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Commit 1572891f authored by Rohit Vaswani's avatar Rohit Vaswani Committed by Runmin Wang
Browse files

lib: spinlock: Cause a watchdog bite on spin_dump 



Currently we cause a BUG_ON once a spin_bug is detected, but
that causes a whole lot of processing and the other CPUs would
have proceeded to perform other actions and the state of the system
is moved by the time we can analyze it.
Provide an option to trigger  a watchdog bite instead so that we
can get the traces as close to the issue as possible.

Change-Id: Ic8d692ebd02c6940a3b4e5798463744db20b0026
Signed-off-by: default avatarRohit Vaswani <rvaswani@codeaurora.org>
Signed-off-by: default avatarPrasad Sodagudi <psodagud@codeaurora.org>
parent 098a0591

kernel/locking/spinlock_debug.c

+7 −0
Original line number Diff line number Diff line
@@ -12,6 +12,8 @@ 
#include <linux/debug_locks.h>

#include <linux/delay.h>

#include <linux/export.h>

#include <linux/bug.h>

#include <soc/qcom/watchdog.h>



void __raw_spin_lock_init(raw_spinlock_t *lock, const char *name,

			  struct lock_class_key *key)
@@ -64,6 +66,11 @@ static void spin_dump(raw_spinlock_t *lock, const char *msg) 
		owner ? owner->comm : "<none>",

		owner ? task_pid_nr(owner) : -1,

		lock->owner_cpu);

#ifdef CONFIG_DEBUG_SPINLOCK_BITE_ON_BUG

	msm_trigger_wdog_bite();

#elif defined(CONFIG_DEBUG_SPINLOCK_PANIC_ON_BUG)

	BUG();

#endif

	dump_stack();

}

lib/Kconfig.debug

+23 −1
Original line number Diff line number Diff line
@@ -1064,6 +1064,28 @@ config DEBUG_SPINLOCK 
	  and certain other kinds of spinlock errors commonly made.  This is

	  best used in conjunction with the NMI watchdog so that spinlock

	  deadlocks are also debuggable.

choice

        prompt "Perform Action on spinlock bug"

        depends on DEBUG_SPINLOCK



        default DEBUG_SPINLOCK_BITE_ON_BUG



        config DEBUG_SPINLOCK_BITE_ON_BUG

                bool "Cause a Watchdog Bite on Spinlock bug"

                depends on QCOM_WATCHDOG_V2

                help

                  On a spinlock bug, cause a watchdog bite so that we can get

                  the precise state of the system captured at the time of spin

                  dump. This is mutually exclusive with the below

                  DEBUG_SPINLOCK_PANIC_ON_BUG config.



        config DEBUG_SPINLOCK_PANIC_ON_BUG

                bool "Cause a Kernel Panic on Spinlock bug"

                help

                  On a spinlock bug, cause a kernel panic so that we can get the complete

                  information about the system at the time of spin dump in the dmesg.

                  This is mutually exclusive with the above DEBUG_SPINLOCK_BITE_ON_BUG.

endchoice



config DEBUG_MUTEXES

	bool "Mutex debugging: basic checks"