diff options
| author | Roland Dreier <roland@purestorage.com> | 2012-11-06 03:02:40 +0100 |
|---|---|---|
| committer | Nicholas Bellinger <nab@linux-iscsi.org> | 2012-11-08 05:12:07 +0100 |
| commit | 998866b0740f128fd2c107c167c8385406dadae0 (patch) | |
| tree | d923a10a89785c75d3fb93949bd72b4332930efb /drivers/target | |
| parent | target: Fix exception path pr_reg put regression for PR RELEASE (diff) | |
| download | linux-998866b0740f128fd2c107c167c8385406dadae0.tar.xz linux-998866b0740f128fd2c107c167c8385406dadae0.zip | |
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.c | 4 |
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"); |