Hi David, hi Jakub,
here are a few bugfixes for batman-adv which we would like to have integrated into net.
Please pull or let me know of any problem!
Thank you, Simon
The following changes since commit fff8f17c1a6fc802ca23bbd3a276abfde8cc58e6:
batman-adv: Do not let TT changes list grows indefinitely (2024-12-05 22:38:26 +0100)
are available in the Git repository at:
git://git.open-mesh.org/linux-merge.git tags/batadv-net-pullrequest-20250207
for you to fetch changes up to f4c9c2cc827d803159730b1da813a0c595969831:
batman-adv: Fix incorrect offset in batadv_tt_tvlv_ogm_handler_v1() (2025-01-28 22:06:56 +0100)
---------------------------------------------------------------- Here are some batman-adv bugfixes:
- Fix panic during interface removal in BATMAN V, by Andy Strohman
- Cleanup BATMAN V/ELP metric handling, by Sven Eckelmann (2 patches)
- Fix incorrect offset in batadv_tt_tvlv_ogm_handler_v1(), by Remi Pommarel
---------------------------------------------------------------- Andy Strohman (1): batman-adv: fix panic during interface removal
Remi Pommarel (1): batman-adv: Fix incorrect offset in batadv_tt_tvlv_ogm_handler_v1()
Sven Eckelmann (2): batman-adv: Ignore neighbor throughput metrics in error case batman-adv: Drop unmanaged ELP metric worker
net/batman-adv/bat_v.c | 2 - net/batman-adv/bat_v_elp.c | 122 ++++++++++++++++++++++++++----------- net/batman-adv/bat_v_elp.h | 2 - net/batman-adv/translation-table.c | 12 ++-- net/batman-adv/types.h | 3 - 5 files changed, 91 insertions(+), 50 deletions(-)
From: Andy Strohman andrew@andrewstrohman.com
Reference counting is used to ensure that batadv_hardif_neigh_node and batadv_hard_iface are not freed before/during batadv_v_elp_throughput_metric_update work is finished.
But there isn't a guarantee that the hard if will remain associated with a soft interface up until the work is finished.
This fixes a crash triggered by reboot that looks like this:
Call trace: batadv_v_mesh_free+0xd0/0x4dc [batman_adv] batadv_v_elp_throughput_metric_update+0x1c/0xa4 process_one_work+0x178/0x398 worker_thread+0x2e8/0x4d0 kthread+0xd8/0xdc ret_from_fork+0x10/0x20
(the batadv_v_mesh_free call is misleading, and does not actually happen)
I was able to make the issue happen more reliably by changing hardif_neigh->bat_v.metric_work work to be delayed work. This allowed me to track down and confirm the fix.
Cc: stable@vger.kernel.org Fixes: c833484e5f38 ("batman-adv: ELP - compute the metric based on the estimated throughput") Signed-off-by: Andy Strohman andrew@andrewstrohman.com [sven@narfation.org: prevent entering batadv_v_elp_get_throughput without soft_iface] Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de --- net/batman-adv/bat_v_elp.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 1d704574e6bf..fbf499bcc671 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -66,12 +66,19 @@ static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface) static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) { struct batadv_hard_iface *hard_iface = neigh->if_incoming; + struct net_device *soft_iface = hard_iface->soft_iface; struct ethtool_link_ksettings link_settings; struct net_device *real_netdev; struct station_info sinfo; u32 throughput; int ret;
+ /* don't query throughput when no longer associated with any + * batman-adv interface + */ + if (!soft_iface) + return BATADV_THROUGHPUT_DEFAULT_VALUE; + /* if the user specified a customised value for this interface, then * return it directly */ @@ -141,7 +148,7 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh)
default_throughput: if (!(hard_iface->bat_v.flags & BATADV_WARNING_DEFAULT)) { - batadv_info(hard_iface->soft_iface, + batadv_info(soft_iface, "WiFi driver or ethtool info does not provide information about link speeds on interface %s, therefore defaulting to hardcoded throughput values of %u.%1u Mbps. Consider overriding the throughput manually or checking your driver.\n", hard_iface->net_dev->name, BATADV_THROUGHPUT_DEFAULT_VALUE / 10,
Hello:
This series was applied to netdev/net.git (main) by Simon Wunderlich sw@simonwunderlich.de:
On Fri, 7 Feb 2025 10:58:20 +0100 you wrote:
From: Andy Strohman andrew@andrewstrohman.com
Reference counting is used to ensure that batadv_hardif_neigh_node and batadv_hard_iface are not freed before/during batadv_v_elp_throughput_metric_update work is finished.
[...]
Here is the summary with links: - [1/4] batman-adv: fix panic during interface removal https://git.kernel.org/netdev/net/c/ccb7276a6d26 - [2/4] batman-adv: Ignore neighbor throughput metrics in error case https://git.kernel.org/netdev/net/c/e7e34ffc976a - [3/4] batman-adv: Drop unmanaged ELP metric worker https://git.kernel.org/netdev/net/c/8c8ecc98f5c6 - [4/4] batman-adv: Fix incorrect offset in batadv_tt_tvlv_ogm_handler_v1() https://git.kernel.org/netdev/net/c/f4c9c2cc827d
You are awesome, thank you!
From: Sven Eckelmann sven@narfation.org
If a temporary error happened in the evaluation of the neighbor throughput information, then the invalid throughput result should not be stored in the throughtput EWMA.
Cc: stable@vger.kernel.org Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de --- net/batman-adv/bat_v_elp.c | 50 ++++++++++++++++++++++++++------------ 1 file changed, 34 insertions(+), 16 deletions(-)
diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index fbf499bcc671..65e52de52bcd 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -59,11 +59,13 @@ static void batadv_v_elp_start_timer(struct batadv_hard_iface *hard_iface) /** * batadv_v_elp_get_throughput() - get the throughput towards a neighbour * @neigh: the neighbour for which the throughput has to be obtained + * @pthroughput: calculated throughput towards the given neighbour in multiples + * of 100kpbs (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc). * - * Return: The throughput towards the given neighbour in multiples of 100kpbs - * (a value of '1' equals 0.1Mbps, '10' equals 1Mbps, etc). + * Return: true when value behind @pthroughput was set */ -static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) +static bool batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh, + u32 *pthroughput) { struct batadv_hard_iface *hard_iface = neigh->if_incoming; struct net_device *soft_iface = hard_iface->soft_iface; @@ -77,14 +79,16 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) * batman-adv interface */ if (!soft_iface) - return BATADV_THROUGHPUT_DEFAULT_VALUE; + return false;
/* if the user specified a customised value for this interface, then * return it directly */ throughput = atomic_read(&hard_iface->bat_v.throughput_override); - if (throughput != 0) - return throughput; + if (throughput != 0) { + *pthroughput = throughput; + return true; + }
/* if this is a wireless device, then ask its throughput through * cfg80211 API @@ -111,19 +115,24 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) * possible to delete this neighbor. For now set * the throughput metric to 0. */ - return 0; + *pthroughput = 0; + return true; } if (ret) goto default_throughput;
- if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)) - return sinfo.expected_throughput / 100; + if (sinfo.filled & BIT(NL80211_STA_INFO_EXPECTED_THROUGHPUT)) { + *pthroughput = sinfo.expected_throughput / 100; + return true; + }
/* try to estimate the expected throughput based on reported tx * rates */ - if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE)) - return cfg80211_calculate_bitrate(&sinfo.txrate) / 3; + if (sinfo.filled & BIT(NL80211_STA_INFO_TX_BITRATE)) { + *pthroughput = cfg80211_calculate_bitrate(&sinfo.txrate) / 3; + return true; + }
goto default_throughput; } @@ -142,8 +151,10 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) hard_iface->bat_v.flags &= ~BATADV_FULL_DUPLEX;
throughput = link_settings.base.speed; - if (throughput && throughput != SPEED_UNKNOWN) - return throughput * 10; + if (throughput && throughput != SPEED_UNKNOWN) { + *pthroughput = throughput * 10; + return true; + } }
default_throughput: @@ -157,7 +168,8 @@ static u32 batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh) }
/* if none of the above cases apply, return the base_throughput */ - return BATADV_THROUGHPUT_DEFAULT_VALUE; + *pthroughput = BATADV_THROUGHPUT_DEFAULT_VALUE; + return true; }
/** @@ -169,15 +181,21 @@ void batadv_v_elp_throughput_metric_update(struct work_struct *work) { struct batadv_hardif_neigh_node_bat_v *neigh_bat_v; struct batadv_hardif_neigh_node *neigh; + u32 throughput; + bool valid;
neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v, metric_work); neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node, bat_v);
- ewma_throughput_add(&neigh->bat_v.throughput, - batadv_v_elp_get_throughput(neigh)); + valid = batadv_v_elp_get_throughput(neigh, &throughput); + if (!valid) + goto put_neigh; + + ewma_throughput_add(&neigh->bat_v.throughput, throughput);
+put_neigh: /* decrement refcounter to balance increment performed before scheduling * this task */
From: Sven Eckelmann sven@narfation.org
The ELP worker needs to calculate new metric values for all neighbors "reachable" over an interface. Some of the used metric sources require locks which might need to sleep. This sleep is incompatible with the RCU list iterator used for the recorded neighbors. The initial approach to work around of this problem was to queue another work item per neighbor and then run this in a new context.
Even when this solved the RCU vs might_sleep() conflict, it has a major problems: Nothing was stopping the work item in case it is not needed anymore - for example because one of the related interfaces was removed or the batman-adv module was unloaded - resulting in potential invalid memory accesses.
Directly canceling the metric worker also has various problems:
* cancel_work_sync for a to-be-deactivated interface is called with rtnl_lock held. But the code in the ELP metric worker also tries to use rtnl_lock() - which will never return in this case. This also means that cancel_work_sync would never return because it is waiting for the worker to finish. * iterating over the neighbor list for the to-be-deactivated interface is currently done using the RCU specific methods. Which means that it is possible to miss items when iterating over it without the associated spinlock - a behaviour which is acceptable for a periodic metric check but not for a cleanup routine (which must "stop" all still running workers)
The better approch is to get rid of the per interface neighbor metric worker and handle everything in the interface worker. The original problems are solved by:
* creating a list of neighbors which require new metric information inside the RCU protected context, gathering the metric according to the new list outside the RCU protected context * only use rcu_trylock inside metric gathering code to avoid a deadlock when the cancel_delayed_work_sync is called in the interface removal code (which is called with the rtnl_lock held)
Cc: stable@vger.kernel.org Fixes: c833484e5f38 ("batman-adv: ELP - compute the metric based on the estimated throughput") Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de --- net/batman-adv/bat_v.c | 2 -- net/batman-adv/bat_v_elp.c | 71 ++++++++++++++++++++++++++------------ net/batman-adv/bat_v_elp.h | 2 -- net/batman-adv/types.h | 3 -- 4 files changed, 48 insertions(+), 30 deletions(-)
diff --git a/net/batman-adv/bat_v.c b/net/batman-adv/bat_v.c index ac11f1f08db0..d35479c465e2 100644 --- a/net/batman-adv/bat_v.c +++ b/net/batman-adv/bat_v.c @@ -113,8 +113,6 @@ static void batadv_v_hardif_neigh_init(struct batadv_hardif_neigh_node *hardif_neigh) { ewma_throughput_init(&hardif_neigh->bat_v.throughput); - INIT_WORK(&hardif_neigh->bat_v.metric_work, - batadv_v_elp_throughput_metric_update); }
/** diff --git a/net/batman-adv/bat_v_elp.c b/net/batman-adv/bat_v_elp.c index 65e52de52bcd..b065578b4436 100644 --- a/net/batman-adv/bat_v_elp.c +++ b/net/batman-adv/bat_v_elp.c @@ -18,6 +18,7 @@ #include <linux/if_ether.h> #include <linux/jiffies.h> #include <linux/kref.h> +#include <linux/list.h> #include <linux/minmax.h> #include <linux/netdevice.h> #include <linux/nl80211.h> @@ -26,6 +27,7 @@ #include <linux/rcupdate.h> #include <linux/rtnetlink.h> #include <linux/skbuff.h> +#include <linux/slab.h> #include <linux/stddef.h> #include <linux/string.h> #include <linux/types.h> @@ -41,6 +43,18 @@ #include "routing.h" #include "send.h"
+/** + * struct batadv_v_metric_queue_entry - list of hardif neighbors which require + * and metric update + */ +struct batadv_v_metric_queue_entry { + /** @hardif_neigh: hardif neighbor scheduled for metric update */ + struct batadv_hardif_neigh_node *hardif_neigh; + + /** @list: list node for metric_queue */ + struct list_head list; +}; + /** * batadv_v_elp_start_timer() - restart timer for ELP periodic work * @hard_iface: the interface for which the timer has to be reset @@ -137,10 +151,17 @@ static bool batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh, goto default_throughput; }
+ /* only use rtnl_trylock because the elp worker will be cancelled while + * the rntl_lock is held. the cancel_delayed_work_sync() would otherwise + * wait forever when the elp work_item was started and it is then also + * trying to rtnl_lock + */ + if (!rtnl_trylock()) + return false; + /* if not a wifi interface, check if this device provides data via * ethtool (e.g. an Ethernet adapter) */ - rtnl_lock(); ret = __ethtool_get_link_ksettings(hard_iface->net_dev, &link_settings); rtnl_unlock(); if (ret == 0) { @@ -175,31 +196,19 @@ static bool batadv_v_elp_get_throughput(struct batadv_hardif_neigh_node *neigh, /** * batadv_v_elp_throughput_metric_update() - worker updating the throughput * metric of a single hop neighbour - * @work: the work queue item + * @neigh: the neighbour to probe */ -void batadv_v_elp_throughput_metric_update(struct work_struct *work) +static void +batadv_v_elp_throughput_metric_update(struct batadv_hardif_neigh_node *neigh) { - struct batadv_hardif_neigh_node_bat_v *neigh_bat_v; - struct batadv_hardif_neigh_node *neigh; u32 throughput; bool valid;
- neigh_bat_v = container_of(work, struct batadv_hardif_neigh_node_bat_v, - metric_work); - neigh = container_of(neigh_bat_v, struct batadv_hardif_neigh_node, - bat_v); - valid = batadv_v_elp_get_throughput(neigh, &throughput); if (!valid) - goto put_neigh; + return;
ewma_throughput_add(&neigh->bat_v.throughput, throughput); - -put_neigh: - /* decrement refcounter to balance increment performed before scheduling - * this task - */ - batadv_hardif_neigh_put(neigh); }
/** @@ -273,14 +282,16 @@ batadv_v_elp_wifi_neigh_probe(struct batadv_hardif_neigh_node *neigh) */ static void batadv_v_elp_periodic_work(struct work_struct *work) { + struct batadv_v_metric_queue_entry *metric_entry; + struct batadv_v_metric_queue_entry *metric_safe; struct batadv_hardif_neigh_node *hardif_neigh; struct batadv_hard_iface *hard_iface; struct batadv_hard_iface_bat_v *bat_v; struct batadv_elp_packet *elp_packet; + struct list_head metric_queue; struct batadv_priv *bat_priv; struct sk_buff *skb; u32 elp_interval; - bool ret;
bat_v = container_of(work, struct batadv_hard_iface_bat_v, elp_wq.work); hard_iface = container_of(bat_v, struct batadv_hard_iface, bat_v); @@ -316,6 +327,8 @@ static void batadv_v_elp_periodic_work(struct work_struct *work)
atomic_inc(&hard_iface->bat_v.elp_seqno);
+ INIT_LIST_HEAD(&metric_queue); + /* The throughput metric is updated on each sent packet. This way, if a * node is dead and no longer sends packets, batman-adv is still able to * react timely to its death. @@ -340,16 +353,28 @@ static void batadv_v_elp_periodic_work(struct work_struct *work)
/* Reading the estimated throughput from cfg80211 is a task that * may sleep and that is not allowed in an rcu protected - * context. Therefore schedule a task for that. + * context. Therefore add it to metric_queue and process it + * outside rcu protected context. */ - ret = queue_work(batadv_event_workqueue, - &hardif_neigh->bat_v.metric_work); - - if (!ret) + metric_entry = kzalloc(sizeof(*metric_entry), GFP_ATOMIC); + if (!metric_entry) { batadv_hardif_neigh_put(hardif_neigh); + continue; + } + + metric_entry->hardif_neigh = hardif_neigh; + list_add(&metric_entry->list, &metric_queue); } rcu_read_unlock();
+ list_for_each_entry_safe(metric_entry, metric_safe, &metric_queue, list) { + batadv_v_elp_throughput_metric_update(metric_entry->hardif_neigh); + + batadv_hardif_neigh_put(metric_entry->hardif_neigh); + list_del(&metric_entry->list); + kfree(metric_entry); + } + restart_timer: batadv_v_elp_start_timer(hard_iface); out: diff --git a/net/batman-adv/bat_v_elp.h b/net/batman-adv/bat_v_elp.h index 9e2740195fa2..c9cb0a307100 100644 --- a/net/batman-adv/bat_v_elp.h +++ b/net/batman-adv/bat_v_elp.h @@ -10,7 +10,6 @@ #include "main.h"
#include <linux/skbuff.h> -#include <linux/workqueue.h>
int batadv_v_elp_iface_enable(struct batadv_hard_iface *hard_iface); void batadv_v_elp_iface_disable(struct batadv_hard_iface *hard_iface); @@ -19,6 +18,5 @@ void batadv_v_elp_iface_activate(struct batadv_hard_iface *primary_iface, void batadv_v_elp_primary_iface_set(struct batadv_hard_iface *primary_iface); int batadv_v_elp_packet_recv(struct sk_buff *skb, struct batadv_hard_iface *if_incoming); -void batadv_v_elp_throughput_metric_update(struct work_struct *work);
#endif /* _NET_BATMAN_ADV_BAT_V_ELP_H_ */ diff --git a/net/batman-adv/types.h b/net/batman-adv/types.h index 04f6398b3a40..85a50096f5b2 100644 --- a/net/batman-adv/types.h +++ b/net/batman-adv/types.h @@ -596,9 +596,6 @@ struct batadv_hardif_neigh_node_bat_v { * neighbor */ unsigned long last_unicast_tx; - - /** @metric_work: work queue callback item for metric update */ - struct work_struct metric_work; };
/**
From: Remi Pommarel repk@triplefau.lt
Since commit 4436df478860 ("batman-adv: Add flex array to struct batadv_tvlv_tt_data"), the introduction of batadv_tvlv_tt_data's flex array member in batadv_tt_tvlv_ogm_handler_v1() put tt_changes at invalid offset. Those TT changes are supposed to be filled from the end of batadv_tvlv_tt_data structure (including vlan_data flexible array), but only the flex array size is taken into account missing completely the size of the fixed part of the structure itself.
Fix the tt_change offset computation by using struct_size() instead of flex_array_size() so both flex array member and its container structure sizes are taken into account.
Cc: stable@vger.kernel.org Fixes: 4436df478860 ("batman-adv: Add flex array to struct batadv_tvlv_tt_data") Signed-off-by: Remi Pommarel repk@triplefau.lt Signed-off-by: Sven Eckelmann sven@narfation.org Signed-off-by: Simon Wunderlich sw@simonwunderlich.de --- net/batman-adv/translation-table.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-)
diff --git a/net/batman-adv/translation-table.c b/net/batman-adv/translation-table.c index 760d51fdbdf6..7d5de4cbb814 100644 --- a/net/batman-adv/translation-table.c +++ b/net/batman-adv/translation-table.c @@ -3959,23 +3959,21 @@ static void batadv_tt_tvlv_ogm_handler_v1(struct batadv_priv *bat_priv, struct batadv_tvlv_tt_change *tt_change; struct batadv_tvlv_tt_data *tt_data; u16 num_entries, num_vlan; - size_t flex_size; + size_t tt_data_sz;
if (tvlv_value_len < sizeof(*tt_data)) return;
tt_data = tvlv_value; - tvlv_value_len -= sizeof(*tt_data); - num_vlan = ntohs(tt_data->num_vlan);
- flex_size = flex_array_size(tt_data, vlan_data, num_vlan); - if (tvlv_value_len < flex_size) + tt_data_sz = struct_size(tt_data, vlan_data, num_vlan); + if (tvlv_value_len < tt_data_sz) return;
tt_change = (struct batadv_tvlv_tt_change *)((void *)tt_data - + flex_size); - tvlv_value_len -= flex_size; + + tt_data_sz); + tvlv_value_len -= tt_data_sz;
num_entries = batadv_tt_entries(tvlv_value_len);
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Simon Wunderlich