* [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null
@ 2009-02-06 8:27 Bryan Wu
2009-02-06 10:06 ` Alan Cox
2009-02-07 0:05 ` Andrew Morton
0 siblings, 2 replies; 4+ messages in thread
From: Bryan Wu @ 2009-02-06 8:27 UTC (permalink / raw)
To: alan; +Cc: linux-kernel, Sonic Zhang, Bryan Wu
From: Sonic Zhang <sonic.zhang@analog.com>
when pass bootargs console=null into kernel from u-boot, the booted up
kernel can't be pinged through. This happens after the kernel is upgraded
to 2.6.28.
Should check if tty_driver is NULL before call kref_get() in tty_driver_kref_get().
Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>
---
include/linux/tty_driver.h | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
index 08e0883..2a602a8 100644
--- a/include/linux/tty_driver.h
+++ b/include/linux/tty_driver.h
@@ -312,7 +312,8 @@ extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
extern void tty_driver_kref_put(struct tty_driver *driver);
extern inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
{
- kref_get(&d->kref);
+ if (d)
+ kref_get(&d->kref);
return d;
}
--
1.5.6.3
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null
2009-02-06 8:27 [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null Bryan Wu
@ 2009-02-06 10:06 ` Alan Cox
2009-02-07 0:05 ` Andrew Morton
1 sibling, 0 replies; 4+ messages in thread
From: Alan Cox @ 2009-02-06 10:06 UTC (permalink / raw)
To: Bryan Wu; +Cc: linux-kernel, Sonic Zhang, Bryan Wu
On Fri, 6 Feb 2009 16:27:57 +0800
Bryan Wu <cooloney@kernel.org> wrote:
> From: Sonic Zhang <sonic.zhang@analog.com>
>
> when pass bootargs console=null into kernel from u-boot, the booted up
> kernel can't be pinged through. This happens after the kernel is upgraded
> to 2.6.28.
>
> Should check if tty_driver is NULL before call kref_get() in tty_driver_kref_get().
Should not call tty_driver_kref_get(NULL) in the first place....
Need to fix the real bug not paper over it
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null
2009-02-06 8:27 [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null Bryan Wu
2009-02-06 10:06 ` Alan Cox
@ 2009-02-07 0:05 ` Andrew Morton
2009-02-07 0:09 ` Alan Cox
1 sibling, 1 reply; 4+ messages in thread
From: Andrew Morton @ 2009-02-07 0:05 UTC (permalink / raw)
To: Bryan Wu; +Cc: alan, linux-kernel, sonic.zhang, cooloney
On Fri, 6 Feb 2009 16:27:57 +0800
Bryan Wu <cooloney@kernel.org> wrote:
> From: Sonic Zhang <sonic.zhang@analog.com>
>
> when pass bootargs console=null into kernel from u-boot, the booted up
> kernel can't be pinged through. This happens after the kernel is upgraded
> to 2.6.28.
>
> Should check if tty_driver is NULL before call kref_get() in tty_driver_kref_get().
>
> Signed-off-by: Sonic Zhang <sonic.zhang@analog.com>
> Signed-off-by: Bryan Wu <cooloney@kernel.org>
> ---
> include/linux/tty_driver.h | 3 ++-
> 1 files changed, 2 insertions(+), 1 deletions(-)
>
> diff --git a/include/linux/tty_driver.h b/include/linux/tty_driver.h
> index 08e0883..2a602a8 100644
> --- a/include/linux/tty_driver.h
> +++ b/include/linux/tty_driver.h
> @@ -312,7 +312,8 @@ extern struct tty_driver *tty_find_polling_driver(char *name, int *line);
> extern void tty_driver_kref_put(struct tty_driver *driver);
> extern inline struct tty_driver *tty_driver_kref_get(struct tty_driver *d)
> {
> - kref_get(&d->kref);
> + if (d)
> + kref_get(&d->kref);
> return d;
> }
>
Did any earlier kernel versions handle this situation OK?
If so, we might need to be back-compatible with buggy userspace :(
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null
2009-02-07 0:05 ` Andrew Morton
@ 2009-02-07 0:09 ` Alan Cox
0 siblings, 0 replies; 4+ messages in thread
From: Alan Cox @ 2009-02-07 0:09 UTC (permalink / raw)
To: Andrew Morton; +Cc: Bryan Wu, linux-kernel, sonic.zhang
> Did any earlier kernel versions handle this situation OK?
>
> If so, we might need to be back-compatible with buggy userspace :(
Nothing to do with userspace. You can't call tty_driver_kref_get(NULL),
it's completely bogus.
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2009-02-07 0:09 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz follow: Atom feed
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2009-02-06 8:27 [PATCH] tty: fix bug - kernel can't be pinged through when bootargs console=null Bryan Wu
2009-02-06 10:06 ` Alan Cox
2009-02-07 0:05 ` Andrew Morton
2009-02-07 0:09 ` Alan Cox
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