[PATCH] firmware_loader: fix memory leak for paged buffer

[Prateek Sood]

vfree() is being called on paged buffer allocated
using alloc_page() and mapped using vmap().

Freeing of pages in vfree() relies on nr_pages of
struct vm_struct. vmap() does not update nr_pages.
It can lead to memory leaks.

Signed-off-by: Prateek Sood <prs...@codeaurora.org>
---
 drivers/base/firmware_loader/firmware.h |  2 ++
 drivers/base/firmware_loader/main.c     | 17 +++++++++++------
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/drivers/base/firmware_loader/firmware.h 
b/drivers/base/firmware_loader/firmware.h
index 933e2192..d08efc7 100644
--- a/drivers/base/firmware_loader/firmware.h
+++ b/drivers/base/firmware_loader/firmware.h
@@ -142,10 +142,12 @@ static inline void fw_state_done(struct fw_priv *fw_priv)
 void fw_free_paged_buf(struct fw_priv *fw_priv);
 int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed);
 int fw_map_paged_buf(struct fw_priv *fw_priv);
+bool fw_is_paged_buf(struct fw_priv *fw_priv);
 #else
 static inline void fw_free_paged_buf(struct fw_priv *fw_priv) {}
 static inline int fw_grow_paged_buf(struct fw_priv *fw_priv, int pages_needed) 
{ return -ENXIO; }
 static inline int fw_map_paged_buf(struct fw_priv *fw_priv) { return -ENXIO; }
+static inline bool fw_is_paged_buf(struct fw_priv *fw_priv) { return false; }
 #endif
 
 #endif /* __FIRMWARE_LOADER_H */
diff --git a/drivers/base/firmware_loader/main.c 
b/drivers/base/firmware_loader/main.c
index ca871b1..36bf455 100644
--- a/drivers/base/firmware_loader/main.c
+++ b/drivers/base/firmware_loader/main.c
@@ -252,9 +252,11 @@ static void __free_fw_priv(struct kref *ref)
        list_del(&fw_priv->list);
        spin_unlock(&fwc->lock);
 
-       fw_free_paged_buf(fw_priv); /* free leftover pages */
-       if (!fw_priv->allocated_size)
+       if (fw_is_paged_buf(fw_priv))
+               fw_free_paged_buf(fw_priv);
+       else if (!fw_priv->allocated_size)
                vfree(fw_priv->data);
+
        kfree_const(fw_priv->fw_name);
        kfree(fw_priv);
 }
@@ -268,6 +270,11 @@ static void free_fw_priv(struct fw_priv *fw_priv)
 }
 
 #ifdef CONFIG_FW_LOADER_PAGED_BUF
+bool fw_is_paged_buf(struct fw_priv *fw_priv)
+{
+       return fw_priv->is_paged_buf;
+}
+
 void fw_free_paged_buf(struct fw_priv *fw_priv)
 {
        int i;
@@ -275,6 +282,8 @@ void fw_free_paged_buf(struct fw_priv *fw_priv)
        if (!fw_priv->pages)
                return;
 
+       vunmap(fw_priv->data);
+
        for (i = 0; i < fw_priv->nr_pages; i++)
                __free_page(fw_priv->pages[i]);
        kvfree(fw_priv->pages);
@@ -328,10 +337,6 @@ int fw_map_paged_buf(struct fw_priv *fw_priv)
        if (!fw_priv->data)
                return -ENOMEM;
 
-       /* page table is no longer needed after mapping, let's free */
-       kvfree(fw_priv->pages);
-       fw_priv->pages = NULL;
-
        return 0;
 }
 #endif
-- 
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