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Commit 4f659aa5 authored by Prasad Sodagudi's avatar Prasad Sodagudi
Browse files

rcu: Induce msm watchdog bite for rcu stalls 



Every RCU stall need to be debugged, So collect the ram
dumps on every RCU stall to debug further by inducing
non secure watchdog bite whenever rcu stall detected.

Change-Id: I6c1cfddc92f06b48c3f22fe9970b70f2ec670bf6
Signed-off-by: default avatarPrasad Sodagudi <psodagud@codeaurora.org>
parent 647076b6

kernel/rcu/tree.c

+12 −0
Original line number Diff line number Diff line
@@ -57,6 +57,8 @@ 
#include <linux/trace_events.h>

#include <linux/suspend.h>



#include <soc/qcom/watchdog.h>



#include "tree.h"

#include "rcu.h"
@@ -1298,6 +1300,11 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) 


	rcu_check_gp_kthread_starvation(rsp);



#ifdef CONFIG_RCU_STALL_WATCHDOG_BITE

	/* Induce watchdog bite */

	msm_trigger_wdog_bite();

#endif



	force_quiescent_state(rsp);  /* Kick them all. */

}
@@ -1333,6 +1340,11 @@ static void print_cpu_stall(struct rcu_state *rsp) 
			   jiffies + 3 * rcu_jiffies_till_stall_check() + 3);

	raw_spin_unlock_irqrestore(&rnp->lock, flags);



#ifdef CONFIG_RCU_STALL_WATCHDOG_BITE

	/* Induce non secure watchdog bite to collect context */

	msm_trigger_wdog_bite();

#endif



	/*

	 * Attempt to revive the RCU machinery by forcing a context switch.

	 *

lib/Kconfig.debug

+11 −0
Original line number Diff line number Diff line
@@ -1455,6 +1455,17 @@ config RCU_CPU_STALL_TIMEOUT 
	  RCU grace period persists, additional CPU stall warnings are

	  printed at more widely spaced intervals.



config RCU_STALL_WATCHDOG_BITE

	bool "RCU stall induce watchdog bite"

	depends on RCU_STALL_COMMON && QCOM_WATCHDOG_V2

	help

	  Induce watchdog bite if RCU grace period extends more than

	  specified no of seconds instead of just warning messages.

	  This helps to collect ram dumps and cpu context for

	  postmortem analysis. Generally if a given RCU grace period

	  extends more than the specified number of seconds,

	  a CPU stall warning is printed.



config RCU_TRACE

	bool "Enable tracing for RCU"

	depends on DEBUG_KERNEL