Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Sean Young]

On Mon, Apr 23, 2018 at 07:34:22AM -0300, Mauro Carvalho Chehab wrote:
> Em Mon, 23 Apr 2018 10:04:20 +0100
> Sean Young  escreveu:
> 
> > On Sun, Apr 22, 2018 at 11:47:51AM +0200, Greg KH wrote:
> > > On Mon, Apr 16, 2018 at 10:15:28AM +0100, Sean Young wrote:  
> > > > On Mon, Apr 16, 2018 at 10:50:15AM +0200, Greg KH wrote:  
> > > > > On Mon, Apr 16, 2018 at 09:43:45AM +0100, Sean Young wrote:  
> > > > > > On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:  
> > > > > > > What is the git commit id of this patch, and the other patches in 
> > > > > > > this
> > > > > > > series and the 4.14 patch series that you sent out?  
> > > > > > 
> > > > > > lirc_zilog was dropped in v4.16, so this can't be patched upstream. 
> > > > > >  
> > > > > 
> > > > > Ah you are right, should we just ditch them here as well as they
> > > > > obviously do not work? :)
> > > > >   
> > > > > > > Please read:
> > > > > > > 
> > > > > > > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > > > > > > for how to do this in a way that I can pick them up.  
> > > > > > 
> > > > > > These patches have been tested with different types of hardware. Is 
> > > > > > there
> > > > > > anything else I can do to get these patches included?  
> > > > > 
> > > > > When submitting patches to stable, you need to be explicit as to why
> > > > > they are needed, and if they are not upstream, why not.
> > > > > 
> > > > > In this case, for obviously broken code that is not used anymore (as
> > > > > it is gone in 4.16), why don't we just take the patch that removed the
> > > > > driver to the stable trees as well?  
> > > > 
> > > > Well in v4.16 the ir-kbd-i2c.c driver can do what the lirc_zilog does in
> > > > v4.15 (and earlier), so it wasn't ditched as such. It's a case of 
> > > > replaced
> > > > by mainline.
> > > > 
> > > > Since I was getting bug reports on it, there must be users of the 
> > > > lirc_zilog
> > > > driver.
> > > > 
> > > > That being said, the old lirc_dev and lirc_zilog is pretty awful code.  
> > > 
> > > Ok, I've queued these up for 4.14.y now.  4.15 is end-of-life, so I
> > > can't apply these patches there, sorry.  
> > 
> > Ok, thanks.
> > 
> > I wonder why Ubuntu picked 4.15 as the kernel for their upcoming 18.04 LTS
> > release.
> 
> I've no idea. Maybe it might be due to spectre/meltdown? Anyway, they'll
> need to maintain it for a long time. So, I won't be surprised if they
> decide to take over LTS maintainership upstream. In the mean time, if the
> bug is seriously enough, you may consider sending them fixup patches
> directly, although I guess that they use a bugzilla instead for patches
> to the distro, with makes harder/painful to send them fixups.
> 
> The Ubuntu FAQ (https://wiki.ubuntu.com/Kernel/FAQ) points to an IRC
> freenode channel (#ubuntu-kernel). Perhaps you could ping them there
> and ask them about that.

Following their advice, I've resent the patches to 
kernel-t...@lists.ubuntu.com; I'm afraid stable got cc'ed again in the
process, please ignore (sorry!)


Sean

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Mauro Carvalho Chehab]

Em Mon, 23 Apr 2018 10:04:20 +0100
Sean Young  escreveu:

> On Sun, Apr 22, 2018 at 11:47:51AM +0200, Greg KH wrote:
> > On Mon, Apr 16, 2018 at 10:15:28AM +0100, Sean Young wrote:  
> > > On Mon, Apr 16, 2018 at 10:50:15AM +0200, Greg KH wrote:  
> > > > On Mon, Apr 16, 2018 at 09:43:45AM +0100, Sean Young wrote:  
> > > > > On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:  
> > > > > > What is the git commit id of this patch, and the other patches in 
> > > > > > this
> > > > > > series and the 4.14 patch series that you sent out?  
> > > > > 
> > > > > lirc_zilog was dropped in v4.16, so this can't be patched upstream.  
> > > > 
> > > > Ah you are right, should we just ditch them here as well as they
> > > > obviously do not work? :)
> > > >   
> > > > > > Please read:
> > > > > > 
> > > > > > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > > > > > for how to do this in a way that I can pick them up.  
> > > > > 
> > > > > These patches have been tested with different types of hardware. Is 
> > > > > there
> > > > > anything else I can do to get these patches included?  
> > > > 
> > > > When submitting patches to stable, you need to be explicit as to why
> > > > they are needed, and if they are not upstream, why not.
> > > > 
> > > > In this case, for obviously broken code that is not used anymore (as
> > > > it is gone in 4.16), why don't we just take the patch that removed the
> > > > driver to the stable trees as well?  
> > > 
> > > Well in v4.16 the ir-kbd-i2c.c driver can do what the lirc_zilog does in
> > > v4.15 (and earlier), so it wasn't ditched as such. It's a case of replaced
> > > by mainline.
> > > 
> > > Since I was getting bug reports on it, there must be users of the 
> > > lirc_zilog
> > > driver.
> > > 
> > > That being said, the old lirc_dev and lirc_zilog is pretty awful code.  
> > 
> > Ok, I've queued these up for 4.14.y now.  4.15 is end-of-life, so I
> > can't apply these patches there, sorry.  
> 
> Ok, thanks.
> 
> I wonder why Ubuntu picked 4.15 as the kernel for their upcoming 18.04 LTS
> release.

I've no idea. Maybe it might be due to spectre/meltdown? Anyway, they'll
need to maintain it for a long time. So, I won't be surprised if they
decide to take over LTS maintainership upstream. In the mean time, if the
bug is seriously enough, you may consider sending them fixup patches
directly, although I guess that they use a bugzilla instead for patches
to the distro, with makes harder/painful to send them fixups.

The Ubuntu FAQ (https://wiki.ubuntu.com/Kernel/FAQ) points to an IRC
freenode channel (#ubuntu-kernel). Perhaps you could ping them there
and ask them about that.


Thanks,
Mauro

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Sean Young]

On Sun, Apr 22, 2018 at 11:47:51AM +0200, Greg KH wrote:
> On Mon, Apr 16, 2018 at 10:15:28AM +0100, Sean Young wrote:
> > On Mon, Apr 16, 2018 at 10:50:15AM +0200, Greg KH wrote:
> > > On Mon, Apr 16, 2018 at 09:43:45AM +0100, Sean Young wrote:
> > > > On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:
> > > > > What is the git commit id of this patch, and the other patches in this
> > > > > series and the 4.14 patch series that you sent out?
> > > > 
> > > > lirc_zilog was dropped in v4.16, so this can't be patched upstream.
> > > 
> > > Ah you are right, should we just ditch them here as well as they
> > > obviously do not work? :)
> > > 
> > > > > Please read:
> > > > > 
> > > > > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > > > > for how to do this in a way that I can pick them up.
> > > > 
> > > > These patches have been tested with different types of hardware. Is 
> > > > there
> > > > anything else I can do to get these patches included?
> > > 
> > > When submitting patches to stable, you need to be explicit as to why
> > > they are needed, and if they are not upstream, why not.
> > > 
> > > In this case, for obviously broken code that is not used anymore (as
> > > it is gone in 4.16), why don't we just take the patch that removed the
> > > driver to the stable trees as well?
> > 
> > Well in v4.16 the ir-kbd-i2c.c driver can do what the lirc_zilog does in
> > v4.15 (and earlier), so it wasn't ditched as such. It's a case of replaced
> > by mainline.
> > 
> > Since I was getting bug reports on it, there must be users of the lirc_zilog
> > driver.
> > 
> > That being said, the old lirc_dev and lirc_zilog is pretty awful code.
> 
> Ok, I've queued these up for 4.14.y now.  4.15 is end-of-life, so I
> can't apply these patches there, sorry.

Ok, thanks.

I wonder why Ubuntu picked 4.15 as the kernel for their upcoming 18.04 LTS
release.


Sean

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Greg KH]

On Mon, Apr 16, 2018 at 10:15:28AM +0100, Sean Young wrote:
> On Mon, Apr 16, 2018 at 10:50:15AM +0200, Greg KH wrote:
> > On Mon, Apr 16, 2018 at 09:43:45AM +0100, Sean Young wrote:
> > > On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:
> > > > What is the git commit id of this patch, and the other patches in this
> > > > series and the 4.14 patch series that you sent out?
> > > 
> > > lirc_zilog was dropped in v4.16, so this can't be patched upstream.
> > 
> > Ah you are right, should we just ditch them here as well as they
> > obviously do not work? :)
> > 
> > > > Please read:
> > > > 
> > > > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > > > for how to do this in a way that I can pick them up.
> > > 
> > > These patches have been tested with different types of hardware. Is there
> > > anything else I can do to get these patches included?
> > 
> > When submitting patches to stable, you need to be explicit as to why
> > they are needed, and if they are not upstream, why not.
> > 
> > In this case, for obviously broken code that is not used anymore (as
> > it is gone in 4.16), why don't we just take the patch that removed the
> > driver to the stable trees as well?
> 
> Well in v4.16 the ir-kbd-i2c.c driver can do what the lirc_zilog does in
> v4.15 (and earlier), so it wasn't ditched as such. It's a case of replaced
> by mainline.
> 
> Since I was getting bug reports on it, there must be users of the lirc_zilog
> driver.
> 
> That being said, the old lirc_dev and lirc_zilog is pretty awful code.

Ok, I've queued these up for 4.14.y now.  4.15 is end-of-life, so I
can't apply these patches there, sorry.

greg k-h

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Sean Young]

On Mon, Apr 16, 2018 at 10:50:15AM +0200, Greg KH wrote:
> On Mon, Apr 16, 2018 at 09:43:45AM +0100, Sean Young wrote:
> > On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:
> > > What is the git commit id of this patch, and the other patches in this
> > > series and the 4.14 patch series that you sent out?
> > 
> > lirc_zilog was dropped in v4.16, so this can't be patched upstream.
> 
> Ah you are right, should we just ditch them here as well as they
> obviously do not work? :)
> 
> > > Please read:
> > > 
> > > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > > for how to do this in a way that I can pick them up.
> > 
> > These patches have been tested with different types of hardware. Is there
> > anything else I can do to get these patches included?
> 
> When submitting patches to stable, you need to be explicit as to why
> they are needed, and if they are not upstream, why not.
> 
> In this case, for obviously broken code that is not used anymore (as
> it is gone in 4.16), why don't we just take the patch that removed the
> driver to the stable trees as well?

Well in v4.16 the ir-kbd-i2c.c driver can do what the lirc_zilog does in
v4.15 (and earlier), so it wasn't ditched as such. It's a case of replaced
by mainline.

Since I was getting bug reports on it, there must be users of the lirc_zilog
driver.

That being said, the old lirc_dev and lirc_zilog is pretty awful code.


Sean

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Greg KH]

On Mon, Apr 16, 2018 at 09:43:45AM +0100, Sean Young wrote:
> On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:
> > On Sun, Apr 15, 2018 at 10:54:20AM +0100, Sean Young wrote:
> > > commit 615cd3fe6ccc ("[media] media: lirc_dev: make better use of
> > > file->private_data") removed the reference get from open, so on the first
> > > close the reference count hits zero and the lirc device is freed.
> > > 
> > > BUG: unable to handle kernel NULL pointer dereference at 0040
> > > IP: lirc_thread+0x94/0x520 [lirc_zilog]
> > > PGD 22d69c067 P4D 22d69c067 PUD 22d69d067 PMD 0
> > > Oops:  [#1] SMP NOPTI
> > > CPU: 2 PID: 701 Comm: zilog-rx-i2c-7 Tainted: P C OE
> > > 4.15.14-300.fc27.x86_64 #1
> > > Hardware name: Gigabyte Technology Co., Ltd. 
> > > GA-MA790FXT-UD5P/GA-MA790FXT-UD5P, BIOS F6 08/06/2009
> > > RIP: 0010:lirc_thread+0x94/0x520 [lirc_zilog]
> > > RSP: 0018:b482c131be98 EFLAGS: 00010246
> > > RAX:  RBX: 8fdabf056000 RCX: 
> > > RDX:  RSI: 0246 RDI: 0246
> > > RBP: 8fdab740af00 R08: 8fdacfd214a0 R09: 
> > > R10:  R11: 0040 R12: b482c10dba48
> > > R13: 8fdabea89e00 R14: 8fdab740af00 R15: c0b5e500
> > > FS:  () GS:8fdacfd0() 
> > > knlGS:
> > > CS:  0010 DS:  ES:  CR0: 80050033
> > > CR2: 0040 CR3: 0002124c CR4: 06e0
> > > Call Trace:
> > >  ? __schedule+0x247/0x880
> > >  ? get_ir_tx+0x40/0x40 [lirc_zilog]
> > >  kthread+0x113/0x130
> > >  ? kthread_create_worker_on_cpu+0x70/0x70
> > >  ? do_syscall_64+0x74/0x180
> > >  ? SyS_exit_group+0x10/0x10
> > >  ret_from_fork+0x22/0x40
> > > Code: 20 8b 85 80 00 00 00 85 c0 0f 84 a6 00 00 00 bf 04 01 00 00 e8 ee 
> > > 34 d4 d7 e8 69 88 56 d7 84 c0 75 69 48 8b 45 18 c6 44 24 37 00 <48> 8b 58 
> > > 40 4c 8d 6b 18 4c 89 ef e8 fc 4d d4 d7 4c 89 ef 48 89
> > > RIP: lirc_thread+0x94/0x520 [lirc_zilog] RSP: b482c131be98
> > > CR2: 0040
> > > This code has been replaced completely in kernel v4.16 by a new driver,
> > > see commit acaa34bf06e9 ("media: rc: implement zilog transmitter"), and
> > > commit f95367a7b758 ("media: staging: remove lirc_zilog driver").
> > > 
> > > Fixes: 615cd3fe6ccc ("[media] media: lirc_dev: make better use of 
> > > file->private_data")
> > > 
> > > Cc: sta...@vger.kernel.org # v4.15
> > > Reported-by: Warren Sturm 
> > > Tested-by: Warren Sturm 
> > > Signed-off-by: Sean Young 
> > > ---
> > >  drivers/staging/media/lirc/lirc_zilog.c | 1 +
> > >  1 file changed, 1 insertion(+)
> > > 
> > > diff --git a/drivers/staging/media/lirc/lirc_zilog.c 
> > > b/drivers/staging/media/lirc/lirc_zilog.c
> > > index 6bd0717bf76e..bf6869e48a0f 100644
> > > --- a/drivers/staging/media/lirc/lirc_zilog.c
> > > +++ b/drivers/staging/media/lirc/lirc_zilog.c
> > > @@ -1291,6 +1291,7 @@ static int open(struct inode *node, struct file 
> > > *filep)
> > >  
> > >   lirc_init_pdata(node, filep);
> > >   ir = lirc_get_pdata(filep);
> > > + get_ir_device(ir, false);
> > >  
> > >   atomic_inc(>open_count);
> > >  
> > > -- 
> > > 2.14.3
> > 
> > What is the git commit id of this patch, and the other patches in this
> > series and the 4.14 patch series that you sent out?
> 
> lirc_zilog was dropped in v4.16, so this can't be patched upstream.

Ah you are right, should we just ditch them here as well as they
obviously do not work? :)

> > Please read:
> > https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> > for how to do this in a way that I can pick them up.
> 
> These patches have been tested with different types of hardware. Is there
> anything else I can do to get these patches included?

When submitting patches to stable, you need to be explicit as to why
they are needed, and if they are not upstream, why not.

In this case, for obviously broken code that is not used anymore (as
it is gone in 4.16), why don't we just take the patch that removed the
driver to the stable trees as well?

thanks,

greg k-h

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Sean Young]

On Mon, Apr 16, 2018 at 09:52:28AM +0200, Greg KH wrote:
> On Sun, Apr 15, 2018 at 10:54:20AM +0100, Sean Young wrote:
> > commit 615cd3fe6ccc ("[media] media: lirc_dev: make better use of
> > file->private_data") removed the reference get from open, so on the first
> > close the reference count hits zero and the lirc device is freed.
> > 
> > BUG: unable to handle kernel NULL pointer dereference at 0040
> > IP: lirc_thread+0x94/0x520 [lirc_zilog]
> > PGD 22d69c067 P4D 22d69c067 PUD 22d69d067 PMD 0
> > Oops:  [#1] SMP NOPTI
> > CPU: 2 PID: 701 Comm: zilog-rx-i2c-7 Tainted: P C OE
> > 4.15.14-300.fc27.x86_64 #1
> > Hardware name: Gigabyte Technology Co., Ltd. 
> > GA-MA790FXT-UD5P/GA-MA790FXT-UD5P, BIOS F6 08/06/2009
> > RIP: 0010:lirc_thread+0x94/0x520 [lirc_zilog]
> > RSP: 0018:b482c131be98 EFLAGS: 00010246
> > RAX:  RBX: 8fdabf056000 RCX: 
> > RDX:  RSI: 0246 RDI: 0246
> > RBP: 8fdab740af00 R08: 8fdacfd214a0 R09: 
> > R10:  R11: 0040 R12: b482c10dba48
> > R13: 8fdabea89e00 R14: 8fdab740af00 R15: c0b5e500
> > FS:  () GS:8fdacfd0() knlGS:
> > CS:  0010 DS:  ES:  CR0: 80050033
> > CR2: 0040 CR3: 0002124c CR4: 06e0
> > Call Trace:
> >  ? __schedule+0x247/0x880
> >  ? get_ir_tx+0x40/0x40 [lirc_zilog]
> >  kthread+0x113/0x130
> >  ? kthread_create_worker_on_cpu+0x70/0x70
> >  ? do_syscall_64+0x74/0x180
> >  ? SyS_exit_group+0x10/0x10
> >  ret_from_fork+0x22/0x40
> > Code: 20 8b 85 80 00 00 00 85 c0 0f 84 a6 00 00 00 bf 04 01 00 00 e8 ee 34 
> > d4 d7 e8 69 88 56 d7 84 c0 75 69 48 8b 45 18 c6 44 24 37 00 <48> 8b 58 40 
> > 4c 8d 6b 18 4c 89 ef e8 fc 4d d4 d7 4c 89 ef 48 89
> > RIP: lirc_thread+0x94/0x520 [lirc_zilog] RSP: b482c131be98
> > CR2: 0040
> > This code has been replaced completely in kernel v4.16 by a new driver,
> > see commit acaa34bf06e9 ("media: rc: implement zilog transmitter"), and
> > commit f95367a7b758 ("media: staging: remove lirc_zilog driver").
> > 
> > Fixes: 615cd3fe6ccc ("[media] media: lirc_dev: make better use of 
> > file->private_data")
> > 
> > Cc: sta...@vger.kernel.org # v4.15
> > Reported-by: Warren Sturm 
> > Tested-by: Warren Sturm 
> > Signed-off-by: Sean Young 
> > ---
> >  drivers/staging/media/lirc/lirc_zilog.c | 1 +
> >  1 file changed, 1 insertion(+)
> > 
> > diff --git a/drivers/staging/media/lirc/lirc_zilog.c 
> > b/drivers/staging/media/lirc/lirc_zilog.c
> > index 6bd0717bf76e..bf6869e48a0f 100644
> > --- a/drivers/staging/media/lirc/lirc_zilog.c
> > +++ b/drivers/staging/media/lirc/lirc_zilog.c
> > @@ -1291,6 +1291,7 @@ static int open(struct inode *node, struct file 
> > *filep)
> >  
> > lirc_init_pdata(node, filep);
> > ir = lirc_get_pdata(filep);
> > +   get_ir_device(ir, false);
> >  
> > atomic_inc(>open_count);
> >  
> > -- 
> > 2.14.3
> 
> What is the git commit id of this patch, and the other patches in this
> series and the 4.14 patch series that you sent out?

lirc_zilog was dropped in v4.16, so this can't be patched upstream.

> Please read:
> https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
> for how to do this in a way that I can pick them up.

These patches have been tested with different types of hardware. Is there
anything else I can do to get these patches included?

Thanks,

Sean

Re: [PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Greg KH]

On Sun, Apr 15, 2018 at 10:54:20AM +0100, Sean Young wrote:
> commit 615cd3fe6ccc ("[media] media: lirc_dev: make better use of
> file->private_data") removed the reference get from open, so on the first
> close the reference count hits zero and the lirc device is freed.
> 
> BUG: unable to handle kernel NULL pointer dereference at 0040
> IP: lirc_thread+0x94/0x520 [lirc_zilog]
> PGD 22d69c067 P4D 22d69c067 PUD 22d69d067 PMD 0
> Oops:  [#1] SMP NOPTI
> CPU: 2 PID: 701 Comm: zilog-rx-i2c-7 Tainted: P C OE
> 4.15.14-300.fc27.x86_64 #1
> Hardware name: Gigabyte Technology Co., Ltd. 
> GA-MA790FXT-UD5P/GA-MA790FXT-UD5P, BIOS F6 08/06/2009
> RIP: 0010:lirc_thread+0x94/0x520 [lirc_zilog]
> RSP: 0018:b482c131be98 EFLAGS: 00010246
> RAX:  RBX: 8fdabf056000 RCX: 
> RDX:  RSI: 0246 RDI: 0246
> RBP: 8fdab740af00 R08: 8fdacfd214a0 R09: 
> R10:  R11: 0040 R12: b482c10dba48
> R13: 8fdabea89e00 R14: 8fdab740af00 R15: c0b5e500
> FS:  () GS:8fdacfd0() knlGS:
> CS:  0010 DS:  ES:  CR0: 80050033
> CR2: 0040 CR3: 0002124c CR4: 06e0
> Call Trace:
>  ? __schedule+0x247/0x880
>  ? get_ir_tx+0x40/0x40 [lirc_zilog]
>  kthread+0x113/0x130
>  ? kthread_create_worker_on_cpu+0x70/0x70
>  ? do_syscall_64+0x74/0x180
>  ? SyS_exit_group+0x10/0x10
>  ret_from_fork+0x22/0x40
> Code: 20 8b 85 80 00 00 00 85 c0 0f 84 a6 00 00 00 bf 04 01 00 00 e8 ee 34 d4 
> d7 e8 69 88 56 d7 84 c0 75 69 48 8b 45 18 c6 44 24 37 00 <48> 8b 58 40 4c 8d 
> 6b 18 4c 89 ef e8 fc 4d d4 d7 4c 89 ef 48 89
> RIP: lirc_thread+0x94/0x520 [lirc_zilog] RSP: b482c131be98
> CR2: 0040
> This code has been replaced completely in kernel v4.16 by a new driver,
> see commit acaa34bf06e9 ("media: rc: implement zilog transmitter"), and
> commit f95367a7b758 ("media: staging: remove lirc_zilog driver").
> 
> Fixes: 615cd3fe6ccc ("[media] media: lirc_dev: make better use of 
> file->private_data")
> 
> Cc: sta...@vger.kernel.org # v4.15
> Reported-by: Warren Sturm 
> Tested-by: Warren Sturm 
> Signed-off-by: Sean Young 
> ---
>  drivers/staging/media/lirc/lirc_zilog.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/staging/media/lirc/lirc_zilog.c 
> b/drivers/staging/media/lirc/lirc_zilog.c
> index 6bd0717bf76e..bf6869e48a0f 100644
> --- a/drivers/staging/media/lirc/lirc_zilog.c
> +++ b/drivers/staging/media/lirc/lirc_zilog.c
> @@ -1291,6 +1291,7 @@ static int open(struct inode *node, struct file *filep)
>  
>   lirc_init_pdata(node, filep);
>   ir = lirc_get_pdata(filep);
> + get_ir_device(ir, false);
>  
>   atomic_inc(>open_count);
>  
> -- 
> 2.14.3

What is the git commit id of this patch, and the other patches in this
series and the 4.14 patch series that you sent out?

Please read:
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how to do this in a way that I can pick them up.

thanks,

greg k-h

[PATCH stable v4.15 1/3] media: staging: lirc_zilog: broken reference counting

[Sean Young]

commit 615cd3fe6ccc ("[media] media: lirc_dev: make better use of
file->private_data") removed the reference get from open, so on the first
close the reference count hits zero and the lirc device is freed.

BUG: unable to handle kernel NULL pointer dereference at 0040
IP: lirc_thread+0x94/0x520 [lirc_zilog]
PGD 22d69c067 P4D 22d69c067 PUD 22d69d067 PMD 0
Oops:  [#1] SMP NOPTI
CPU: 2 PID: 701 Comm: zilog-rx-i2c-7 Tainted: P C OE
4.15.14-300.fc27.x86_64 #1
Hardware name: Gigabyte Technology Co., Ltd. GA-MA790FXT-UD5P/GA-MA790FXT-UD5P, 
BIOS F6 08/06/2009
RIP: 0010:lirc_thread+0x94/0x520 [lirc_zilog]
RSP: 0018:b482c131be98 EFLAGS: 00010246
RAX:  RBX: 8fdabf056000 RCX: 
RDX:  RSI: 0246 RDI: 0246
RBP: 8fdab740af00 R08: 8fdacfd214a0 R09: 
R10:  R11: 0040 R12: b482c10dba48
R13: 8fdabea89e00 R14: 8fdab740af00 R15: c0b5e500
FS:  () GS:8fdacfd0() knlGS:
CS:  0010 DS:  ES:  CR0: 80050033
CR2: 0040 CR3: 0002124c CR4: 06e0
Call Trace:
 ? __schedule+0x247/0x880
 ? get_ir_tx+0x40/0x40 [lirc_zilog]
 kthread+0x113/0x130
 ? kthread_create_worker_on_cpu+0x70/0x70
 ? do_syscall_64+0x74/0x180
 ? SyS_exit_group+0x10/0x10
 ret_from_fork+0x22/0x40
Code: 20 8b 85 80 00 00 00 85 c0 0f 84 a6 00 00 00 bf 04 01 00 00 e8 ee 34 d4 
d7 e8 69 88 56 d7 84 c0 75 69 48 8b 45 18 c6 44 24 37 00 <48> 8b 58 40 4c 8d 6b 
18 4c 89 ef e8 fc 4d d4 d7 4c 89 ef 48 89
RIP: lirc_thread+0x94/0x520 [lirc_zilog] RSP: b482c131be98
CR2: 0040
This code has been replaced completely in kernel v4.16 by a new driver,
see commit acaa34bf06e9 ("media: rc: implement zilog transmitter"), and
commit f95367a7b758 ("media: staging: remove lirc_zilog driver").

Fixes: 615cd3fe6ccc ("[media] media: lirc_dev: make better use of 
file->private_data")

Cc: sta...@vger.kernel.org # v4.15
Reported-by: Warren Sturm 
Tested-by: Warren Sturm 
Signed-off-by: Sean Young 
---
 drivers/staging/media/lirc/lirc_zilog.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/staging/media/lirc/lirc_zilog.c 
b/drivers/staging/media/lirc/lirc_zilog.c
index 6bd0717bf76e..bf6869e48a0f 100644
--- a/drivers/staging/media/lirc/lirc_zilog.c
+++ b/drivers/staging/media/lirc/lirc_zilog.c
@@ -1291,6 +1291,7 @@ static int open(struct inode *node, struct file *filep)
 
lirc_init_pdata(node, filep);
ir = lirc_get_pdata(filep);
+   get_ir_device(ir, false);
 
atomic_inc(>open_count);
 
-- 
2.14.3