2015-11-25 11:19:49

by Pan Xinhui

[permalink] [raw]
Subject: [PATCH] tty/n_gsm.c: fix false positive WARN_ON and do some codes improvement

From: xinhui <[email protected]>

If gsm driver fails to activate one mux, and this mux is not stored in
gsm_mux[], there would be a warning in gsm_cleanup_mux(). Actually this
is a legal case. So just do a simple check instead of WARN_ON.

There is one filed gsm->num to store its index of gsm_mux[]. So use
gsm->num to remove itself from gsm_mux[] instead of the for-loop
traverse.

Reported-by: Dmitry Vyukov <[email protected]>
Fixes: 5a64096700dc ("tty/n_gsm.c: fix a memory leak in gsmld_open")
Signed-off-by: Pan Xinhui <[email protected]>
---
drivers/tty/n_gsm.c | 12 +++++-------
1 files changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index c3fe026..56377e1 100644
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -2037,15 +2037,13 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm)

gsm->dead = 1;

+ /* open failed before registering => nothing to do*/
+ if (gsm_mux[gsm->num] != gsm)
+ return;
+
spin_lock(&gsm_mux_lock);
- for (i = 0; i < MAX_MUX; i++) {
- if (gsm_mux[i] == gsm) {
- gsm_mux[i] = NULL;
- break;
- }
- }
+ gsm_mux[gsm->num] = NULL;
spin_unlock(&gsm_mux_lock);
- WARN_ON(i == MAX_MUX);

/* In theory disconnecting DLCI 0 is sufficient but for some
modems this is apparently not the case. */
--
1.7.1


2015-11-25 11:28:31

by Pan Xinhui

[permalink] [raw]
Subject: Re: [PATCH] tty/n_gsm.c: fix false positive WARN_ON and do some codes improvement

Hi, Jiri
I made this patch based on your idea. Any modification is welcome. :)

PS. "xinhui" or "xinhui.pan"@linux.vnet.ibm.com are same mail account, both of them are alias.

thanks
xinhui

On 2015/11/25 19:18, xinhui wrote:
> From: xinhui <[email protected]>
>
> If gsm driver fails to activate one mux, and this mux is not stored in
> gsm_mux[], there would be a warning in gsm_cleanup_mux(). Actually this
> is a legal case. So just do a simple check instead of WARN_ON.
>
> There is one filed gsm->num to store its index of gsm_mux[]. So use
> gsm->num to remove itself from gsm_mux[] instead of the for-loop
> traverse.
>
> Reported-by: Dmitry Vyukov <[email protected]>
> Fixes: 5a64096700dc ("tty/n_gsm.c: fix a memory leak in gsmld_open")
> Signed-off-by: Pan Xinhui <[email protected]>
> ---
> drivers/tty/n_gsm.c | 12 +++++-------
> 1 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
> index c3fe026..56377e1 100644
> --- a/drivers/tty/n_gsm.c
> +++ b/drivers/tty/n_gsm.c
> @@ -2037,15 +2037,13 @@ static void gsm_cleanup_mux(struct gsm_mux *gsm)
>
> gsm->dead = 1;
>
> + /* open failed before registering => nothing to do*/
> + if (gsm_mux[gsm->num] != gsm)
> + return;
> +
> spin_lock(&gsm_mux_lock);
> - for (i = 0; i < MAX_MUX; i++) {
> - if (gsm_mux[i] == gsm) {
> - gsm_mux[i] = NULL;
> - break;
> - }
> - }
> + gsm_mux[gsm->num] = NULL;
> spin_unlock(&gsm_mux_lock);
> - WARN_ON(i == MAX_MUX);
>
> /* In theory disconnecting DLCI 0 is sufficient but for some
> modems this is apparently not the case. */
>

2015-12-14 21:38:44

by Greg Kroah-Hartman

[permalink] [raw]
Subject: Re: [PATCH] tty/n_gsm.c: fix false positive WARN_ON and do some codes improvement

On Wed, Nov 25, 2015 at 07:18:37PM +0800, xinhui wrote:
> From: xinhui <[email protected]>
>
> If gsm driver fails to activate one mux, and this mux is not stored in
> gsm_mux[], there would be a warning in gsm_cleanup_mux(). Actually this
> is a legal case. So just do a simple check instead of WARN_ON.
>
> There is one filed gsm->num to store its index of gsm_mux[]. So use
> gsm->num to remove itself from gsm_mux[] instead of the for-loop
> traverse.
>
> Reported-by: Dmitry Vyukov <[email protected]>
> Fixes: 5a64096700dc ("tty/n_gsm.c: fix a memory leak in gsmld_open")
> Signed-off-by: Pan Xinhui <[email protected]>

the signed-off-by name has to match your from: name :(

2015-12-15 05:43:23

by Pan Xinhui

[permalink] [raw]
Subject: Re: [PATCH] tty/n_gsm.c: fix false positive WARN_ON and do some codes improvement

Hi, Greg
This patch is dropped, I have created another patch based on Jiri' patch.
On 2015/12/15 02:55, Greg Kroah-Hartman wrote:
> On Wed, Nov 25, 2015 at 07:18:37PM +0800, xinhui wrote:
>> From: xinhui <[email protected]>
>>
>> If gsm driver fails to activate one mux, and this mux is not stored in
>> gsm_mux[], there would be a warning in gsm_cleanup_mux(). Actually this
>> is a legal case. So just do a simple check instead of WARN_ON.
>>
>> There is one filed gsm->num to store its index of gsm_mux[]. So use
>> gsm->num to remove itself from gsm_mux[] instead of the for-loop
>> traverse.
>>
>> Reported-by: Dmitry Vyukov <[email protected]>
>> Fixes: 5a64096700dc ("tty/n_gsm.c: fix a memory leak in gsmld_open")
>> Signed-off-by: Pan Xinhui <[email protected]>
>
> the signed-off-by name has to match your from: name :(
>