inet: fix races with reqsk timers
reqsk_queue_destroy() and reqsk_queue_unlink() should use
del_timer_sync() instead of del_timer() before calling reqsk_put(),
otherwise we could free a req still used by another cpu.
But before doing so, reqsk_queue_destroy() must release syn_wait_lock
spinlock or risk a dead lock, as reqsk_timer_handler() might
need to take this same spinlock from reqsk_queue_unlink() (called from
inet_csk_reqsk_queue_drop())
Fixes: fa76ce7328
("inet: get rid of central tcp/dccp listener timer")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
parent
9d332d92a9
commit
2235f2ac75
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@ -103,10 +103,16 @@ void reqsk_queue_destroy(struct request_sock_queue *queue)
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spin_lock_bh(&queue->syn_wait_lock);
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spin_lock_bh(&queue->syn_wait_lock);
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while ((req = lopt->syn_table[i]) != NULL) {
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while ((req = lopt->syn_table[i]) != NULL) {
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lopt->syn_table[i] = req->dl_next;
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lopt->syn_table[i] = req->dl_next;
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/* Because of following del_timer_sync(),
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* we must release the spinlock here
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* or risk a dead lock.
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*/
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spin_unlock_bh(&queue->syn_wait_lock);
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atomic_inc(&lopt->qlen_dec);
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atomic_inc(&lopt->qlen_dec);
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if (del_timer(&req->rsk_timer))
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if (del_timer_sync(&req->rsk_timer))
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reqsk_put(req);
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reqsk_put(req);
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reqsk_put(req);
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reqsk_put(req);
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spin_lock_bh(&queue->syn_wait_lock);
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}
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}
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spin_unlock_bh(&queue->syn_wait_lock);
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spin_unlock_bh(&queue->syn_wait_lock);
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}
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}
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@ -593,7 +593,7 @@ static bool reqsk_queue_unlink(struct request_sock_queue *queue,
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}
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}
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spin_unlock(&queue->syn_wait_lock);
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spin_unlock(&queue->syn_wait_lock);
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if (del_timer(&req->rsk_timer))
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if (del_timer_sync(&req->rsk_timer))
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reqsk_put(req);
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reqsk_put(req);
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return found;
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return found;
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}
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}
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