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Subject[PATCH 4/4] livepatch: Handle allocation failure in the sample of shadow variable API
Date
klp_shadow_alloc() is not handled in the sample of shadow variable API.
It is not strictly necessary because livepatch_fix1_dummy_free() is
able to handle the potential failure. But it is an example and it should
use the API a clean way.

Signed-off-by: Petr Mladek <pmladek@suse.com>
---
samples/livepatch/livepatch-shadow-fix1.c | 22 ++++++++++++++++------
1 file changed, 16 insertions(+), 6 deletions(-)

diff --git a/samples/livepatch/livepatch-shadow-fix1.c b/samples/livepatch/livepatch-shadow-fix1.c
index de0363b288a7..918ce17b43fd 100644
--- a/samples/livepatch/livepatch-shadow-fix1.c
+++ b/samples/livepatch/livepatch-shadow-fix1.c
@@ -66,6 +66,7 @@ static struct dummy *livepatch_fix1_dummy_alloc(void)
{
struct dummy *d;
int *leak;
+ int **shadow_leak;

d = kzalloc(sizeof(*d), GFP_KERNEL);
if (!d)
@@ -80,18 +81,27 @@ static struct dummy *livepatch_fix1_dummy_alloc(void)
* pointer to handle resource release.
*/
leak = kzalloc(sizeof(*leak), GFP_KERNEL);
- if (!leak) {
- kfree(d);
- return NULL;
+ if (!leak)
+ goto err_leak;
+
+ shadow_leak = klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
+ shadow_leak_ctor, &leak);
+ if (!shadow_leak) {
+ pr_err("%s: failed to allocate shadow variable for the leaking pointer: dummy @ %p, leak @ %p\n",
+ __func__, d, leak);
+ goto err_shadow;
}

- klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
- shadow_leak_ctor, &leak);
-
pr_info("%s: dummy @ %p, expires @ %lx\n",
__func__, d, d->jiffies_expire);

return d;
+
+err_shadow:
+ kfree(leak);
+err_leak:
+ kfree(d);
+ return NULL;
}

static void livepatch_fix1_dummy_leak_dtor(void *obj, void *shadow_data)
--
2.16.4
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