longli
3988009733
Issue: WCSWREL-119 Fix RCU warning when call ieee80211_bss_get_ie
...
[Description]
[ 179.414989] =============================
[ 179.419033] WARNING: suspicious RCU usage
[ 179.428095] 5.11.0-rc1-next-20210104-04456-g31eb08622591 #1 Tainted: G O
[ 179.438042] -----------------------------
[ 179.443768] net/wireless/util.c:911 suspicious rcu_dereference_check() usage!
[ 179.453802]
[ 179.453802] other info that might help us debug this:
[ 179.453802]
[ 179.463924]
[ 179.463924] rcu_scheduler_active = 2, debug_locks = 1
[ 179.472528] 3 locks held by wpa_supplicant/586:
[ 179.477109] #0 : c18c5058 (cb_lock){++++}-{3:3}, at: genl_rcv+0x14/0x34
[ 179.486226] #1 : c18be65c (rtnl_mutex){+.+.}-{3:3}, at: nl80211_pre_doit+0x104/0x1e8
[ 179.496033] #2 : c8382da0 (&wdev->mtx){+.+.}-{3:3}, at: nl80211_connect+0x580/0x7ac
[ 179.505687]
[ 179.505687] stack backtrace:
[ 179.511970] CPU: 0 PID: 586 Comm: wpa_supplicant Tainted: G O 5.11.0-rc1-next-20210104-04456-g31eb08622591 #1
[ 179.523233] Hardware name: Freescale i.MX6 SoloX (Device Tree)
[ 179.529093] [<c0111814>] (unwind_backtrace) from [<c010bd5c>] (show_stack+0x10/0x14)
[ 179.536883] [<c010bd5c>] (show_stack) from [<c0eeae24>] (dump_stack+0xcc/0xf4)
[ 179.544142] [<c0eeae24>] (dump_stack) from [<c0ded2b4>] (ieee80211_bss_get_elem+0x84/0x98)
[ 179.552443] [<c0ded2b4>] (ieee80211_bss_get_elem) from [<bf0e11bc>] (woal_cfg80211_assoc+0x50c/0x98c [moal])
[ 179.562737] [<bf0e11bc>] (woal_cfg80211_assoc [moal]) from [<bf0e4e2c>] (woal_cfg80211_connect+0x174/0x584 [moal])
[ 179.573748] [<bf0e4e2c>] (woal_cfg80211_connect [moal]) from [<c0e30450>] (cfg80211_connect+0x1d8/0x7fc)
[ 179.583590] [<c0e30450>] (cfg80211_connect) from [<c0e02aac>] (nl80211_connect+0x59c/0x7ac)
[ 179.591985] [<c0e02aac>] (nl80211_connect) from [<c0c21860>] (genl_rcv_msg+0x174/0x35c)
[ 179.600029] [<c0c21860>] (genl_rcv_msg) from [<c0c20960>] (netlink_rcv_skb+0xbc/0x11c)
[ 179.607975] [<c0c20960>] (netlink_rcv_skb) from [<c0c20fec>] (genl_rcv+0x20/0x34)
[ 179.615486] [<c0c20fec>] (genl_rcv) from [<c0c20004>] (netlink_unicast+0x1ac/0x2e0)
[ 179.623173] [<c0c20004>] (netlink_unicast) from [<c0c2030c>] (netlink_sendmsg+0x1d4/0x408)
[ 179.631465] [<c0c2030c>] (netlink_sendmsg) from [<c0b9d080>] (____sys_sendmsg+0x1c4/0x274)
[ 179.639764] [<c0b9d080>] (____sys_sendmsg) from [<c0b9ee08>] (___sys_sendmsg+0xa4/0xd8)
[ 179.647803] [<c0b9ee08>] (___sys_sendmsg) from [<c0b9efe0>] (sys_sendmsg+0x50/0x94)
[ 179.655491] [<c0b9efe0>] (sys_sendmsg) from [<c0100080>] (ret_fast_syscall+0x0/0x2c)
[ 179.663265] Exception stack(0xc839bfa8 to 0xc839bff0)
[ 179.668342] bfa0: 01352b30 01351da0 00000005 bec05770 00000000 00000000
[ 179.676545] bfc0: 01352b30 01351da0 b6f49550 00000128 bec05770 bec057e8 00000001 00000004
[ 179.684744] bfe0: 00000128 bec05720 b6c24bbf b6ba4616
[ 179.718172] wlan: Connected to bssid c0:XX:XX:XX:3e:85 successfully
[Analysis]
RCU warning is happened at rcu_dereference -> rcu_dereference_check, rcu_read_lock_held() is a condition check in it.
When rcu_read_lock_held() return false, warning will be printed.
[Fix]
When call ieee80211_bss_get_ie(), the code and related ie need be wrapped around by rcu_read_lock()/rcu_read_unlock().
Signed-off-by: longli <li.long@nxp.com>
Reviewed-by: Sherry Sun <sherry.sun@nxp.com>
2021-03-01 19:06:54 +08:00
