* [PATCH] dmaengine: idxd: Fix double free in idxd_setup_wqs()
@ 2025-08-11 10:43 Dan Carpenter
2025-08-11 15:43 ` Dave Jiang
2025-08-20 17:39 ` Vinod Koul
0 siblings, 2 replies; 3+ messages in thread
From: Dan Carpenter @ 2025-08-11 10:43 UTC (permalink / raw)
To: Shuai Xue, Colin Ian King
Cc: Vinicius Costa Gomes, Dave Jiang, Vinod Koul, Fenghua Yu,
dmaengine, linux-kernel, kernel-janitors
The clean up in idxd_setup_wqs() has had a couple bugs because the error
handling is a bit subtle. It's simpler to just re-write it in a cleaner
way. The issues here are:
1) If "idxd->max_wqs" is <= 0 then we call put_device(conf_dev) when
"conf_dev" hasn't been initialized.
2) If kzalloc_node() fails then again "conf_dev" is invalid. It's
either uninitialized or it points to the "conf_dev" from the
previous iteration so it leads to a double free.
It's better to free partial loop iterations within the loop and then
the unwinding at the end can handle whole loop iterations. I also
renamed the labels to describe what the goto does and not where the goto
was located.
Fixes: 3fd2f4bc010c ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_wqs")
Reported-by: Colin Ian King <colin.i.king@gmail.com>
Closes: https://lore.kernel.org/all/20250811095836.1642093-1-colin.i.king@gmail.com/
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
---
drivers/dma/idxd/init.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)
diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
index 35bdefd3728b..dda01a4398e1 100644
--- a/drivers/dma/idxd/init.c
+++ b/drivers/dma/idxd/init.c
@@ -189,27 +189,30 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
idxd->wq_enable_map = bitmap_zalloc_node(idxd->max_wqs, GFP_KERNEL, dev_to_node(dev));
if (!idxd->wq_enable_map) {
rc = -ENOMEM;
- goto err_bitmap;
+ goto err_free_wqs;
}
for (i = 0; i < idxd->max_wqs; i++) {
wq = kzalloc_node(sizeof(*wq), GFP_KERNEL, dev_to_node(dev));
if (!wq) {
rc = -ENOMEM;
- goto err;
+ goto err_unwind;
}
idxd_dev_set_type(&wq->idxd_dev, IDXD_DEV_WQ);
conf_dev = wq_confdev(wq);
wq->id = i;
wq->idxd = idxd;
- device_initialize(wq_confdev(wq));
+ device_initialize(conf_dev);
conf_dev->parent = idxd_confdev(idxd);
conf_dev->bus = &dsa_bus_type;
conf_dev->type = &idxd_wq_device_type;
rc = dev_set_name(conf_dev, "wq%d.%d", idxd->id, wq->id);
- if (rc < 0)
- goto err;
+ if (rc < 0) {
+ put_device(conf_dev);
+ kfree(wq);
+ goto err_unwind;
+ }
mutex_init(&wq->wq_lock);
init_waitqueue_head(&wq->err_queue);
@@ -220,15 +223,20 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
wq->enqcmds_retries = IDXD_ENQCMDS_RETRIES;
wq->wqcfg = kzalloc_node(idxd->wqcfg_size, GFP_KERNEL, dev_to_node(dev));
if (!wq->wqcfg) {
+ put_device(conf_dev);
+ kfree(wq);
rc = -ENOMEM;
- goto err;
+ goto err_unwind;
}
if (idxd->hw.wq_cap.op_config) {
wq->opcap_bmap = bitmap_zalloc(IDXD_MAX_OPCAP_BITS, GFP_KERNEL);
if (!wq->opcap_bmap) {
+ kfree(wq->wqcfg);
+ put_device(conf_dev);
+ kfree(wq);
rc = -ENOMEM;
- goto err_opcap_bmap;
+ goto err_unwind;
}
bitmap_copy(wq->opcap_bmap, idxd->opcap_bmap, IDXD_MAX_OPCAP_BITS);
}
@@ -239,13 +247,7 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
return 0;
-err_opcap_bmap:
- kfree(wq->wqcfg);
-
-err:
- put_device(conf_dev);
- kfree(wq);
-
+err_unwind:
while (--i >= 0) {
wq = idxd->wqs[i];
if (idxd->hw.wq_cap.op_config)
@@ -254,11 +256,10 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
conf_dev = wq_confdev(wq);
put_device(conf_dev);
kfree(wq);
-
}
bitmap_free(idxd->wq_enable_map);
-err_bitmap:
+err_free_wqs:
kfree(idxd->wqs);
return rc;
--
2.47.2
^ permalink raw reply related [flat|nested] 3+ messages in thread* Re: [PATCH] dmaengine: idxd: Fix double free in idxd_setup_wqs()
2025-08-11 10:43 [PATCH] dmaengine: idxd: Fix double free in idxd_setup_wqs() Dan Carpenter
@ 2025-08-11 15:43 ` Dave Jiang
2025-08-20 17:39 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Dave Jiang @ 2025-08-11 15:43 UTC (permalink / raw)
To: Dan Carpenter, Shuai Xue, Colin Ian King
Cc: Vinicius Costa Gomes, Vinod Koul, Fenghua Yu, dmaengine,
linux-kernel, kernel-janitors
On 8/11/25 3:43 AM, Dan Carpenter wrote:
> The clean up in idxd_setup_wqs() has had a couple bugs because the error
> handling is a bit subtle. It's simpler to just re-write it in a cleaner
> way. The issues here are:
>
> 1) If "idxd->max_wqs" is <= 0 then we call put_device(conf_dev) when
> "conf_dev" hasn't been initialized.
> 2) If kzalloc_node() fails then again "conf_dev" is invalid. It's
> either uninitialized or it points to the "conf_dev" from the
> previous iteration so it leads to a double free.
>
> It's better to free partial loop iterations within the loop and then
> the unwinding at the end can handle whole loop iterations. I also
> renamed the labels to describe what the goto does and not where the goto
> was located.
>
> Fixes: 3fd2f4bc010c ("dmaengine: idxd: fix memory leak in error handling path of idxd_setup_wqs")
> Reported-by: Colin Ian King <colin.i.king@gmail.com>
> Closes: https://lore.kernel.org/all/20250811095836.1642093-1-colin.i.king@gmail.com/
> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> ---
> drivers/dma/idxd/init.c | 33 +++++++++++++++++----------------
> 1 file changed, 17 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/dma/idxd/init.c b/drivers/dma/idxd/init.c
> index 35bdefd3728b..dda01a4398e1 100644
> --- a/drivers/dma/idxd/init.c
> +++ b/drivers/dma/idxd/init.c
> @@ -189,27 +189,30 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
> idxd->wq_enable_map = bitmap_zalloc_node(idxd->max_wqs, GFP_KERNEL, dev_to_node(dev));
> if (!idxd->wq_enable_map) {
> rc = -ENOMEM;
> - goto err_bitmap;
> + goto err_free_wqs;
> }
>
> for (i = 0; i < idxd->max_wqs; i++) {
> wq = kzalloc_node(sizeof(*wq), GFP_KERNEL, dev_to_node(dev));
> if (!wq) {
> rc = -ENOMEM;
> - goto err;
> + goto err_unwind;
> }
>
> idxd_dev_set_type(&wq->idxd_dev, IDXD_DEV_WQ);
> conf_dev = wq_confdev(wq);
> wq->id = i;
> wq->idxd = idxd;
> - device_initialize(wq_confdev(wq));
> + device_initialize(conf_dev);
> conf_dev->parent = idxd_confdev(idxd);
> conf_dev->bus = &dsa_bus_type;
> conf_dev->type = &idxd_wq_device_type;
> rc = dev_set_name(conf_dev, "wq%d.%d", idxd->id, wq->id);
> - if (rc < 0)
> - goto err;
> + if (rc < 0) {
> + put_device(conf_dev);
> + kfree(wq);
> + goto err_unwind;
> + }
>
> mutex_init(&wq->wq_lock);
> init_waitqueue_head(&wq->err_queue);
> @@ -220,15 +223,20 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
> wq->enqcmds_retries = IDXD_ENQCMDS_RETRIES;
> wq->wqcfg = kzalloc_node(idxd->wqcfg_size, GFP_KERNEL, dev_to_node(dev));
> if (!wq->wqcfg) {
> + put_device(conf_dev);
> + kfree(wq);
> rc = -ENOMEM;
> - goto err;
> + goto err_unwind;
> }
>
> if (idxd->hw.wq_cap.op_config) {
> wq->opcap_bmap = bitmap_zalloc(IDXD_MAX_OPCAP_BITS, GFP_KERNEL);
> if (!wq->opcap_bmap) {
> + kfree(wq->wqcfg);
> + put_device(conf_dev);
> + kfree(wq);
> rc = -ENOMEM;
> - goto err_opcap_bmap;
> + goto err_unwind;
> }
> bitmap_copy(wq->opcap_bmap, idxd->opcap_bmap, IDXD_MAX_OPCAP_BITS);
> }
> @@ -239,13 +247,7 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
>
> return 0;
>
> -err_opcap_bmap:
> - kfree(wq->wqcfg);
> -
> -err:
> - put_device(conf_dev);
> - kfree(wq);
> -
> +err_unwind:
> while (--i >= 0) {
> wq = idxd->wqs[i];
> if (idxd->hw.wq_cap.op_config)
> @@ -254,11 +256,10 @@ static int idxd_setup_wqs(struct idxd_device *idxd)
> conf_dev = wq_confdev(wq);
> put_device(conf_dev);
> kfree(wq);
> -
> }
> bitmap_free(idxd->wq_enable_map);
>
> -err_bitmap:
> +err_free_wqs:
> kfree(idxd->wqs);
>
> return rc;
> --
> 2.47.2
^ permalink raw reply [flat|nested] 3+ messages in thread* Re: [PATCH] dmaengine: idxd: Fix double free in idxd_setup_wqs()
2025-08-11 10:43 [PATCH] dmaengine: idxd: Fix double free in idxd_setup_wqs() Dan Carpenter
2025-08-11 15:43 ` Dave Jiang
@ 2025-08-20 17:39 ` Vinod Koul
1 sibling, 0 replies; 3+ messages in thread
From: Vinod Koul @ 2025-08-20 17:39 UTC (permalink / raw)
To: Shuai Xue, Colin Ian King, Dan Carpenter
Cc: Vinicius Costa Gomes, Dave Jiang, Fenghua Yu, dmaengine,
linux-kernel, kernel-janitors
On Mon, 11 Aug 2025 13:43:39 +0300, Dan Carpenter wrote:
> The clean up in idxd_setup_wqs() has had a couple bugs because the error
> handling is a bit subtle. It's simpler to just re-write it in a cleaner
> way. The issues here are:
>
> 1) If "idxd->max_wqs" is <= 0 then we call put_device(conf_dev) when
> "conf_dev" hasn't been initialized.
> 2) If kzalloc_node() fails then again "conf_dev" is invalid. It's
> either uninitialized or it points to the "conf_dev" from the
> previous iteration so it leads to a double free.
>
> [...]
Applied, thanks!
[1/1] dmaengine: idxd: Fix double free in idxd_setup_wqs()
commit: 39aaa337449e71a41d4813be0226a722827ba606
Best regards,
--
~Vinod
^ permalink raw reply [flat|nested] 3+ messages in thread
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