pstore/ram_core: Proper checking for post_init errors (e.g. improper ECC size)

We will implement variable-sized ECC buffers soon, so post_init routine
might fail much more likely, so we'd better check for its errors.

To make error handling simple, modify persistent_ram_free() to it be safe
at all times.

Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 15 insertions, 7 deletions

diff --git a/fs/pstore/ram_core.c b/fs/pstore/ram_core.c
index 26531856daf8..f62ebf2dfed7 100644
--- a/fs/pstore/ram_core.c
+++ b/fs/pstore/ram_core.c
@@ -427,11 +427,17 @@ static int __devinit persistent_ram_post_init(struct persistent_ram_zone *prz,
 
 void persistent_ram_free(struct persistent_ram_zone *prz)
 {
-        if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
-                vunmap(prz->vaddr);
-        } else {
-                iounmap(prz->vaddr);
-                release_mem_region(prz->paddr, prz->size);
+        if (!prz)
+                return;
+
+        if (prz->vaddr) {
+                if (pfn_valid(prz->paddr >> PAGE_SHIFT)) {
+                        vunmap(prz->vaddr);
+                } else {
+                        iounmap(prz->vaddr);
+                        release_mem_region(prz->paddr, prz->size);
+                }
+                prz->vaddr = NULL;
         }
         persistent_ram_free_old(prz);
         kfree(prz);
@@ -454,10 +460,12 @@ struct persistent_ram_zone * __devinit persistent_ram_new(phys_addr_t start,
         if (ret)
                 goto err;
 
-        persistent_ram_post_init(prz, ecc);
+        ret = persistent_ram_post_init(prz, ecc);
+        if (ret)
+                goto err;
 
         return prz;
 err:
-        kfree(prz);
+        persistent_ram_free(prz);
         return ERR_PTR(ret);
 }