Re: [PATCH] Input: cyapa - do not call input_device_enabled from power mode handler

[Marek Szyprowski <m.szyprowski@samsung.com>]

On 11.12.2020 08:09, Dmitry Torokhov wrote:
> Input device's user counter is supposed to be accessed only while holding
> input->mutex.  Commit d69f0a43c677 ("Input: use input_device_enabled()")
> recently switched cyapa to using the dedicated API and it uncovered the
> fact that cyapa driver violated this constraint.
>
> This patch removes checks whether the input device is open when clearing
> device queues when changing device's power mode as there is no harm in
> sending input events through closed input device - the events will simply
> be dropped by the input core.
>
> Note that there are more places in cyapa driver that call
> input_device_enabled() without holding input->mutex, those are left
> unfixed for now.
>
> Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
>
> Marek, could you please try this one?

The warning is still there:

------------[ cut here ]------------
WARNING: CPU: 1 PID: 1787 at drivers/input/input.c:2230 
input_device_enabled+0x68/0x6c
Modules linked in: cmac bnep mwifiex_sdio mwifiex sha256_generic 
libsha256 sha256_arm btmrvl_sdio btmrvl cfg80211 bluetooth s5p_mfc 
exynos_gsc v4l2_mem2mem videob
CPU: 1 PID: 1787 Comm: rtcwake Not tainted 
5.10.0-rc7-next-20201210-00001-g70a81f43fddf #2204
Hardware name: Samsung Exynos (Flattened Device Tree)
[<c0111a58>] (unwind_backtrace) from [<c010d390>] (show_stack+0x10/0x14)
[<c010d390>] (show_stack) from [<c0b3503c>] (dump_stack+0xb4/0xd4)
[<c0b3503c>] (dump_stack) from [<c0127428>] (__warn+0xd8/0x11c)
[<c0127428>] (__warn) from [<c012751c>] (warn_slowpath_fmt+0xb0/0xb8)
[<c012751c>] (warn_slowpath_fmt) from [<c07fbccc>] 
(input_device_enabled+0x68/0x6c)
[<c07fbccc>] (input_device_enabled) from [<c080a204>] 
(cyapa_reinitialize+0x4c/0x154)
[<c080a204>] (cyapa_reinitialize) from [<c080a354>] (cyapa_resume+0x48/0x98)
[<c080a354>] (cyapa_resume) from [<c06b0230>] (dpm_run_callback+0xb0/0x3c8)
[<c06b0230>] (dpm_run_callback) from [<c06b0604>] (device_resume+0xbc/0x260)
[<c06b0604>] (device_resume) from [<c06b29e4>] (dpm_resume+0x14c/0x51c)
[<c06b29e4>] (dpm_resume) from [<c06b35b8>] (dpm_resume_end+0xc/0x18)
[<c06b35b8>] (dpm_resume_end) from [<c01a1270>] 
(suspend_devices_and_enter+0x1b4/0xbd4)
[<c01a1270>] (suspend_devices_and_enter) from [<c01a1fa4>] 
(pm_suspend+0x314/0x42c)
[<c01a1fa4>] (pm_suspend) from [<c019fe90>] (state_store+0x6c/0xc8)
[<c019fe90>] (state_store) from [<c0388438>] (kernfs_fop_write+0x10c/0x228)
[<c0388438>] (kernfs_fop_write) from [<c02dc3e8>] (vfs_write+0xc8/0x530)
[<c02dc3e8>] (vfs_write) from [<c02dc98c>] (ksys_write+0x60/0xd8)
[<c02dc98c>] (ksys_write) from [<c0100060>] (ret_fast_syscall+0x0/0x2c)
Exception stack(0xc3923fa8 to 0xc3923ff0)
irq event stamp: 54139
hardirqs last  enabled at (54147): [<c01a5f20>] vprintk_emit+0x2b8/0x308
hardirqs last disabled at (54154): [<c01a5ee4>] vprintk_emit+0x27c/0x308
softirqs last  enabled at (50722): [<c01017a8>] __do_softirq+0x528/0x684
softirqs last disabled at (50671): [<c0130ac8>] irq_exit+0x1ec/0x1f8
---[ end trace 1fbefe3f239ae597 ]---

>   drivers/input/mouse/cyapa_gen3.c |    5 +----
>   drivers/input/mouse/cyapa_gen5.c |    3 +--
>   2 files changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/input/mouse/cyapa_gen3.c b/drivers/input/mouse/cyapa_gen3.c
> index a97f4acb6452..4a9022faf945 100644
> --- a/drivers/input/mouse/cyapa_gen3.c
> +++ b/drivers/input/mouse/cyapa_gen3.c
> @@ -907,7 +907,6 @@ static u16 cyapa_get_wait_time_for_pwr_cmd(u8 pwr_mode)
>   static int cyapa_gen3_set_power_mode(struct cyapa *cyapa, u8 power_mode,
>   		u16 always_unused, enum cyapa_pm_stage pm_stage)
>   {
> -	struct input_dev *input = cyapa->input;
>   	u8 power;
>   	int tries;
>   	int sleep_time;
> @@ -953,7 +952,6 @@ static int cyapa_gen3_set_power_mode(struct cyapa *cyapa, u8 power_mode,
>   	 * depending on the command's content.
>   	 */
>   	if (cyapa->operational &&
> -	    input && input_device_enabled(input) &&
>   	    (pm_stage == CYAPA_PM_RUNTIME_SUSPEND ||
>   	     pm_stage == CYAPA_PM_RUNTIME_RESUME)) {
>   		/* Try to polling in 120Hz, read may fail, just ignore it. */
> @@ -1223,8 +1221,7 @@ static int cyapa_gen3_try_poll_handler(struct cyapa *cyapa)
>   	    (data.finger_btn & OP_DATA_VALID) != OP_DATA_VALID)
>   		return -EINVAL;
>   
> -	return cyapa_gen3_event_process(cyapa, &data);
> -
> +	return cyapa->input ? cyapa_gen3_event_process(cyapa, &data) : 0;
>   }
>   
>   static int cyapa_gen3_initialize(struct cyapa *cyapa) { return 0; }
> diff --git a/drivers/input/mouse/cyapa_gen5.c b/drivers/input/mouse/cyapa_gen5.c
> index abf42f77b4c5..afc5aa4dcf47 100644
> --- a/drivers/input/mouse/cyapa_gen5.c
> +++ b/drivers/input/mouse/cyapa_gen5.c
> @@ -518,8 +518,7 @@ int cyapa_empty_pip_output_data(struct cyapa *cyapa,
>   			*len = length;
>   			/* Response found, success. */
>   			return 0;
> -		} else if (cyapa->operational &&
> -			   input && input_device_enabled(input) &&
> +		} else if (cyapa->operational && input &&
>   			   (pm_stage == CYAPA_PM_RUNTIME_RESUME ||
>   			    pm_stage == CYAPA_PM_RUNTIME_SUSPEND)) {
>   			/* Parse the data and report it if it's valid. */
>
Best regards
-- 
Marek Szyprowski, PhD
Samsung R&D Institute Poland