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lib/test_meminit.c: fix -Wmaybe-uninitialized false positive 

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.

Link: http://lkml.kernel.org/r/20190617131210.2190280-1-arnd@arndb.de
Fixes: af734ee6ec85 ("lib: introduce test_meminit module")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Arnd Bergmann 2019-07-16 16:27:39 -07:00 committed by Linus Torvalds
parent b4658cdd8c
commit d3a811617a
1 changed files with 26 additions and 24 deletions
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50
lib/test_meminit.c
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@ -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);