Commit 0e438cdc authored by Kevin Wolf's avatar Kevin Wolf
Browse files

coroutine: Let CoMutex remember who holds it 



In cases of deadlocks, knowing who holds a given CoMutex is really
helpful for debugging. Keeping the information around doesn't cost much
and allows us to add another assertion to keep the code correct, so
let's just add it.

Signed-off-by: default avatarKevin Wolf <kwolf@redhat.com>
Reviewed-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Reviewed-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent 8b2bd093

include/qemu/coroutine.h

+1 −0
Original line number Diff line number Diff line
@@ -143,6 +143,7 @@ bool qemu_co_queue_empty(CoQueue *queue); 
 */

typedef struct CoMutex {

    bool locked;

    Coroutine *holder;

    CoQueue queue;

} CoMutex;

util/qemu-coroutine-lock.c

+3 −0
Original line number Diff line number Diff line
@@ -129,6 +129,7 @@ void coroutine_fn qemu_co_mutex_lock(CoMutex *mutex) 
    }



    mutex->locked = true;

    mutex->holder = self;



    trace_qemu_co_mutex_lock_return(mutex, self);

}
@@ -140,9 +141,11 @@ void coroutine_fn qemu_co_mutex_unlock(CoMutex *mutex) 
    trace_qemu_co_mutex_unlock_entry(mutex, self);



    assert(mutex->locked == true);

    assert(mutex->holder == self);

    assert(qemu_in_coroutine());



    mutex->locked = false;

    mutex->holder = NULL;

    qemu_co_queue_next(&mutex->queue);



    trace_qemu_co_mutex_unlock_return(mutex, self);