Hi YueHaibing,
Thanks for the patch.
On Thu, May 16, 2019 at 9:42 AM YueHaibing <yuehaibing@xxxxxxxxxx> wrote:
>
> If ulite_probe is not called or failed to registed
s/registed/register
> uart_register_driver, unload the module will call
> uart_unregister_driver, which will tigger NULL
s/tigger/trigger
> pointer dereference like this:
>
> BUG: KASAN: null-ptr-deref in tty_unregister_driver+0x19/0x100
> Read of size 4 at addr 0000000000000034 by task syz-executor.0/4246
>
> CPU: 0 PID: 4246 Comm: syz-executor.0 Tainted: G C 5.1.0+ #26
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
> Call Trace:
> dump_stack+0xa9/0x10e
> ? tty_unregister_driver+0x19/0x100
> ? tty_unregister_driver+0x19/0x100
> __kasan_report+0x171/0x18d
> ? tty_unregister_driver+0x19/0x100
> kasan_report+0xe/0x20
> tty_unregister_driver+0x19/0x100
> uart_unregister_driver+0x30/0xc0
> __x64_sys_delete_module+0x244/0x330
> ? __ia32_sys_delete_module+0x330/0x330
> ? __x64_sys_clock_gettime+0xe3/0x160
> ? trace_hardirqs_on_thunk+0x1a/0x1c
> ? trace_hardirqs_off_caller+0x3e/0x130
> ? lockdep_hardirqs_off+0xb5/0x100
> ? mark_held_locks+0x1a/0x90
> ? do_syscall_64+0x14/0x2a0
> do_syscall_64+0x72/0x2a0
> entry_SYSCALL_64_after_hwframe+0x49/0xbe
>
> This patch fix this by moving uart_unregister_driver
> to ulite_remove.
>
Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
> Fixes: 415b43bdb008 ("tty: serial: uartlite: Move uart register to probe")
> Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
> ---
> drivers/tty/serial/uartlite.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/tty/serial/uartlite.c b/drivers/tty/serial/uartlite.c
> index b8b912b..2e49fb6 100644
> --- a/drivers/tty/serial/uartlite.c
> +++ b/drivers/tty/serial/uartlite.c
> @@ -867,6 +867,7 @@ static int ulite_remove(struct platform_device *pdev)
> pm_runtime_disable(&pdev->dev);
> pm_runtime_set_suspended(&pdev->dev);
> pm_runtime_dont_use_autosuspend(&pdev->dev);
> + uart_unregister_driver(&ulite_uart_driver);
> return rc;
> }
>
> @@ -897,7 +898,6 @@ static int __init ulite_init(void)
> static void __exit ulite_exit(void)
> {
> platform_driver_unregister(&ulite_platform_driver);
> - uart_unregister_driver(&ulite_uart_driver);
> }
>
> module_init(ulite_init);
> --
> 1.8.3.1
>
>
