On Mon, Jun 17, 2019 at 3:12 PM Arnd Bergmann <[email protected]> wrote: > > The conditional logic is too complicated for the compiler to > fully comprehend: > > lib/test_meminit.c: In function 'test_meminit_init': > lib/test_meminit.c:236:5: error: 'buf_copy' may be used uninitialized in this > function [-Werror=maybe-uninitialized] > kfree(buf_copy); > ^~~~~~~~~~~~~~~ > lib/test_meminit.c:201:14: note: 'buf_copy' was declared here > > Simplify it by splitting out the non-rcu section. > > Fixes: af734ee6ec85 ("lib: introduce test_meminit module") > Signed-off-by: Arnd Bergmann <[email protected]> Acked-by: Alexander Potapenko <[email protected]> > --- > lib/test_meminit.c | 50 ++++++++++++++++++++++++---------------------- > 1 file changed, 26 insertions(+), 24 deletions(-) > > diff --git a/lib/test_meminit.c b/lib/test_meminit.c > index ed7efec1387b..7ae2183ff1f4 100644 > --- a/lib/test_meminit.c > +++ b/lib/test_meminit.c > @@ -208,35 +208,37 @@ static int __init do_kmem_cache_size(size_t size, bool > want_ctor, > /* Check that buf is zeroed, if it must be. */ > fail = check_buf(buf, size, want_ctor, want_rcu, want_zero); > fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0); > + > + if (!want_rcu) { > + kmem_cache_free(c, buf); > + continue; > + } > + > /* > * If this is an RCU cache, use a critical section to ensure > we > * can touch objects after they're freed. > */ > - if (want_rcu) { > - rcu_read_lock(); > - /* > - * Copy the buffer to check that it's not wiped on > - * free(). > - */ > - buf_copy = kmalloc(size, GFP_KERNEL); > - if (buf_copy) > - memcpy(buf_copy, buf, size); > - } > - kmem_cache_free(c, buf); > - if (want_rcu) { > - /* > - * Check that |buf| is intact after kmem_cache_free(). > - * |want_zero| is false, because we wrote garbage to > - * the buffer already. > - */ > - fail |= check_buf(buf, size, want_ctor, want_rcu, > - false); > - if (buf_copy) { > - fail |= (bool)memcmp(buf, buf_copy, size); > - kfree(buf_copy); > - } > - rcu_read_unlock(); > + rcu_read_lock(); > + /* > + * Copy the buffer to check that it's not wiped on > + * free(). > + */ > + buf_copy = kmalloc(size, GFP_KERNEL); > + if (buf_copy) > + memcpy(buf_copy, buf, size); > + > + /* > + * Check that |buf| is intact after kmem_cache_free(). > + * |want_zero| is false, because we wrote garbage to > + * the buffer already. > + */ > + fail |= check_buf(buf, size, want_ctor, want_rcu, > + false); > + if (buf_copy) { > + fail |= (bool)memcmp(buf, buf_copy, size); > + kfree(buf_copy); > } > + rcu_read_unlock(); > } > kmem_cache_destroy(c); > > -- > 2.20.0 >
-- Alexander Potapenko Software Engineer Google Germany GmbH Erika-Mann-Straße, 33 80636 München Geschäftsführer: Paul Manicle, Halimah DeLaine Prado Registergericht und -nummer: Hamburg, HRB 86891 Sitz der Gesellschaft: Hamburg
