From: Fabio Estevam mwifiex synchronous commands keep the caller-provided data buffer in cmd_node->data_buf. Several callers pass stack-allocated objects there. If wait_event_interruptible_timeout() is interrupted, the caller can return and release that stack object while the firmware command is still the current command. A late firmware response then reaches the normal response handler, which can copy data through cmd_node->data_buf into the stale stack address. This fixes a stack corruption observed during repeated association and disassociation cycles. The panic trace showed the command wait being interrupted immediately before a bad pointer dereference: cmd_wait_q terminated: -512 Unable to handle kernel paging request at virtual address 002c583837384662 Kernel panic - not syncing: stack-protector: Kernel stack is corrupted ... Tainted: [M]=MACHINE_CHECK The fault address decodes as little-endian ASCII: 0x002c583837384662 -> "bF878X,\0" which is a fragment of the VERSION_EXT firmware string exposed as debugfs "verext": w8997o-V4, RF878X, FP92, 16.92.21.p153.7 The same runs also showed corrupted control data containing: 0x2400372e333531 -> "153.7\0$" which is the tail of the same VERSION_EXT string. This points at a late VERSION_EXT response writing through a stale stack-backed data_buf after the interrupted wait returned. After cancelling pending commands on an interrupted or timed-out wait, detach the caller-owned data buffer from the still-current command. This preserves the existing command cancellation behaviour while preventing a late response from writing through a pointer whose lifetime ended with the waiting caller. Tested on an i.MX8MP board using an 88W8997. Cc: stable@vger.kernel.org Fixes: 3d026d09b28d ("mwifiex: cancel pending commands for signal") Signed-off-by: Fabio Estevam --- drivers/net/wireless/marvell/mwifiex/sta_ioctl.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c b/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c index 9460d5352b23..19196848778c 100644 --- a/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c +++ b/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c @@ -57,6 +57,18 @@ int mwifiex_wait_queue_complete(struct mwifiex_adapter *adapter, mwifiex_dbg(adapter, ERROR, "cmd_wait_q terminated: %d\n", status); mwifiex_cancel_all_pending_cmd(adapter); + + /* The command response path writes through cmd_node->data_buf. + * On an interrupted wait, the caller can return and release a + * stack-allocated data_buf before a late firmware response is + * processed. Detach the caller-owned buffer from the current + * command so a late response cannot corrupt freed stack memory. + */ + spin_lock_bh(&adapter->mwifiex_cmd_lock); + if (adapter->curr_cmd == cmd_queued) + adapter->curr_cmd->data_buf = NULL; + spin_unlock_bh(&adapter->mwifiex_cmd_lock); + return status; } -- 2.43.0