4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ 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 <pmla...@suse.com> for
catching this) and NULL returned.

Signed-off-by: Nicholas Mc Guire <hof...@osadl.org>
Fixes: 439e7271dc2b ("livepatch: introduce shadow variable API")
Acked-by: Joe Lawrence <joe.lawre...@redhat.com>
Reviewed-by: Petr Mladek <pmla...@suse.com>
Acked-by: Miroslav Benes <mbe...@suse.cz>
Signed-off-by: Jiri Kosina <jkos...@suse.cz>
Signed-off-by: Sasha Levin <sas...@kernel.org>
---
 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



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