CVE-2022-49841

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> serial: imx: Add missing .thaw_noirq hook<br /> <br /> The following warning is seen with non-console UART instance when<br /> system hibernates.<br /> <br /> [ 37.371969] ------------[ cut here ]------------<br /> [ 37.376599] uart3_root_clk already disabled<br /> [ 37.380810] WARNING: CPU: 0 PID: 296 at drivers/clk/clk.c:952 clk_core_disable+0xa4/0xb0<br /> ...<br /> [ 37.506986] Call trace:<br /> [ 37.509432] clk_core_disable+0xa4/0xb0<br /> [ 37.513270] clk_disable+0x34/0x50<br /> [ 37.516672] imx_uart_thaw+0x38/0x5c<br /> [ 37.520250] platform_pm_thaw+0x30/0x6c<br /> [ 37.524089] dpm_run_callback.constprop.0+0x3c/0xd4<br /> [ 37.528972] device_resume+0x7c/0x160<br /> [ 37.532633] dpm_resume+0xe8/0x230<br /> [ 37.536036] hibernation_snapshot+0x288/0x430<br /> [ 37.540397] hibernate+0x10c/0x2e0<br /> [ 37.543798] state_store+0xc4/0xd0<br /> [ 37.547203] kobj_attr_store+0x1c/0x30<br /> [ 37.550953] sysfs_kf_write+0x48/0x60<br /> [ 37.554619] kernfs_fop_write_iter+0x118/0x1ac<br /> [ 37.559063] new_sync_write+0xe8/0x184<br /> [ 37.562812] vfs_write+0x230/0x290<br /> [ 37.566214] ksys_write+0x68/0xf4<br /> [ 37.569529] __arm64_sys_write+0x20/0x2c<br /> [ 37.573452] invoke_syscall.constprop.0+0x50/0xf0<br /> [ 37.578156] do_el0_svc+0x11c/0x150<br /> [ 37.581648] el0_svc+0x30/0x140<br /> [ 37.584792] el0t_64_sync_handler+0xe8/0xf0<br /> [ 37.588976] el0t_64_sync+0x1a0/0x1a4<br /> [ 37.592639] ---[ end trace 56e22eec54676d75 ]---<br /> <br /> On hibernating, pm core calls into related hooks in sequence like:<br /> <br /> .freeze<br /> .freeze_noirq<br /> .thaw_noirq<br /> .thaw<br /> <br /> With .thaw_noirq hook being absent, the clock will be disabled in a<br /> unbalanced call which results the warning above.<br /> <br /> imx_uart_freeze()<br /> clk_prepare_enable()<br /> imx_uart_suspend_noirq()<br /> clk_disable()<br /> imx_uart_thaw<br /> clk_disable_unprepare()<br /> <br /> Adding the missing .thaw_noirq hook as imx_uart_resume_noirq() will have<br /> the call sequence corrected as below and thus fix the warning.<br /> <br /> imx_uart_freeze()<br /> clk_prepare_enable()<br /> imx_uart_suspend_noirq()<br /> clk_disable()<br /> imx_uart_resume_noirq()<br /> clk_enable()<br /> imx_uart_thaw<br /> clk_disable_unprepare()