[PATCH v2] nvdimm/pmem: Fix leak on dax_add_host() failure

[PATCH v2] nvdimm/pmem: Fix leak on dax_add_host() failure

[Mathieu Desnoyers]

Fix a leak on dax_add_host() error, where "goto out_cleanup_dax" is done
before setting pmem->dax_dev, which therefore issues the two following
calls on NULL pointers:

out_cleanup_dax:
        kill_dax(pmem->dax_dev);
        put_dax(pmem->dax_dev);

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Dave Jiang <dave.jiang@intel.com>
Reviewed-by: Fan Ni <fan.ni@samsung.com>
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@kernel.org>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Vishal Verma <vishal.l.verma@intel.com>
Cc: Dave Jiang <dave.jiang@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Russell King <linux@armlinux.org.uk>
Cc: linux-arch@vger.kernel.org
Cc: linux-cxl@vger.kernel.org
Cc: linux-fsdevel@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-xfs@vger.kernel.org
Cc: dm-devel@lists.linux.dev
Cc: nvdimm@lists.linux.dev
---
Changes since v1:
- Add Reviewed-by tags.
---
 drivers/nvdimm/pmem.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index 4e8fdcb3f1c8..9fe358090720 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -566,12 +566,11 @@ static int pmem_attach_disk(struct device *dev,
 	set_dax_nomc(dax_dev);
 	if (is_nvdimm_sync(nd_region))
 		set_dax_synchronous(dax_dev);
+	pmem->dax_dev = dax_dev;
 	rc = dax_add_host(dax_dev, disk);
 	if (rc)
 		goto out_cleanup_dax;
 	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
-	pmem->dax_dev = dax_dev;
-
 	rc = device_add_disk(dev, disk, pmem_attribute_groups);
 	if (rc)
 		goto out_remove_host;
-- 
2.39.2

Re: [PATCH v2] nvdimm/pmem: Fix leak on dax_add_host() failure

[Mathieu Desnoyers]

On 2024-02-15 09:43, Mathieu Desnoyers wrote:
> Fix a leak on dax_add_host() error, where "goto out_cleanup_dax" is done
> before setting pmem->dax_dev, which therefore issues the two following
> calls on NULL pointers:

Hi Andrew,

I notice that you should update the patch you have in your tree
(https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/nvdimm-pmem-fix-leak-on-dax_add_host-failure.patch)
with this updated version which includes additional Reviewed-by tags and
removes unneeded context that appears to be taken from the previous cover
letter.

Following your request, I have extracted this patch from the series.

Thanks,

Mathieu

> 
> out_cleanup_dax:
>          kill_dax(pmem->dax_dev);
>          put_dax(pmem->dax_dev);
> 
> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
> Reviewed-by: Dan Williams <dan.j.williams@intel.com>
> Reviewed-by: Dave Jiang <dave.jiang@intel.com>
> Reviewed-by: Fan Ni <fan.ni@samsung.com>
> Cc: Alasdair Kergon <agk@redhat.com>
> Cc: Mike Snitzer <snitzer@kernel.org>
> Cc: Mikulas Patocka <mpatocka@redhat.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Linus Torvalds <torvalds@linux-foundation.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Vishal Verma <vishal.l.verma@intel.com>
> Cc: Dave Jiang <dave.jiang@intel.com>
> Cc: Matthew Wilcox <willy@infradead.org>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Russell King <linux@armlinux.org.uk>
> Cc: linux-arch@vger.kernel.org
> Cc: linux-cxl@vger.kernel.org
> Cc: linux-fsdevel@vger.kernel.org
> Cc: linux-mm@kvack.org
> Cc: linux-xfs@vger.kernel.org
> Cc: dm-devel@lists.linux.dev
> Cc: nvdimm@lists.linux.dev
> ---
> Changes since v1:
> - Add Reviewed-by tags.
> ---
>   drivers/nvdimm/pmem.c | 3 +--
>   1 file changed, 1 insertion(+), 2 deletions(-)
> 
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 4e8fdcb3f1c8..9fe358090720 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -566,12 +566,11 @@ static int pmem_attach_disk(struct device *dev,
>   	set_dax_nomc(dax_dev);
>   	if (is_nvdimm_sync(nd_region))
>   		set_dax_synchronous(dax_dev);
> +	pmem->dax_dev = dax_dev;
>   	rc = dax_add_host(dax_dev, disk);
>   	if (rc)
>   		goto out_cleanup_dax;
>   	dax_write_cache(dax_dev, nvdimm_has_cache(nd_region));
> -	pmem->dax_dev = dax_dev;
> -
>   	rc = device_add_disk(dev, disk, pmem_attribute_groups);
>   	if (rc)
>   		goto out_remove_host;

-- 
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com