CVE-2024-36908

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> blk-iocost: do not WARN if iocg was already offlined<br /> <br /> In iocg_pay_debt(), warn is triggered if &amp;#39;active_list&amp;#39; is empty, which<br /> is intended to confirm iocg is active when it has debt. However, warn<br /> can be triggered during a blkcg or disk removal, if iocg_waitq_timer_fn()<br /> is run at that time:<br /> <br /> WARNING: CPU: 0 PID: 2344971 at block/blk-iocost.c:1402 iocg_pay_debt+0x14c/0x190<br /> Call trace:<br /> iocg_pay_debt+0x14c/0x190<br /> iocg_kick_waitq+0x438/0x4c0<br /> iocg_waitq_timer_fn+0xd8/0x130<br /> __run_hrtimer+0x144/0x45c<br /> __hrtimer_run_queues+0x16c/0x244<br /> hrtimer_interrupt+0x2cc/0x7b0<br /> <br /> The warn in this situation is meaningless. Since this iocg is being<br /> removed, the state of the &amp;#39;active_list&amp;#39; is irrelevant, and &amp;#39;waitq_timer&amp;#39;<br /> is canceled after removing &amp;#39;active_list&amp;#39; in ioc_pd_free(), which ensures<br /> iocg is freed after iocg_waitq_timer_fn() returns.<br /> <br /> Therefore, add the check if iocg was already offlined to avoid warn<br /> when removing a blkcg or disk.