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Message-ID: <8c774af24fa89d44924998064a996a2c.sboyd@kernel.org>
Date: Wed, 12 Apr 2023 21:15:39 -0700
From: Stephen Boyd <sboyd@...nel.org>
To: Jishnu Prakash <quic_jprakash@...cinc.com>, agross@...nel.org,
devicetree@...r.kernel.org, gregkh@...uxfoundation.org,
linus.walleij@...aro.org, linux-kernel@...r.kernel.org,
quic_collinsd@...cinc.com, quic_kamalw@...cinc.com,
quic_subbaram@...cinc.com, robh+dt@...nel.org
Cc: linux-arm-msm@...r.kernel.org, linux-arm-msm-owner@...r.kernel.org,
Jishnu Prakash <quic_jprakash@...cinc.com>
Subject: Re: [PATCH] spmi: Add a check for remove callback when removing a SPMI driver
Quoting Jishnu Prakash (2022-12-20 21:37:12)
> When removing a SPMI driver, there can be a crash due to NULL pointer
> dereference if it does not have a remove callback defined. This is
> one such call trace observed when removing the QCOM SPMI PMIC driver:
>
> dump_backtrace.cfi_jt+0x0/0x8
> dump_stack_lvl+0xd8/0x16c
> panic+0x188/0x498
> __cfi_slowpath+0x0/0x214
> __cfi_slowpath+0x1dc/0x214
> spmi_drv_remove+0x16c/0x1e0
> device_release_driver_internal+0x468/0x79c
> driver_detach+0x11c/0x1a0
> bus_remove_driver+0xc4/0x124
> driver_unregister+0x58/0x84
> cleanup_module+0x1c/0xc24 [qcom_spmi_pmic]
> __do_sys_delete_module+0x3ec/0x53c
> __arm64_sys_delete_module+0x18/0x28
> el0_svc_common+0xdc/0x294
> el0_svc+0x38/0x9c
> el0_sync_handler+0x8c/0xf0
> el0_sync+0x1b4/0x1c0
>
> If a driver has all its resources allocated through devm_() APIs and
> does not need any other explicit cleanup, it would not require a
> remove callback to be defined. Hence, add a check for remove callback
> presence before calling it when removing a SPMI driver.
>
> Signed-off-by: Jishnu Prakash <quic_jprakash@...cinc.com>
> ---
Applied to spmi-next
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