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Commit bf98d686 authored by Rohit Vaswani's avatar Rohit Vaswani Committed by Raghavendra Rao Ananta
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 avatarRishabh Bhatnagar <rishabhb@codeaurora.org>
[rananta@codeaurora.org: Resolved trivial merge conflicts]
Signed-off-by: default avatarRaghavendra Rao Ananta <rananta@codeaurora.org>
parent 55aef73e

kernel/locking/spinlock_debug.c

+8 −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 +66,12 @@ static void spin_dump(raw_spinlock_t *lock, const char *msg) 
		owner ? owner->comm : "<none>",

		owner ? task_pid_nr(owner) : -1,

		READ_ONCE(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 −0
Original line number Diff line number Diff line
@@ -1085,6 +1085,29 @@ config LOCK_DEBUGGING_SUPPORT 
	depends on TRACE_IRQFLAGS_SUPPORT && STACKTRACE_SUPPORT && LOCKDEP_SUPPORT

	default y



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 PROVE_LOCKING

	bool "Lock debugging: prove locking correctness"

	depends on DEBUG_KERNEL && LOCK_DEBUGGING_SUPPORT