[v2] scsi: qla2xxx: Fix double free of fcport in error handling path

[PATCH V2] scsi: qla2xxx: Fix double free of fcport in error handling path

Posted by Yongzhi Liu 1 year, 7 months ago

When dma_alloc_coherent() or qla2x00_start_sp() return an error,
the callback function qla2x00_els_dcmd_sp_free in qla2x00_sp_release
will call qla2x00_free_fcport() to kfree fcport. We shouldn't call
qla2x00_free_fcport() again in the error handling path.

Fix this by cleaning up the redundant qla2x00_free_fcport() and
replacing error handling with a goto chain.

Fixes: 82f522ae0d97 ("scsi: qla2xxx: Fix double free of fcport")
Signed-off-by: Yongzhi Liu <hyperlyzcs@gmail.com>
---
 drivers/scsi/qla2xxx/qla_iocb.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 0b41e8a06602..7b6a1db55672 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -2749,10 +2749,8 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 			    GFP_KERNEL);
 
 	if (!elsio->u.els_logo.els_logo_pyld) {
-		/* ref: INIT */
-		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		qla2x00_free_fcport(fcport);
-		return QLA_FUNCTION_FAILED;
+		rval = QLA_FUNCTION_FAILED;
+		goto free_sp;
 	}
 
 	memset(&logo_pyld, 0, sizeof(struct els_logo_payload));
@@ -2774,10 +2772,8 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 
 	rval = qla2x00_start_sp(sp);
 	if (rval != QLA_SUCCESS) {
-		/* ref: INIT */
-		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		qla2x00_free_fcport(fcport);
-		return QLA_FUNCTION_FAILED;
+		rval = QLA_FUNCTION_FAILED;
+		goto free_sp;
 	}
 
 	ql_dbg(ql_dbg_io, vha, 0x3074,
@@ -2787,6 +2783,7 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 
 	wait_for_completion(&elsio->u.els_logo.comp);
 
+free_sp:
 	/* ref: INIT */
 	kref_put(&sp->cmd_kref, qla2x00_sp_release);
 	return rval;
-- 
2.36.1

Re: [PATCH V2] scsi: qla2xxx: Fix double free of fcport in error handling path

Posted by Markus Elfring 1 year, 7 months ago

…> Fix this by cleaning up the redundant qla2x00_free_fcport() and
> replacing error handling with a goto chain.

I imagine that there can be a need to provide the desired software adjustment
as a patch series with two separate update steps.
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc5#n81

* Deletion of inappropriate function calls

* Optimisation of exception handling



How do you think about to refer to the affected function
(instead of the hint “error handling path”) in the summary phrase?

Regards,
Markus

[PATCH V3 1/2] scsi: qla2xxx: Fix double free of fcport in qla24xx_els_dcmd_iocb

Posted by Yongzhi Liu 1 year, 7 months ago

When dma_alloc_coherent() or qla2x00_start_sp() return an error,
the callback function qla2x00_els_dcmd_sp_free in qla2x00_sp_release
will call qla2x00_free_fcport() to kfree fcport. We shouldn't call
qla2x00_free_fcport() again in the error handling path.

Fix this by cleaning the duplicate qla2x00_free_fcport() calls up.

Fixes: 82f522ae0d97 ("scsi: qla2xxx: Fix double free of fcport")
Signed-off-by: Yongzhi Liu <hyperlyzcs@gmail.com>
---
V2 -> V3: Improve patch summary and provide a patch serises with two separate update steps
V1 -> V2: Optimisation of exception handling

 drivers/scsi/qla2xxx/qla_iocb.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 0b41e8a06602..faec66bd1951 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -2751,7 +2751,6 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 	if (!elsio->u.els_logo.els_logo_pyld) {
 		/* ref: INIT */
 		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		qla2x00_free_fcport(fcport);
 		return QLA_FUNCTION_FAILED;
 	}
 
@@ -2776,7 +2775,6 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 	if (rval != QLA_SUCCESS) {
 		/* ref: INIT */
 		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		qla2x00_free_fcport(fcport);
 		return QLA_FUNCTION_FAILED;
 	}
 
-- 
2.36.1

Re: [PATCH V3 1/2] scsi: qla2xxx: Fix double free of fcport in qla24xx_els_dcmd_iocb

Posted by Markus Elfring 1 year, 7 months ago

* I would usually expect a corresponding cover letter for patch series.

* Would you like to add parentheses to the function name in the summary phrase?


> When dma_alloc_coherent() or qla2x00_start_sp() return an error,

                                                  call returned?


> the callback function qla2x00_els_dcmd_sp_free in qla2x00_sp_release
> will call qla2x00_free_fcport() to kfree fcport. We shouldn't call

                                     free “fcport”?


> qla2x00_free_fcport() again in the error handling path.

                                                    paths?



> Fix this by cleaning the duplicate qla2x00_free_fcport() calls up.

Would the wording “Thus delete duplicate qla2x00_free_fcport() calls.” be a bit nicer?


…
> ---
> V2 -> V3: Improve patch summary and provide a patch serises with two separate update steps
…

* How do you think about to avoid the repetition of version identifiers
  (according to the selected enumeration style)?

* You would probably like to avoid another typo here.

Regards,
Markus

[PATCH V3 2/2] scsi: qla2xxx: Optimisation of exception handling in qla24xx_els_dcmd_iocb

Posted by Yongzhi Liu 1 year, 7 months ago

To avoid duplicate error handling code a bit more, use more common goto
chain in qla24xx_els_dcmd_iocb.

Signed-off-by: Yongzhi Liu <hyperlyzcs@gmail.com>
---
V2 -> V3: Improve patch summary and provide a patch serises with two separate update steps
V1 -> V2: Optimisation of exception handling

 drivers/scsi/qla2xxx/qla_iocb.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index faec66bd1951..a3a3904cbb47 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -2749,9 +2749,8 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 			    GFP_KERNEL);
 
 	if (!elsio->u.els_logo.els_logo_pyld) {
-		/* ref: INIT */
-		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		return QLA_FUNCTION_FAILED;
+		rval = QLA_FUNCTION_FAILED;
+		goto put_ref;
 	}
 
 	memset(&logo_pyld, 0, sizeof(struct els_logo_payload));
@@ -2773,9 +2772,8 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 
 	rval = qla2x00_start_sp(sp);
 	if (rval != QLA_SUCCESS) {
-		/* ref: INIT */
-		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		return QLA_FUNCTION_FAILED;
+		rval = QLA_FUNCTION_FAILED;
+		goto put_ref;
 	}
 
 	ql_dbg(ql_dbg_io, vha, 0x3074,
@@ -2784,7 +2782,7 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 	    fcport->d_id.b.area, fcport->d_id.b.al_pa);
 
 	wait_for_completion(&elsio->u.els_logo.comp);
-
+put_ref:
 	/* ref: INIT */
 	kref_put(&sp->cmd_kref, qla2x00_sp_release);
 	return rval;
-- 
2.36.1

Re: [PATCH V3 2/2] scsi: qla2xxx: Optimisation of exception handling in qla24xx_els_dcmd_iocb

Posted by Markus Elfring 1 year, 7 months ago

Would you like to use the summary phrase “Use common error handling code in qla24xx_els_dcmd_iocb()”?


> To avoid duplicate error handling code a bit more, use more common goto
> chain in qla24xx_els_dcmd_iocb.

How do you think about the following wording?

   Add a jump target so that a bit of exception handling can be better reused
   at the end of this function implementation.


Can the tag “Suggested-by” be helpful for an improved change description?
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc6#n586

Regards,
Markus

[PATCH V4 0/2] Bugfix and optimisation of exception handling

Posted by Yongzhi Liu 1 year, 7 months ago

Hi maintainers,

This patch series includes two patches that address a double free
bug in the driver scsi/qla2xxx, and optimize error handling code
in the qla24xx_els_dcmd_iocb().

Patch 1/2: Fix double free of fcport in qla24xx_els_dcmd_iocb()

Patch 2/2: Use common error handling code in qla24xx_els_dcmd_iocb()

The changelog for the patch series is as follows.

V3 -> V4: Improve patch summary and description
V2 -> V3: Improve patch summary and provide a patch serises with
two separate update steps
V1 -> V2: Optimisation of exception handling

Please review and let me know if you have any questions or concerns.

Best regards,
Yongzhi Liu

 drivers/scsi/qla2xxx/qla_iocb.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

-- 
2.36.1

[PATCH V4 1/2] scsi: qla2xxx: Fix double free of fcport in qla24xx_els_dcmd_iocb()

Posted by Yongzhi Liu 1 year, 7 months ago

When dma_alloc_coherent() or qla2x00_start_sp() returned an error,
the callback function qla2x00_els_dcmd_sp_free in qla2x00_sp_release
called qla2x00_free_fcport() to free "fcport". We shouldn't call
qla2x00_free_fcport() again in the error handling paths, and thus
delete the duplicate qla2x00_free_fcport() calls.

Fixes: 82f522ae0d97 ("scsi: qla2xxx: Fix double free of fcport")
Signed-off-by: Yongzhi Liu <hyperlyzcs@gmail.com>
---
 drivers/scsi/qla2xxx/qla_iocb.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index 0b41e8a06602..faec66bd1951 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -2751,7 +2751,6 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 	if (!elsio->u.els_logo.els_logo_pyld) {
 		/* ref: INIT */
 		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		qla2x00_free_fcport(fcport);
 		return QLA_FUNCTION_FAILED;
 	}
 
@@ -2776,7 +2775,6 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 	if (rval != QLA_SUCCESS) {
 		/* ref: INIT */
 		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		qla2x00_free_fcport(fcport);
 		return QLA_FUNCTION_FAILED;
 	}
 
-- 
2.36.1

[PATCH V4 2/2] scsi: qla2xxx: Use common error handling code in qla24xx_els_dcmd_iocb()

Posted by Yongzhi Liu 1 year, 7 months ago

Add a jump target so that a bit of exception handling can be better reused
at the end of this function implementation.

Signed-off-by: Yongzhi Liu <hyperlyzcs@gmail.com>
Suggested-by: Markus Elfring <Markus.Elfring@web.de>
---
 drivers/scsi/qla2xxx/qla_iocb.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/scsi/qla2xxx/qla_iocb.c b/drivers/scsi/qla2xxx/qla_iocb.c
index faec66bd1951..a3a3904cbb47 100644
--- a/drivers/scsi/qla2xxx/qla_iocb.c
+++ b/drivers/scsi/qla2xxx/qla_iocb.c
@@ -2749,9 +2749,8 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 			    GFP_KERNEL);
 
 	if (!elsio->u.els_logo.els_logo_pyld) {
-		/* ref: INIT */
-		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		return QLA_FUNCTION_FAILED;
+		rval = QLA_FUNCTION_FAILED;
+		goto put_ref;
 	}
 
 	memset(&logo_pyld, 0, sizeof(struct els_logo_payload));
@@ -2773,9 +2772,8 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 
 	rval = qla2x00_start_sp(sp);
 	if (rval != QLA_SUCCESS) {
-		/* ref: INIT */
-		kref_put(&sp->cmd_kref, qla2x00_sp_release);
-		return QLA_FUNCTION_FAILED;
+		rval = QLA_FUNCTION_FAILED;
+		goto put_ref;
 	}
 
 	ql_dbg(ql_dbg_io, vha, 0x3074,
@@ -2784,7 +2782,7 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
 	    fcport->d_id.b.area, fcport->d_id.b.al_pa);
 
 	wait_for_completion(&elsio->u.els_logo.comp);
-
+put_ref:
 	/* ref: INIT */
 	kref_put(&sp->cmd_kref, qla2x00_sp_release);
 	return rval;
-- 
2.36.1

Re: [PATCH V2] scsi: qla2xxx: Fix double free of fcport in error handling path

Posted by Markus Elfring 1 year, 7 months ago

…
> Fix this by cleaning up the redundant qla2x00_free_fcport() and
> replacing error handling with a goto chain.
…

Can the following wording approach be a bit nicer?

   Thus clean duplicate qla2x00_free_fcport() calls up
   and use more common error handling code instead.



> ---
>  drivers/scsi/qla2xxx/qla_iocb.c | 13 +++++--------
…

Unfortunately, you overlooked to add a patch version description behind the marker line.

See also:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.9-rc5#n713


…
> +++ b/drivers/scsi/qla2xxx/qla_iocb.c
…
> @@ -2787,6 +2783,7 @@ qla24xx_els_dcmd_iocb(scsi_qla_host_t *vha, int els_opcode,
>
>  	wait_for_completion(&elsio->u.els_logo.comp);
>
> +free_sp:

* I suggest to omit a blank line here.

* How do you think about to use the label “put_ref”?


>  	/* ref: INIT */
>  	kref_put(&sp->cmd_kref, qla2x00_sp_release);
>  	return rval;


Regards,
Markus