Hi Marek,

W dniu 07.12.2020 o 14:32, Marek Szyprowski pisze:

Hi Andrzej,

On 08.06.2020 13:22, Andrzej Pietrasiewicz wrote:

quoted

Use the newly added helper in relevant input drivers.

Signed-off-by: Andrzej Pietrasiewicz <redacted>

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

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