CVE-2024-57939

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 spinlockt which can sleep with PREEMPTRT enabled. That causes the following warning:

BUG: sleeping function called from invalid context at kernel/locking/spinlockrt.c:48 inatomic(): 1, irqsdisabled(): 1, nonblock: 0, pid: 285, name: mutex preemptcount: 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: dumpbacktrace+0x1c/0x24 showstack+0x2c/0x38 dumpstacklvl+0x5a/0x72 dumpstack+0x14/0x1c _mightresched+0x130/0x13a rtspinlock+0x2a/0x5c die+0x24/0x112 dotrapinsnillegal+0xa0/0xea newvmallocrestorecontexta0+0xcc/0xd8 Oops - illegal instruction [#1]

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