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of/overlay: only treat a positive changeset id as registered

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of_overlay_fdt_apply() stores the idr_alloc() return value in
ovcs->id before checking it. On failure the stored id is negative,
free_overlay_changeset()'s "if (ovcs->id)" check passes, idr_remove()
is called with a negative id and list_del() runs on ovcs->ovcs_list,
which is not initialized until after the id allocation. An allocation
failure at that point dereferences NULL.

Make free_overlay_changeset() treat only a strict-positive id as
registered. The rest of the function already copes with a
partially-initialized ovcs, so the error path stays a plain
goto err_free_ovcs.

Fixes: 61b4de4e0b ("of: overlay: minor restructuring")
Cc: stable@vger.kernel.org
Suggested-by: Geert Uytterhoeven <geert@linux-m68k.org>
Assisted-by: Claude:claude-fable-5 [Claude Code]
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Abdurrahman Hussain <abdurrahman@nexthop.ai>
Link: https://patch.msgid.link/20260831-nh-of-alias-overlay-v7-5-02754604805a@nexthop.ai
Signed-off-by: Rob Herring (Arm) <robh@kernel.org>
This commit is contained in:
Abdurrahman Hussain 2026-08-31 18:29:23 -07:00 committed by Rob Herring (Arm)
parent 814f2da699
commit 44081d708b
1 changed files with 2 additions and 1 deletions
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3
drivers/of/overlay.c
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@ -864,7 +864,8 @@ static void free_overlay_changeset(struct overlay_changeset *ovcs)
if (ovcs->cset.entries.next)
of_changeset_destroy(&ovcs->cset);
if (ovcs->id) {
/* a failed idr_alloc() leaves its negative error in ovcs->id */
if (ovcs->id > 0) {
idr_remove(&ovcs_idr, ovcs->id);
list_del(&ovcs->ovcs_list);
ovcs->id = 0;