From 78b495c39add820ab66ab897af9bd77a5f2e91f6 Mon Sep 17 00:00:00 2001 From: Artem Bityutskiy Date: Mon, 3 Sep 2012 17:12:29 +0300 Subject: [PATCH] UBI: fix a horrible memory deallocation bug UBI was mistakingly using 'kfree()' instead of 'kmem_cache_free()' when freeing "attach eraseblock" structures in vtbl.c. Thankfully, this happened only when we were doing auto-format, so many systems were unaffected. However, there are still many users affected. It is strange, but the system did not crash and nothing bad happened when the SLUB memory allocator was used. However, in case of SLOB we observed an crash right away. This problem was introduced in 2.6.39 by commit "6c1e875 UBI: add slab cache for ubi_scan_leb objects" A note for stable trees: Because variable were renamed, this won't cleanly apply to older kernels. Changing names like this should help: 1. ai -> si 2. aeb_slab_cache -> seb_slab_cache 3. new_aeb -> new_seb Reported-by: Richard Genoud Tested-by: Richard Genoud Tested-by: Artem Bityutskiy Cc: stable@vger.kernel.org [v2.6.39+] Signed-off-by: Artem Bityutskiy --- drivers/mtd/ubi/vtbl.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c index 437bc193e170..568307cc7caf 100644 --- a/drivers/mtd/ubi/vtbl.c +++ b/drivers/mtd/ubi/vtbl.c @@ -340,7 +340,7 @@ static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai, * of this LEB as it will be deleted and freed in 'ubi_add_to_av()'. */ err = ubi_add_to_av(ubi, ai, new_aeb->pnum, new_aeb->ec, vid_hdr, 0); - kfree(new_aeb); + kmem_cache_free(ai->aeb_slab_cache, new_aeb); ubi_free_vid_hdr(ubi, vid_hdr); return err; @@ -353,7 +353,7 @@ static int create_vtbl(struct ubi_device *ubi, struct ubi_attach_info *ai, list_add(&new_aeb->u.list, &ai->erase); goto retry; } - kfree(new_aeb); + kmem_cache_free(ai->aeb_slab_cache, new_aeb); out_free: ubi_free_vid_hdr(ubi, vid_hdr); return err;