lkml.org 
[lkml]   [2020]   [Sep]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 2/3] ipmi: Add timeout waiting for device GUID
Date
We have observed hosts with misbehaving BMCs that receive a Get Device
GUID command but don't respond. This leads to an indefinite wait in the
ipmi_msghandler's __get_guid function, showing up as hung task messages
for modprobe.

According to IPMI 2.0 specification chapter 20, the implementation of
the Get Device GUID command is optional. Therefore, add a timeout to
waiting for its response and treat the lack of one the same as missing a
device GUID.

Signed-off-by: Stefan Nuernberger <snu@amazon.com>
Signed-off-by: Markus Boehme <markubo@amazon.com>
---
drivers/char/ipmi/ipmi_msghandler.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/char/ipmi/ipmi_msghandler.c b/drivers/char/ipmi/ipmi_msghandler.c
index 2b213c9..2a2e8b2 100644
--- a/drivers/char/ipmi/ipmi_msghandler.c
+++ b/drivers/char/ipmi/ipmi_msghandler.c
@@ -3184,18 +3184,26 @@ static void guid_handler(struct ipmi_smi *intf, struct ipmi_recv_msg *msg)

static void __get_guid(struct ipmi_smi *intf)
{
- int rv;
+ long rv;
struct bmc_device *bmc = intf->bmc;

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);
+ goto out;
+ }

+ rv = wait_event_timeout(intf->waitq, bmc->dyn_guid_set != 2, 5 * HZ);
+ if (rv == 0) {
+ dev_warn_once(intf->si_dev,
+ "Timed out waiting for GUID. Assuming GUID is not available.\n");
+ bmc->dyn_guid_set = 0;
+ }
+
+out:
/* dyn_guid_set makes the guid data available. */
smp_rmb();

--
2.7.4
\
 
 \ /
  Last update: 2020-09-07 18:28    [W:0.080 / U:0.204 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site