[PATCH AUTOSEL for 4.4 062/101] ipmi/watchdog: fix wdog hang on panic waiting for ipmi response

Sasha Levin
2018-03-08T05:06:53Z

From: Robert Lippert <roblip@gmail.com>

[ Upstream commit 2c1175c2e8e5487233cabde358a19577562ac83e ]

Commit c49c097610fe ("ipmi: Don't call receive handler in the
panic context") means that the panic_recv_free is not called during a
panic and the atomic count does not drop to 0.

Fix this by only expecting one decrement of the atomic variable
which comes from panic_smi_free.

Signed-off-by: Robert Lippert <rlippert@google.com>
Signed-off-by: Corey Minyard <cminyard@mvista.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/char/ipmi/ipmi_watchdog.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_watchdog.c b/drivers/char/ipmi/ipmi_watchdog.c
index 40d400fe5bb7..4ada103945f0 100644
--- a/drivers/char/ipmi/ipmi_watchdog.c
+++ b/drivers/char/ipmi/ipmi_watchdog.c
@@ -515,7 +515,7 @@ static void panic_halt_ipmi_heartbeat(void)
msg.cmd = IPMI_WDOG_RESET_TIMER;
msg.data = NULL;
msg.data_len = 0;
- atomic_add(2, &panic_done_count);
+ atomic_add(1, &panic_done_count);
rv = ipmi_request_supply_msgs(watchdog_user,
(struct ipmi_addr *) &addr,
0,
@@ -525,7 +525,7 @@ static void panic_halt_ipmi_heartbeat(void)
&panic_halt_heartbeat_recv_msg,
1);
if (rv)
- atomic_sub(2, &panic_done_count);
+ atomic_sub(1, &panic_done_count);
}

static struct ipmi_smi_msg panic_halt_smi_msg = {
@@ -549,12 +549,12 @@ static void panic_halt_ipmi_set_timeout(void)
/* Wait for the messages to be free. */
while (atomic_read(&panic_done_count) != 0)
ipmi_poll_interface(watchdog_user);
- atomic_add(2, &panic_done_count);
+ atomic_add(1, &panic_done_count);
rv = i_ipmi_set_timeout(&panic_halt_smi_msg,
&panic_halt_recv_msg,
&send_heartbeat_now);
if (rv) {
- atomic_sub(2, &panic_done_count);
+ atomic_sub(1, &panic_done_count);
printk(KERN_WARNING PFX
"Unable to extend the watchdog timeout.");
} else {
--
2.14.1