RE: [PATCH] i2c: imx: correct the method of getting private data in notifier_call

[Aisheng Dong]

> From: Anson Huang
> Sent: Wednesday, April 17, 2019 10:00 AM
> 
> The way of getting private imx_i2c_struct in i2c_imx_clk_notifier_call() is
> incorrect, should use clk_change_nb element to get correct address and avoid
> below kernel dump during POST_RATE_CHANGE notify by clk
> framework:
> 
> Unable to handle kernel paging request at virtual address 03ef1488 pgd =
> (ptrval) [03ef1488] *pgd=00000000 Internal error: Oops: 5 [#1] PREEMPT SMP
> ARM Hardware name: Freescale i.MX6 Quad/DualLite (Device Tree)
> Workqueue: events reduce_bus_freq_handler PC is at
> i2c_imx_set_clk+0x10/0xb8 LR is at i2c_imx_clk_notifier_call+0x20/0x28
> pc : [<806a893c>]    lr : [<806a8a04>]    psr: a0080013
> sp : bf399dd8  ip : bf3432ac  fp : bf7c1dc0
> r10: 00000002  r9 : 00000000  r8 : 00000000
> r7 : 03ef1480  r6 : bf399e50  r5 : ffffffff  r4 : 00000000
> r3 : bf025300  r2 : bf399e50  r1 : 00b71b00  r0 : bf399be8
> Flags: NzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> Control: 10c5387d  Table: 4e03004a  DAC: 00000051 Process kworker/2:1
> (pid: 38, stack limit = 0x(ptrval))
> Stack: (0xbf399dd8 to 0xbf39a000)
> 9dc0:
> 806a89e4 00000000
> 9de0: ffffffff bf399e50 00000002 806a8a04 806a89e4 80142900 ffffffff
> 00000000
> 9e00: bf34ef18 bf34ef04 00000000 ffffffff bf399e50 80142d84 00000000
> bf399e6c
> 9e20: bf34ef00 80f214c4 bf025300 00000002 80f08d08 bf017480 00000000
> 80142df0
> 9e40: 00000000 80166ed8 80c27638 8045de58 bf352340 03ef1480
> 00b71b00 0f82e242
> 9e60: bf025300 00000002 03ef1480 80f60e5c 00000001 8045edf0
> 00000002 8045eb08
> 9e80: bf025300 00000002 03ef1480 8045ee10 03ef1480 8045eb08
> bf01be40 00000002
> 9ea0: 03ef1480 8045ee10 07de2900 8045eb08 bf01b780 00000002
> 07de2900 8045ee10
> 9ec0: 80c27898 bf399ee4 bf020a80 00000002 1f78a400 8045ee10 80f60e5c
> 80460514
> 9ee0: 80f60e5c bf01b600 bf01b480 80460460 0f82e242 bf383a80 bf383a00
> 80f60e5c
> 9f00: 00000000 bf7c1dc0 80f60e70 80460564 80f60df0 80f60d24 80f60df0
> 8011e72c
> 9f20: 00000000 80f60df0 80f60e6c bf7c4f00 00000000 8011e7ac bf274000
> 8013bd84
> 9f40: bf7c1dd8 80f03d00 bf274000 bf7c1dc0 bf274014 bf7c1dd8 80f03d00
> bf398000
> 9f60: 00000008 8013bfb4 00000000 bf25d100 bf25d0c0 00000000
> bf274000 8013bf88
> 9f80: bf25d11c bf0cfebc 00000000 8014140c bf25d0c0 801412ec 00000000
> 00000000
> 9fa0: 00000000 00000000 00000000 801010e8 00000000 00000000
> 00000000 00000000
> 9fc0: 00000000 00000000 00000000 00000000 00000000 00000000
> 00000000 00000000
> 9fe0: 00000000 00000000 00000000 00000000 00000013 00000000
> 00000000 00000000 [<806a893c>] (i2c_imx_set_clk) from [<806a8a04>]
> (i2c_imx_clk_notifier_call+0x20/0x28)
> [<806a8a04>] (i2c_imx_clk_notifier_call) from [<80142900>]
> (notifier_call_chain+0x44/0x84) [<80142900>] (notifier_call_chain) from
> [<80142d84>] (__srcu_notifier_call_chain+0x44/0x98)
> [<80142d84>] (__srcu_notifier_call_chain) from [<80142df0>]
> (srcu_notifier_call_chain+0x18/0x20)
> [<80142df0>] (srcu_notifier_call_chain) from [<8045de58>]
> (__clk_notify+0x78/0xa4) [<8045de58>] (__clk_notify) from [<8045edf0>]
> (__clk_recalc_rates+0x60/0xb4) [<8045edf0>] (__clk_recalc_rates) from
> [<8045ee10>] (__clk_recalc_rates+0x80/0xb4)
> Code: e92d40f8 e5903298 e59072a0 e1530001 (e5975008) ---[ end trace
> fc7f5514b97b6cbb ]---
> 
> Fixes: 90ad2cbe88c2("i2c: imx: use clk notifier for rate changes")
> Signed-off-by: Anson Huang <Anson.Huang@xxxxxxx>

Please also provide how to reproduce it.
And it seems not a new issue, should we CC stable?

Regards
Dong Aisheng

> ---
>  drivers/i2c/busses/i2c-imx.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/i2c/busses/i2c-imx.c b/drivers/i2c/busses/i2c-imx.c index
> c0c3043..fd70b11 100644
> --- a/drivers/i2c/busses/i2c-imx.c
> +++ b/drivers/i2c/busses/i2c-imx.c
> @@ -515,9 +515,9 @@ static int i2c_imx_clk_notifier_call(struct
> notifier_block *nb,
>  				     unsigned long action, void *data)  {
>  	struct clk_notifier_data *ndata = data;
> -	struct imx_i2c_struct *i2c_imx = container_of(&ndata->clk,
> +	struct imx_i2c_struct *i2c_imx = container_of(nb,
>  						      struct imx_i2c_struct,
> -						      clk);
> +						      clk_change_nb);
> 
>  	if (action & POST_RATE_CHANGE)
>  		i2c_imx_set_clk(i2c_imx, ndata->new_rate);
> --
> 2.7.4