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authorNicholas Bellinger <nab@linux-iscsi.org>2013-09-06 20:46:50 -0700
committerNicholas Bellinger <nab@linux-iscsi.org>2013-09-10 16:48:54 -0700
commitd5705c4ab5035be618a34c95505727acac2e70ec (patch)
tree512bd3f2a432db2e1ae147a46950927ce2cb0502 /drivers/target
parent0105c257be8bfb7370631e442eff3213adbfdcb7 (diff)
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>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/iscsi/iscsi_target_tq.c19
1 files changed, 13 insertions, 6 deletions
diff --git a/drivers/target/iscsi/iscsi_target_tq.c b/drivers/target/iscsi/iscsi_target_tq.c
index 81289520f96..1a5bbec03f3 100644
--- a/drivers/target/iscsi/iscsi_target_tq.c
+++ b/drivers/target/iscsi/iscsi_target_tq.c
@@ -189,16 +189,20 @@ static void iscsi_deallocate_extra_thread_sets(void)
spin_lock_bh(&ts->ts_state_lock);
ts->status = ISCSI_THREAD_SET_DIE;
- spin_unlock_bh(&ts->ts_state_lock);
if (ts->rx_thread) {
- send_sig(SIGINT, ts->rx_thread, 1);
+ complete(&ts->rx_start_comp);
+ spin_unlock_bh(&ts->ts_state_lock);
kthread_stop(ts->rx_thread);
+ spin_lock_bh(&ts->ts_state_lock);
}
if (ts->tx_thread) {
- send_sig(SIGINT, ts->tx_thread, 1);
+ complete(&ts->tx_start_comp);
+ spin_unlock_bh(&ts->ts_state_lock);
kthread_stop(ts->tx_thread);
+ spin_lock_bh(&ts->ts_state_lock);
}
+ spin_unlock_bh(&ts->ts_state_lock);
/*
* Release this thread_id in the thread_set_bitmap
*/
@@ -400,7 +404,8 @@ static void iscsi_check_to_add_additional_sets(void)
static int iscsi_signal_thread_pre_handler(struct iscsi_thread_set *ts)
{
spin_lock_bh(&ts->ts_state_lock);
- if ((ts->status == ISCSI_THREAD_SET_DIE) || signal_pending(current)) {
+ if (ts->status == ISCSI_THREAD_SET_DIE || kthread_should_stop() ||
+ signal_pending(current)) {
spin_unlock_bh(&ts->ts_state_lock);
return -1;
}
@@ -419,7 +424,8 @@ struct iscsi_conn *iscsi_rx_thread_pre_handler(struct iscsi_thread_set *ts)
goto sleep;
}
- flush_signals(current);
+ if (ts->status != ISCSI_THREAD_SET_DIE)
+ flush_signals(current);
if (ts->delay_inactive && (--ts->thread_count == 0)) {
spin_unlock_bh(&ts->ts_state_lock);
@@ -472,7 +478,8 @@ struct iscsi_conn *iscsi_tx_thread_pre_handler(struct iscsi_thread_set *ts)
goto sleep;
}
- flush_signals(current);
+ if (ts->status != ISCSI_THREAD_SET_DIE)
+ flush_signals(current);
if (ts->delay_inactive && (--ts->thread_count == 0)) {
spin_unlock_bh(&ts->ts_state_lock);