mm: mempool: kasan: don't poot mempool objects in quarantine

Currently we may put reserved by mempool elements into quarantine via
kasan_kfree().  This is totally wrong since quarantine may really free
these objects.  So when mempool will try to use such element,
use-after-free will happen.  Or mempool may decide that it no longer
need that element and double-free it.

So don't put object into quarantine in kasan_kfree(), just poison it.
Rename kasan_kfree() to kasan_poison_kfree() to respect that.

Also, we shouldn't use kasan_slab_alloc()/kasan_krealloc() in
kasan_unpoison_element() because those functions may update allocation
stacktrace.  This would be wrong for the most of the remove_element call
sites.

(The only call site where we may want to update alloc stacktrace is
 in mempool_alloc(). Kmemleak solves this by calling
 kmemleak_update_trace(), so we could make something like that too.
 But this is out of scope of this patch).

Fixes: 55834c59098d ("mm: kasan: initial memory quarantine implementation")
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Andrey Ryabinin <[email protected]>
Reported-by: Kuthonuzo Luruo <[email protected]>
Acked-by: Alexander Potapenko <[email protected]>
Cc: Dmitriy Vyukov <[email protected]>
Cc: Kostya Serebryany <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

0 files changed, 0 insertions, 0 deletions