From 1352f09b4cc4f9dce386620b118401738bbf0d5f Mon Sep 17 00:00:00 2001 From: Geert Uytterhoeven Date: Tue, 5 Dec 2017 16:27:02 +0100 Subject: [PATCH] of: overlay: Fix memory leak in of_overlay_apply() error path If of_resolve_phandles() fails, free_overlay_changeset() is called in the error path. However, that function returns early if the list hasn't been initialized yet, before freeing the object. Explicitly calling kfree() instead would solve that issue. However, that complicates matter, by having to consider which of two different methods to use to dispose of the same object. Hence make free_overlay_changeset() consider initialization state of the different parts of the object, making it always safe to call (once!) to dispose of a (partially) initialized overlay_changeset: - Only destroy the changeset if the list was initialized, - Make init_overlay_changeset() store the ID in ovcs->id on success, to avoid calling idr_remove() with an error value or an already released ID. Reported-by: Colin King Fixes: f948d6d8b792bb90 ("of: overlay: avoid race condition between applying multiple overlays") Signed-off-by: Geert Uytterhoeven Reviewed-by: Frank Rowand Signed-off-by: Rob Herring --- drivers/of/overlay.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/drivers/of/overlay.c b/drivers/of/overlay.c index 2b852a3..bb3f123 100644 --- a/drivers/of/overlay.c +++ b/drivers/of/overlay.c @@ -522,7 +522,7 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs, struct device_node *node, *overlay_node; struct fragment *fragment; struct fragment *fragments; - int cnt, ret; + int cnt, id, ret; /* * Warn for some issues. Can not return -EINVAL for these until @@ -543,9 +543,9 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs, of_changeset_init(&ovcs->cset); - ovcs->id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL); - if (ovcs->id <= 0) - return ovcs->id; + id = idr_alloc(&ovcs_idr, ovcs, 1, 0, GFP_KERNEL); + if (id <= 0) + return id; cnt = 0; @@ -611,6 +611,7 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs, goto err_free_fragments; } + ovcs->id = id; ovcs->count = cnt; ovcs->fragments = fragments; @@ -619,7 +620,7 @@ static int init_overlay_changeset(struct overlay_changeset *ovcs, err_free_fragments: kfree(fragments); err_free_idr: - idr_remove(&ovcs_idr, ovcs->id); + idr_remove(&ovcs_idr, id); pr_err("%s() failed, ret = %d\n", __func__, ret); @@ -630,9 +631,8 @@ static void free_overlay_changeset(struct overlay_changeset *ovcs) { int i; - if (!ovcs->cset.entries.next) - return; - of_changeset_destroy(&ovcs->cset); + if (ovcs->cset.entries.next) + of_changeset_destroy(&ovcs->cset); if (ovcs->id) idr_remove(&ovcs_idr, ovcs->id); -- 2.7.4