[PATCH] driver: core: Fix list corruption after device_del()

[PATCH] driver: core: Fix list corruption after device_del()

[Takashi Iwai]

The device_links_purge() function (called from device_del()) tries to
remove the links.needs_suppliers list entry, but it's using
list_del(), hence it doesn't initialize after the removal.  This is OK
for normal cases where device_del() is called via device_destroy().
However, it's not guaranteed that the device object will be really
deleted soon after device_del().  In a minor case like HD-audio codec
reconfiguration that re-initializes the device after device_del(), it
may lead to a crash by the corrupted list entry.

As a simple fix, replace list_del() with list_del_init() in order to
make the list intact after the device_del() call.

Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
Cc: <stable@vger.kernel.org>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209207
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 drivers/base/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index d661ada1518f..e8cb66093f21 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -1386,7 +1386,7 @@ static void device_links_purge(struct device *dev)
 		return;
 
 	mutex_lock(&wfs_lock);
-	list_del(&dev->links.needs_suppliers);
+	list_del_init(&dev->links.needs_suppliers);
 	mutex_unlock(&wfs_lock);
 
 	/*
-- 
2.26.2

Re: [PATCH] driver: core: Fix list corruption after device_del()

[Rafael J. Wysocki]

On Tue, Dec 8, 2020 at 8:03 PM Takashi Iwai <tiwai@suse.de> wrote:
>
> The device_links_purge() function (called from device_del()) tries to
> remove the links.needs_suppliers list entry, but it's using
> list_del(), hence it doesn't initialize after the removal.  This is OK
> for normal cases where device_del() is called via device_destroy().
> However, it's not guaranteed that the device object will be really
> deleted soon after device_del().  In a minor case like HD-audio codec
> reconfiguration that re-initializes the device after device_del(), it
> may lead to a crash by the corrupted list entry.
>
> As a simple fix, replace list_del() with list_del_init() in order to
> make the list intact after the device_del() call.
>
> Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
> Cc: <stable@vger.kernel.org>
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209207
> Signed-off-by: Takashi Iwai <tiwai@suse.de>

Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

> ---
>  drivers/base/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index d661ada1518f..e8cb66093f21 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1386,7 +1386,7 @@ static void device_links_purge(struct device *dev)
>                 return;
>
>         mutex_lock(&wfs_lock);
> -       list_del(&dev->links.needs_suppliers);
> +       list_del_init(&dev->links.needs_suppliers);
>         mutex_unlock(&wfs_lock);
>
>         /*
> --
> 2.26.2
>

Re: [PATCH] driver: core: Fix list corruption after device_del()

[Greg Kroah-Hartman]

On Tue, Dec 08, 2020 at 08:03:26PM +0100, Takashi Iwai wrote:
> The device_links_purge() function (called from device_del()) tries to
> remove the links.needs_suppliers list entry, but it's using
> list_del(), hence it doesn't initialize after the removal.  This is OK
> for normal cases where device_del() is called via device_destroy().
> However, it's not guaranteed that the device object will be really
> deleted soon after device_del().  In a minor case like HD-audio codec
> reconfiguration that re-initializes the device after device_del(), it
> may lead to a crash by the corrupted list entry.
> 
> As a simple fix, replace list_del() with list_del_init() in order to
> make the list intact after the device_del() call.
> 
> Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
> Cc: <stable@vger.kernel.org>
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209207
> Signed-off-by: Takashi Iwai <tiwai@suse.de>
> ---
>  drivers/base/core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/base/core.c b/drivers/base/core.c
> index d661ada1518f..e8cb66093f21 100644
> --- a/drivers/base/core.c
> +++ b/drivers/base/core.c
> @@ -1386,7 +1386,7 @@ static void device_links_purge(struct device *dev)
>  		return;
>  
>  	mutex_lock(&wfs_lock);
> -	list_del(&dev->links.needs_suppliers);
> +	list_del_init(&dev->links.needs_suppliers);
>  	mutex_unlock(&wfs_lock);

Can this wait until 5.11-rc1 and then get backported, as it has been
around for a while, or are you hitting this on 5.10-rc7 now and need
this for 5.10-final?

thanks,

greg k-h

Re: [PATCH] driver: core: Fix list corruption after device_del()

[Takashi Iwai]

On Tue, 08 Dec 2020 20:52:34 +0100,
Greg Kroah-Hartman wrote:
> 
> On Tue, Dec 08, 2020 at 08:03:26PM +0100, Takashi Iwai wrote:
> > The device_links_purge() function (called from device_del()) tries to
> > remove the links.needs_suppliers list entry, but it's using
> > list_del(), hence it doesn't initialize after the removal.  This is OK
> > for normal cases where device_del() is called via device_destroy().
> > However, it's not guaranteed that the device object will be really
> > deleted soon after device_del().  In a minor case like HD-audio codec
> > reconfiguration that re-initializes the device after device_del(), it
> > may lead to a crash by the corrupted list entry.
> > 
> > As a simple fix, replace list_del() with list_del_init() in order to
> > make the list intact after the device_del() call.
> > 
> > Fixes: e2ae9bcc4aaa ("driver core: Add support for linking devices during device addition")
> > Cc: <stable@vger.kernel.org>
> > BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=209207
> > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > ---
> >  drivers/base/core.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/drivers/base/core.c b/drivers/base/core.c
> > index d661ada1518f..e8cb66093f21 100644
> > --- a/drivers/base/core.c
> > +++ b/drivers/base/core.c
> > @@ -1386,7 +1386,7 @@ static void device_links_purge(struct device *dev)
> >  		return;
> >  
> >  	mutex_lock(&wfs_lock);
> > -	list_del(&dev->links.needs_suppliers);
> > +	list_del_init(&dev->links.needs_suppliers);
> >  	mutex_unlock(&wfs_lock);
> 
> Can this wait until 5.11-rc1 and then get backported, as it has been
> around for a while, or are you hitting this on 5.10-rc7 now and need
> this for 5.10-final?

This is rather a minor (but long-standing) issue, so no problem to
wait for 5.11.


thanks,

Takashi