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

[fan <nifan.cxl@gmail.com>]

On Mon, Feb 12, 2024 at 11:27:22AM -0500, 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:
> 
> 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>
> 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

Reviewed-by: Fan Ni <fan.ni@samsung.com>

> ---
>  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
>