* patch "ARM: amba: Fix race condition with driver_override" added to char-misc-linus
@ 2018-04-26 8:35 gregkh
0 siblings, 0 replies; 3+ messages in thread
From: gregkh @ 2018-04-26 8:35 UTC (permalink / raw)
To: geert+renesas, gregkh, stable, tkjos
This is a note to let you know that I've just added the patch titled
ARM: amba: Fix race condition with driver_override
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 6a7228d90d42bcacfe38786756ba62762b91c20a Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Tue, 10 Apr 2018 15:21:44 +0200
Subject: ARM: amba: Fix race condition with driver_override
The driver_override implementation is susceptible to a race condition
when different threads are reading vs storing a different driver
override. Add locking to avoid this race condition.
Cfr. commits 6265539776a0810b ("driver core: platform: fix race
condition with driver_override") and 9561475db680f714 ("PCI: Fix race
condition with driver_override").
Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/amba/bus.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index f8c01fbef64d..4a3ac31c07d0 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -69,8 +69,12 @@ static ssize_t driver_override_show(struct device *_dev,
struct device_attribute *attr, char *buf)
{
struct amba_device *dev = to_amba_device(_dev);
+ ssize_t len;
- return sprintf(buf, "%s\n", dev->driver_override);
+ device_lock(_dev);
+ len = sprintf(buf, "%s\n", dev->driver_override);
+ device_unlock(_dev);
+ return len;
}
static ssize_t driver_override_store(struct device *_dev,
@@ -78,7 +82,7 @@ static ssize_t driver_override_store(struct device *_dev,
const char *buf, size_t count)
{
struct amba_device *dev = to_amba_device(_dev);
- char *driver_override, *old = dev->driver_override, *cp;
+ char *driver_override, *old, *cp;
/* We need to keep extra room for a newline */
if (count >= (PAGE_SIZE - 1))
@@ -92,12 +96,15 @@ static ssize_t driver_override_store(struct device *_dev,
if (cp)
*cp = '\0';
+ device_lock(_dev);
+ old = dev->driver_override;
if (strlen(driver_override)) {
dev->driver_override = driver_override;
} else {
kfree(driver_override);
dev->driver_override = NULL;
}
+ device_unlock(_dev);
kfree(old);
--
2.17.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: patch "ARM: amba: Fix race condition with driver_override" added to char-misc-linus
2018-04-25 16:07 gregkh
@ 2018-04-26 7:43 ` Geert Uytterhoeven
0 siblings, 0 replies; 3+ messages in thread
From: Geert Uytterhoeven @ 2018-04-26 7:43 UTC (permalink / raw)
To: Greg KH; +Cc: Geert Uytterhoeven, stable, Todd Kjos
Hi Greg,
On Wed, Apr 25, 2018 at 6:07 PM, <gregkh@linuxfoundation.org> wrote:
> This is a note to let you know that I've just added the patch titled
>
> ARM: amba: Fix race condition with driver_override
>
> to my char-misc git tree which can be found at
> git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
> in the char-misc-linus branch.
>
> The patch will show up in the next release of the linux-next tree
> (usually sometime within the next 24 hours during the week.)
>
> The patch will hopefully also be merged in Linus's tree for the
> next -rc kernel release.
>
> If you have any questions about this process, please let me know.
Doh, I hadn't noticed you modified my patch, and introduced a bug...
> From 6b614a87f3f477571e319281e84dba11e0ea0a76 Mon Sep 17 00:00:00 2001
> From: Geert Uytterhoeven <geert+renesas@glider.be>
> Date: Tue, 10 Apr 2018 15:21:44 +0200
> Subject: ARM: amba: Fix race condition with driver_override
>
> The driver_override implementation is susceptible to a race condition
> when different threads are reading vs storing a different driver
> override. Add locking to avoid this race condition.
>
> Cfr. commits 6265539776a0810b ("driver core: platform: fix race
> condition with driver_override") and 9561475db680f714 ("PCI: Fix race
> condition with driver_override").
>
> Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
> Reviewed-by: Todd Kjos <tkjos@google.com>
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> drivers/amba/bus.c | 11 +++++++++--
> 1 file changed, 9 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
> index 594c228d2f02..c77eb6e65646 100644
> --- a/drivers/amba/bus.c
> +++ b/drivers/amba/bus.c
> @@ -69,11 +69,15 @@ static ssize_t driver_override_show(struct device *_dev,
> struct device_attribute *attr, char *buf)
> {
> struct amba_device *dev = to_amba_device(_dev);
> + ssize_t len;
>
> if (!dev->driver_override)
> return 0;
With the above still present, it should be covered by the lock below, too.
Else the output is still subject to the race condition.
>
> - return sprintf(buf, "%s\n", dev->driver_override);
> + device_lock(_dev);
> + len = sprintf(buf, "%s\n", dev->driver_override);
> + device_unlock(_dev);
> + return len;
> }
>
> static ssize_t driver_override_store(struct device *_dev,
> @@ -81,7 +85,7 @@ static ssize_t driver_override_store(struct device *_dev,
> const char *buf, size_t count)
> {
> struct amba_device *dev = to_amba_device(_dev);
> - char *driver_override, *old = dev->driver_override, *cp;
> + char *driver_override, *old, *cp;
>
> if (count > PATH_MAX)
> return -EINVAL;
> @@ -94,12 +98,15 @@ static ssize_t driver_override_store(struct device *_dev,
> if (cp)
> *cp = '\0';
>
> + device_lock(_dev);
> + old = dev->driver_override;
> if (strlen(driver_override)) {
> dev->driver_override = driver_override;
> } else {
> kfree(driver_override);
> dev->driver_override = NULL;
> }
> + device_unlock(_dev);
>
> kfree(old);
>
> --
> 2.17.0
>
>
--
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
^ permalink raw reply [flat|nested] 3+ messages in thread
* patch "ARM: amba: Fix race condition with driver_override" added to char-misc-linus
@ 2018-04-25 16:07 gregkh
2018-04-26 7:43 ` Geert Uytterhoeven
0 siblings, 1 reply; 3+ messages in thread
From: gregkh @ 2018-04-25 16:07 UTC (permalink / raw)
To: geert+renesas, gregkh, stable, tkjos
This is a note to let you know that I've just added the patch titled
ARM: amba: Fix race condition with driver_override
to my char-misc git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From 6b614a87f3f477571e319281e84dba11e0ea0a76 Mon Sep 17 00:00:00 2001
From: Geert Uytterhoeven <geert+renesas@glider.be>
Date: Tue, 10 Apr 2018 15:21:44 +0200
Subject: ARM: amba: Fix race condition with driver_override
The driver_override implementation is susceptible to a race condition
when different threads are reading vs storing a different driver
override. Add locking to avoid this race condition.
Cfr. commits 6265539776a0810b ("driver core: platform: fix race
condition with driver_override") and 9561475db680f714 ("PCI: Fix race
condition with driver_override").
Fixes: 3cf385713460eb2b ("ARM: 8256/1: driver coamba: add device binding path 'driver_override'")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Todd Kjos <tkjos@google.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/amba/bus.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/amba/bus.c b/drivers/amba/bus.c
index 594c228d2f02..c77eb6e65646 100644
--- a/drivers/amba/bus.c
+++ b/drivers/amba/bus.c
@@ -69,11 +69,15 @@ static ssize_t driver_override_show(struct device *_dev,
struct device_attribute *attr, char *buf)
{
struct amba_device *dev = to_amba_device(_dev);
+ ssize_t len;
if (!dev->driver_override)
return 0;
- return sprintf(buf, "%s\n", dev->driver_override);
+ device_lock(_dev);
+ len = sprintf(buf, "%s\n", dev->driver_override);
+ device_unlock(_dev);
+ return len;
}
static ssize_t driver_override_store(struct device *_dev,
@@ -81,7 +85,7 @@ static ssize_t driver_override_store(struct device *_dev,
const char *buf, size_t count)
{
struct amba_device *dev = to_amba_device(_dev);
- char *driver_override, *old = dev->driver_override, *cp;
+ char *driver_override, *old, *cp;
if (count > PATH_MAX)
return -EINVAL;
@@ -94,12 +98,15 @@ static ssize_t driver_override_store(struct device *_dev,
if (cp)
*cp = '\0';
+ device_lock(_dev);
+ old = dev->driver_override;
if (strlen(driver_override)) {
dev->driver_override = driver_override;
} else {
kfree(driver_override);
dev->driver_override = NULL;
}
+ device_unlock(_dev);
kfree(old);
--
2.17.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
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2018-04-26 8:35 patch "ARM: amba: Fix race condition with driver_override" added to char-misc-linus gregkh
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2018-04-26 7:43 ` Geert Uytterhoeven
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