Re: [PATCH v2 2/2] HID: picolcd: Avoid framebuffer last-close deadlock

[Helge Deller <deller@gmx.de>]

On 9/28/26 18:17, Aveline Noir wrote:
> Closing the last framebuffer descriptor can deadlock against PicoLCD's
> deferred update worker. fb_release() holds info->lock while waiting for
> deferred work, and picolcd_fb_update() takes the same lock. Lockdep
> reports the cycle through deferred-work completion and fbdefio_state->lock.
> Repeated framebuffer open/write/close with concurrent device destruction
> reproduces the hang in a PREEMPT_RT QEMU guest.
> 
> Use a private update mutex in the deferred worker instead of info->lock.
> Take it in picolcd_set_par() as well to preserve serialization of pixel
> format conversion and framebuffer updates. Initialize it before exposing
> the framebuffer.
> 
> The test with the preceding output-request fix hung in the first round
> and reported a circular locking dependency. With this change, all five
> rounds completed, including 29 successful framebuffer write cycles and
> concurrent LCD, backlight, two LED and UHID destroy operations, without
> BUG/WARNING. The original syzkaller reproducer and persistent-open
> framebuffer tests also passed again. These are bounded virtual-device
> tests; physical hardware and suspend/resume remain untested.
> 
> Fixes: 3efc61d95259 ("fbdev: Fix invalid page access after closing
> deferred I/O devices")
> Signed-off-by: Aveline Noir <jm5905938@gmail.com>

For this patch:
Acked-by: Helge Deller <deller@gmx.de> # fbdev

I'm not sure about how to handle this patch series at all.
There is still a review missing for patch #1.
Shall I take this patch (#2 of 2) via fbdev git tree?

Helge