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Commit 6eb04ca8 authored by Guilherme G. Piccoli's avatar Guilherme G. Piccoli Committed by Jiri Kosina
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HID: nintendo: Prevent divide-by-zero on code



It was reported [0] that adding a generic joycon to the system caused
a kernel crash on Steam Deck, with the below panic spew:

divide error: 0000 [#1] PREEMPT SMP NOPTI
[...]
Hardware name: Valve Jupiter/Jupiter, BIOS F7A0119 10/24/2023
RIP: 0010:nintendo_hid_event+0x340/0xcc1 [hid_nintendo]
[...]
Call Trace:
 [...]
 ? exc_divide_error+0x38/0x50
 ? nintendo_hid_event+0x340/0xcc1 [hid_nintendo]
 ? asm_exc_divide_error+0x1a/0x20
 ? nintendo_hid_event+0x307/0xcc1 [hid_nintendo]
 hid_input_report+0x143/0x160
 hidp_session_run+0x1ce/0x700 [hidp]

Since it's a divide-by-0 error, by tracking the code for potential
denominator issues, we've spotted 2 places in which this could happen;
so let's guard against the possibility and log in the kernel if the
condition happens. This is specially useful since some data that
fills some denominators are read from the joycon HW in some cases,
increasing the potential for flaws.

[0] https://github.com/ValveSoftware/SteamOS/issues/1070

Signed-off-by: default avatarGuilherme G. Piccoli <gpiccoli@igalia.com>
Tested-by: default avatarSam Lantinga <slouken@libsdl.org>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent 0b7dd38c
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