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wifi: mwifiex: Detach sync cmd buffer on interrupted wait

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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: 3d026d09b2 ("mwifiex: cancel pending commands for signal")
Signed-off-by: Fabio Estevam <festevam@nabladev.com>
Link: https://patch.msgid.link/20260724203320.78793-1-festevam@gmail.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Fabio Estevam
2026-07-24 17:33:19 -03:00
committed by Johannes Berg
parent 9a197e71eb
commit ef06882c7d
1 changed files with 12 additions and 0 deletions
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12
drivers/net/wireless/marvell/mwifiex/sta_ioctl.c
View File

@@ -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;
}