Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

Bluetooth: btnxpuart: Fix random crash seen while removing driver

This fixes the random kernel crash seen while removing the driver, when running the load/unload test over multiple iterations.

1) modprobe btnxpuart 2) hciconfig hci0 reset 3) hciconfig (check hci0 interface up with valid BD address) 4) modprobe -r btnxpuart Repeat steps 1 to 4

The ps_wakeup() call in btnxpuart_close() schedules the psdata->work(), which gets scheduled after module is removed, causing a kernel crash.

This hidden issue got highlighted after enabling Power Save by default in 4183a7be7700 (Bluetooth: btnxpuart: Enable Power Save feature on startup)

The new ps_cleanup() deasserts UART break immediately while closing serdev device, cancels any scheduled ps_work and destroys the ps_lock mutex.

[ 85.884604] Unable to handle kernel paging request at virtual address ffffd4a61638f258 [ 85.884624] Mem abort info: [ 85.884625] ESR = 0x0000000086000007 [ 85.884628] EC = 0x21: IABT (current EL), IL = 32 bits [ 85.884633] SET = 0, FnV = 0 [ 85.884636] EA = 0, S1PTW = 0 [ 85.884638] FSC = 0x07: level 3 translation fault [ 85.884642] swapper pgtable: 4k pages, 48-bit VAs, pgdp=0000000041dd0000 [ 85.884646] [ffffd4a61638f258] pgd=1000000095fff003, p4d=1000000095fff003, pud=100000004823d003, pmd=100000004823e003, pte=0000000000000000 [ 85.884662] Internal error: Oops: 0000000086000007 [#1] PREEMPT SMP [ 85.…