Re: [PATCH] gpio: mvebu: fix NULL pointer dereference in suspend/resume

[Zhou, Yun]

On 6/8/26 16:26, Baruch Siach wrote:
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> Hi Yun Zhou,
>
> On Mon, Jun 08 2026, Yun Zhou wrote:
> > mvebu_pwm_suspend() and mvebu_pwm_resume() are called for all GPIO
> > banks during suspend/resume, but not all banks have PWM functionality.
> > GPIO banks without PWM have mvchip->mvpwm set to NULL.
> >
> > Calling mvebu_pwm_suspend() with mvpwm == NULL causes a NULL pointer
> > dereference when it tries to access mvpwm->blink_select.
> >
> >    Unable to handle kernel NULL pointer dereference at virtual address 00000020 when write
> >    [00000020] *pgd=00000000
> >    Internal error: Oops: 815 [#1] PREEMPT ARM
> >    Modules linked in:
> >    CPU: 0 UID: 0 PID: 406 Comm: sh Not tainted 6.12.74-rt12-yocto-standard-g4e96f98fb7db-dirty #353
> >    Hardware name: Marvell Armada 370/XP (Device Tree)
> >    PC is at regmap_mmio_read+0x38/0x54
> >    LR is at regmap_mmio_read+0x38/0x54
> >    pc : [<c05fd2ac>]    lr : [<c05fd2ac>]    psr: 200f0013
> >    sp : f0c11d10  ip : 00000000  fp : c100d2f0
> >    r10: c14fb854  r9 : 00000000  r8 : 00000000
> >    r7 : c1799c00  r6 : 00000020  r5 : 00000020  r4 : c179c7c0
> >    r3 : f0a231a0  r2 : 00000020  r1 : 00000020  r0 : 00000000
> >    Flags: nzCv  IRQs on  FIQs on  Mode SVC_32  ISA ARM  Segment none
> >    Control: 10c5387d  Table: 135ec059  DAC: 00000051
> >    Call trace:
> >     regmap_mmio_read from _regmap_bus_reg_read+0x78/0xac
> >     _regmap_bus_reg_read from _regmap_read+0x60/0x154
> >     _regmap_read from regmap_read+0x3c/0x60
> >     regmap_read from mvebu_gpio_suspend+0xa4/0x14c
> >     mvebu_gpio_suspend from dpm_run_callback+0x54/0x180
> >     dpm_run_callback from device_suspend+0x124/0x630
> >     device_suspend from dpm_suspend+0x124/0x270
> >     dpm_suspend from dpm_suspend_start+0x64/0x6c
> >     dpm_suspend_start from suspend_devices_and_enter+0x140/0x8e8
> >     suspend_devices_and_enter from pm_suspend+0x2fc/0x308
> >     pm_suspend from state_store+0x6c/0xc8
> >     state_store from kernfs_fop_write_iter+0x10c/0x1f8
> >     kernfs_fop_write_iter from vfs_write+0x270/0x468
> >     vfs_write from ksys_write+0x70/0xf0
> >     ksys_write from ret_fast_syscall+0x0/0x54
> >
> > Add a NULL check for mvchip->mvpwm before calling the PWM
> > suspend/resume functions.
> >
> > Fixes: 85b7d8abfec7 ("gpio: mvebu: add pwm support for Armada 370/XP/38x")
> Commit summary for 85b7d8abfec7 is "gpio: mvebu: add pwm support for
> Armada 8K/7K". I could not find a commit matching the summary line above
> in upstream git. Commit 757642f9a584e ("gpio: mvebu: Add limited PWM
> support") introduced mvebu_pwm_suspend() and mvebu_pwm_resume(). I think
> that is the one being fixed.
>
> baruch
You are right. I will fix it in v2.

Thanks,
Yun