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authorRoland Dreier <roland@purestorage.com>2012-11-05 18:02:40 -0800
committerNicholas Bellinger <nab@linux-iscsi.org>2012-11-07 20:12:07 -0800
commit998866b0740f128fd2c107c167c8385406dadae0 (patch)
treed923a10a89785c75d3fb93949bd72b4332930efb /drivers/target
parentbb7a8c8eb9678666fb05f3bc542581365399a161 (diff)
iscsi-target: Fix potential deadlock on lock taken in timer
We need to disable BHs when taking sess_idr_lock because the iscsit_handle_time2retain_timeout() timer function takes se_tpg->session_lock, and iscsit_close_session() nests sess_idr_lock inside se_tpg->session_lock. So if the timer can run inside sess_idr_lock, we have a potential AB-BA deadlock. Fix this by disabling BHs when taking sess_idr_lock. This was found because of a lockdep warning, but it looks like a real (if highly theoretical) deadlock. In any case avoiding lockdep spew so that we can find other issues is a worthy cause. Signed-off-by: Roland Dreier <roland@purestorage.com> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Diffstat (limited to 'drivers/target')
-rw-r--r--drivers/target/iscsi/iscsi_target_login.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/target/iscsi/iscsi_target_login.c b/drivers/target/iscsi/iscsi_target_login.c
index f8dbec05d5e5..3f34ecf87b1e 100644
--- a/drivers/target/iscsi/iscsi_target_login.c
+++ b/drivers/target/iscsi/iscsi_target_login.c
@@ -254,9 +254,9 @@ static int iscsi_login_zero_tsih_s1(
kfree(sess);
return -ENOMEM;
}
- spin_lock(&sess_idr_lock);
+ spin_lock_bh(&sess_idr_lock);
ret = idr_get_new(&sess_idr, NULL, &sess->session_index);
- spin_unlock(&sess_idr_lock);
+ spin_unlock_bh(&sess_idr_lock);
if (ret < 0) {
pr_err("idr_get_new() for sess_idr failed\n");