep 17 00:00:00 2001
+From: Justus Winter <4winter@informatik.uni-hamburg.de>
+Date: Sun, 16 Aug 2015 12:54:41 +0200
+Subject: [PATCH gnumach 4/4] vm: fix locking issues
+
+Avoid accessing fields of `vm_object' objects without having it
+locked.  These problems have been found using a code transformation
+done by Coccinelle that instrumented all accesses with a runtime
+check, and manual inspection.
+
+* vm/memory_object.c (memory_object_data_supply): Avoid accessing
+fields without the lock.
+* vm/vm_fault.c (vm_fault_page): Likewise.
+* vm/vm_map.c (vm_map_submap): Properly lock `object'.
+(vm_map_copy_overwrite): Avoid accessing fields without the lock.
+(vm_map_copyin): Lock `src_object'.
+* vm/vm_object.c (_vm_object_setup): Likewise.
+(vm_object_allocate): Likewise.
+(vm_object_terminate): Avoid accessing fields without the lock.
+(vm_object_copy_delayed): Lock `src_object' earlier, lock `new_copy'.
+(vm_object_shadow): Lock `result'.
+(vm_object_enter): Properly lock `object'.  Avoid accessing fields
+without the lock.
+* vm/vm_pageout.c (vm_pageout_setup): Properly lock `old_object'.
+---
+ vm/memory_object.c | 17 +++++++----
+ vm/vm_fault.c      | 39 +++++++++++++++++++------
+ vm/vm_map.c        | 55 ++++++++++++++++++++++++-----------
+ vm/vm_object.c     | 84 +++++++++++++++++++++++++++++++++++++-----------------
+ vm/vm_pageout.c    |  9 ++----
+ 5 files changed, 141 insertions(+), 63 deletions(-)
+
+diff --git a/vm/memory_object.c b/vm/memory_object.c
+index 097ed23..0a07429 100644
+--- a/vm/memory_object.c
++++ b/vm/memory_object.c
+@@ -101,6 +101,7 @@ kern_return_t memory_object_data_supply(
+ 	vm_page_t	*page_list;
+ 	boolean_t	was_absent;
+ 	vm_map_copy_t	orig_copy = data_copy;
++	pager_request_t pager_request;
+ 
+ 	/*
+ 	 *	Look for bogus arguments
+@@ -270,6 +271,7 @@ retry_lookup:
+ 	/*
+ 	 *	Send reply if one was requested.
+ 	 */
++	pager_request = object->pager_request;
+ 	vm_object_paging_end(object);
+ 	vm_object_unlock(object);
+ 
+@@ -279,7 +281,7 @@ retry_lookup:
+ 	if (IP_VALID(reply_to)) {
+ 		memory_object_supply_completed(
+ 				reply_to, reply_to_type,
+-				object->pager_request,
++				pager_request,
+ 				original_offset,
+ 				original_length,
+ 				result,
+@@ -788,7 +790,9 @@ MACRO_END
+ 			continue;
+ 
+ 		    case MEMORY_OBJECT_LOCK_RESULT_MUST_CLEAN:
+-		    case MEMORY_OBJECT_LOCK_RESULT_MUST_RETURN:
++		    case MEMORY_OBJECT_LOCK_RESULT_MUST_RETURN:;
++			vm_offset_t object_paging_offset;
++
+ 			/*
+ 			 * The clean and return cases are similar.
+ 			 *
+@@ -811,6 +815,7 @@ MACRO_END
+ 			        PAGEOUT_PAGES;
+ 			}
+ 
++			object_paging_offset = object->paging_offset;
+ 			vm_object_unlock(object);
+ 
+ 			/*
+@@ -821,8 +826,7 @@ MACRO_END
+ 			if (new_object == VM_OBJECT_NULL) {
+ 			    new_object = vm_object_allocate(original_size);
+ 			    new_offset = 0;
+-			    paging_offset = m->offset +
+-					object->paging_offset;
++			    paging_offset = m->offset + object_paging_offset;
+ 			    pageout_action = page_lock_result;
+ 			}
+ 
+@@ -831,7 +835,7 @@ MACRO_END
+ 			 *	new object.
+ 			 */
+ 			m = vm_pageout_setup(m,
+-					m->offset + object->paging_offset,
++					m->offset + object_paging_offset,
+ 					new_object,
+ 					new_offset,
+ 					should_flush);
+@@ -859,11 +863,12 @@ MACRO_END
+ 	}
+ 
+ 	if (IP_VALID(reply_to)) {
++		pager_request_t pager_request = object->pager_request;
+ 		vm_object_unlock(object);
+ 
+ 		/* consumes our naked send-once/send right for reply_to */
+ 		(void) memory_object_lock_completed(reply_to, reply_to_type,
+-			object->pager_request, original_offset, original_size);
++			pager_request, original_offset, original_size);
+ 
+ 		vm_object_lock(object);
+ 	}
+diff --git a/vm/vm_fault.c b/vm/vm_fault.c
+index 46779f6..101ebce 100644
+--- a/vm/vm_fault.c
++++ b/vm/vm_fault.c
+@@ -229,6 +229,17 @@ vm_fault_return_t vm_fault_page(
+ 	boolean_t	look_for_page;
+ 	vm_prot_t	access_required;
+ 
++	/* We need to unlock an object before making requests to a
++	   memory manager.  We use this object to temporarily store
++	   object attributes needed for the request to avoid accessing
++	   the object while it is unlocked.  */
++	struct
++	{
++		struct ipc_port *	pager;
++		pager_request_t		pager_request;
++		vm_offset_t		paging_offset;
++	} obj;
++
+ 	if (resume) {
+ 		vm_fault_state_t *state =
+ 			(vm_fault_state_t *) current_thread()->ith_other;
+@@ -510,11 +521,16 @@ vm_fault_return_t vm_fault_page(
+ 
+ 					new_unlock_request = m->unlock_request =
+ 						(access_required | m->unlock_request);
++					obj.pager = object->pager;
++					obj.pager_request =
++						object->pager_request;
++					obj.paging_offset =
++						object->paging_offset;
+ 					vm_object_unlock(object);
+ 					if ((rc = memory_object_data_unlock(
+-						object->pager,
+-						object->pager_request,
+-						offset + object->paging_offset,
++						obj.pager,
++						obj.pager_request,
++						offset + obj.paging_offset,
+ 						PAGE_SIZE,
+ 						new_unlock_request))
+ 					     != KERN_SUCCESS) {
+@@ -633,6 +649,11 @@ vm_fault_return_t vm_fault_page(
+ 			m->absent = TRUE;
+ 			object->absent_count++;
+ 
++			/* Save attributes for the request.  */
++			obj.pager = object->pager;
++			obj.pager_request = object->pager_request;
++			obj.paging_offset = object->paging_offset;
++
+ 			/*
+ 			 *	We have a busy page, so we can
+ 			 *	release the object lock.
+@@ -647,16 +668,16 @@ vm_fault_return_t vm_fault_page(
+ 		    	vm_stat_sample(SAMPLED_PC_VM_PAGEIN_FAULTS);
+ 			current_task()->pageins++;
+ 
+-			if ((rc = memory_object_data_request(object->pager,
+-				object->pager_request,
+-				m->offset + object->paging_offset,
++			if ((rc = memory_object_data_request(obj.pager,
++				obj.pager_request,
++				m->offset + obj.paging_offset,
+ 				PAGE_SIZE, access_required)) != KERN_SUCCESS) {
+ 				if (rc != MACH_SEND_INTERRUPTED)
+ 					printf("%s(0x%p, 0x%p, 0x%lx, 0x%x, 0x%x) failed, %x\n",
+ 						"memory_object_data_request",
+-						object->pager,
+-						object->pager_request,
+-						m->offset + object->paging_offset,
++						obj.pager,
++						obj.pager_request,
++						m->offset + obj.paging_offset,
+ 						PAGE_SIZE, access_required, rc);
+ 				/*
+ 				 *	Don't want to leave a busy page around,
+diff --git a/vm/vm_map.c b/vm/vm_map.c
+index ae3ce21..9098dfd 100644
+--- a/vm/vm_map.c
++++ b/vm/vm_map.c
+@@ -1182,16 +1182,20 @@ kern_return_t vm_map_submap(
+ 
+ 	if ((entry->vme_start == start) && (entry->vme_end == end) &&
+ 	    (!entry->is_sub_map) &&
+-	    ((object = entry->object.vm_object) == vm_submap_object) &&
+-	    (object->resident_page_count == 0) &&
+-	    (object->copy == VM_OBJECT_NULL) &&
+-	    (object->shadow == VM_OBJECT_NULL) &&
+-	    (!object->pager_created)) {
+-		entry->object.vm_object = VM_OBJECT_NULL;
+-		vm_object_deallocate(object);
+-		entry->is_sub_map = TRUE;
+-		vm_map_reference(entry->object.sub_map = submap);
+-		result = KERN_SUCCESS;
++	    ((object = entry->object.vm_object) == vm_submap_object)) {
++		vm_object_lock(object);
++		if ((object->resident_page_count == 0) &&
++		    (object->copy == VM_OBJECT_NULL) &&
++		    (object->shadow == VM_OBJECT_NULL) &&
++		    (!object->pager_created)) {
++			vm_object_unlock(object);
++			entry->object.vm_object = VM_OBJECT_NULL;
++			vm_object_deallocate(object);
++			entry->is_sub_map = TRUE;
++			vm_map_reference(entry->object.sub_map = submap);
++			result = KERN_SUCCESS;
++		} else
++			vm_object_unlock(object);
+ 	}
+ 	vm_map_unlock(map);
+ 
+@@ -2122,6 +2126,7 @@ start_pass_1:
+ 	for (entry = tmp_entry;;) {
+ 		vm_size_t	sub_size = (entry->vme_end - entry->vme_start);
+ 		vm_map_entry_t	next = entry->vme_next;
++		vm_object_t	object;
+ 
+ 		if ( ! (entry->protection & VM_PROT_WRITE)) {
+ 			vm_map_unlock(dst_map);
+@@ -2157,10 +2162,13 @@ start_pass_1:
+ 		/*
+ 		 *	Check for permanent objects in the destination.
+ 		 */
+-
+-		if ((entry->object.vm_object != VM_OBJECT_NULL) &&
+-			   !entry->object.vm_object->temporary)
+-			contains_permanent_objects = TRUE;
++		object = entry->object.vm_object;
++		if ((object != VM_OBJECT_NULL)
++		    && ! contains_permanent_objects) {
++			vm_object_lock(object);
++			contains_permanent_objects = object->temporary;
++			vm_object_unlock(object);
++		}
+ 
+ 		size -= sub_size;
+ 		entry = next;
+@@ -2220,6 +2228,7 @@ start_pass_1:
+ 		vm_map_entry_t	copy_entry = vm_map_copy_first_entry(copy);
+ 		vm_size_t	copy_size = (copy_entry->vme_end - copy_entry->vme_start);
+ 		vm_object_t	object;
++		int		temporary;
+ 
+ 		entry = tmp_entry;
+ 		size = (entry->vme_end - entry->vme_start);
+@@ -2275,8 +2284,15 @@ start_pass_1:
+ 		 */
+ 
+ 		object = entry->object.vm_object;
++		temporary = 0;
++		if (object != VM_OBJECT_NULL) {
++			vm_object_lock(object);
++			temporary = object->temporary;
++			vm_object_unlock(object);
++		}
++
+ 		if (!entry->is_shared &&
+-		    ((object == VM_OBJECT_NULL) || object->temporary)) {
++		    ((object == VM_OBJECT_NULL) || temporary)) {
+ 			vm_object_t	old_object = entry->object.vm_object;
+ 			vm_offset_t	old_offset = entry->offset;
+ 
+@@ -3219,11 +3235,15 @@ kern_return_t vm_map_copyin(
+ 		/*
+ 		 *	Attempt non-blocking copy-on-write optimizations.
+ 		 */
+-
++		if (src_object)
++			vm_object_lock(src_object);
+ 		if (src_destroy &&
+ 		    (src_object == VM_OBJECT_NULL ||
+ 		     (src_object->temporary && !src_object->use_shared_copy)))
+ 		{
++		    if (src_object)
++			vm_object_unlock(src_object);
++
+ 		    /*
+ 		     * If we are destroying the source, and the object
+ 		     * is temporary, and not shared writable,
+@@ -3243,6 +3263,9 @@ kern_return_t vm_map_copyin(
+ 		    goto CopySuccessful;
+ 		}
+ 
++		if (src_object)
++			vm_object_unlock(src_object);
++
+ 		if (!was_wired &&
+ 		    vm_object_copy_temporary(
+ 				&new_entry->object.vm_object,
+diff --git a/vm/vm_object.c b/vm/vm_object.c
+index deac0c2..1d3e727 100644
+--- a/vm/vm_object.c
++++ b/vm/vm_object.c
+@@ -217,9 +217,11 @@ static void _vm_object_setup(
+ 	vm_size_t	size)
+ {
+ 	*object = vm_object_template;
+-	queue_init(&object->memq);
+ 	vm_object_lock_init(object);
++	vm_object_lock(object);
++	queue_init(&object->memq);
+ 	object->size = size;
++	vm_object_unlock(object);
+ }
+ 
+ vm_object_t _vm_object_allocate(
+@@ -244,8 +246,11 @@ vm_object_t vm_object_allocate(
+ 	port = ipc_port_alloc_kernel();
+ 	if (port == IP_NULL)
+ 		panic("vm_object_allocate");
++
++	vm_object_lock(object);
+ 	object->pager_name = port;
+ 	ipc_kobject_set(port, (ipc_kobject_t) object, IKOT_PAGING_NAME);
++	vm_object_unlock(object);
+ 
+ 	return object;
+ }
+@@ -540,6 +545,12 @@ void vm_object_terminate(
+ {
+ 	vm_page_t	p;
+ 	vm_object_t	shadow_object;
++	struct ipc_port	*pager;
++	pager_request_t	pager_request;
++	struct ipc_port	*pager_name;
++#if	MACH_PAGEMAP
++	vm_external_t	existence_info;
++#endif	/* MACH_PAGEMAP */
+ 
+ 	/*
+ 	 *	Make sure the object isn't already being terminated
+@@ -637,20 +648,26 @@ void vm_object_terminate(
+ 	 *	using memory_object_terminate.
+ 	 */
+ 
++	/* Copy attributes while object is locked.  */
++	pager = object->pager;
++	pager_request = object->pager_request;
++	pager_name = object->pager_name;
++#if	MACH_PAGEMAP
++	existence_info = object->existence_info;
++#endif	/* MACH_PAGEMAP */
++
+ 	vm_object_unlock(object);
+ 
+-	if (object->pager != IP_NULL) {
++	if (pager != IP_NULL) {
+ 		/* consumes our rights for pager, pager_request, pager_name */
+-		memory_object_release(object->pager,
+-					     object->pager_request,
+-					     object->pager_name);
+-	} else if (object->pager_name != IP_NULL) {
++		memory_object_release(pager, pager_request, pager_name);
++	} else if (pager_name != IP_NULL) {
+ 		/* consumes our right for pager_name */
+-		ipc_port_dealloc_kernel(object->pager_name);
++		ipc_port_dealloc_kernel(pager_name);
+ 	}
+ 
+ #if	MACH_PAGEMAP
+-	vm_external_destroy(object->existence_info);
++	vm_external_destroy(existence_info);
+ #endif	/* MACH_PAGEMAP */
+ 
+ 	/*
+@@ -1474,14 +1491,11 @@ vm_object_t vm_object_copy_delayed(
+ 	 *	must be done carefully, to avoid deadlock.
+ 	 */
+ 
+-	/*
+-	 *	Allocate a new copy object before locking, even
+-	 *	though we may not need it later.
+-	 */
++	vm_object_lock(src_object);
+ 
+ 	new_copy = vm_object_allocate(src_object->size);
+ 
+-	vm_object_lock(src_object);
++	vm_object_lock(new_copy);
+ 
+ 	/*
+ 	 *	See whether we can reuse the result of a previous
+@@ -1519,7 +1533,7 @@ vm_object_t vm_object_copy_delayed(
+ 			old_copy->ref_count++;
+ 			vm_object_unlock(old_copy);
+ 			vm_object_unlock(src_object);
+-
++			vm_object_unlock(new_copy);
+ 			vm_object_deallocate(new_copy);
+ 
+ 			return old_copy;
+@@ -1574,7 +1588,7 @@ vm_object_t vm_object_copy_delayed(
+ 	}
+ 
+ 	vm_object_unlock(src_object);
+-	
++	vm_object_unlock(new_copy);
+ 	return new_copy;
+ }
+ 
+@@ -1711,6 +1725,8 @@ void vm_object_shadow(
+ 	if ((result = vm_object_allocate(length)) == VM_OBJECT_NULL)
+ 		panic("vm_object_shadow: no object for shadowing");
+ 
++	vm_object_lock(result);
++
+ 	/*
+ 	 *	The new object shadows the source object, adding
+ 	 *	a reference to it.  Our caller changes his reference
+@@ -1733,6 +1749,7 @@ void vm_object_shadow(
+ 
+ 	*offset = 0;
+ 	*object = result;
++	vm_object_unlock(result);
+ }
+ 
+ /*
+@@ -2053,8 +2070,10 @@ restart:
+ 	object = (po == IKOT_PAGER) ? (vm_object_t) pager->ip_kobject
+ 				    : VM_OBJECT_NULL;
+ 
+-	if ((object != VM_OBJECT_NULL) && !must_init) {
++	if (object != VM_OBJECT_NULL)
+ 		vm_object_lock(object);
++
++	if ((object != VM_OBJECT_NULL) && !must_init) {
+ 		if (object->ref_count == 0) {
+ 			queue_remove(&vm_object_cached_list, object,
+ 					vm_object_t, cached_list);
+@@ -2062,10 +2081,9 @@ restart:
+ 			vm_object_cached_pages_update(-object->resident_page_count);
+ 		}
+ 		object->ref_count++;
+-		vm_object_unlock(object);
+-
+ 		vm_stat.hits++;
+ 	}
++
+ 	assert((object == VM_OBJECT_NULL) || (object->ref_count > 0) ||
+ 		((object->paging_in_progress != 0) && internal));
+ 
+@@ -2085,6 +2103,10 @@ restart:
+ 		return(object);
+ 
+ 	if (must_init) {
++		vm_size_t pager_size;
++		pager_request_t pager_request;
++		struct ipc_port *pager_name;
++
+ 		/*
+ 		 *	Copy the naked send right we were given.
+ 		 */
+@@ -2112,6 +2134,11 @@ restart:
+ 		 *	Let the pager know we're using it.
+ 		 */
+ 
++		/* Store attributes while we're holding the lock.  */
++		pager_size = object->size;
++		pager_request = object->pager_request;
++		pager_name = object->pager_name;
++
+ 		if (internal) {
+ 			/* acquire a naked send right for the DMM */
+ 			ipc_port_t DMM = memory_manager_default_reference();
+@@ -2123,12 +2150,15 @@ restart:
+ 			/* default-pager objects are ready immediately */
+ 			object->pager_ready = TRUE;
+ 
++			/* Unlock object across call to memory manager.  */
++			vm_object_unlock(object);
++
+ 			/* consumes the naked send right for DMM */
+ 			(void) memory_object_create(DMM,
+ 				pager,
+-				object->size,
+-				object->pager_request,
+-				object->pager_name,
++				pager_size,
++				pager_request,
++				pager_name,
+ 				PAGE_SIZE);
+ 		} else {
+ 			/* the object is external and not temporary */
+@@ -2138,13 +2168,16 @@ restart:
+ 			/* user pager objects are not ready until marked so */
+ 			object->pager_ready = FALSE;
+ 
++			/* Unlock object across call to memory manager.  */
++			vm_object_unlock(object);
++
+ 			(void) memory_object_init(pager,
+-				object->pager_request,
+-				object->pager_name,
++				pager_request,
++				pager_name,
+ 				PAGE_SIZE);
+-
+ 		}
+ 
++		/* Object was unlocked across call to memory manager.  */
+ 		vm_object_lock(object);
+ 		object->pager_initialized = TRUE;
+ 
+@@ -2152,9 +2185,8 @@ restart:
+ 			object->pager_ready = TRUE;
+ 
+ 		vm_object_wakeup(object, VM_OBJECT_EVENT_INITIALIZED);
+-	} else {
+-		vm_object_lock(object);
+ 	}
++
+ 	/*
+ 	 *	[At this point, the object must be locked]
+ 	 */
+diff --git a/vm/vm_pageout.c b/vm/vm_pageout.c
+index 51a6a0d..b676c7b 100644
+--- a/vm/vm_pageout.c
++++ b/vm/vm_pageout.c
+@@ -252,6 +252,8 @@ vm_pageout_setup(
+ 		vm_object_unlock(new_object);
+ 	}
+ 
++	vm_object_lock(old_object);
++
+ 	if (flush) {
+ 		/*
+ 		 *	Create a place-holder page where the old one was,
+@@ -262,7 +264,6 @@ vm_pageout_setup(
+ 							== VM_PAGE_NULL)
+ 			vm_page_more_fictitious();
+ 
+-		vm_object_lock(old_object);
+ 		vm_page_lock_queues();
+ 		vm_page_remove(m);
+ 		vm_page_unlock_queues();
+@@ -281,8 +282,6 @@ vm_pageout_setup(
+ 					VM_EXTERNAL_STATE_EXISTS);
+ #endif	/* MACH_PAGEMAP */
+ 
+-		vm_object_unlock(old_object);
+-
+ 		vm_object_lock(new_object);
+ 
+ 		/*
+@@ -305,7 +304,6 @@ vm_pageout_setup(
+ 		 */
+ 		vm_page_copy(m, new_m);
+ 
+-		vm_object_lock(old_object);
+ 		m->dirty = FALSE;
+ 		pmap_clear_modify(m->phys_addr);
+ 
+@@ -328,8 +326,6 @@ vm_pageout_setup(
+ 					VM_EXTERNAL_STATE_EXISTS);
+ #endif	/* MACH_PAGEMAP */
+ 
+-		vm_object_unlock(old_object);
+-
+ 		vm_object_lock(new_object);
+ 
+ 		/*
+@@ -383,6 +379,7 @@ vm_pageout_setup(
+ 	 */
+ 
+ 	vm_object_unlock(new_object);
++	vm_object_unlock(old_object);
+ 
+ 	/*
+ 	 *	Return the placeholder page to simplify cleanup.
+-- 
+2.1.4
+