riscv: Fix sleeping in invalid context in die()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: riscv: Fix sleeping in invalid context in die() 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.

References

• https://git.kernel.org/stable/c/8c38baa03ac8e18140faf36a3b955d30cad48e74
• https://git.kernel.org/stable/c/10c24df2e303f517fab0359392c11b6b1d553f2b
• https://git.kernel.org/stable/c/c21df31fc2a4afc02a6e56511364e9e793ea92ec
• https://git.kernel.org/stable/c/f48f060a4b36b5e96628f6c3fb1540f1e8dedb69
• https://git.kernel.org/stable/c/76ab0afcdbe8c9685b589016ee1c0e25fe596707
• https://git.kernel.org/stable/c/6a97f4118ac07cfdc316433f385dbdc12af5025e