CVE-2024-50249

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> ACPI: CPPC: Make rmw_lock a raw_spin_lock<br /> <br /> The following BUG was triggered:<br /> <br /> =============================<br /> [ BUG: Invalid wait context ]<br /> 6.12.0-rc2-XXX #406 Not tainted<br /> -----------------------------<br /> kworker/1:1/62 is trying to lock:<br /> ffffff8801593030 (&amp;cpc_ptr-&gt;rmw_lock){+.+.}-{3:3}, at: cpc_write+0xcc/0x370<br /> other info that might help us debug this:<br /> context-{5:5}<br /> 2 locks held by kworker/1:1/62:<br /> #0: ffffff897ef5ec98 (&amp;rq-&gt;__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x50<br /> #1: ffffff880154e238 (&amp;sg_policy-&gt;update_lock){....}-{2:2}, at: sugov_update_shared+0x3c/0x280<br /> stack backtrace:<br /> CPU: 1 UID: 0 PID: 62 Comm: kworker/1:1 Not tainted 6.12.0-rc2-g9654bd3e8806 #406<br /> Workqueue: 0x0 (events)<br /> Call trace:<br /> dump_backtrace+0xa4/0x130<br /> show_stack+0x20/0x38<br /> dump_stack_lvl+0x90/0xd0<br /> dump_stack+0x18/0x28<br /> __lock_acquire+0x480/0x1ad8<br /> lock_acquire+0x114/0x310<br /> _raw_spin_lock+0x50/0x70<br /> cpc_write+0xcc/0x370<br /> cppc_set_perf+0xa0/0x3a8<br /> cppc_cpufreq_fast_switch+0x40/0xc0<br /> cpufreq_driver_fast_switch+0x4c/0x218<br /> sugov_update_shared+0x234/0x280<br /> update_load_avg+0x6ec/0x7b8<br /> dequeue_entities+0x108/0x830<br /> dequeue_task_fair+0x58/0x408<br /> __schedule+0x4f0/0x1070<br /> schedule+0x54/0x130<br /> worker_thread+0xc0/0x2e8<br /> kthread+0x130/0x148<br /> ret_from_fork+0x10/0x20<br /> <br /> sugov_update_shared() locks a raw_spinlock while cpc_write() locks a<br /> spinlock.<br /> <br /> To have a correct wait-type order, update rmw_lock to a raw spinlock and<br /> ensure that interrupts will be disabled on the CPU holding it.<br /> <br /> [ rjw: Changelog edits ]