From: "Pali Rohár" <pali.rohar@gmail.com>
To: dmitry.torokhov@gmail.com
Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
andreyknvl@google.com, kcc@google.com, glider@google.com,
ktsan@googlegroups.com, Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH] input: fix data race __ps2_command
Date: Fri, 25 Sep 2015 13:38:11 +0200 [thread overview]
Message-ID: <20150925113811.GG27119@pali> (raw)
In-Reply-To: <1441634675-114118-1-git-send-email-dvyukov@google.com>
On Monday 07 September 2015 16:04:35 Dmitry Vyukov wrote:
> The data race happens on ps2dev->cmdcnt and ps2dev->cmdbuf contents.
> __ps2_command reads that data concurrently with the interrupt handler.
> As the result, for example, if a response arrives just after the
> timeout, __ps2_command can copy out garbage from ps2dev->cmdbuf
> but then see that ps2dev->cmdcnt is 0 and return success.
>
> Stop the interrupt handler with serio_pause_rx() before
> reading the results.
>
> The data race was found with KernelThreadSanitizer (KTSAN).
>
> Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
> ---
> drivers/input/serio/libps2.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
> index 7551699..8f93336 100644
> --- a/drivers/input/serio/libps2.c
> +++ b/drivers/input/serio/libps2.c
> @@ -234,17 +234,19 @@ int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
> !(ps2dev->flags & PS2_FLAG_CMD), timeout);
> }
>
> + serio_pause_rx(ps2dev->serio);
> if (param)
> for (i = 0; i < receive; i++)
> param[i] = ps2dev->cmdbuf[(receive - 1) - i];
>
> if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
> - goto out;
> -
> + goto out_paused;
> rc = 0;
> + goto out_paused;
>
> out:
> serio_pause_rx(ps2dev->serio);
> +out_paused:
> ps2dev->flags = 0;
> serio_continue_rx(ps2dev->serio);
>
Hi! Was this patch queued? Or is there any problem with it? Because I
did not see any response for more weeks on any mailing list.
--
Pali Rohár
pali.rohar@gmail.com
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WARNING: multiple messages have this Message-ID (diff)
From: "Pali Rohár" <pali.rohar@gmail.com>
To: dmitry.torokhov@gmail.com
Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
andreyknvl@google.com, kcc@google.com, glider@google.com,
ktsan@googlegroups.com, Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH] input: fix data race __ps2_command
Date: Fri, 25 Sep 2015 13:38:11 +0200 [thread overview]
Message-ID: <20150925113811.GG27119@pali> (raw)
In-Reply-To: <1441634675-114118-1-git-send-email-dvyukov@google.com>
On Monday 07 September 2015 16:04:35 Dmitry Vyukov wrote:
> The data race happens on ps2dev->cmdcnt and ps2dev->cmdbuf contents.
> __ps2_command reads that data concurrently with the interrupt handler.
> As the result, for example, if a response arrives just after the
> timeout, __ps2_command can copy out garbage from ps2dev->cmdbuf
> but then see that ps2dev->cmdcnt is 0 and return success.
>
> Stop the interrupt handler with serio_pause_rx() before
> reading the results.
>
> The data race was found with KernelThreadSanitizer (KTSAN).
>
> Signed-off-by: Dmitry Vyukov <dvyukov@google.com>
> ---
> drivers/input/serio/libps2.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/serio/libps2.c b/drivers/input/serio/libps2.c
> index 7551699..8f93336 100644
> --- a/drivers/input/serio/libps2.c
> +++ b/drivers/input/serio/libps2.c
> @@ -234,17 +234,19 @@ int __ps2_command(struct ps2dev *ps2dev, unsigned char *param, int command)
> !(ps2dev->flags & PS2_FLAG_CMD), timeout);
> }
>
> + serio_pause_rx(ps2dev->serio);
> if (param)
> for (i = 0; i < receive; i++)
> param[i] = ps2dev->cmdbuf[(receive - 1) - i];
>
> if (ps2dev->cmdcnt && (command != PS2_CMD_RESET_BAT || ps2dev->cmdcnt != 1))
> - goto out;
> -
> + goto out_paused;
> rc = 0;
> + goto out_paused;
>
> out:
> serio_pause_rx(ps2dev->serio);
> +out_paused:
> ps2dev->flags = 0;
> serio_continue_rx(ps2dev->serio);
>
Hi! Was this patch queued? Or is there any problem with it? Because I
did not see any response for more weeks on any mailing list.
--
Pali Rohár
pali.rohar@gmail.com
next prev parent reply other threads:[~2015-09-25 11:38 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-07 14:04 [PATCH] input: fix data race __ps2_command Dmitry Vyukov
2015-09-25 11:38 ` Pali Rohár [this message]
2015-09-25 11:38 ` Pali Rohár
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