On Mon, 28 Jan 2019, Sasha Levin wrote:
> From: Nicholas Mc Guire <hofrat@xxxxxxxxx>
>
> [ Upstream commit 5f30b2e823484ce6a79f2b59901b6351c15effa6 ]
>
> kzalloc() return should always be checked - notably in example code
> where this may be seen as reference. On failure of allocation in
> livepatch_fix1_dummy_alloc() respectively dummy_alloc() previous
> allocation is freed (thanks to Petr Mladek <pmladek@xxxxxxxx> for
> catching this) and NULL returned.
>
> Signed-off-by: Nicholas Mc Guire <hofrat@xxxxxxxxx>
> Fixes: 439e7271dc2b ("livepatch: introduce shadow variable API")
> Acked-by: Joe Lawrence <joe.lawrence@xxxxxxxxxx>
> Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>
> Acked-by: Miroslav Benes <mbenes@xxxxxxx>
> Signed-off-by: Jiri Kosina <jkosina@xxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
Hi Sasha,
I am not sure what stable policy is, but the patch is for samples/
directory and I do not think it is something which should necessarily go
to stable. It is your call though.
Regards,
Miroslav
> ---
> samples/livepatch/livepatch-shadow-fix1.c | 5 +++++
> samples/livepatch/livepatch-shadow-mod.c | 4 ++++
> 2 files changed, 9 insertions(+)
>
> diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c
> index 49b13553eaae..e8f1bd6b29b1 100644
> --- a/samples/livepatch/livepatch-shadow-fix1.c
> +++ b/samples/livepatch/livepatch-shadow-fix1.c
> @@ -89,6 +89,11 @@ struct dummy *livepatch_fix1_dummy_alloc(void)
> * pointer to handle resource release.
> */
> leak = kzalloc(sizeof(int), GFP_KERNEL);
> + if (!leak) {
> + kfree(d);
> + return NULL;
> + }
> +
> klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
> shadow_leak_ctor, leak);
>
> diff --git a/samples/livepatch/livepatch-shadow-mod.c b/samples/livepatch/livepatch-shadow-mod.c
> index 4c54b250332d..4aa8a88d3cd6 100644
> --- a/samples/livepatch/livepatch-shadow-mod.c
> +++ b/samples/livepatch/livepatch-shadow-mod.c
> @@ -118,6 +118,10 @@ noinline struct dummy *dummy_alloc(void)
>
> /* Oops, forgot to save leak! */
> leak = kzalloc(sizeof(int), GFP_KERNEL);
> + if (!leak) {
> + kfree(d);
> + return NULL;
> + }
>
> pr_info("%s: dummy @ %p, expires @ %lx\n",
> __func__, d, d->jiffies_expire);
> --
> 2.19.1
>
