Commit 60c21d9f08bf ("kernel/sysrq: reset watchdog on all cpus while during
sysrq-w")
shouldn't remove touch_nmi_watchdog() call because
touch_all_softlockup_watchdogs()
resets only softlockup watchdogs, but doesn't reset NMI watchdog used in hard
lockup
detector.
So, bring it back. Plus, remove the second touch_all_softlockup_watchdogs() call
which becomes redundant, and add a comment.
This patch is delta between v2-v1 version of the upstream patch:
http://lkml.kernel.org/g/[email protected]
https://jira.sw.ru/browse/PSBM-47486
Fixes: 60c21d9f08bf ("kernel/sysrq: reset watchdog on all cpus while during
sysrq-w")
Signed-off-by: Andrey Ryabinin <[email protected]>
---
kernel/sched/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d21ccf0..1a3ff8c 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5176,14 +5176,16 @@ void show_state_filter(unsigned long state_filter)
/*
* reset the NMI-timeout, listing all files on a slow
* console might take a lot of time:
+ * Also, reset softlockup watchdogs on all CPUs, because
+ * another CPU might be blocked waiting for us to process
+ * an IPI.
*/
+ touch_nmi_watchdog();
touch_all_softlockup_watchdogs();
if (!state_filter || (p->state & state_filter))
sched_show_task(p);
} while_each_thread(g, p);
- touch_all_softlockup_watchdogs();
-
#if 0
/*
* This results in soft lockups, because it writes too much data to
--
2.7.3
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