This doubly linked list is common for all the multifd and migration
threads so we need to avoid concurrent access.
Add a mutex to protect the data from concurrent access. This fixes a
crash when removing two MigrationThread objects from the list at the
same time during cleanup of multifd threads.
Fixes: 671326201d ("migration: Introduce interface query-migrationthreads")
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20230607161306.31425-3-farosas@suse.de>
Signed-off-by: Juan Quintela <quintela@redhat.com>
		
	
			
		
			
				
	
	
		
			65 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			65 lines
		
	
	
		
			1.6 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 *  Migration Threads info
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 *
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 *  Copyright (c) 2022 HUAWEI TECHNOLOGIES CO., LTD.
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 *
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 *  Authors:
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 *  Jiang Jiacheng <jiangjiacheng@huawei.com>
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 *
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 *  This work is licensed under the terms of the GNU GPL, version 2 or later.
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 *  See the COPYING file in the top-level directory.
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 */
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#include "qemu/osdep.h"
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#include "qemu/queue.h"
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#include "qemu/lockable.h"
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#include "threadinfo.h"
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QemuMutex migration_threads_lock;
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static QLIST_HEAD(, MigrationThread) migration_threads;
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static void __attribute__((constructor)) migration_threads_init(void)
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{
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    qemu_mutex_init(&migration_threads_lock);
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}
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MigrationThread *migration_threads_add(const char *name, int thread_id)
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{
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    MigrationThread *thread =  g_new0(MigrationThread, 1);
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    thread->name = name;
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    thread->thread_id = thread_id;
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    WITH_QEMU_LOCK_GUARD(&migration_threads_lock) {
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        QLIST_INSERT_HEAD(&migration_threads, thread, node);
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    }
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    return thread;
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}
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void migration_threads_remove(MigrationThread *thread)
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{
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    QEMU_LOCK_GUARD(&migration_threads_lock);
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    if (thread) {
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        QLIST_REMOVE(thread, node);
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        g_free(thread);
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    }
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}
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MigrationThreadInfoList *qmp_query_migrationthreads(Error **errp)
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{
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    MigrationThreadInfoList *head = NULL;
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    MigrationThreadInfoList **tail = &head;
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    MigrationThread *thread = NULL;
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    QEMU_LOCK_GUARD(&migration_threads_lock);
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    QLIST_FOREACH(thread, &migration_threads, node) {
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        MigrationThreadInfo *info = g_new0(MigrationThreadInfo, 1);
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        info->name = g_strdup(thread->name);
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        info->thread_id = thread->thread_id;
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        QAPI_LIST_APPEND(tail, info);
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    }
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    return head;
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}
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