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linux-user: Fix mmap_lock ordering

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mmap_lock() can be called while tb_lock() is being held. To
avoid deadlock when one thread is holding mmap_lock and another
tb_lock, _always_ lock first tb_lock().

Signed-off-by: Riku Voipio <riku.voipio@nokia.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
This commit is contained in:
Riku Voipio 2009-12-04 15:16:31 +02:00 committed by Aurelien Jarno
parent f76cfe56d9
commit d032d1b4b4
1 changed files with 2 additions and 2 deletions
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4
linux-user/main.c
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@ -99,13 +99,14 @@ static int pending_cpus;
/* Make sure everything is in a consistent state for calling fork(). */ /* Make sure everything is in a consistent state for calling fork(). */
void fork_start(void) void fork_start(void)
{ {
mmap_fork_start();
pthread_mutex_lock(&tb_lock); pthread_mutex_lock(&tb_lock);
pthread_mutex_lock(&exclusive_lock); pthread_mutex_lock(&exclusive_lock);
mmap_fork_start();
} }
void fork_end(int child) void fork_end(int child)
{ {
mmap_fork_end(child);
if (child) { if (child) {
/* Child processes created by fork() only have a single thread. /* Child processes created by fork() only have a single thread.
Discard information about the parent threads. */ Discard information about the parent threads. */
@ -122,7 +123,6 @@ void fork_end(int child)
pthread_mutex_unlock(&exclusive_lock); pthread_mutex_unlock(&exclusive_lock);
pthread_mutex_unlock(&tb_lock); pthread_mutex_unlock(&tb_lock);
} }
mmap_fork_end(child);
} }
/* Wait for pending exclusive operations to complete. The exclusive lock /* Wait for pending exclusive operations to complete. The exclusive lock