Hello Petr Mladek,
The patch e91c2518a5d2: "livepatch: Initialize shadow variables
safely by a custom callback" from Apr 16, 2018, leads to the
following static checker warning:
samples/livepatch/livepatch-shadow-fix1.c:86 livepatch_fix1_dummy_alloc()
error: 'klp_shadow_alloc()' 'leak' too small (4 vs 8)
samples/livepatch/livepatch-shadow-fix1.c
53 static int shadow_leak_ctor(void *obj, void *shadow_data, void *ctor_data)
54 {
55 void **shadow_leak = shadow_data;
56 void *leak = ctor_data;
57
58 *shadow_leak = leak;
59 return 0;
60 }
61
62 static struct dummy *livepatch_fix1_dummy_alloc(void)
63 {
64 struct dummy *d;
65 void *leak;
66
67 d = kzalloc(sizeof(*d), GFP_KERNEL);
68 if (!d)
69 return NULL;
70
71 d->jiffies_expire = jiffies +
72 msecs_to_jiffies(1000 * EXPIRE_PERIOD);
73
74 /*
75 * Patch: save the extra memory location into a SV_LEAK shadow
76 * variable. A patched dummy_free routine can later fetch this
77 * pointer to handle resource release.
78 */
79 leak = kzalloc(sizeof(int), GFP_KERNEL);
80 if (!leak) {
81 kfree(d);
82 return NULL;
83 }
84
85 klp_shadow_alloc(d, SV_LEAK, sizeof(leak), GFP_KERNEL,
^^^^^^^^^^^^
This doesn't seem right at all? Leak is a pointer. Why is leak a void
pointer instead of an int pointer?
86 shadow_leak_ctor, leak);
87
88 pr_info("%s: dummy @ %p, expires @ %lx\n",
89 __func__, d, d->jiffies_expire);
90
91 return d;
92 }
regards,
dan carpenter
