* [PATCH] mmc: core: Add error check to avoid kernel panic caused by NULL pointer
@ 2020-06-02 17:29 Corey Gao
2020-06-16 11:26 ` Ulf Hansson
0 siblings, 1 reply; 2+ messages in thread
From: Corey Gao @ 2020-06-02 17:29 UTC (permalink / raw)
To: ulf.hansson; +Cc: linux-mmc, linux-kernel, gaoce123
If __mmc_start_req(host, mrq) fails with error, the mrq->cmd->mrq will
be NULL. This will cause kernel panic in the following
mmc_wait_for_req_done(host, mrq). Add error check to cancle unnecessary
mmc_wait_for_req_done(host, mrq) if __mmc_start_req(host, mrq) fails.
Signed-off-by: Corey Gao <gaoce123@gmail.com>
---
drivers/mmc/core/core.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 2553d903a82b..b13b484e64aa 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -734,9 +734,11 @@ EXPORT_SYMBOL(mmc_start_req);
*/
void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
{
- __mmc_start_req(host, mrq);
+ int err;
- if (!mrq->cap_cmd_during_tfr)
+ err = __mmc_start_req(host, mrq);
+
+ if (!mrq->cap_cmd_during_tfr && !err)
mmc_wait_for_req_done(host, mrq);
}
EXPORT_SYMBOL(mmc_wait_for_req);
--
2.17.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] mmc: core: Add error check to avoid kernel panic caused by NULL pointer
2020-06-02 17:29 [PATCH] mmc: core: Add error check to avoid kernel panic caused by NULL pointer Corey Gao
@ 2020-06-16 11:26 ` Ulf Hansson
0 siblings, 0 replies; 2+ messages in thread
From: Ulf Hansson @ 2020-06-16 11:26 UTC (permalink / raw)
To: Corey Gao; +Cc: linux-mmc, Linux Kernel Mailing List
On Tue, 2 Jun 2020 at 19:31, Corey Gao <gaoce123@gmail.com> wrote:
>
> If __mmc_start_req(host, mrq) fails with error, the mrq->cmd->mrq will
> be NULL. This will cause kernel panic in the following
> mmc_wait_for_req_done(host, mrq). Add error check to cancle unnecessary
> mmc_wait_for_req_done(host, mrq) if __mmc_start_req(host, mrq) fails.
The above is a bit hard for me to follow, can you please try to
elaborate on the problem. Moreover, please, provide a stack trace, as
that is easier to follow for me.
Kind regards
Uffe
>
> Signed-off-by: Corey Gao <gaoce123@gmail.com>
> ---
> drivers/mmc/core/core.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
> index 2553d903a82b..b13b484e64aa 100644
> --- a/drivers/mmc/core/core.c
> +++ b/drivers/mmc/core/core.c
> @@ -734,9 +734,11 @@ EXPORT_SYMBOL(mmc_start_req);
> */
> void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq)
> {
> - __mmc_start_req(host, mrq);
> + int err;
>
> - if (!mrq->cap_cmd_during_tfr)
> + err = __mmc_start_req(host, mrq);
> +
> + if (!mrq->cap_cmd_during_tfr && !err)
> mmc_wait_for_req_done(host, mrq);
> }
> EXPORT_SYMBOL(mmc_wait_for_req);
> --
> 2.17.1
>
^ permalink raw reply [flat|nested] 2+ messages in thread
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