| Message ID | 20210923185106.501848-1-f.fainelli@gmail.com (mailing list archive) |
|---|---|
| State | Deferred |
| Headers | show |
| Series | PM / Suspend: Avoid soft lockup warning with suspend_test | expand |
On 9/23/21 11:51 AM, Florian Fainelli wrote: > When testing with a large (>= 22 seconds) pm_test_delay we can see the > NMI soft lockup barfing at us because a task has been blocked for too > long. This can be reproduced with: > > echo devices > /sys/power/pm_test > echo 30 > /sys/module/suspend/parameters/pm_test_delay > > Unroll the loop and touch the NMI watchdog every 1s to avoid the lockup > warnings. > > Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> Looks like I cannot reproduce the NMI soft lockup warnings with 5.10 and newer, however I can easily trigger RCU stalls. Let me sleep on it for a bit and see what needs fixing in 5.15 and newer. Any feedback welcome.
diff --git a/kernel/power/suspend.c b/kernel/power/suspend.c index eb75f394a059..7441f0011ccd 100644 --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -30,6 +30,7 @@ #include <trace/events/power.h> #include <linux/compiler.h> #include <linux/moduleparam.h> +#include <linux/nmi.h> #include "power.h" @@ -324,10 +325,15 @@ MODULE_PARM_DESC(pm_test_delay, static int suspend_test(int level) { #ifdef CONFIG_PM_DEBUG + unsigned int i; + if (pm_test_level == level) { pr_info("suspend debug: Waiting for %d second(s).\n", pm_test_delay); - mdelay(pm_test_delay * 1000); + for (i = 0; i < pm_test_delay; i++) { + mdelay(1000); + touch_nmi_watchdog(); + } return 1; } #endif /* !CONFIG_PM_DEBUG */
When testing with a large (>= 22 seconds) pm_test_delay we can see the NMI soft lockup barfing at us because a task has been blocked for too long. This can be reproduced with: echo devices > /sys/power/pm_test echo 30 > /sys/module/suspend/parameters/pm_test_delay Unroll the loop and touch the NMI watchdog every 1s to avoid the lockup warnings. Signed-off-by: Florian Fainelli <f.fainelli@gmail.com> --- kernel/power/suspend.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)