[PATCH 5.15 036/145] riscv: Avoid enabling interrupts in die()

From: Mattias Nissler mnissler@rivosinc.com

[ Upstream commit 130aee3fd9981297ff9354e5d5609cd59aafbbea ]

While working on something else, I noticed that the kernel would start accepting interrupts again after crashing in an interrupt handler. Since the kernel is already in inconsistent state, enabling interrupts is dangerous and opens up risk of kernel state deteriorating further. Interrupts do get enabled via what looks like an unintended side effect of spin_unlock_irq, so switch to the more cautious spin_lock_irqsave/spin_unlock_irqrestore instead.

Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code") Signed-off-by: Mattias Nissler mnissler@rivosinc.com Reviewed-by: Björn Töpel bjorn@kernel.org Link: https://lore.kernel.org/r/20230215144828.3370316-1-mnissler@rivosinc.com Cc: stable@vger.kernel.org Signed-off-by: Palmer Dabbelt palmer@rivosinc.com Signed-off-by: Sasha Levin sashal@kernel.org --- arch/riscv/kernel/traps.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c index 502cba5029ca4..4f38b3c47e6d5 100644 --- a/arch/riscv/kernel/traps.c +++ b/arch/riscv/kernel/traps.c @@ -34,10 +34,11 @@ void die(struct pt_regs *regs, const char *str) static int die_counter; int ret; long cause; + unsigned long flags;

oops_enter();

- spin_lock_irq(&die_lock); + spin_lock_irqsave(&die_lock, flags); console_verbose(); bust_spinlocks(1);

@@ -54,7 +55,7 @@ void die(struct pt_regs *regs, const char *str)

bust_spinlocks(0); add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE); - spin_unlock_irq(&die_lock); + spin_unlock_irqrestore(&die_lock, flags); oops_exit();

if (in_interrupt())