[PATCH v3 14/17] fbcon: Move console_lock for register/unlink/unregister

[Daniel Vetter]

On Mon, Apr 11, 2022 at 03:27:47PM -0700, Nathan Chancellor wrote:
> Hi Daniel,
> 
> On Tue, Apr 05, 2022 at 11:03:32PM +0200, Daniel Vetter wrote:
> > Ideally console_lock becomes an implementation detail of fbcon.c and
> > doesn't show up anywhere in fbmem.c. We're still pretty far from that,
> > but at least the register/unregister code is there now.
> > 
> > With this the do_fb_ioctl() handler is the only code in fbmem.c still
> > calling console_lock().
> > 
> > Acked-by: Sam Ravnborg <sam at ravnborg.org>
> > Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> > Cc: Daniel Vetter <daniel at ffwll.ch>
> > Cc: Thomas Zimmermann <tzimmermann at suse.de>
> > Cc: Du Cheng <ducheng2 at gmail.com>
> > Cc: Claudio Suarez <cssk at net-c.es>
> > Cc: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
> > Cc: Tetsuo Handa <penguin-kernel at I-love.SAKURA.ne.jp>
> > Cc: Matthew Wilcox <willy at infradead.org>
> > Cc: Sam Ravnborg <sam at ravnborg.org>
> > Cc: Zheyu Ma <zheyuma97 at gmail.com>
> > Cc: Guenter Roeck <linux at roeck-us.net>
> > Cc: Alex Deucher <alexander.deucher at amd.com>
> > Cc: Zhen Lei <thunder.leizhen at huawei.com>
> > Cc: Xiyu Yang <xiyuyang19 at fudan.edu.cn>
> 
> This patch as commit 6e7da3af008b ("fbcon: Move console_lock for
> register/unlink/unregister") in next-20220411 causes a lock up on my
> test Intel desktop; I get no output on my display and I cannot ssh into
> the machine. Bisect log below. If back out of this patch and the ones
> that follow in this series on top of next-20220411, everything works
> properly (i.e. 'git diff 6e7da3af008b^..efc3acbc105a | git apply -R').
> 
> What information would be helpful for debugging this? The system has an
> i7-11700 in it and it is booting under UEFI, so I assume it should be
> using EFI_FB. I am happy to offer any debugging information or test any
> patches.

I think I got it, typing a patch now for you to test. Thanks a lot for the
bug report and bisect!
-Daniel

> 
> # bad: [d12d7e1cfe38e0c36d28c7a9fbbc436ad0d17c14] Add linux-next specific files for 20220411
> # good: [8b57b3046107b50ebecb65537a172ef3d6cec673] Merge tag 'tty-5.18-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
> git bisect start 'd12d7e1cfe38e0c36d28c7a9fbbc436ad0d17c14' '8b57b3046107b50ebecb65537a172ef3d6cec673'
> # bad: [8f0b3ef070bd35e80da1caa85824fc344fb6b82e] Merge branch 'for-linux-next' of git://anongit.freedesktop.org/drm/drm-misc
> git bisect bad 8f0b3ef070bd35e80da1caa85824fc344fb6b82e
> # good: [69ae2d6587df089ec1c21bddddc7852df403d3ce] Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/hid/hid.git
> git bisect good 69ae2d6587df089ec1c21bddddc7852df403d3ce
> # good: [43ffc7321ed6ce13e5424fa687576f4442c25f9d] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/bluetooth/bluetooth-next.git
> git bisect good 43ffc7321ed6ce13e5424fa687576f4442c25f9d
> # good: [d44c2642c40b6c11e4a0afc76d491287c074376c] drm/gem: Delete gem array fencing helpers
> git bisect good d44c2642c40b6c11e4a0afc76d491287c074376c
> # good: [3223e922ccf8b5c3dd0b05faeaba407655ee0774] orinoco: Prepare cleanup of powerpc's asm/prom.h
> git bisect good 3223e922ccf8b5c3dd0b05faeaba407655ee0774
> # good: [689333136327b6cd618df85d83d79f2aa620d585] fbcon: Move fbcon_bmove(_rec) functions
> git bisect good 689333136327b6cd618df85d83d79f2aa620d585
> # good: [840db0076b05a1dd4c2ded8d08f8481e0297d09f] Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/cryptodev-2.6.git
> git bisect good 840db0076b05a1dd4c2ded8d08f8481e0297d09f
> # bad: [6e7da3af008b72520f5318507f455f344b27f022] fbcon: Move console_lock for register/unlink/unregister
> git bisect bad 6e7da3af008b72520f5318507f455f344b27f022
> # good: [6b2060cf9138a2cd5f3468a949d3869abed049ef] fb: Delete fb_info->queue
> git bisect good 6b2060cf9138a2cd5f3468a949d3869abed049ef
> # good: [d443d93864726ad68c0a741d1e7b03934a9af143] fbcon: move more common code into fb_open()
> git bisect good d443d93864726ad68c0a741d1e7b03934a9af143
> # good: [43553559121ca90965b572cf8a1d6d0fd618b449] fbcon: Consistently protect deferred_takeover with console_lock()
> git bisect good 43553559121ca90965b572cf8a1d6d0fd618b449
> # first bad commit: [6e7da3af008b72520f5318507f455f344b27f022] fbcon: Move console_lock for register/unlink/unregister
> 
> Cheers,
> Nathan

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch