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FAILED: patch "[PATCH] wifi: mac80211: keep fallback association elements alive" failed to apply to 5.15-stable tree

PATCH New [email protected] 2 participants 2 messages Oct 5 – Oct 6

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Stable branch mac80211
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#0 lore raw

The patch below does not apply to the 5.15-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

To reproduce the conflict and resubmit, you may use the following commands:

git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.15.y
git checkout FETCH_HEAD
git cherry-pick -x a10a2f80476d166fd81c361ec0319493671b694e
# <resolve conflicts, build, test, etc.>
git commit -s
git send-email --to '<[email protected]>' --in-reply-to '2026100555-despite-exonerate-bff7@gregkh' --subject-prefix 'PATCH 5.15.y' 'HEAD^..'

Possible dependencies:

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From a10a2f80476d166fd81c361ec0319493671b694e Mon Sep 17 00:00:00 2001
From: Zhao Li <[email protected]>
Date: Thu, 10 Sep 2026 14:52:51 +0800
Subject: [PATCH] wifi: mac80211: keep fallback association elements alive

Associating to a non-transmitted MBSSID profile reads freed memory while determining the operating channel and applying HT capabilities.

When an association response omits WMM, HT, or VHT information, ieee80211_assoc_config_link() parses the cached BSS IEs and copies the missing element pointers out of that fallback parse. For a non-transmitted MBSSID profile those pointers refer to merged-profile storage owned by the parse object, and the fallback block frees that object at its end. The copied pointers are used afterwards to determine the operating channel, configure bandwidth, and apply HT capabilities.

Keep the fallback parse result alive until association setup finishes.

Fixes 5023b14cf4df ("mac80211: support profile split between elements")
Cc [email protected]
Assisted-by LLM sparse kasan
[reorder variable declaration]
Signed-off-by Zhao Li <[email protected]>
Signed-off-by Johannes Berg <[email protected]>
net/mac80211/mlme.c +2 -2
index f51167f0fc46..3c31c16860ab 100644
@@ -5877,6 +5877,7 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 	bool is_6ghz = cbss->channel->band == NL80211_BAND_6GHZ;
 	bool is_s1g = cbss->channel->band == NL80211_BAND_S1GHZ;
 	const struct cfg80211_bss_ies *bss_ies = NULL;
+	struct ieee802_11_elems *bss_elems = NULL;
 	struct ieee80211_supported_band *sband;
 	struct ieee802_11_elems *elems;
 	u16 capab_info;

@@ -6007,7 +6008,6 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 	     (is_5ghz && link->u.mgd.conn.mode >= IEEE80211_CONN_MODE_VHT &&
 	      (!elems->vht_cap_elem || !elems->vht_operation)))) {
 		const struct cfg80211_bss_ies *ies;
-		struct ieee802_11_elems *bss_elems;
 
 		rcu_read_lock();
 		ies = rcu_dereference(cbss->ies);

@@ -6069,7 +6069,6 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 					   "AP bug: VHT operation missing from AssocResp\n");
 			}
 		}
-		kfree(bss_elems);
 	}
 
 	/*

@@ -6342,6 +6341,7 @@ static bool ieee80211_assoc_config_link(struct ieee80211_link_data *link,
 	ret = true;
 out:
 	kfree(elems);
+	kfree(bss_elems);
 	kfree(bss_ies);
 	return ret;
 }
maintainer
#1 lore raw

PATCH 1/1 wifi: mac80211: keep fallback association elements alive

From: Zhao Li <[email protected]>

[ Upstream commit a10a2f80476d166fd81c361ec0319493671b694e ]

Associating to a non-transmitted MBSSID profile reads freed memory while determining the operating channel and applying HT capabilities.

When an association response omits WMM, HT, or VHT information, ieee80211_assoc_config_link() parses the cached BSS IEs and copies the missing element pointers out of that fallback parse. For a non-transmitted MBSSID profile those pointers refer to merged-profile storage owned by the parse object, and the fallback block frees that object at its end. The copied pointers are used afterwards to determine the operating channel, configure bandwidth, and apply HT capabilities.

Keep the fallback parse result alive until association setup finishes.

Fixes 5023b14cf4df ("mac80211: support profile split between elements")
Cc [email protected]
Assisted-by LLM sparse kasan
[reorder variable declaration]
Signed-off-by Zhao Li <[email protected]>
Signed-off-by Johannes Berg <[email protected]>
[ sashal: Applied the changes to ieee80211_assoc_success() instead of ieee80211_assoc_config_link(). ]
Signed-off-by Sasha Levin <[email protected]>
---
 net/mac80211/mlme.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)
net/mac80211/mlme.c +2 -3
index 5617540b40b29..bfd4654d404f0 100644
@@ -3310,6 +3310,7 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 	u16 capab_info, aid;
 	struct ieee80211_bss_conf *bss_conf = &sdata->vif.bss_conf;
 	const struct cfg80211_bss_ies *bss_ies = NULL;
+	struct ieee802_11_elems *bss_elems = NULL;
 	struct ieee80211_mgd_assoc_data *assoc_data = ifmgd->assoc_data;
 	bool is_6ghz = cbss->channel->band == NL80211_BAND_6GHZ;
 	bool is_s1g = cbss->channel->band == NL80211_BAND_S1GHZ;

@@ -3376,7 +3377,6 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 	     (!(ifmgd->flags & IEEE80211_STA_DISABLE_VHT) &&
 	      (!elems->vht_cap_elem || !elems->vht_operation)))) {
 		const struct cfg80211_bss_ies *ies;
-		struct ieee802_11_elems *bss_elems;
 
 		rcu_read_lock();
 		ies = rcu_dereference(cbss->ies);

@@ -3432,8 +3432,6 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 			sdata_info(sdata,
 				   "AP bug: VHT operation missing from AssocResp\n");
 		}
-
-		kfree(bss_elems);
 	}
 
 	/*

@@ -3685,6 +3683,7 @@ static bool ieee80211_assoc_success(struct ieee80211_sub_if_data *sdata,
 	ret = true;
  out:
 	kfree(elems);
+	kfree(bss_elems);
 	kfree(bss_ies);
 	return ret;
 }
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