The libiscsi code was using both spin_lock()/spin_unlock()
and spin_lock_bh()/spin_unlock_bh() on its session lock.
In addition, lock validation found that libiscsi.c was
taking a HARDIRQ-unsafe lock while holding an HARDIRQ-
irq-safe lock:
> [ 2528.738454] =====================================================
> [ 2528.744679] WARNING: HARDIRQ-safe -> HARDIRQ-unsafe lock order detected
> [ 2528.749891] 4.15.0-00006-g4548e6f42022-dirty #418 Not tainted
> [ 2528.754356] -----------------------------------------------------
> [ 2528.759643] kworker/0:1H/100 [HC0[0]:SC0[0]:HE0:SE1] is trying to acquire:
> [ 2528.764608] (&(&session->frwd_lock)->rlock){+.-.}, at: [<0000000097d8de0f>] iscsi_eh_cmd_timed_out+0x3d/0x2b0
> [ 2528.769164]
> and this task is already holding:
> [ 2528.771313] (&(&q->__queue_lock)->rlock){-.-.}, at: [<00000000a105bf06>] blk_timeout_work+0x22/0x120
> [ 2528.773825] which would create a new lock dependency:
> [ 2528.775216] (&(&q->__queue_lock)->rlock){-.-.} -> (&(&session->frwd_lock)->rlock){+.-.}
> [ 2528.777071]
> but this new dependency connects a HARDIRQ-irq-safe lock:
> [ 2528.778945] (&(&q->__queue_lock)->rlock){-.-.}
> [ 2528.778948]
> ... which became HARDIRQ-irq-safe at:
> [ 2528.781204] _raw_spin_lock_irqsave+0x3c/0x4b
> [ 2528.781966] cfq_idle_slice_timer+0x2f/0x100
> [ 2528.782705] __hrtimer_run_queues+0xdc/0x440
> [ 2528.783448] hrtimer_interrupt+0xb1/0x210
> [ 2528.784149] smp_apic_timer_interrupt+0x6d/0x260
> [ 2528.784954] apic_timer_interrupt+0xac/0xc0
> [ 2528.785679] native_safe_halt+0x2/0x10
> [ 2528.786280] default_idle+0x1f/0x180
> [ 2528.786806] do_idle+0x166/0x1e0
> [ 2528.787288] cpu_startup_entry+0x6f/0x80
> [ 2528.787874] start_secondary+0x186/0x1e0
> [ 2528.788448] secondary_startup_64+0xa5/0xb0
> [ 2528.789070]
> to a HARDIRQ-irq-unsafe lock:
> [ 2528.789913] (&(&session->frwd_lock)->rlock){+.-.}
> [ 2528.789915]
> ... which became HARDIRQ-irq-unsafe at:
> [ 2528.791548] ...
> [ 2528.791553] _raw_spin_lock_bh+0x34/0x40
> [ 2528.792366] iscsi_conn_setup+0x166/0x220
> [ 2528.792960] iscsi_tcp_conn_setup+0x10/0x40
> [ 2528.793526] iscsi_sw_tcp_conn_create+0x1b/0x160
> [ 2528.794111] iscsi_if_rx+0xf9f/0x1580
> [ 2528.794542] netlink_unicast+0x1f7/0x2f0
> [ 2528.795105] netlink_sendmsg+0x2c9/0x3c0
> [ 2528.795636] sock_sendmsg+0x30/0x40
> [ 2528.796068] ___sys_sendmsg+0x269/0x2c0
> [ 2528.796544] __sys_sendmsg+0x51/0x90
> [ 2528.797028] entry_SYSCALL_64_fastpath+0x25/0x9c
> [ 2528.797595]
> ...
This commit avoids possible reverse deadlock.
Signed-off-by: Lee Duncan <lduncan@xxxxxxxx>
---
drivers/scsi/libiscsi.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/drivers/scsi/libiscsi.c b/drivers/scsi/libiscsi.c
index 82c3fd4bc938..055357b2fe9e 100644
--- a/drivers/scsi/libiscsi.c
+++ b/drivers/scsi/libiscsi.c
@@ -1248,9 +1248,9 @@ int iscsi_complete_pdu(struct iscsi_conn *conn, struct iscsi_hdr *hdr,
{
int rc;
- spin_lock(&conn->session->lock);
+ spin_lock_bh(&conn->session->lock);
rc = __iscsi_complete_pdu(conn, hdr, data, datalen);
- spin_unlock(&conn->session->lock);
+ spin_unlock_bh(&conn->session->lock);
return rc;
}
EXPORT_SYMBOL_GPL(iscsi_complete_pdu);
@@ -1749,14 +1749,14 @@ static void iscsi_tmf_timedout(unsigned long data)
struct iscsi_conn *conn = (struct iscsi_conn *)data;
struct iscsi_session *session = conn->session;
- spin_lock(&session->lock);
+ spin_lock_bh(&session->lock);
if (conn->tmf_state == TMF_QUEUED) {
conn->tmf_state = TMF_TIMEDOUT;
ISCSI_DBG_EH(session, "tmf timedout\n");
/* unblock eh_abort() */
wake_up(&conn->ehwait);
}
- spin_unlock(&session->lock);
+ spin_unlock_bh(&session->lock);
}
static int iscsi_exec_task_mgmt_fn(struct iscsi_conn *conn,
@@ -1908,7 +1908,7 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
ISCSI_DBG_EH(session, "scsi cmd %p timedout\n", sc);
- spin_lock(&session->lock);
+ spin_lock_bh(&session->lock);
task = (struct iscsi_task *)sc->SCp.ptr;
if (!task) {
/*
@@ -2022,7 +2022,7 @@ static enum blk_eh_timer_return iscsi_eh_cmd_timed_out(struct scsi_cmnd *sc)
done:
if (task)
task->last_timeout = jiffies;
- spin_unlock(&session->lock);
+ spin_unlock_bh(&session->lock);
ISCSI_DBG_EH(session, "return %s\n", rc == BLK_EH_RESET_TIMER ?
"timer reset" : "nh");
return rc;
@@ -2034,7 +2034,7 @@ static void iscsi_check_transport_timeouts(unsigned long data)
struct iscsi_session *session = conn->session;
unsigned long recv_timeout, next_timeout = 0, last_recv;
- spin_lock(&session->lock);
+ spin_lock_bh(&session->lock);
if (session->state != ISCSI_STATE_LOGGED_IN)
goto done;
@@ -2051,7 +2051,7 @@ static void iscsi_check_transport_timeouts(unsigned long data)
"last ping %lu, now %lu\n",
conn->ping_timeout, conn->recv_timeout,
last_recv, conn->last_ping, jiffies);
- spin_unlock(&session->lock);
+ spin_unlock_bh(&session->lock);
iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
return;
}
@@ -2067,7 +2067,7 @@ static void iscsi_check_transport_timeouts(unsigned long data)
ISCSI_DBG_CONN(conn, "Setting next tmo %lu\n", next_timeout);
mod_timer(&conn->transport_timer, next_timeout);
done:
- spin_unlock(&session->lock);
+ spin_unlock_bh(&session->lock);
}
static void iscsi_prep_abort_task_pdu(struct iscsi_task *task,
--
2.13.6
