Description of problem: There maybe pending USR interrupt before requesting irq, however uart_add_one_port has not executed, so there will be kernel panic: [ 0.795668] Unable to handle kernel NULL pointer dereference at virtual addre ss 0000000000000080 [ 0.802701] Mem abort info: [ 0.805367] ESR = 0x0000000096000004 [ 0.808950] EC = 0x25: DABT (current EL), IL = 32 bits [ 0.814033] SET = 0, FnV = 0 [ 0.816950] EA = 0, S1PTW = 0 [ 0.819950] FSC = 0x04: level 0 translation fault [ 0.824617] Data abort info: [ 0.827367] ISV = 0, ISS = 0x00000004 [ 0.831033] CM = 0, WnR = 0 [ 0.833866] [0000000000000080] user address but active_mm is swapper [ 0.839951] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP [ 0.845953] Modules linked in: [ 0.848869] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 6.1.1+g56321e101aca #1 [ 0.855617] Hardware name: Freescale i.MX8MP EVK (DT) [ 0.860452] pstate: 000000c5 (nzcv daIF -PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.867117] pc : __imx_uart_rxint.constprop.0+0x11c/0x2c0 [ 0.872283] lr : imx_uart_int+0xf8/0x1ec The issue only happends in the inmate linux when Jailhouse hypervisor enabled. The test procedure is: while true; do jailhouse enable imx8mp.cell jailhouse cell linux xxxx sleep 10 jailhouse cell destroy 1 jailhouse disable sleep 5 done And during the upper test, press keys to the 2nd linux console. When `jailhouse cell destroy 1`, the 2nd linux has no chance to put the uart to a quiese state, so USR1/2 may has pending interrupts. Then when `jailhosue cell linux xx` to start 2nd linux again, the issue trigger.