CVE-2024-40922: 
Linux Kernel vulnerability analysis and mitigation

CVE-2024-40922 affects the Linux kernel's iouring subsystem. The vulnerability was discovered when iorsrcrefquiesce() was found to be locking a mutex while not in TASKRUNNING state, which occurred due to failing to restore the state after ioruntaskwork_sig() and attempts to break out of the waiting loop (Kernel Git).

The vulnerability manifests in the iouring/rsrc.c file where the iorsrcrefquiesce() function attempts to lock a mutex while the task is not in TASKRUNNING state. This occurs at kernel/sched/core.c:10099 in the _mightsleep function, triggered through a call trace involving _mutexlockcommon, iorsrcrefquiesce, iosqebuffersunregister, and _iouring_register functions (Kernel Git).

The vulnerability could lead to potential system instability or crashes when the io_uring subsystem attempts to perform mutex operations in an invalid task state (Kernel Git).

The vulnerability has been patched by adding a call to _setcurrentstate(TASKRUNNING) before attempting to lock the mutex in the iorsrcref_quiesce() function. The fix was implemented in commit 54559642b96116b45e4b5ca7fd9f7835b8561272 and has been backported to stable kernel versions (Kernel Git).