htb_lookup_leaf has a BUG_ON that can trigger with the following:
tc qdisc del dev lo root
tc qdisc add dev lo root handle 1: htb default 1
tc class add dev lo parent 1: classid 1:1 htb rate 64bit
tc qdisc add dev lo parent 1:1 handle 2: netem
tc qdisc add dev lo parent 2:1 handle 3: blackhole
ping -I lo -c1 -W0.001 127.0.0.1
The root cause is the following:
1. htb_dequeue calls htb_dequeue_tree which calls the dequeue handler on
the selected leaf qdisc
2. netem_dequeue calls enqueue on the child qdisc
3. blackhole_enqueue drops the packet and returns a value that is not
just NET_XMIT_SUCCESS
4. Because of this, netem_dequeue calls qdisc_tree_reduce_backlog, and
since qlen is now 0, it calls htb_qlen_notify -> htb_deactivate ->
htb_deactiviate_prios -> htb_remove_class_from_row -> htb_safe_rb_erase
5. As this is the only class in the selected hprio rbtree,
__rb_change_child in __rb_erase_augmented sets the rb_root pointer to
NULL
6. Because blackhole_dequeue returns NULL, netem_dequeue returns NULL,
which causes htb_dequeue_tree to call htb_lookup_leaf with the same
hprio rbtree, and fail the BUG_ON
The function graph for this scenario is shown here:
0) | htb_enqueue() {
0) + 13.635 us | netem_enqueue();
0) 4.719 us | htb_activate_prios();
0) # 2249.199 us | }
0) | htb_dequeue() {
0) 2.355 us | htb_lookup_leaf();
0) | netem_dequeue() {
0) + 11.061 us | blackhole_enqueue();
0) | qdisc_tree_reduce_backlog() {
0) | qdisc_lookup_rcu() {
0) 1.873 us | qdisc_match_from_root();
0) 6.292 us | }
0) 1.894 us | htb_search();
0) | htb_qlen_notify() {
0) 2.655 us | htb_deactivate_prios();
0) 6.933 us | }
0) + 25.227 us | }
0) 1.983 us | blackhole_dequeue();
0) + 86.553 us | }
0) # 2932.761 us | qdisc_warn_nonwc();
0) | htb_lookup_leaf() {
0) | BUG_ON();
------------------------------------------
The full original bug report can be seen here [1].
We can fix this just by returning NULL instead of the BUG_ON,
as htb_dequeue_tree returns NULL when htb_lookup_leaf returns
NULL.
[1] https://lore.kernel.org/netdev/pF5XOOIim0IuEfhI-SOxTgRvNoDwuux7UHKnE_Y5-zVd4wmGvNk2ceHjKb8ORnzw0cGwfmVu42g9dL7XyJLf1NEzaztboTWcm0Ogxuojoeo=@willsroot.io/
Fixes: 512bb43eb5 ("pkt_sched: sch_htb: Optimize WARN_ONs in htb_dequeue_tree() etc.")
Signed-off-by: William Liu <will@willsroot.io>
Signed-off-by: Savino Dicanosa <savy@syst3mfailure.io>
Link: https://patch.msgid.link/20250717022816.221364-1-will@willsroot.io
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
A race condition can occur when 'agg' is modified in qfq_change_agg
(called during qfq_enqueue) while other threads access it
concurrently. For example, qfq_dump_class may trigger a NULL
dereference, and qfq_delete_class may cause a use-after-free.
This patch addresses the issue by:
1. Moved qfq_destroy_class into the critical section.
2. Added sch_tree_lock protection to qfq_dump_class and
qfq_dump_class_stats.
Fixes: 462dbc9101 ("pkt_sched: QFQ Plus: fair-queueing service at DRR cost")
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Also storing tcf_action into struct tcf_skbedit_params
makes sure there is no discrepancy in tcf_skbedit_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-12-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_police_params
makes sure there is no discrepancy in tcf_police_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-11-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_pedit_params
makes sure there is no discrepancy in tcf_pedit_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-10-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_nat_params
makes sure there is no discrepancy in tcf_nat_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-9-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_mpls_params
makes sure there is no discrepancy in tcf_mpls_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-8-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_ctinfo_params
makes sure there is no discrepancy in tcf_ctinfo_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 21c167aa0b ("net/sched: act_ctinfo: use percpu stats")
missed that stats_dscp_set, stats_dscp_error and stats_cpmark_set
might be written (and read) locklessly.
Use atomic64_t for these three fields, I doubt act_ctinfo is used
heavily on big SMP hosts anyway.
Fixes: 24ec483cec ("net: sched: Introduce act_ctinfo action")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Pedro Tammela <pctammela@mojatatu.com>
Link: https://patch.msgid.link/20250709090204.797558-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_ct_params
makes sure there is no discrepancy in tcf_ct_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_csum_params
makes sure there is no discrepancy in tcf_csum_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Also storing tcf_action into struct tcf_connmark_parms
makes sure there is no discrepancy in tcf_connmark_act().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250709090204.797558-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
netem_enqueue's duplication prevention logic breaks when a netem
resides in a qdisc tree with other netems - this can lead to a
soft lockup and OOM loop in netem_dequeue, as seen in [1].
Ensure that a duplicating netem cannot exist in a tree with other
netems.
Previous approaches suggested in discussions in chronological order:
1) Track duplication status or ttl in the sk_buff struct. Considered
too specific a use case to extend such a struct, though this would
be a resilient fix and address other previous and potential future
DOS bugs like the one described in loopy fun [2].
2) Restrict netem_enqueue recursion depth like in act_mirred with a
per cpu variable. However, netem_dequeue can call enqueue on its
child, and the depth restriction could be bypassed if the child is a
netem.
3) Use the same approach as in 2, but add metadata in netem_skb_cb
to handle the netem_dequeue case and track a packet's involvement
in duplication. This is an overly complex approach, and Jamal
notes that the skb cb can be overwritten to circumvent this
safeguard.
4) Prevent the addition of a netem to a qdisc tree if its ancestral
path contains a netem. However, filters and actions can cause a
packet to change paths when re-enqueued to the root from netem
duplication, leading us to the current solution: prevent a
duplicating netem from inhabiting the same tree as other netems.
[1] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/
[2] https://lwn.net/Articles/719297/
Fixes: 0afb51e728 ("[PKT_SCHED]: netem: reinsert for duplication")
Reported-by: William Liu <will@willsroot.io>
Reported-by: Savino Dicanosa <savy@syst3mfailure.io>
Signed-off-by: William Liu <will@willsroot.io>
Signed-off-by: Savino Dicanosa <savy@syst3mfailure.io>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/20250708164141.875402-1-will@willsroot.io
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
To prevent a potential crash in agg_dequeue (net/sched/sch_qfq.c)
when cl->qdisc->ops->peek(cl->qdisc) returns NULL, we check the return
value before using it, similar to the existing approach in sch_hfsc.c.
To avoid code duplication, the following changes are made:
1. Changed qdisc_warn_nonwc(include/net/pkt_sched.h) into a static
inline function.
2. Moved qdisc_peek_len from net/sched/sch_hfsc.c to
include/net/pkt_sched.h so that sch_qfq can reuse it.
3. Applied qdisc_peek_len in agg_dequeue to avoid crashing.
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Reviewed-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://patch.msgid.link/20250705212143.3982664-1-xmei5@asu.edu
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Refine qdisc_pkt_len_init to include headers up through
the inner transport header when computing header size
for encapsulations. Also refine net/sched/sch_cake.c
borrowed from qdisc_pkt_len_init().
Signed-off-by: Fengyuan Gong <gfengyuan@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250702160741.1204919-1-gfengyuan@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tc_action_net_exit() got an rtnl exclusion in commit
a159d3c4b8 ("net_sched: acquire RTNL in tc_action_net_exit()")
Since then, commit 16af606739 ("net: sched: implement reference
counted action release") made this RTNL exclusion obsolete for
most cases.
Only tcf_action_offload_del() might still require it.
Move the rtnl locking into tcf_idrinfo_destroy() when
an offload action is found.
Most netns do not have actions, yet deleting them is adding a lot
of pressure on RTNL, which is for many the most contended mutex
in the kernel.
We are moving to a per-netns 'rtnl', so tc_action_net_exit()
will not be able to grab 'rtnl' a single time for a batch of netns.
Before the patch:
perf probe -a rtnl_lock
perf record -e probe:rtnl_lock -a /bin/bash -c 'unshare -n "/bin/true"; sleep 1'
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.305 MB perf.data (25 samples) ]
After the patch:
perf record -e probe:rtnl_lock -a /bin/bash -c 'unshare -n "/bin/true"; sleep 1'
[ perf record: Woken up 1 times to write data ]
[ perf record: Captured and wrote 0.304 MB perf.data (9 samples) ]
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Vlad Buslov <vladbu@nvidia.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Link: https://patch.msgid.link/20250702071230.1892674-1-edumazet@google.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Certain classful qdiscs may invoke their classes' dequeue handler on an
enqueue operation. This may unexpectedly empty the child qdisc and thus
make an in-flight class passive via qlen_notify(). Most qdiscs do not
expect such behaviour at this point in time and may re-activate the
class eventually anyways which will lead to a use-after-free.
The referenced fix commit attempted to fix this behavior for the HFSC
case by moving the backlog accounting around, though this turned out to
be incomplete since the parent's parent may run into the issue too.
The following reproducer demonstrates this use-after-free:
tc qdisc add dev lo root handle 1: drr
tc filter add dev lo parent 1: basic classid 1:1
tc class add dev lo parent 1: classid 1:1 drr
tc qdisc add dev lo parent 1:1 handle 2: hfsc def 1
tc class add dev lo parent 2: classid 2:1 hfsc rt m1 8 d 1 m2 0
tc qdisc add dev lo parent 2:1 handle 3: netem
tc qdisc add dev lo parent 3:1 handle 4: blackhole
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
tc class delete dev lo classid 1:1
echo 1 | socat -u STDIN UDP4-DATAGRAM:127.0.0.1:8888
Since backlog accounting issues leading to a use-after-frees on stale
class pointers is a recurring pattern at this point, this patch takes
a different approach. Instead of trying to fix the accounting, the patch
ensures that qdisc_tree_reduce_backlog always calls qlen_notify when
the child qdisc is empty. This solves the problem because deletion of
qdiscs always involves a call to qdisc_reset() and / or
qdisc_purge_queue() which ultimately resets its qlen to 0 thus causing
the following qdisc_tree_reduce_backlog() to report to the parent. Note
that this may call qlen_notify on passive classes multiple times. This
is not a problem after the recent patch series that made all the
classful qdiscs qlen_notify() handlers idempotent.
Fixes: 3f98113810 ("sch_hfsc: Fix qlen accounting bug when using peek in hfsc_enqueue()")
Signed-off-by: Lion Ackermann <nnamrec@gmail.com>
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Acked-by: Cong Wang <xiyou.wangcong@gmail.com>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Link: https://patch.msgid.link/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Replace the deprecated strncpy() with the two-argument version of
strscpy() as the destination is an array
and buffer should be NUL-terminated.
Signed-off-by: Pranav Tyagi <pranav.tyagi03@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250620103653.6957-1-pranav.tyagi03@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since taprio’s taprio_dev_notifier() isn’t protected by an
RCU read-side critical section, a race with advance_sched()
can lead to a use-after-free.
Adding rcu_read_lock() inside taprio_dev_notifier() prevents this.
Fixes: fed87cc671 ("net/sched: taprio: automatically calculate queueMaxSDU based on TC gate durations")
Cc: stable@vger.kernel.org
Signed-off-by: Hyunwoo Kim <imv4bel@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/aEzIYYxt0is9upYG@v4bel-B760M-AORUS-ELITE-AX
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Current release - regressions:
- af_unix: allow passing cred for embryo without SO_PASSCRED/SO_PASSPIDFD
Current release - new code bugs:
- eth: airoha: correct enable mask for RX queues 16-31
- veth: prevent NULL pointer dereference in veth_xdp_rcv when peer
disappears under traffic
- ipv6: move fib6_config_validate() to ip6_route_add(), prevent invalid
routes
Previous releases - regressions:
- phy: phy_caps: don't skip better duplex match on non-exact match
- dsa: b53: fix untagged traffic sent via cpu tagged with VID 0
- Revert "wifi: mwifiex: Fix HT40 bandwidth issue.", it caused transient
packet loss, exact reason not fully understood, yet
Previous releases - always broken:
- net: clear the dst when BPF is changing skb protocol (IPv4 <> IPv6)
- sched: sfq: fix a potential crash on gso_skb handling
- Bluetooth: intel: improve rx buffer posting to avoid causing issues
in the firmware
- eth: intel: i40e: make reset handling robust against multiple requests
- eth: mlx5: ensure FW pages are always allocated on the local NUMA
node, even when device is configure to 'serve' another node
- wifi: ath12k: fix GCC_GCC_PCIE_HOT_RST definition for WCN7850,
prevent kernel crashes
- wifi: ath11k: avoid burning CPU in ath11k_debugfs_fw_stats_request()
for 3 sec if fw_stats_done is not set
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'net-6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Pull networking fixes from Jakub Kicinski:
"Including fixes from bluetooth and wireless.
Current release - regressions:
- af_unix: allow passing cred for embryo without SO_PASSCRED/SO_PASSPIDFD
Current release - new code bugs:
- eth: airoha: correct enable mask for RX queues 16-31
- veth: prevent NULL pointer dereference in veth_xdp_rcv when peer
disappears under traffic
- ipv6: move fib6_config_validate() to ip6_route_add(), prevent
invalid routes
Previous releases - regressions:
- phy: phy_caps: don't skip better duplex match on non-exact match
- dsa: b53: fix untagged traffic sent via cpu tagged with VID 0
- Revert "wifi: mwifiex: Fix HT40 bandwidth issue.", it caused
transient packet loss, exact reason not fully understood, yet
Previous releases - always broken:
- net: clear the dst when BPF is changing skb protocol (IPv4 <> IPv6)
- sched: sfq: fix a potential crash on gso_skb handling
- Bluetooth: intel: improve rx buffer posting to avoid causing issues
in the firmware
- eth: intel: i40e: make reset handling robust against multiple
requests
- eth: mlx5: ensure FW pages are always allocated on the local NUMA
node, even when device is configure to 'serve' another node
- wifi: ath12k: fix GCC_GCC_PCIE_HOT_RST definition for WCN7850,
prevent kernel crashes
- wifi: ath11k: avoid burning CPU in ath11k_debugfs_fw_stats_request()
for 3 sec if fw_stats_done is not set"
* tag 'net-6.16-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (70 commits)
selftests: drv-net: rss_ctx: Add test for ntuple rules targeting default RSS context
net: ethtool: Don't check if RSS context exists in case of context 0
af_unix: Allow passing cred for embryo without SO_PASSCRED/SO_PASSPIDFD.
ipv6: Move fib6_config_validate() to ip6_route_add().
net: drv: netdevsim: don't napi_complete() from netpoll
net/mlx5: HWS, Add error checking to hws_bwc_rule_complex_hash_node_get()
veth: prevent NULL pointer dereference in veth_xdp_rcv
net_sched: remove qdisc_tree_flush_backlog()
net_sched: ets: fix a race in ets_qdisc_change()
net_sched: tbf: fix a race in tbf_change()
net_sched: red: fix a race in __red_change()
net_sched: prio: fix a race in prio_tune()
net_sched: sch_sfq: reject invalid perturb period
net: phy: phy_caps: Don't skip better duplex macth on non-exact match
MAINTAINERS: Update Kuniyuki Iwashima's email address.
selftests: net: add test case for NAT46 looping back dst
net: clear the dst when changing skb protocol
net/mlx5e: Fix number of lanes to UNKNOWN when using data_rate_oper
net/mlx5e: Fix leak of Geneve TLV option object
net/mlx5: HWS, make sure the uplink is the last destination
...
Gerrard Tai reported a race condition in ETS, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
Fixes: b05972f01e ("net: sched: tbf: don't call qdisc_put() while holding tree lock")
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Suggested-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250611111515.1983366-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Gerrard Tai reported a race condition in TBF, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
Fixes: b05972f01e ("net: sched: tbf: don't call qdisc_put() while holding tree lock")
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Suggested-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Zhengchao Shao <shaozhengchao@huawei.com>
Link: https://patch.msgid.link/20250611111515.1983366-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Gerrard Tai reported a race condition in RED, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
Fixes: 0c8d13ac96 ("net: sched: red: delay destroying child qdisc on replace")
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Suggested-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250611111515.1983366-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
Fixes: 7b8e0b6e65 ("net: sched: prio: delay destroying child qdiscs on change")
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Suggested-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250611111515.1983366-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Gerrard Tai reported that SFQ perturb_period has no range check yet,
and this can be used to trigger a race condition fixed in a separate patch.
We want to make sure ctl->perturb_period * HZ will not overflow
and is positive.
Tested:
tc qd add dev lo root sfq perturb -10 # negative value : error
Error: sch_sfq: invalid perturb period.
tc qd add dev lo root sfq perturb 1000000000 # too big : error
Error: sch_sfq: invalid perturb period.
tc qd add dev lo root sfq perturb 2000000 # acceptable value
tc -s -d qd sh dev lo
qdisc sfq 8005: root refcnt 2 limit 127p quantum 64Kb depth 127 flows 128 divisor 1024 perturb 2000000sec
Sent 0 bytes 0 pkt (dropped 0, overlimits 0 requeues 0)
backlog 0b 0p requeues 0
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20250611083501.1810459-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
SFQ has an assumption of always being able to queue at least one packet.
However, after the blamed commit, sch->q.len can be inflated by packets
in sch->gso_skb, and an enqueue() on an empty SFQ qdisc can be followed
by an immediate drop.
Fix sfq_drop() to properly clear q->tail in this situation.
Tested:
ip netns add lb
ip link add dev to-lb type veth peer name in-lb netns lb
ethtool -K to-lb tso off # force qdisc to requeue gso_skb
ip netns exec lb ethtool -K in-lb gro on # enable NAPI
ip link set dev to-lb up
ip -netns lb link set dev in-lb up
ip addr add dev to-lb 192.168.20.1/24
ip -netns lb addr add dev in-lb 192.168.20.2/24
tc qdisc replace dev to-lb root sfq limit 100
ip netns exec lb netserver
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
netperf -H 192.168.20.2 -l 100 &
Fixes: a53851e2c3 ("net: sched: explicit locking in gso_cpu fallback")
Reported-by: Marcus Wichelmann <marcus.wichelmann@hetzner-cloud.de>
Closes: https://lore.kernel.org/netdev/9da42688-bfaa-4364-8797-e9271f3bdaef@hetzner-cloud.de/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Link: https://patch.msgid.link/20250606165127.3629486-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Move this API to the canonical timer_*() namespace.
[ tglx: Redone against pre rc1 ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/all/aB2X0jCKQO56WdMt@gmail.com
Cross-merge networking fixes after downstream PR (net-6.15-rc8).
Conflicts:
80f2ab46c2 ("irdma: free iwdev->rf after removing MSI-X")
4bcc063939 ("ice, irdma: fix an off by one in error handling code")
c24a65b6a2 ("iidc/ice/irdma: Update IDC to support multiple consumers")
https://lore.kernel.org/20250513130630.280ee6c5@canb.auug.org.au
No extra adjacent changes.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When enqueuing the first packet to an HFSC class, hfsc_enqueue() calls the
child qdisc's peek() operation before incrementing sch->q.qlen and
sch->qstats.backlog. If the child qdisc uses qdisc_peek_dequeued(), this may
trigger an immediate dequeue and potential packet drop. In such cases,
qdisc_tree_reduce_backlog() is called, but the HFSC qdisc's qlen and backlog
have not yet been updated, leading to inconsistent queue accounting. This
can leave an empty HFSC class in the active list, causing further
consequences like use-after-free.
This patch fixes the bug by moving the increment of sch->q.qlen and
sch->qstats.backlog before the call to the child qdisc's peek() operation.
This ensures that queue length and backlog are always accurate when packet
drops or dequeues are triggered during the peek.
Fixes: 12d0ad3be9 ("net/sched/sch_hfsc.c: handle corner cases where head may change invalidating calculated deadline")
Reported-by: Mingi Cho <mincho@theori.io>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20250518222038.58538-2-xiyou.wangcong@gmail.com
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Make sctp_compute_cksum() just use the new function skb_crc32c(),
instead of calling __skb_checksum() with a skb_checksum_ops struct that
does CRC32C. This is faster and simpler.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Link: https://patch.msgid.link/20250519175012.36581-6-ebiggers@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sch_frag_data_storage is a per-CPU variable and relies on disabled BH
for its locking. Without per-CPU locking in local_bh_disable() on
PREEMPT_RT this data structure requires explicit locking.
Add local_lock_t to the struct and use local_lock_nested_bh() for locking.
This change adds only lockdep coverage and does not alter the functional
behaviour for !PREEMPT_RT.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Link: https://patch.msgid.link/20250512092736.229935-12-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
mirred_nest_level is a per-CPU variable and relies on disabled BH for its
locking. Without per-CPU locking in local_bh_disable() on PREEMPT_RT
this data structure requires explicit locking.
Move mirred_nest_level to struct netdev_xmit as u8, provide wrappers.
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Cong Wang <xiyou.wangcong@gmail.com>
Cc: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Juri Lelli <juri.lelli@redhat.com>
Link: https://patch.msgid.link/20250512092736.229935-11-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Previously, when reducing a qdisc's limit via the ->change() operation, only
the main skb queue was trimmed, potentially leaving packets in the gso_skb
list. This could result in NULL pointer dereference when we only check
sch->limit against sch->q.qlen.
This patch introduces a new helper, qdisc_dequeue_internal(), which ensures
both the gso_skb list and the main queue are properly flushed when trimming
excess packets. All relevant qdiscs (codel, fq, fq_codel, fq_pie, hhf, pie)
are updated to use this helper in their ->change() routines.
Fixes: 76e3cc126b ("codel: Controlled Delay AQM")
Fixes: 4b549a2ef4 ("fq_codel: Fair Queue Codel AQM")
Fixes: afe4fd0624 ("pkt_sched: fq: Fair Queue packet scheduler")
Fixes: ec97ecf1eb ("net: sched: add Flow Queue PIE packet scheduler")
Fixes: 10239edf86 ("net-qdisc-hhf: Heavy-Hitter Filter (HHF) qdisc")
Fixes: d4b36210c2 ("net: pkt_sched: PIE AQM scheme")
Reported-by: Will <willsroot@protonmail.com>
Reported-by: Savy <savy@syst3mfailure.io>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alan reported a NULL pointer dereference in htb_next_rb_node()
after we made htb_qlen_notify() idempotent.
It turns out in the following case it introduced some regression:
htb_dequeue_tree():
|-> fq_codel_dequeue()
|-> qdisc_tree_reduce_backlog()
|-> htb_qlen_notify()
|-> htb_deactivate()
|-> htb_next_rb_node()
|-> htb_deactivate()
For htb_next_rb_node(), after calling the 1st htb_deactivate(), the
clprio[prio]->ptr could be already set to NULL, which means
htb_next_rb_node() is vulnerable here.
For htb_deactivate(), although we checked qlen before calling it, in
case of qlen==0 after qdisc_tree_reduce_backlog(), we may call it again
which triggers the warning inside.
To fix the issues here, we need to:
1) Make htb_deactivate() idempotent, that is, simply return if we
already call it before.
2) Make htb_next_rb_node() safe against ptr==NULL.
Many thanks to Alan for testing and for the reproducer.
Fixes: 5ba8b837b5 ("sch_htb: make htb_qlen_notify() idempotent")
Reported-by: Alan J. Wylie <alan@wylie.me.uk>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Link: https://patch.msgid.link/20250428232955.1740419-2-xiyou.wangcong@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Merge tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next
Martin KaFai Lau says:
====================
pull-request: bpf-next 2025-05-02
We've added 14 non-merge commits during the last 10 day(s) which contain
a total of 13 files changed, 740 insertions(+), 121 deletions(-).
The main changes are:
1) Avoid skipping or repeating a sk when using a UDP bpf_iter,
from Jordan Rife.
2) Fixed a crash when a bpf qdisc is set in
the net.core.default_qdisc, from Amery Hung.
3) A few other fixes in the bpf qdisc, from Amery Hung.
- Always call qdisc_watchdog_init() in the .init prologue such that
the .reset/.destroy epilogue can always call qdisc_watchdog_cancel()
without issue.
- bpf_qdisc_init_prologue() was incorrectly returning an error
when the bpf qdisc is set as the default_qdisc and the mq is creating
the default_qdisc. It is now fixed.
* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next:
selftests/bpf: Cleanup bpf qdisc selftests
selftests/bpf: Test attaching a bpf qdisc with incomplete operators
bpf: net_sched: Make some Qdisc_ops ops mandatory
selftests/bpf: Test setting and creating bpf qdisc as default qdisc
bpf: net_sched: Fix bpf qdisc init prologue when set as default qdisc
selftests/bpf: Add tests for bucket resume logic in UDP socket iterators
selftests/bpf: Return socket cookies from sock_iter_batch progs
bpf: udp: Avoid socket skips and repeats during iteration
bpf: udp: Use bpf_udp_iter_batch_item for bpf_udp_iter_state batch items
bpf: udp: Get rid of st_bucket_done
bpf: udp: Make sure iter->batch always contains a full bucket snapshot
bpf: udp: Make mem flags configurable through bpf_iter_udp_realloc_batch
bpf: net_sched: Fix using bpf qdisc as default qdisc
selftests/bpf: Fix compilation errors
====================
Link: https://patch.msgid.link/20250503010755.4030524-1-martin.lau@linux.dev
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The patch makes all currently supported Qdisc_ops (i.e., .enqueue,
.dequeue, .init, .reset, and .destroy) mandatory.
Make .init, .reset and .destroy mandatory as bpf qdisc relies on prologue
and epilogue to check attach points and correctly initialize/cleanup
resources. The prologue/epilogue will only be generated for an struct_ops
operator only if users implement the operator.
Make .enqueue and .dequeue mandatory as bpf qdisc infra does not provide
a default data path.
Fixes: c824034495 ("bpf: net_sched: Support implementation of Qdisc_ops in bpf")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Allow .init to proceed if qdisc_lookup() returns NULL as it only happens
when called by qdisc_create_dflt() in mq/mqprio_init and the parent qdisc
has not been added to qdisc_hash yet. In qdisc_create(), the caller,
__tc_modify_qdisc(), would have made sure the parent qdisc already exist.
In addition, call qdisc_watchdog_init() whether .init succeeds or not to
prevent null-pointer dereference. In qdisc_create() and
qdisc_create_dflt(), if .init fails, .destroy will be called. As a
result, the destroy epilogue could call qdisc_watchdog_cancel() with an
uninitialized timer, causing null-pointer deference in hrtimer_cancel().
Fixes: c824034495 ("bpf: net_sched: Support implementation of Qdisc_ops in bpf")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Use bpf_try_module_get()/bpf_module_put() instead of try_module_get()/
module_put() when handling default qdisc since users can assign a bpf
qdisc to it.
To trigger the bug:
$ bpftool struct_ops register bpf_qdisc_fq.bpf.o /sys/fs/bpf
$ echo bpf_fq > /proc/sys/net/core/default_qdisc
Fixes: c824034495 ("bpf: net_sched: Support implementation of Qdisc_ops in bpf")
Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://patch.msgid.link/20250429192128.3860571-1-ameryhung@gmail.com
As described in Gerrard's report [1], there are use cases where a netem
child qdisc will make the parent qdisc's enqueue callback reentrant.
In the case of qfq, there won't be a UAF, but the code will add the same
classifier to the list twice, which will cause memory corruption.
This patch checks whether the class was already added to the agg->active
list (cl_is_active) before doing the addition to cater for the reentrant
case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Fixes: 37d9cf1a3c ("sched: Fix detection of empty queues in child qdiscs")
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20250425220710.3964791-5-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As described in Gerrard's report [1], there are use cases where a netem
child qdisc will make the parent qdisc's enqueue callback reentrant.
In the case of ets, there won't be a UAF, but the code will add the same
classifier to the list twice, which will cause memory corruption.
In addition to checking for qlen being zero, this patch checks whether
the class was already added to the active_list (cl_is_active) before
doing the addition to cater for the reentrant case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Fixes: 37d9cf1a3c ("sched: Fix detection of empty queues in child qdiscs")
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20250425220710.3964791-4-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As described in Gerrard's report [1], we have a UAF case when an hfsc class
has a netem child qdisc. The crux of the issue is that hfsc is assuming
that checking for cl->qdisc->q.qlen == 0 guarantees that it hasn't inserted
the class in the vttree or eltree (which is not true for the netem
duplicate case).
This patch checks the n_active class variable to make sure that the code
won't insert the class in the vttree or eltree twice, catering for the
reentrant case.
[1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Fixes: 37d9cf1a3c ("sched: Fix detection of empty queues in child qdiscs")
Reported-by: Gerrard Tai <gerrard.tai@starlabs.sg>
Acked-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20250425220710.3964791-3-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
