We have observed issues wherein the IPMI driver will sleep forever in
uninterruptible wait with mutexes held (specifically, dyn_mutex and
bmc_reg_mutex, acquired by __bmc_get_device_id). This occurs ultimately
due to a BMC firmware bug; the BMC will fail to respond to requests,
apparently related to the request rate, and the current logic will wait
forever.
When the problem occurs, as each successive process queries the BMC,
they will block in D state waiting to acquire the mutex, and with time
the machine hangs. The BMC vendor has agreed it may be a hardware fault.
This patch addresses the problem by replacing wait_event() with
wait_event_timeout(). If the event times out (meaning the problem has
occurred) the bmc->dyn_id_set and bmc->dyn_guid_set are set to 0 and the
process eventually returns.
Fixes: aa9c9ab2443e ("ipmi: allow dynamic BMC version information")
Signed-off-by: Jay Vosburgh <[email protected]>
Signed-off-by: Ioanna Alifieraki <[email protected]>
---
drivers/char/ipmi/ipmi_msghandler.c | 14 ++++++++++----
1 file changed, 10 insertions(+), 4 deletions(-)
diff --git a/drivers/char/ipmi/ipmi_msghandler.c
b/drivers/char/ipmi/ipmi_msghandler.c
index 703433493c85..a510839853b5 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -2572,7 +2572,9 @@ static int __get_device_id(struct ipmi_smi *intf, struct
bmc_device *bmc)
if (rv)
goto out_reset_handler;
- wait_event(intf->waitq, bmc->dyn_id_set != 2);
+ rv = wait_event_timeout(intf->waitq, bmc->dyn_id_set != 2, HZ * 5);
+ if (!rv)
+ bmc->dyn_id_set = 0;
if (!bmc->dyn_id_set) {
if (bmc->cc != IPMI_CC_NO_ERROR &&
@@ -3337,11 +3339,15 @@ static void __get_guid(struct ipmi_smi *intf)
bmc->dyn_guid_set = 2;
intf->null_user_handler = guid_handler;
rv = send_guid_cmd(intf, 0);
- if (rv)
+ if (rv) {
/* Send failed, no GUID available. */
bmc->dyn_guid_set = 0;
- else
- wait_event(intf->waitq, bmc->dyn_guid_set != 2);
+ } else {
+ rv = wait_event_timeout(intf->waitq, bmc->dyn_guid_set != 2,
+ HZ * 5);
+ if (!rv)
+ bmc->dyn_guid_set = 0;
+ }
/* dyn_guid_set makes the guid data available. */
smp_rmb();
--
2.34.1
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