From: Jishnu Prakash <quic_jprakash@xxxxxxxxxxx> [ Upstream commit b56eef3e16d888883fefab47425036de80dd38fc ] 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. Link: https://lore.kernel.org/r/1671601032-18397-2-git-send-email-quic_jprakash@xxxxxxxxxxx Fixes: 6f00f8c8635f ("mfd: qcom-spmi-pmic: Use devm_of_platform_populate()") Fixes: 5a86bf343976 ("spmi: Linux driver framework for SPMI") Signed-off-by: Jishnu Prakash <quic_jprakash@xxxxxxxxxxx> Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx> Link: https://lore.kernel.org/r/20230413223834.4084793-7-sboyd@xxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/spmi/spmi.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/spmi/spmi.c b/drivers/spmi/spmi.c index aa3edabc2b0fe..55f1cad836ba2 100644 --- a/drivers/spmi/spmi.c +++ b/drivers/spmi/spmi.c @@ -356,7 +356,8 @@ static int spmi_drv_remove(struct device *dev) const struct spmi_driver *sdrv = to_spmi_driver(dev->driver); pm_runtime_get_sync(dev); - sdrv->remove(to_spmi_device(dev)); + if (sdrv->remove) + sdrv->remove(to_spmi_device(dev)); pm_runtime_put_noidle(dev); pm_runtime_disable(dev); -- 2.39.2
