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* [syzbot] WARNING in drm_gem_shmem_vm_open
@ 2021-08-19  8:21 syzbot
  2021-08-20 15:45 ` syzbot
  2022-01-31  7:50 ` syzbot
  0 siblings, 2 replies; 6+ messages in thread
From: syzbot @ 2021-08-19  8:21 UTC (permalink / raw)
  To: airlied, christian.koenig, daniel, dri-devel, linaro-mm-sig,
	linux-kernel, linux-media, maarten.lankhorst, mripard,
	sumit.semwal, syzkaller-bugs, tzimmermann

Hello,

syzbot found the following issue on:

HEAD commit:    614cb2751d31 Merge tag 'trace-v5.14-rc6' of git://git.kern..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=1462cb61300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=96f0602203250753
dashboard link: https://syzkaller.appspot.com/bug?extid=91525b2bd4b5dff71619
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122bce0e300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+91525b2bd4b5dff71619@syzkaller.appspotmail.com

------------[ cut here ]------------
WARNING: CPU: 0 PID: 11697 at drivers/gpu/drm/drm_gem_shmem_helper.c:562 drm_gem_shmem_vm_open+0x96/0xb0 drivers/gpu/drm/drm_gem_shmem_helper.c:562
Modules linked in:
CPU: 0 PID: 11697 Comm: syz-executor.3 Not tainted 5.14.0-rc6-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:drm_gem_shmem_vm_open+0x96/0xb0 drivers/gpu/drm/drm_gem_shmem_helper.c:562
Code: 89 c6 e8 7d ec 23 fd 85 db 75 1a e8 34 e5 23 fd 48 89 ef 5b 5d 41 5c e9 e8 61 f5 ff e8 23 e5 23 fd 0f 0b eb ca e8 1a e5 23 fd <0f> 0b eb dd e8 b1 1f 6a fd eb 89 e8 aa 1f 6a fd eb a8 0f 1f 84 00
RSP: 0018:ffffc9000b3cfb90 EFLAGS: 00010293
RAX: 0000000000000000 RBX: 00000000fffffffc RCX: 0000000000000000
RDX: ffff8880364eb880 RSI: ffffffff8451c3e6 RDI: 0000000000000003
RBP: ffff888033c70948 R08: 0000000000000000 R09: 0000000000000000
R10: ffffffff8451c3c3 R11: 0000000000000001 R12: ffff888146490800
R13: ffff888033c70a50 R14: 0000000020166000 R15: ffff888033c709d8
FS:  00007fbe43056700(0000) GS:ffff8880b9c00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005422b8 CR3: 0000000036274000 CR4: 0000000000350ef0
Call Trace:
 __split_vma+0x23c/0x550 mm/mmap.c:2764
 __do_munmap+0x32a/0x11c0 mm/mmap.c:2868
 do_munmap mm/mmap.c:2922 [inline]
 munmap_vma_range mm/mmap.c:604 [inline]
 mmap_region+0x85a/0x1760 mm/mmap.c:1753
 do_mmap+0x86e/0x1180 mm/mmap.c:1584
 vm_mmap_pgoff+0x1b7/0x290 mm/util.c:519
 ksys_mmap_pgoff+0x4a8/0x620 mm/mmap.c:1635
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x4665e9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fbe43056188 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665e9
RDX: 0000000000000000 RSI: 0000000000002000 RDI: 0000000020166000
RBP: 00000000004bfcc4 R08: 0000000000000004 R09: 0000000000000000
R10: 0000000000000013 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007fffb615701f R14: 00007fbe43056300 R15: 0000000000022000
----------------
Code disassembly (best guess):
   0:	89 c6                	mov    %eax,%esi
   2:	e8 7d ec 23 fd       	callq  0xfd23ec84
   7:	85 db                	test   %ebx,%ebx
   9:	75 1a                	jne    0x25
   b:	e8 34 e5 23 fd       	callq  0xfd23e544
  10:	48 89 ef             	mov    %rbp,%rdi
  13:	5b                   	pop    %rbx
  14:	5d                   	pop    %rbp
  15:	41 5c                	pop    %r12
  17:	e9 e8 61 f5 ff       	jmpq   0xfff56204
  1c:	e8 23 e5 23 fd       	callq  0xfd23e544
  21:	0f 0b                	ud2    
  23:	eb ca                	jmp    0xffffffef
  25:	e8 1a e5 23 fd       	callq  0xfd23e544
  2a:	0f 0b                	ud2     <-- trapping instruction
  2c:	eb dd                	jmp    0xb
  2e:	e8 b1 1f 6a fd       	callq  0xfd6a1fe4
  33:	eb 89                	jmp    0xffffffbe
  35:	e8 aa 1f 6a fd       	callq  0xfd6a1fe4
  3a:	eb a8                	jmp    0xffffffe4
  3c:	0f                   	.byte 0xf
  3d:	1f                   	(bad)  
  3e:	84 00                	test   %al,(%rax)


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzkaller@googlegroups.com.

syzbot will keep track of this issue. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING in drm_gem_shmem_vm_open
  2021-08-19  8:21 [syzbot] WARNING in drm_gem_shmem_vm_open syzbot
@ 2021-08-20 15:45 ` syzbot
  2021-08-20 19:23   ` Thomas Zimmermann
  2022-01-31  7:50 ` syzbot
  1 sibling, 1 reply; 6+ messages in thread
From: syzbot @ 2021-08-20 15:45 UTC (permalink / raw)
  To: airlied, christian.koenig, daniel.vetter, daniel.vetter, daniel,
	dri-devel, linaro-mm-sig-owner, linaro-mm-sig, linux-kernel,
	linux-media, maarten.lankhorst, melissa.srw, mripard,
	sumit.semwal, syzkaller-bugs, tzimmermann

syzbot has bisected this issue to:

commit ea40d7857d5250e5400f38c69ef9e17321e9c4a2
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Fri Oct 9 23:21:56 2020 +0000

    drm/vkms: fbdev emulation support

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11c31d55300000
start commit:   614cb2751d31 Merge tag 'trace-v5.14-rc6' of git://git.kern..
git tree:       upstream
final oops:     https://syzkaller.appspot.com/x/report.txt?x=13c31d55300000
console output: https://syzkaller.appspot.com/x/log.txt?x=15c31d55300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=96f0602203250753
dashboard link: https://syzkaller.appspot.com/bug?extid=91525b2bd4b5dff71619
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122bce0e300000

Reported-by: syzbot+91525b2bd4b5dff71619@syzkaller.appspotmail.com
Fixes: ea40d7857d52 ("drm/vkms: fbdev emulation support")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING in drm_gem_shmem_vm_open
  2021-08-20 15:45 ` syzbot
@ 2021-08-20 19:23   ` Thomas Zimmermann
  2021-08-20 19:33     ` Daniel Vetter
  0 siblings, 1 reply; 6+ messages in thread
From: Thomas Zimmermann @ 2021-08-20 19:23 UTC (permalink / raw)
  To: syzbot, airlied, christian.koenig, daniel.vetter, daniel.vetter,
	daniel, dri-devel, linaro-mm-sig-owner, linaro-mm-sig,
	linux-kernel, linux-media, maarten.lankhorst, melissa.srw,
	mripard, sumit.semwal, syzkaller-bugs


[-- Attachment #1.1: Type: text/plain, Size: 1635 bytes --]

Hi

Am 20.08.21 um 17:45 schrieb syzbot:
> syzbot has bisected this issue to:

Good bot!

> 
> commit ea40d7857d5250e5400f38c69ef9e17321e9c4a2
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Fri Oct 9 23:21:56 2020 +0000
> 
>      drm/vkms: fbdev emulation support

Here's a guess.

GEM SHMEM + fbdev emulation requires that 
(drm_mode_config.prefer_shadow_fbdev = true). Otherwise, deferred I/O 
and SHMEM conflict over the use of page flags IIRC.

 From a quick grep, vkms doesn't set prefer_shadow_fbdev and an alarming 
amount of SHMEM-based drivers don't do either.

Best regards
Thomas

> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11c31d55300000
> start commit:   614cb2751d31 Merge tag 'trace-v5.14-rc6' of git://git.kern..
> git tree:       upstream
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=13c31d55300000
> console output: https://syzkaller.appspot.com/x/log.txt?x=15c31d55300000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=96f0602203250753
> dashboard link: https://syzkaller.appspot.com/bug?extid=91525b2bd4b5dff71619
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122bce0e300000
> 
> Reported-by: syzbot+91525b2bd4b5dff71619@syzkaller.appspotmail.com
> Fixes: ea40d7857d52 ("drm/vkms: fbdev emulation support")
> 
> For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer


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^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING in drm_gem_shmem_vm_open
  2021-08-20 19:23   ` Thomas Zimmermann
@ 2021-08-20 19:33     ` Daniel Vetter
  0 siblings, 0 replies; 6+ messages in thread
From: Daniel Vetter @ 2021-08-20 19:33 UTC (permalink / raw)
  To: Thomas Zimmermann
  Cc: syzbot, Dave Airlie, Christian König, Daniel Vetter,
	dri-devel, linaro-mm-sig-owner,
	moderated list:DMA BUFFER SHARING FRAMEWORK,
	Linux Kernel Mailing List,
	open list:DMA BUFFER SHARING FRAMEWORK, Maarten Lankhorst,
	Melissa Wen, Maxime Ripard, Sumit Semwal, syzkaller-bugs

On Fri, Aug 20, 2021 at 9:23 PM Thomas Zimmermann <tzimmermann@suse.de> wrote:
> Hi
>
> Am 20.08.21 um 17:45 schrieb syzbot:
> > syzbot has bisected this issue to:
>
> Good bot!
>
> >
> > commit ea40d7857d5250e5400f38c69ef9e17321e9c4a2
> > Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> > Date:   Fri Oct 9 23:21:56 2020 +0000
> >
> >      drm/vkms: fbdev emulation support
>
> Here's a guess.
>
> GEM SHMEM + fbdev emulation requires that
> (drm_mode_config.prefer_shadow_fbdev = true). Otherwise, deferred I/O
> and SHMEM conflict over the use of page flags IIRC.

But we should only set up defio if fb->dirty is set, which vkms
doesn't do. So there's something else going on? So there must be
something else funny going on here I think ... No idea what's going on
really.
-Daniel

>  From a quick grep, vkms doesn't set prefer_shadow_fbdev and an alarming
> amount of SHMEM-based drivers don't do either.
>
> Best regards
> Thomas
>
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=11c31d55300000
> > start commit:   614cb2751d31 Merge tag 'trace-v5.14-rc6' of git://git.kern..
> > git tree:       upstream
> > final oops:     https://syzkaller.appspot.com/x/report.txt?x=13c31d55300000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=15c31d55300000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=96f0602203250753
> > dashboard link: https://syzkaller.appspot.com/bug?extid=91525b2bd4b5dff71619
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=122bce0e300000
> >
> > Reported-by: syzbot+91525b2bd4b5dff71619@syzkaller.appspotmail.com
> > Fixes: ea40d7857d52 ("drm/vkms: fbdev emulation support")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> >
>
> --
> Thomas Zimmermann
> Graphics Driver Developer
> SUSE Software Solutions Germany GmbH
> Maxfeldstr. 5, 90409 Nürnberg, Germany
> (HRB 36809, AG Nürnberg)
> Geschäftsführer: Felix Imendörffer
>


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

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING in drm_gem_shmem_vm_open
  2021-08-19  8:21 [syzbot] WARNING in drm_gem_shmem_vm_open syzbot
  2021-08-20 15:45 ` syzbot
@ 2022-01-31  7:50 ` syzbot
  2022-05-12 13:10   ` Dmitry Vyukov
  1 sibling, 1 reply; 6+ messages in thread
From: syzbot @ 2022-01-31  7:50 UTC (permalink / raw)
  To: airlied, bugs-a21, christian.koenig, daniel.vetter,
	daniel.vetter, daniel, dri-devel, javierm, linaro-mm-sig-owner,
	linaro-mm-sig, linux-kernel, linux-media, maarten.lankhorst,
	maxime, melissa.srw, mripard, sumit.semwal, syzkaller-bugs,
	tzimmermann

syzbot suspects this issue was fixed by commit:

commit 0499f419b76f94ede08304aad5851144813ac55c
Author: Javier Martinez Canillas <javierm@redhat.com>
Date:   Mon Jan 10 09:56:25 2022 +0000

    video: vga16fb: Only probe for EGA and VGA 16 color graphic cards

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=126571e0700000
start commit:   5d6ab0bb408f Merge tag 'xtensa-20211008' of git://github.c..
git tree:       upstream
kernel config:  https://syzkaller.appspot.com/x/.config?x=32e6048063923b7b
dashboard link: https://syzkaller.appspot.com/bug?extid=91525b2bd4b5dff71619
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11073300b00000

If the result looks correct, please mark the issue as fixed by replying with:

#syz fix: video: vga16fb: Only probe for EGA and VGA 16 color graphic cards

For information about bisection process see: https://goo.gl/tpsmEJ#bisection

^ permalink raw reply	[flat|nested] 6+ messages in thread

* Re: [syzbot] WARNING in drm_gem_shmem_vm_open
  2022-01-31  7:50 ` syzbot
@ 2022-05-12 13:10   ` Dmitry Vyukov
  0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Vyukov @ 2022-05-12 13:10 UTC (permalink / raw)
  To: syzbot
  Cc: airlied, bugs-a21, christian.koenig, daniel.vetter,
	daniel.vetter, daniel, dri-devel, javierm, linaro-mm-sig-owner,
	linaro-mm-sig, linux-kernel, linux-media, maarten.lankhorst,
	maxime, melissa.srw, mripard, sumit.semwal, syzkaller-bugs,
	tzimmermann

On Mon, 31 Jan 2022 at 08:50, syzbot
<syzbot+91525b2bd4b5dff71619@syzkaller.appspotmail.com> wrote:
>
> syzbot suspects this issue was fixed by commit:
>
> commit 0499f419b76f94ede08304aad5851144813ac55c
> Author: Javier Martinez Canillas <javierm@redhat.com>
> Date:   Mon Jan 10 09:56:25 2022 +0000
>
>     video: vga16fb: Only probe for EGA and VGA 16 color graphic cards
>
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=126571e0700000
> start commit:   5d6ab0bb408f Merge tag 'xtensa-20211008' of git://github.c..
> git tree:       upstream
> kernel config:  https://syzkaller.appspot.com/x/.config?x=32e6048063923b7b
> dashboard link: https://syzkaller.appspot.com/bug?extid=91525b2bd4b5dff71619
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11073300b00000
>
> If the result looks correct, please mark the issue as fixed by replying with:
>
> #syz fix: video: vga16fb: Only probe for EGA and VGA 16 color graphic cards

Not sure, but maybe:

#syz fix: video: vga16fb: Only probe for EGA and VGA 16 color graphic cards

^ permalink raw reply	[flat|nested] 6+ messages in thread

end of thread, other threads:[~2022-05-12 13:12 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-08-19  8:21 [syzbot] WARNING in drm_gem_shmem_vm_open syzbot
2021-08-20 15:45 ` syzbot
2021-08-20 19:23   ` Thomas Zimmermann
2021-08-20 19:33     ` Daniel Vetter
2022-01-31  7:50 ` syzbot
2022-05-12 13:10   ` Dmitry Vyukov

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