Re: [PATCH v4 2/7] Input: use input_device_enabled()

[Andrzej Pietrasiewicz]

Hi Marek,

W dniu 07.12.2020 o 14:32, Marek Szyprowski pisze:
> Hi Andrzej,
>
> On 08.06.2020 13:22, Andrzej Pietrasiewicz wrote:
> > Use the newly added helper in relevant input drivers.
> >
> > Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@xxxxxxxxxxxxx>
>
> This patch landed recently in linux-next as commit d69f0a43c677 ("Input:
> use input_device_enabled()"). Sadly it causes following warning during
> system suspend/resume cycle on ARM 32bit Samsung Exynos5250-based Snow
> Chromebook with kernel compiled from exynos_defconfig:
>
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 1777 at drivers/input/input.c:2230
> input_device_enabled+0x68/0x6c
> Modules linked in: cmac bnep mwifiex_sdio mwifiex sha256_generic
> libsha256 sha256_arm cfg80211 btmrvl_sdio btmrvl bluetooth s5p_mfc
> exynos_gsc v4l2_mem2mem videob
> CPU: 0 PID: 1777 Comm: rtcwake Not tainted
> 5.10.0-rc6-next-20201207-00001-g49a0dc04c46d-dirty #9902
> Hardware name: Samsung Exynos (Flattened Device Tree)
> [<c0111718>] (unwind_backtrace) from [<c010d050>] (show_stack+0x10/0x14)
> [<c010d050>] (show_stack) from [<c0b32810>] (dump_stack+0xb4/0xd4)
> [<c0b32810>] (dump_stack) from [<c0126e24>] (__warn+0xd8/0x11c)
> [<c0126e24>] (__warn) from [<c0126f18>] (warn_slowpath_fmt+0xb0/0xb8)
> [<c0126f18>] (warn_slowpath_fmt) from [<c07fa2fc>]
> (input_device_enabled+0x68/0x6c)
> [<c07fa2fc>] (input_device_enabled) from [<c080a0f8>]

Apparently you are hitting this line of code in drivers/input/input.c:

lockdep_assert_held(&dev->mutex);

Inspecting input device's "users" member should happen under dev's lock.

Regards,

Andrzej