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livepatch: Handle allocation failure in the sample of shadow variable API 

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>
Reviewed-by: Joe Lawrence <joe.lawrence@redhat.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Petr Mladek 2020-01-16 16:31:45 +01:00 committed by Jiri Kosina
parent be6da98425
commit f46e49a9cc
1 changed files with 16 additions and 6 deletions
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22
samples/livepatch/livepatch-shadow-fix1.c
View File

@ -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;
klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
shadow_leak_ctor, &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;
}
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)