From: Shin-Yi Lin Date: Mon, 20 Apr 2026 03:40:41 +0000 (+0800) Subject: wifi: rtw89: Correct data type for scan index to avoid infinite loop X-Git-Url: http://git.ipfire.org/gitweb/index.cgi?a=commitdiff_plain;h=08fdcb529df6df3562dd2b0035f88dd5be8b3c68;p=thirdparty%2Fkernel%2Flinux.git wifi: rtw89: Correct data type for scan index to avoid infinite loop A kernel soft lockup was observed during Wi-Fi scanning on the 6GHz band. The CPU becomes stuck in rtw89_hw_scan_add_chan_ax for over 20 seconds, leading to a system panic. RIP points to 0f b6 c3 (movzbl %bl, %eax), which zero-extends the low 8 bits of RBX into RAX. RBX (the counter i) has reached a huge value: 0x137466a1. watchdog: BUG: soft lockup - CPU#2 stuck for 26s! [kworker/u16:4:6124] Workqueue: events_unbound cfg80211_wiphy_work [cfg80211] RIP: 0010:rtw89_hw_scan_add_chan_ax+0xb3/0x6e0 [rtw89_core] Code: a0 48 89 45 a8 44 89 6d 9c 44 89 75 98 eb 29 66 66 2e 0f 1f 84 00 00 00 00 00 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 83 c3 01 <0f> b6 c3 41 3b 44 24 74 0f 83 0b 02 00 00 0f b6 c3 48 8d 14 80 49 RSP: 0018:ffffcb48cbaa39f8 EFLAGS: 00000202 RAX: 0000000000000005 RBX: 00000000137466a1 RCX: 0000000000000000 RDX: ffff89ffc9d851a8 RSI: 0000000000004f0d RDI: 0000000096af0130 RBP: ffffcb48cbaa3a60 R08: 0000000000000000 R09: ffff8a00b7502080 R10: ffff8a00b75ff600 R11: 0000000000000000 R12: ffff89ffc7553870 R13: ffff8a00b7ac8f19 R14: ffff8a00b75020d8 R15: ffff89ffc3d54d80 FS: 0000000000000000(0000) GS:ffff8a014f962000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007558d7f9f4c4 CR3: 0000000178040001 CR4: 00000000001706f0 Call Trace: rtw89_hw_scan_prep_chan_list_ax+0x8a/0x400 [rtw89_core] rtw89_hw_scan_start+0x546/0x8a0 [rtw89_core] ? rtw89_fw_h2c_default_cmac_tbl+0x13c/0x1f0 [rtw89_core] rtw89_ops_hw_scan+0xae/0x120 [rtw89_core] drv_hw_scan+0xbb/0x180 [mac80211] __ieee80211_start_scan+0x2fc/0x750 [mac80211] ieee80211_request_scan+0xe/0x20 [mac80211] ieee80211_scan+0x123/0x190 [mac80211] rdev_scan+0x40/0x110 [cfg80211] cfg80211_scan_6ghz+0x5a1/0xa30 [cfg80211] By objdump with source: for (i = 0; i < req->n_6ghz_params; i++) { 5fbc0: 83 c3 01 add $0x1,%ebx --> i++ 5fbc3: 0f b6 c3 movzbl %bl,%eax --> get counter fbc6: 41 3b 44 24 74 cmp 0x74(%r12),%eax * RBX: 00000000137466a1 -> %bl = a1 -> EAX = 000000a1 (161) Fixes: c6aa9a9c4725 ("wifi: rtw89: add RNR support for 6 GHz scan") Signed-off-by: Shin-Yi Lin Signed-off-by: Ping-Ke Shih Link: https://patch.msgid.link/20260420034051.17666-7-pkshih@realtek.com --- diff --git a/drivers/net/wireless/realtek/rtw89/fw.c b/drivers/net/wireless/realtek/rtw89/fw.c index ffa04315a62b..b578f5316b5f 100644 --- a/drivers/net/wireless/realtek/rtw89/fw.c +++ b/drivers/net/wireless/realtek/rtw89/fw.c @@ -8318,7 +8318,7 @@ static int rtw89_update_6ghz_rnr_chan_ax(struct rtw89_dev *rtwdev, struct sk_buff *skb; bool found; int ret = 0; - u8 i; + u32 i; if (!req->n_6ghz_params) return 0;