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@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
stable backport is probably not needed for versions earlier than 6.12
because PREEMPT_RT is not enabled. But it doesn't hurt..
---
arch/riscv/kernel/traps.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/riscv/kernel/traps.c b/arch/riscv/kernel/traps.c
index 51ebfd23e007..8ff8e8b36524 100644
--- a/arch/riscv/kernel/traps.c
+++ b/arch/riscv/kernel/traps.c
@@ -35,7 +35,7 @@
int show_unhandled_signals = 1;
-static DEFINE_SPINLOCK(die_lock);
+static DEFINE_RAW_SPINLOCK(die_lock);
static int copy_code(struct pt_regs *regs, u16 *val, const u16 *insns)
{
@@ -81,7 +81,7 @@ 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);
@@ -100,7 +100,7 @@ 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())
--
2.39.5
