Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 39743c9e authored by Andi Kleen's avatar Andi Kleen Committed by Thomas Gleixner
Browse files

x86: use raw locks during oopses 



Don't want any lockdep or other fragile machinery to run during oopses.
Use raw spinlocks directly for oops locking.
Also disables irq flag tracing there.

[ tglx: arch/x86 adaptation ]

Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent b1992df3

arch/x86/kernel/traps_32.c

+7 −5
Original line number Diff line number Diff line
@@ -350,11 +350,11 @@ int is_valid_bugaddr(unsigned long eip) 
void die(const char * str, struct pt_regs * regs, long err)

{

	static struct {

		spinlock_t lock;

		raw_spinlock_t lock;

		u32 lock_owner;

		int lock_owner_depth;

	} die = {

		.lock =			__SPIN_LOCK_UNLOCKED(die.lock),

		.lock =			__RAW_SPIN_LOCK_UNLOCKED,

		.lock_owner =		-1,

		.lock_owner_depth =	0

	};
@@ -365,13 +365,14 @@ void die(const char * str, struct pt_regs * regs, long err) 


	if (die.lock_owner != raw_smp_processor_id()) {

		console_verbose();

		spin_lock_irqsave(&die.lock, flags);

		__raw_spin_lock(&die.lock);

		raw_local_save_flags(flags);

		die.lock_owner = smp_processor_id();

		die.lock_owner_depth = 0;

		bust_spinlocks(1);

	}

	else

		local_save_flags(flags);

		raw_local_save_flags(flags);



	if (++die.lock_owner_depth < 3) {

		unsigned long esp;
@@ -415,7 +416,8 @@ void die(const char * str, struct pt_regs * regs, long err) 
	bust_spinlocks(0);

	die.lock_owner = -1;

	add_taint(TAINT_DIE);

	spin_unlock_irqrestore(&die.lock, flags);

	__raw_spin_unlock(&die.lock);

	raw_local_irq_restore(flags);



	if (!regs)

		return;

arch/x86/kernel/traps_64.c

+7 −9
Original line number Diff line number Diff line
@@ -462,7 +462,7 @@ void out_of_line_bug(void) 
EXPORT_SYMBOL(out_of_line_bug);

#endif



static DEFINE_SPINLOCK(die_lock);

static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;

static int die_owner = -1;

static unsigned int die_nest_count;
@@ -474,13 +474,13 @@ unsigned __kprobes long oops_begin(void) 
	oops_enter();



	/* racy, but better than risking deadlock. */

	local_irq_save(flags);

	raw_local_irq_save(flags);

	cpu = smp_processor_id();

	if (!spin_trylock(&die_lock)) { 

	if (!__raw_spin_trylock(&die_lock)) {

		if (cpu == die_owner) 

			/* nested oops. should stop eventually */;

		else

			spin_lock(&die_lock);

			__raw_spin_lock(&die_lock);

	}

	die_nest_count++;

	die_owner = cpu;
@@ -494,12 +494,10 @@ void __kprobes oops_end(unsigned long flags) 
	die_owner = -1;

	bust_spinlocks(0);

	die_nest_count--;

	if (die_nest_count)

		/* We still own the lock */

		local_irq_restore(flags);

	else

	if (!die_nest_count)

		/* Nest count reaches zero, release the lock. */

		spin_unlock_irqrestore(&die_lock, flags);

		__raw_spin_unlock(&die_lock);

	raw_local_irq_restore(flags);

	if (panic_on_oops)

		panic("Fatal exception");

	oops_exit();