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

Commit 6e0c853d authored by Stepan Moskovchenko's avatar Stepan Moskovchenko Committed by Gerrit - the friendly Code Review server
Browse files

arm64: update die handler from ARM / x86 



Commit 02df19b4 ("ARM:
7424/1: update die handler from x86") refactored the ARM
die() logic to avoid a deadlock if a kernel oops happens
while holding a spinlock that may also be used in an IRQ
handler. Refactor the ARM64 die() handler in a similar way,
to avoid similar deadlocks, which would have otherwise
prevented the kernel from printing the full panic output
and properly completing the panic() path.

Change-Id: I217a8d719f64b54467fa88a583d83f72193d7580
Signed-off-by: default avatarStepan Moskovchenko <stepanm@codeaurora.org>
parent 173de7d1

arch/arm64/kernel/traps.c

+49 −12
Original line number Diff line number Diff line
@@ -255,39 +255,76 @@ static int __die(const char *str, int err, struct thread_info *thread, 
	return ret;

}



static DEFINE_RAW_SPINLOCK(die_lock);

static arch_spinlock_t die_lock = __ARCH_SPIN_LOCK_UNLOCKED;

static int die_owner = -1;

static unsigned int die_nest_count;



/*

 * This function is protected against re-entrancy.

 */

void die(const char *str, struct pt_regs *regs, int err)

static unsigned long oops_begin(void)

{

	struct thread_info *thread = current_thread_info();

	int ret;

	int cpu;

	unsigned long flags;



	oops_enter();



	raw_spin_lock_irq(&die_lock);

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

	raw_local_irq_save(flags);

	cpu = smp_processor_id();

	if (!arch_spin_trylock(&die_lock)) {

		if (cpu == die_owner)

			/* nested oops. should stop eventually */;

		else

			arch_spin_lock(&die_lock);

	}

	die_nest_count++;

	die_owner = cpu;

	console_verbose();

	bust_spinlocks(1);

	ret = __die(str, err, thread, regs);

	return flags;

}



	if (regs && kexec_should_crash(thread->task))

static void oops_end(unsigned long flags, struct pt_regs *regs, int notify)

{

	if (regs && kexec_should_crash(current))

		crash_kexec(regs);



	bust_spinlocks(0);

	die_owner = -1;

	add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);

	raw_spin_unlock_irq(&die_lock);

	die_nest_count--;

	if (!die_nest_count)

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

		arch_spin_unlock(&die_lock);

	raw_local_irq_restore(flags);

	oops_exit();



	if (in_interrupt())

		panic("Fatal exception in interrupt");

	if (panic_on_oops)

		panic("Fatal exception");

	if (ret != NOTIFY_STOP)

	if (notify != NOTIFY_STOP)

		do_exit(SIGSEGV);

}



/*

 * This function is protected against re-entrancy.

 */

void die(const char *str, struct pt_regs *regs, int err)

{

	struct thread_info *thread = current_thread_info();

	enum bug_trap_type bug_type = BUG_TRAP_TYPE_NONE;

	unsigned long flags = oops_begin();

	int ret;



	if (!user_mode(regs))

		bug_type = report_bug(regs->pc, regs);

	if (bug_type != BUG_TRAP_TYPE_NONE)

		str = "Oops - BUG";



	ret = __die(str, err, thread, regs);



	oops_end(flags, regs, ret);

}



void arm64_notify_die(const char *str, struct pt_regs *regs,

		      struct siginfo *info, int err)

{