From: Qiao Zhou qiaozhou@asrmicro.com
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 qiaozhou@asrmicro.com Signed-off-by: Will Deacon will.deacon@arm.com (cherry picked from commit 6f44a0bacb79a03972c83759711832b382b1b8ac) Signed-off-by: Arnd Bergmann arnd@arndb.de --- 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 5d270ca76aec..6b4579e07aa2 100644 --- a/arch/arm64/kernel/traps.c +++ b/arch/arm64/kernel/traps.c @@ -239,10 +239,12 @@ 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); @@ -252,13 +254,15 @@ 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); }