CVE-2024-40995

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> net/sched: act_api: fix possible infinite loop in tcf_idr_check_alloc()<br /> <br /> syzbot found hanging tasks waiting on rtnl_lock [1]<br /> <br /> A reproducer is available in the syzbot bug.<br /> <br /> When a request to add multiple actions with the same index is sent, the<br /> second request will block forever on the first request. This holds<br /> rtnl_lock, and causes tasks to hang.<br /> <br /> Return -EAGAIN to prevent infinite looping, while keeping documented<br /> behavior.<br /> <br /> [1]<br /> <br /> INFO: task kworker/1:0:5088 blocked for more than 143 seconds.<br /> Not tainted 6.9.0-rc4-syzkaller-00173-g3cdb45594619 #0<br /> "echo 0 &gt; /proc/sys/kernel/hung_task_timeout_secs" disables this message.<br /> task:kworker/1:0 state:D stack:23744 pid:5088 tgid:5088 ppid:2 flags:0x00004000<br /> Workqueue: events_power_efficient reg_check_chans_work<br /> Call Trace:<br /> <br /> context_switch kernel/sched/core.c:5409 [inline]<br /> __schedule+0xf15/0x5d00 kernel/sched/core.c:6746<br /> __schedule_loop kernel/sched/core.c:6823 [inline]<br /> schedule+0xe7/0x350 kernel/sched/core.c:6838<br /> schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6895<br /> __mutex_lock_common kernel/locking/mutex.c:684 [inline]<br /> __mutex_lock+0x5b8/0x9c0 kernel/locking/mutex.c:752<br /> wiphy_lock include/net/cfg80211.h:5953 [inline]<br /> reg_leave_invalid_chans net/wireless/reg.c:2466 [inline]<br /> reg_check_chans_work+0x10a/0x10e0 net/wireless/reg.c:2481