请教论坛的各位大侠,我在linux下调试sc16is752的问题,在应用层调用open函数不成功,通过打印内核信息如下
[   58.351167] Unable to handle kernel NULL pointer dereference at virtual address 00000000
[   58.359609] pgd = cfb10000
[   58.362427] [00000000] *pgd=8f334831, *pte=00000000, *ppte=00000000
[   58.368986] Internal error: Oops: 80000007 [#1] PREEMPT
[   58.374433] Modules linked in: sc16is7xx(O) rtc_ds1307(O) max310x(O) g90b_iomux(O) drv_iodev(O)
[   58.383537] CPU: 0    Tainted: G           O  (3.2.0 #444)
[   58.389261] PC is at 0x0
[   58.391918] LR is at uart_carrier_raised+0x40/0x88
[   58.396915] pc : [<00000000>]    lr : [<c0263fac>]    psr: a0000093
[   58.396922] sp : ce82fcc8  ip : ce82fce8  fp : ce82fce4
[   58.408891] r10: ce8ef400  r9 : 00000001  r8 : ce82fce8
[   58.414338] r7 : ce86e800  r6 : ce87f740  r5 : cf1b5d98  r4 : ce82e000
[   58.421146] r3 : 00000000  r2 : c0263f6c  r1 : cfb35c00  r0 : cf1b5d98
[   58.427956] Flags: NzCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment user
[   58.435488] Control: 10c5387d  Table: 8fb10019  DAC: 00000015
[   58.441481] Process E50_monitor (pid: 1468, stack limit = 0xce82e2f0)
[   58.674606] Backtrace: 
[   58.677182] [<c0263f6c>] (uart_carrier_raised+0x0/0x88) from [<c02551f4>] (tty_port_block_til_ready+0x208/0x33c)
[   58.687796]  r5:ce82e000 r4:ce8ef3f0
[   58.691539] [<c0254fec>] (tty_port_block_til_ready+0x0/0x33c) from [<c02661f8>] (uart_open+0x128/0x198)
[   58.701344] [<c02660d0>] (uart_open+0x0/0x198) from [<c024dcf4>] (tty_open+0x1e0/0x4f8)
[   58.709690]  r8:00000000 r7:c06b725c r6:ce87f740 r5:0fa00001 r4:ce86e800
[   58.716515] r3:00010004
[   58.719259] [<c024db14>] (tty_open+0x0/0x4f8) from [<c00a99e4>] (chrdev_open+0x18c/0x1fc)
[   58.727801] [<c00a9858>] (chrdev_open+0x0/0x1fc) from [<c00a3b68>] (__dentry_open+0x24c/0x318)
[   58.736794] [<c00a391c>] (__dentry_open+0x0/0x318) from [<c00a4b84>] (nameidata_to_filp+0x68/0x70)
[   58.746152] [<c00a4b1c>] (nameidata_to_filp+0x0/0x70) from [<c00b3688>] (do_last.isra.29+0x2b8/0x6f8)
[   58.755768]  r7:cf101c38 r6:00000002 r5:00000000 r4:ce82fed8
[   58.761694] [<c00b33d0>] (do_last.isra.29+0x0/0x6f8) from [<c00b3bc4>] (path_openat+0xc0/0x3cc)
[   58.770773] [<c00b3b04>] (path_openat+0x0/0x3cc) from [<c00b3fdc>] (do_filp_open+0x34/0x88)
[   58.779490] [<c00b3fa8>] (do_filp_open+0x0/0x88) from [<c00a4c70>] (do_sys_open+0xe4/0x17c)
[   58.788198]  r7:00000017 r6:ffffff9c r5:cf30d000 r4:00000002
[   58.794124] [<c00a4b8c>] (do_sys_open+0x0/0x17c) from [<c00a4d2c>] (sys_open+0x24/0x28)
[   58.802490] [<c00a4d08>] (sys_open+0x0/0x28) from [<c0014880>] (ret_fast_syscall+0x0/0x30)


可以看出问题是在uart_carrier_raised这个内核函数,又找到这个函数的定义如下

static int uart_carrier_raised(struct tty_port *port)
{
struct uart_state *state = container_of(port, struct uart_state, port);
struct uart_port *uport = state->uart_port;
int mctrl;
spin_lock_irq(&uport->lock);
uport->ops->enable_ms(uport);
mctrl = uport->ops->get_mctrl(uport);
spin_unlock_irq(&uport->lock);
if (mctrl & TIOCM_CAR)
return 1;
return 0;
}

那么问题有可能是struct uart_state *state = container_of(port, struct uart_state, port);返回的是个空指针造成的,请问是什么原因造成这返回一个空指针的呢?
 
驱动源码粘贴不了