RE: [PATCH 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer dereference in rzg2l_dt_subnode_to_map()

[Biju Das <biju.das.jz@xxxxxxxxxxxxxx>]

Hi Andy,

Thanks for the feedback.

> Subject: Re: [PATCH 1/3] pinctrl: renesas: rzg2l: Fix NULL pointer
> dereference in rzg2l_dt_subnode_to_map()
> 
> Mon, Aug 14, 2023 at 08:24:34AM +0100, Biju Das kirjoitti:
> > Fix the below random NULL pointer crash during boot by serializing
> > pinctrl group and function creation/remove calls in
> > rzg2l_dt_subnode_to_map() with mutex lock.
> 
> > Crash logs:
> > [   15.310036] Unable to handle kernel NULL pointer dereference at
> virtual address 0000000000000000
> > [   15.354291] Unable to handle kernel NULL pointer dereference at
> virtual address 0000000000000000
> > [   15.870714] [0000000000000000] pgd=0000000000000000,
> p4d=0000000000000000
> > [   15.939989] Internal error: Oops: 0000000096000004 2 PREEMPT SMP
> > [   15.946285] Modules linked in: drm_shmem_helper rzg2l_mipi_dsi
> videobuf2_common display_connector gpu_sched mc drm_kms_helper rcar_fcp
> drm rcar_canfd snd_soc_wm8978 rtc_isl1208 can_dev rzg2l_adc snd_soc_rz_ssi
> renesas_rpc_if spi_rspi backlight ipv6
> > [   15.969077] CPU: 1 PID: 117 Comm: systemd-udevd Tainted: G      D
> 6.5.0-rc4-next-20230801-00013-gd1819ab30a54 #986
> > [   15.980351] Hardware name: Renesas SMARC EVK based on r9a07g054l2
> (DT)
> > [   15.986857] pstate: 40400005 (nZcv daif +PAN UAO -TCO -DIT -SSBS
> BTYPE=-)
> > [   15.993797] pc : __pi_strcmp+0x20/0x140
> > [   15.997647] lr : pinmux_func_name_to_selector+0x68/0xa4
> > [   16.002876] sp : ffff800082d9b5a0
> > [   16.006210] x29: ffff800082d9b5a0 x28: 0000000000000002 x27:
> ffff00000cda7080
> > [   16.013338] x26: 0000000000000002 x25: ffff00000a1f26c0 x24:
> ffff00000cda7080
> > [   16.020456] x23: ffff800081224960 x22: ffff00007fc2e598 x21:
> 000000000000000c
> > [   16.027571] x20: ffff00000b6c8840 x19: 000000000000000b x18:
> 0000000000000002
> > [   16.034686] x17: 0000000000000000 x16: 0000000000000000 x15:
> 0000000000000000
> > [   16.041799] x14: 0000000000000001 x13: 0000000000068a68 x12:
> 0000000000000040
> > [   16.048913] x11: ffff00000b092ff8 x10: 0000ffff803d1a68 x9 :
> ffff00000b6c8888
> > [   16.056028] x8 : 0101010101010101 x7 : 0000000000000000 x6 :
> 0000000000000000
> > [   16.063142] x5 : ffff00000b092ff8 x4 : ffff00000b093078 x3 :
> 0000000000000000
> > [   16.070256] x2 : 0000000000000000 x1 : 0000000000000000 x0 :
> ffff00007fc2e598
> > [   16.077370] Call trace:
> > [   16.079807]  __pi_strcmp+0x20/0x140
> > [   16.083296]  pinmux_generic_add_function+0x34/0xcc
> > [   16.088077]  rzg2l_dt_subnode_to_map+0x314/0x44c
> > [   16.092682]  rzg2l_dt_node_to_map+0x164/0x194
> > [   16.097025]  pinctrl_dt_to_map+0x218/0x37c
> > [   16.101107]  create_pinctrl+0x70/0x3d8
> 
> Submitting Patches says why the above is too noisy for the commit message.
> Please, amend accordingly.

OK, got it as per[1], this should be. 

Unable to handle kernel NULL pointer dereference at virtual address
Call trace:
	__pi_strcmp+0x20/0x140
	pinmux_generic_add_function+0x34/0xcc
	rzg2l_dt_subnode_to_map+0x314/0x44c
	rzg2l_dt_node_to_map+0x164/0x194
	pinctrl_dt_to_map+0x218/0x37c
	create_pinctrl+0x70/0x3d8

[1] https://docs.kernel.org/process/submitting-patches.html#backtraces-in-commit-messages

I will send V2 with these changes.

Cheers,
Biju