KASAN reported following issue:
BUG: KASAN: stack-out-of-bounds in tb_retimer_scan+0xffe/0x1550 [thunderbolt]
Read of size 4 at addr ffff88810111fc1c by task kworker/u56:0/11
CPU: 0 UID: 0 PID: 11 Comm: kworker/u56:0 Tainted: G U 6.11.0+ #1387
Tainted: [U]=USER
Workqueue: thunderbolt0 tb_handle_hotplug [thunderbolt]
Call Trace:
<TASK>
dump_stack_lvl+0x6c/0x90
print_report+0xd1/0x630
kasan_report+0xdb/0x110
__asan_report_load4_noabort+0x14/0x20
tb_retimer_scan+0xffe/0x1550 [thunderbolt]
tb_scan_port+0xa6f/0x2060 [thunderbolt]
tb_handle_hotplug+0x17b1/0x3080 [thunderbolt]
process_one_work+0x626/0x1100
worker_thread+0x6c8/0xfa0
kthread+0x2c8/0x3a0
ret_from_fork+0x3a/0x80
ret_from_fork_asm+0x1a/0x30
This happens because the loop variable still gets incremented by one so
max becomes 3 instead of 2, and this makes the second loop read past the
the array declared on the stack.
Fix this by assigning to max directly in the loop body.
Fixes: ff6ab055e070 ("thunderbolt: Add receiver lane margining support for retimers")
CC: stable@xxxxxxxxxxxxxxx
Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx>
---
drivers/thunderbolt/retimer.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/thunderbolt/retimer.c b/drivers/thunderbolt/retimer.c
index 721319329afa..7db9869a9f3f 100644
--- a/drivers/thunderbolt/retimer.c
+++ b/drivers/thunderbolt/retimer.c
@@ -516,7 +516,7 @@ int tb_retimer_scan(struct tb_port *port, bool add)
*/
tb_retimer_set_inbound_sbtx(port);
- for (i = 1; i <= TB_MAX_RETIMER_INDEX; i++) {
+ for (max = 1, i = 1; i <= TB_MAX_RETIMER_INDEX; i++) {
/*
* Last retimer is true only for the last on-board
* retimer (the one connected directly to the Type-C
@@ -527,9 +527,10 @@ int tb_retimer_scan(struct tb_port *port, bool add)
last_idx = i;
else if (ret < 0)
break;
+
+ max = i;
}
- max = i;
ret = 0;
/* Add retimers if they do not exist already */
--
2.45.2
