Messages in this thread | | | Subject | Re: [PATCH v2 3/4] livepatch: Proper error handling in the shadow variables selftest | From | Joe Lawrence <> | Date | Tue, 5 Feb 2019 16:17:13 -0500 |
| |
On 2/4/19 8:56 AM, Petr Mladek wrote: > Add proper error handling when allocating or getting shadow variables > in the selftest. It prevents an invalid pointer access in some situations. > It shows the good programming practice in the others. > > The error codes are just the best guess and specific for this particular > test. In general, klp_shadow_alloc() returns NULL also when the given > shadow variable has already been allocated. In addition, both > klp_shadow_alloc() and klp_shadow_get_or_alloc() might fail from > other reasons when the constructor fails. > > Note, that the error code is not really important even in the real life. > The use of shadow variables should be transparent for the original > livepatched code. > > Signed-off-by: Petr Mladek <pmladek@suse.com> > --- > lib/livepatch/test_klp_shadow_vars.c | 22 ++++++++++++++++++++++ > 1 file changed, 22 insertions(+) > > diff --git a/lib/livepatch/test_klp_shadow_vars.c b/lib/livepatch/test_klp_shadow_vars.c > index f5441c193166..fe5c413efe96 100644 > --- a/lib/livepatch/test_klp_shadow_vars.c > +++ b/lib/livepatch/test_klp_shadow_vars.c > @@ -154,22 +154,37 @@ static int test_klp_shadow_vars_init(void) > * Allocate a few shadow variables with different <obj> and <id>. > */ > sv1 = shadow_alloc(obj, id, size, gfp_flags, shadow_ctor, &var1); > + if (!sv1) > + return -ENOMEM; > + > sv2 = shadow_alloc(obj + 1, id, size, gfp_flags, shadow_ctor, &var2); > + if (!sv2) > + return -ENOMEM; > + > sv3 = shadow_alloc(obj, id + 1, size, gfp_flags, shadow_ctor, &var3); > + if (!sv3) > + return -ENOMEM; > > /* > * Verify we can find our new shadow variables and that they point > * to expected data. > */ > ret = shadow_get(obj, id); > + if (!ret) > + return -EINVAL; > if (ret == sv1 && *sv1 == &var1) > pr_info(" got expected PTR%d -> PTR%d result\n", > ptr_id(sv1), ptr_id(*sv1)); > + > ret = shadow_get(obj + 1, id); > + if (!ret) > + return -EINVAL; > if (ret == sv2 && *sv2 == &var2) > pr_info(" got expected PTR%d -> PTR%d result\n", > ptr_id(sv2), ptr_id(*sv2)); > ret = shadow_get(obj, id + 1); > + if (!ret) > + return -EINVAL; > if (ret == sv3 && *sv3 == &var3) > pr_info(" got expected PTR%d -> PTR%d result\n", > ptr_id(sv3), ptr_id(*sv3)); > @@ -179,7 +194,12 @@ static int test_klp_shadow_vars_init(void) > * The second invocation should return the same shadow var. > */ > sv4 = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4); > + if (!sv4) > + return -ENOMEM; > + > ret = shadow_get_or_alloc(obj + 2, id, size, gfp_flags, shadow_ctor, &var4); > + if (!ret) > + return -EINVAL; > if (ret == sv4 && *sv4 == &var4) > pr_info(" got expected PTR%d -> PTR%d result\n", > ptr_id(sv4), ptr_id(*sv4)); > @@ -207,6 +227,8 @@ static int test_klp_shadow_vars_init(void) > * We should still find an <id+1> variable. > */ > ret = shadow_get(obj, id + 1); > + if (!ret) > + return -EINVAL; > if (ret == sv3 && *sv3 == &var3) > pr_info(" got expected PTR%d -> PTR%d result\n", > ptr_id(sv3), ptr_id(*sv3)); >
Fixes look good to me,
Acked-by: Joe Lawrence <joe.lawrence@redhat.com>
-- Joe
| |