[PATCH net] bnxt_en: Fix memory leak in bnxt_alloc_mem()

[PATCH net] bnxt_en: Fix memory leak in bnxt_alloc_mem()

[Zilin Guan]

In bnxt_alloc_mem(), the function allocates memory for bp->bnapi,
bp->rx_ring, bp->tx_ring, and bp->tx_ring_map.

However, if the allocation for rx_ring, tx_ring, or tx_ring_map fails, the
function currently returns -ENOMEM directly without freeing the previously
allocated memory. This leads to a memory leak.

Fix this by jumping to the alloc_mem_err label when allocation fails,
which ensures that bnxt_free_mem() is called to properly release all
allocated resources.

Compile tested only. Issue found using a prototype static analysis tool
and code review.

Fixes: a960dec98861 ("bnxt_en: Add tx ring mapping logic.")
Fixes: b6ab4b01f53b ("bnxt_en: Separate bnxt_{rx|tx}_ring_info structs from bnxt_napi struct.")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
---
 drivers/net/ethernet/broadcom/bnxt/bnxt.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
index 8419d1eb4035..99dae75146b5 100644
--- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
+++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
@@ -5491,8 +5491,10 @@ static int bnxt_alloc_mem(struct bnxt *bp, bool irq_re_init)
 		bp->rx_ring = kcalloc(bp->rx_nr_rings,
 				      sizeof(struct bnxt_rx_ring_info),
 				      GFP_KERNEL);
-		if (!bp->rx_ring)
-			return -ENOMEM;
+		if (!bp->rx_ring) {
+			rc = -ENOMEM;
+			goto alloc_mem_err;
+		}
 
 		for (i = 0; i < bp->rx_nr_rings; i++) {
 			struct bnxt_rx_ring_info *rxr = &bp->rx_ring[i];
@@ -5512,14 +5514,18 @@ static int bnxt_alloc_mem(struct bnxt *bp, bool irq_re_init)
 		bp->tx_ring = kcalloc(bp->tx_nr_rings,
 				      sizeof(struct bnxt_tx_ring_info),
 				      GFP_KERNEL);
-		if (!bp->tx_ring)
-			return -ENOMEM;
+		if (!bp->tx_ring) {
+			rc = -ENOMEM;
+			goto alloc_mem_err;
+		}
 
 		bp->tx_ring_map = kcalloc(bp->tx_nr_rings, sizeof(u16),
 					  GFP_KERNEL);
 
-		if (!bp->tx_ring_map)
-			return -ENOMEM;
+		if (!bp->tx_ring_map) {
+			rc = -ENOMEM;
+			goto alloc_mem_err;
+		}
 
 		if (bp->flags & BNXT_FLAG_SHARED_RINGS)
 			j = 0;
-- 
2.34.1

Re: [PATCH net] bnxt_en: Fix memory leak in bnxt_alloc_mem()

[Pavan Chebbi]

[-- Attachment #1: Type: text/plain, Size: 2983 bytes --]

On Thu, Jan 22, 2026 at 2:56 PM Zilin Guan <zilin@seu.edu.cn> wrote:
>
> In bnxt_alloc_mem(), the function allocates memory for bp->bnapi,
> bp->rx_ring, bp->tx_ring, and bp->tx_ring_map.
>
> However, if the allocation for rx_ring, tx_ring, or tx_ring_map fails, the
> function currently returns -ENOMEM directly without freeing the previously
> allocated memory. This leads to a memory leak.
>
> Fix this by jumping to the alloc_mem_err label when allocation fails,
> which ensures that bnxt_free_mem() is called to properly release all
> allocated resources.

This fix is not needed. The memory is freed by the caller of bnxt_alloc_mem().

>
> Compile tested only. Issue found using a prototype static analysis tool
> and code review.
>
> Fixes: a960dec98861 ("bnxt_en: Add tx ring mapping logic.")
> Fixes: b6ab4b01f53b ("bnxt_en: Separate bnxt_{rx|tx}_ring_info structs from bnxt_napi struct.")
> Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
> ---
>  drivers/net/ethernet/broadcom/bnxt/bnxt.c | 18 ++++++++++++------
>  1 file changed, 12 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/net/ethernet/broadcom/bnxt/bnxt.c b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> index 8419d1eb4035..99dae75146b5 100644
> --- a/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> +++ b/drivers/net/ethernet/broadcom/bnxt/bnxt.c
> @@ -5491,8 +5491,10 @@ static int bnxt_alloc_mem(struct bnxt *bp, bool irq_re_init)
>                 bp->rx_ring = kcalloc(bp->rx_nr_rings,
>                                       sizeof(struct bnxt_rx_ring_info),
>                                       GFP_KERNEL);
> -               if (!bp->rx_ring)
> -                       return -ENOMEM;
> +               if (!bp->rx_ring) {
> +                       rc = -ENOMEM;
> +                       goto alloc_mem_err;
> +               }
>
>                 for (i = 0; i < bp->rx_nr_rings; i++) {
>                         struct bnxt_rx_ring_info *rxr = &bp->rx_ring[i];
> @@ -5512,14 +5514,18 @@ static int bnxt_alloc_mem(struct bnxt *bp, bool irq_re_init)
>                 bp->tx_ring = kcalloc(bp->tx_nr_rings,
>                                       sizeof(struct bnxt_tx_ring_info),
>                                       GFP_KERNEL);
> -               if (!bp->tx_ring)
> -                       return -ENOMEM;
> +               if (!bp->tx_ring) {
> +                       rc = -ENOMEM;
> +                       goto alloc_mem_err;
> +               }
>
>                 bp->tx_ring_map = kcalloc(bp->tx_nr_rings, sizeof(u16),
>                                           GFP_KERNEL);
>
> -               if (!bp->tx_ring_map)
> -                       return -ENOMEM;
> +               if (!bp->tx_ring_map) {
> +                       rc = -ENOMEM;
> +                       goto alloc_mem_err;
> +               }
>
>                 if (bp->flags & BNXT_FLAG_SHARED_RINGS)
>                         j = 0;
> --
> 2.34.1
>

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Re: [PATCH net] bnxt_en: Fix memory leak in bnxt_alloc_mem()

[Zilin Guan]

On Thu, Jan 22, 2026 at 03:14:08PM +0530, Pavan Chebbi wrote:
> On Thu, Jan 22, 2026 at 2:56 PM Zilin Guan <zilin@seu.edu.cn> wrote:
> >
> > In bnxt_alloc_mem(), the function allocates memory for bp->bnapi,
> > bp->rx_ring, bp->tx_ring, and bp->tx_ring_map.
> >
> > However, if the allocation for rx_ring, tx_ring, or tx_ring_map fails, the
> > function currently returns -ENOMEM directly without freeing the previously
> > allocated memory. This leads to a memory leak.
> >
> > Fix this by jumping to the alloc_mem_err label when allocation fails,
> > which ensures that bnxt_free_mem() is called to properly release all
> > allocated resources.
> 
> This fix is not needed. The memory is freed by the caller of bnxt_alloc_mem().

Hi Pavan,

Thank you for your review and clarification.

I observed that most allocation failure paths in bnxt_alloc_mem() jump to 
alloc_mem_err for error handling, which led me to incorrectly assume that 
this function was strictly responsible for cleaning up its own allocated 
memory upon failure. I failed to realize that the caller also handles the
cleanup for these specific cases.

Thanks for pointing this out. Sorry for the noise.

Best regards,
Zilin Guan

Re: [PATCH net] bnxt_en: Fix memory leak in bnxt_alloc_mem()

[Leon Romanovsky]

On Thu, Jan 22, 2026 at 03:14:08PM +0530, Pavan Chebbi wrote:
> On Thu, Jan 22, 2026 at 2:56 PM Zilin Guan <zilin@seu.edu.cn> wrote:
> >
> > In bnxt_alloc_mem(), the function allocates memory for bp->bnapi,
> > bp->rx_ring, bp->tx_ring, and bp->tx_ring_map.
> >
> > However, if the allocation for rx_ring, tx_ring, or tx_ring_map fails, the
> > function currently returns -ENOMEM directly without freeing the previously
> > allocated memory. This leads to a memory leak.
> >
> > Fix this by jumping to the alloc_mem_err label when allocation fails,
> > which ensures that bnxt_free_mem() is called to properly release all
> > allocated resources.
> 
> This fix is not needed. The memory is freed by the caller of bnxt_alloc_mem().

That is an anti-pattern as well. On error, the function should clean up
all resources it allocated.

Thanks