From: Dan Carpenter Date: Wed, 14 Jun 2023 13:07:15 +0000 (+0300) Subject: media: mediatek: vcodec: Fix potential crash in mtk_vcodec_dbgfs_remove() X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=b19c347b123cd68d6208474194947bdb6dbc1227;p=linux.git media: mediatek: vcodec: Fix potential crash in mtk_vcodec_dbgfs_remove() The list iterator "dbgfs_inst" is always non-NULL. This means that the test for NULL inside the loop is unnecessary and it also means that the test for NULL outside the loop will not work. If we do not find the item on the list with the correct the ctx_id then it will free invalid memory leading to a crash. Fixes: cd403a6a0419 ("media: mediatek: vcodec: Add a debugfs file to get different useful information") Signed-off-by: Dan Carpenter Reviewed-by: Nicolas Dufresne Signed-off-by: Hans Verkuil --- diff --git a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c index b5cdbbfcc388d..2ebf68d33d57a 100644 --- a/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c +++ b/drivers/media/platform/mediatek/vcodec/mtk_vcodec_dbgfs.c @@ -168,14 +168,11 @@ void mtk_vcodec_dbgfs_remove(struct mtk_vcodec_dev *vcodec_dev, int ctx_id) list_for_each_entry(dbgfs_inst, &vcodec_dev->dbgfs.dbgfs_head, node) { if (dbgfs_inst->inst_id == ctx_id) { vcodec_dev->dbgfs.inst_count--; - break; + list_del(&dbgfs_inst->node); + kfree(dbgfs_inst); + return; } } - - if (dbgfs_inst) { - list_del(&dbgfs_inst->node); - kfree(dbgfs_inst); - } } EXPORT_SYMBOL_GPL(mtk_vcodec_dbgfs_remove);