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iscsi-target: Fix race with thread_pre_handler flush_signals + ISCSI_THREAD_SET_DIE
This patch addresses an long standing race in iscsi_[rx,tx]_thread_pre_handler() use of flush_signals(), and between iscsi_deallocate_extra_thread_sets() setting ISCSI_THREAD_SET_DIE before calling kthread_stop(). It addresses the issue by both holding ts_state_lock before calling send_sig() in iscsi_deallocate_extra_thread_sets(), as well as only calling flush_signals() when ts->status != ISCSI_THREAD_SET_DIE within iscsi_[rx,tx]_thread_pre_handler() code. v2 changes: - Add explicit complete(&ts->[rx,tx]_start_comp); before kthread_stop() in iscsi_deallocate_extra_thread_sets() - Drop left-over send_sig() calls in iscsi_deallocate_extra_thread_sets() - Add kthread_should_stop() check in iscsi_signal_thread_pre_handler() Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
This commit is contained in:
parent
0105c257be
commit
d5705c4ab5
1 changed files with 13 additions and 6 deletions
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@ -189,16 +189,20 @@ static void iscsi_deallocate_extra_thread_sets(void)
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spin_lock_bh(&ts->ts_state_lock);
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ts->status = ISCSI_THREAD_SET_DIE;
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spin_unlock_bh(&ts->ts_state_lock);
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if (ts->rx_thread) {
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send_sig(SIGINT, ts->rx_thread, 1);
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complete(&ts->rx_start_comp);
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spin_unlock_bh(&ts->ts_state_lock);
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kthread_stop(ts->rx_thread);
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spin_lock_bh(&ts->ts_state_lock);
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}
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if (ts->tx_thread) {
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send_sig(SIGINT, ts->tx_thread, 1);
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complete(&ts->tx_start_comp);
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spin_unlock_bh(&ts->ts_state_lock);
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kthread_stop(ts->tx_thread);
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spin_lock_bh(&ts->ts_state_lock);
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}
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spin_unlock_bh(&ts->ts_state_lock);
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/*
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* Release this thread_id in the thread_set_bitmap
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*/
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@ -400,7 +404,8 @@ static void iscsi_check_to_add_additional_sets(void)
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static int iscsi_signal_thread_pre_handler(struct iscsi_thread_set *ts)
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{
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spin_lock_bh(&ts->ts_state_lock);
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if ((ts->status == ISCSI_THREAD_SET_DIE) || signal_pending(current)) {
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if (ts->status == ISCSI_THREAD_SET_DIE || kthread_should_stop() ||
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signal_pending(current)) {
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spin_unlock_bh(&ts->ts_state_lock);
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return -1;
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}
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@ -419,7 +424,8 @@ struct iscsi_conn *iscsi_rx_thread_pre_handler(struct iscsi_thread_set *ts)
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goto sleep;
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}
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flush_signals(current);
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if (ts->status != ISCSI_THREAD_SET_DIE)
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flush_signals(current);
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if (ts->delay_inactive && (--ts->thread_count == 0)) {
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spin_unlock_bh(&ts->ts_state_lock);
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@ -472,7 +478,8 @@ struct iscsi_conn *iscsi_tx_thread_pre_handler(struct iscsi_thread_set *ts)
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goto sleep;
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}
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flush_signals(current);
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if (ts->status != ISCSI_THREAD_SET_DIE)
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flush_signals(current);
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if (ts->delay_inactive && (--ts->thread_count == 0)) {
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spin_unlock_bh(&ts->ts_state_lock);
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