riscv: Fix sleeping in invalid context in die()

commit 6a97f4118ac07cfdc316433f385dbdc12af5025e upstream.

die() can be called in exception handler, and therefore cannot sleep.
However, die() takes spinlock_t which can sleep with PREEMPT_RT enabled.
That causes the following warning:

BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 285, name: mutex
preempt_count: 110001, expected: 0
RCU nest depth: 0, expected: 0
CPU: 0 UID: 0 PID: 285 Comm: mutex Not tainted 6.12.0-rc7-00022-ge19049cf7d56-dirty #234
Hardware name: riscv-virtio,qemu (DT)
Call Trace:
    dump_backtrace+0x1c/0x24
    show_stack+0x2c/0x38
    dump_stack_lvl+0x5a/0x72
    dump_stack+0x14/0x1c
    __might_resched+0x130/0x13a
    rt_spin_lock+0x2a/0x5c
    die+0x24/0x112
    do_trap_insn_illegal+0xa0/0xea
    _new_vmalloc_restore_context_a0+0xcc/0xd8
Oops - illegal instruction [#1]

Switch to use raw_spinlock_t, which does not sleep even with PREEMPT_RT
enabled.

Fixes: 76d2a0493a17 ("RISC-V: Init and Halt Code")
Signed-off-by: Nam Cao <namcao@linutronix.de>
Cc: stable@vger.kernel.org
Reviewed-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://lore.kernel.org/r/20241118091333.1185288-1-namcao@linutronix.de
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 227253fde33c4a728d24a8ba3171979430b954ff..f32845d238a094104ed156a3b2ae56ab31af59a6 100644 (file)
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -25,7 +25,7 @@ int show_unhandled_signals = 1;
 
 extern asmlinkage void handle_exception(void);
 
-static DEFINE_SPINLOCK(die_lock);
+static DEFINE_RAW_SPINLOCK(die_lock);
 
 void die(struct pt_regs *regs, const char *str)
 {
@@ -36,7 +36,7 @@ void die(struct pt_regs *regs, const char *str)
 
        oops_enter();
 
-       spin_lock_irqsave(&die_lock, flags);
+       raw_spin_lock_irqsave(&die_lock, flags);
        console_verbose();
        bust_spinlocks(1);
 
@@ -53,7 +53,7 @@ void die(struct pt_regs *regs, const char *str)
 
        bust_spinlocks(0);
        add_taint(TAINT_DIE, LOCKDEP_NOW_UNRELIABLE);
-       spin_unlock_irqrestore(&die_lock, flags);
+       raw_spin_unlock_irqrestore(&die_lock, flags);
        oops_exit();
 
        if (in_interrupt())