From fc42149932f16172f2e88182edd40bf827d264e4 Mon Sep 17 00:00:00 2001 From: Qiao Zhou Date: Fri, 7 Jul 2017 17:29:34 +0800 Subject: [PATCH] arm64: traps: disable irq in die() commit 6f44a0bacb79a03972c83759711832b382b1b8ac upstream. In current die(), the irq is disabled for __die() handle, not including the possible panic() handling. Since the log in __die() can take several hundreds ms, new irq might come and interrupt current die(). If the process calling die() holds some critical resource, and some other process scheduled later also needs it, then it would deadlock. The first panic will not be executed. So here disable irq for the whole flow of die(). Signed-off-by: Qiao Zhou Signed-off-by: Will Deacon Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman --- arch/arm64/kernel/traps.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/traps.c b/arch/arm64/kernel/traps.c index 5963be2e05f0..28bef94cf792 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -266,10 +266,12 @@ void die(const char *str, struct pt_regs *regs, int err) { struct thread_info *thread = current_thread_info(); int ret; + unsigned long flags; + + raw_spin_lock_irqsave(&die_lock, flags); oops_enter(); - raw_spin_lock_irq(&die_lock); console_verbose(); bust_spinlocks(1); ret = __die(str, err, thread, regs); @@ -279,13 +281,15 @@ void die(const char *str, struct pt_regs *regs, int err) bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - raw_spin_unlock_irq(&die_lock); oops_exit(); if (in_interrupt()) panic("Fatal exception in interrupt"); if (panic_on_oops) panic("Fatal exception"); + + raw_spin_unlock_irqrestore(&die_lock, flags); + if (ret != NOTIFY_STOP) do_exit(SIGSEGV); }