From acd54f42abbbd806464468838dbc04efd203d2be Mon Sep 17 00:00:00 2001 From: Dan Carpenter Date: Fri, 8 May 2026 10:51:56 +0300 Subject: [PATCH] rapidio/tsi721: prevent a bad dereference in tsi721_db_dpc() [ Upstream commit fc15e3a30ddd950f009c76765331783b9af94a87 ] With a list_for_each() loop, if we don't find the item we are looking for in the list, then the loop exits with the iterator, which is "dbell" in this loop, pointing to invalid memory. This code uses the "found" variable to determine if we have found the doorbell we are looking for or not. However, the problem that the "found" variable needs to be set to false at the start of each iteration, otherwise after the first correct doorbell, then everything is marked as found. Reset the "found" to false at the start of the iteration and move the variable inside the loop. Link: https://lore.kernel.org/af2WHMZiqMwdYveO@stanley.mountain Fixes: 48618fb4e522 ("RapidIO: add mport driver for Tsi721 bridge") Signed-off-by: Dan Carpenter Cc: Alexandre Bounine Cc: Chul Kim Cc: Matt Porter Signed-off-by: Andrew Morton Signed-off-by: Sasha Levin --- drivers/rapidio/devices/tsi721.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/rapidio/devices/tsi721.c b/drivers/rapidio/devices/tsi721.c index 83323c3d10af..61ac7c8a1c7f 100644 --- a/drivers/rapidio/devices/tsi721.c +++ b/drivers/rapidio/devices/tsi721.c @@ -384,7 +384,6 @@ static void tsi721_db_dpc(struct work_struct *work) idb_work); struct rio_mport *mport; struct rio_dbell *dbell; - int found = 0; u32 wr_ptr, rd_ptr; u64 *idb_entry; u32 regval; @@ -402,6 +401,8 @@ static void tsi721_db_dpc(struct work_struct *work) rd_ptr = ioread32(priv->regs + TSI721_IDQ_RP(IDB_QUEUE)) % IDB_QSIZE; while (wr_ptr != rd_ptr) { + int found = 0; + idb_entry = (u64 *)(priv->idb_base + (TSI721_IDB_ENTRY_SIZE * rd_ptr)); rd_ptr++;