On 6-3-2017 15:50, Daniel J Blueman wrote: > On 6 March 2017 at 21:00, Arend Van Spriel <arend.vanspriel@xxxxxxxxxxxx> wrote: >> + linux-wireless >> >> On 6-3-2017 8:14, Daniel J Blueman wrote: >>> KASAN reported 'struct wireless_dev wdev' was read after being freed. >>> Fix by freeing after the access. >> >> I would rather like to see the KASAN report, because something is off >> here. This function is called with wdev as a parameter so how can it be >> accessed after free here? brcmf_remove_interface() does not free the >> wdev nor the brcmf_cfg80211_vif instance which contains the wdev. >> >> Regards, >> Arend >> >>> Signed-off-by: Daniel J Blueman <daniel@xxxxxxxxx> >>> >>> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c >>> b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c >>> index de19c7c..aa0f470 100644 >>> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c >>> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c >>> @@ -2288,12 +2288,13 @@ int brcmf_p2p_del_vif(struct wiphy *wiphy, >>> struct wireless_dev *wdev) >>> else >>> err = 0; >>> } >>> - brcmf_remove_interface(vif->ifp, true); >>> >>> - brcmf_cfg80211_arm_vif_event(cfg, NULL); >>> if (vif->wdev.iftype != NL80211_IFTYPE_P2P_DEVICE) >>> p2p->bss_idx[P2PAPI_BSSCFG_CONNECTION].vif = NULL; >>> >>> + brcmf_remove_interface(vif->ifp, true); >>> + brcmf_cfg80211_arm_vif_event(cfg, NULL); >>> + >>> return err; >>> } > > Sure, https://quora.org/kernel/brcmfmac/dmesg.txt So this dmesg looks to be about a separate issue during resume, which you sent an email about earlier [1] which is about using wiphy struct after free. However, back to this I further checked the code and it seems the vif is indeed freed through the netdev destructor callback upon calling brcmf_remove_inteface(). However, I would prefer to store vif->wdev.iftype in a local variable and avoid changing the order of the calls in the code. Regards, Arend [1] http://marc.info/?l=linux-netdev&m=148878437808750&w=2 > vmlinux, cfg80211.o, brcmfmac.o and config are in the same path; this > is against v4.9.13 stock.
