<feed xmlns='http://www.w3.org/2005/Atom'>
<title>kernel/include/net, branch linux-5.15.y</title>
<subtitle>Hosts the 0x221E linux distro kernel.</subtitle>
<id>https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-5.15.y</id>
<link rel='self' href='https://universe.0xinfinity.dev/distro/kernel/atom?h=linux-5.15.y'/>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/'/>
<updated>2026-03-04T12:20:36Z</updated>
<entry>
<title>ipv6: ioam: fix heap buffer overflow in __ioam6_fill_trace_data()</title>
<updated>2026-03-04T12:20:36Z</updated>
<author>
<name>Qanux</name>
<email>qjx1298677004@gmail.com</email>
</author>
<published>2026-02-11T04:04:12Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=f4d9d4b8fd839719d564651671e24c62c545c23b'/>
<id>urn:sha1:f4d9d4b8fd839719d564651671e24c62c545c23b</id>
<content type='text'>
[ Upstream commit 6db8b56eed62baacaf37486e83378a72635c04cc ]

On the receive path, __ioam6_fill_trace_data() uses trace-&gt;nodelen
to decide how much data to write for each node. It trusts this field
as-is from the incoming packet, with no consistency check against
trace-&gt;type (the 24-bit field that tells which data items are
present). A crafted packet can set nodelen=0 while setting type bits
0-21, causing the function to write ~100 bytes past the allocated
region (into skb_shared_info), which corrupts adjacent heap memory
and leads to a kernel panic.

Add a shared helper ioam6_trace_compute_nodelen() in ioam6.c to
derive the expected nodelen from the type field, and use it:

  - in ioam6_iptunnel.c (send path, existing validation) to replace
    the open-coded computation;
  - in exthdrs.c (receive path, ipv6_hop_ioam) to drop packets whose
    nodelen is inconsistent with the type field, before any data is
    written.

Per RFC 9197, bits 12-21 are each short (4-octet) fields, so they
are included in IOAM6_MASK_SHORT_FIELDS (changed from 0xff100000 to
0xff1ffc00).

Fixes: 9ee11f0fff20 ("ipv6: ioam: Data plane support for Pre-allocated Trace")
Cc: stable@vger.kernel.org
Signed-off-by: Junxi Qian &lt;qjx1298677004@gmail.com&gt;
Reviewed-by: Justin Iurman &lt;justin.iurman@gmail.com&gt;
Link: https://patch.msgid.link/20260211040412.86195-1-qjx1298677004@gmail.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>Bluetooth: L2CAP: Fix invalid response to L2CAP_ECRED_RECONF_REQ</title>
<updated>2026-03-04T12:20:22Z</updated>
<author>
<name>Luiz Augusto von Dentz</name>
<email>luiz.von.dentz@intel.com</email>
</author>
<published>2026-02-03T20:16:16Z</published>
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<id>urn:sha1:a5fbbfa7cf2147559625f56e3e5892ddc740c931</id>
<content type='text'>
[ Upstream commit 7accb1c4321acb617faf934af59d928b0b047e2b ]

This fixes responding with an invalid result caused by checking the
wrong size of CID which should have been (cmd_len - sizeof(*req)) and
on top of it the wrong result was use L2CAP_CR_LE_INVALID_PARAMS which
is invalid/reserved for reconf when running test like L2CAP/ECFC/BI-03-C:

&gt; ACL Data RX: Handle 64 flags 0x02 dlen 14
      LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6
        MTU: 64
        MPS: 64
        Source CID: 64
&lt; ACL Data TX: Handle 64 flags 0x00 dlen 10
      LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
!        Result: Reserved (0x000c)
         Result: Reconfiguration failed - one or more Destination CIDs invalid (0x0003)

Fiix L2CAP/ECFC/BI-04-C which expects L2CAP_RECONF_INVALID_MPS (0x0002)
when more than one channel gets its MPS reduced:

&gt; ACL Data RX: Handle 64 flags 0x02 dlen 16
      LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 8
        MTU: 264
        MPS: 99
        Source CID: 64
!       Source CID: 65
&lt; ACL Data TX: Handle 64 flags 0x00 dlen 10
      LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
!        Result: Reconfiguration successful (0x0000)
         Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002)

Fix L2CAP/ECFC/BI-05-C when SCID is invalid (85 unconnected):

&gt; ACL Data RX: Handle 64 flags 0x02 dlen 14
      LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6
        MTU: 65
        MPS: 64
!        Source CID: 85
&lt; ACL Data TX: Handle 64 flags 0x00 dlen 10
      LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
!        Result: Reconfiguration successful (0x0000)
         Result: Reconfiguration failed - one or more Destination CIDs invalid (0x0003)

Fix L2CAP/ECFC/BI-06-C when MPS &lt; L2CAP_ECRED_MIN_MPS (64):

&gt; ACL Data RX: Handle 64 flags 0x02 dlen 14
      LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 2 len 6
        MTU: 672
!       MPS: 63
        Source CID: 64
&lt; ACL Data TX: Handle 64 flags 0x00 dlen 10
      LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
!       Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002)
        Result: Reconfiguration failed - other unacceptable parameters (0x0004)

Fix L2CAP/ECFC/BI-07-C when MPS reduced for more than one channel:

&gt; ACL Data RX: Handle 64 flags 0x02 dlen 16
      LE L2CAP: Enhanced Credit Reconfigure Request (0x19) ident 3 len 8
        MTU: 84
!       MPS: 71
        Source CID: 64
!        Source CID: 65
&lt; ACL Data TX: Handle 64 flags 0x00 dlen 10
      LE L2CAP: Enhanced Credit Reconfigure Respond (0x1a) ident 2 len 2
!       Result: Reconfiguration successful (0x0000)
        Result: Reconfiguration failed - reduction in size of MPS not allowed for more than one channel at a time (0x0002)

Link: https://github.com/bluez/bluez/issues/1865
Fixes: 15f02b910562 ("Bluetooth: L2CAP: Add initial code for Enhanced Credit Based Mode")
Signed-off-by: Luiz Augusto von Dentz &lt;luiz.von.dentz@intel.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: annotate data-races in ip6_multipath_hash_{policy,fields}()</title>
<updated>2026-03-04T12:20:08Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2026-01-15T09:41:37Z</published>
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<id>urn:sha1:bb9a9cd41edd4067c5966d1197e4aba760094143</id>
<content type='text'>
[ Upstream commit 03e9d91dd64e2f5ea632df5d59568d91757efc4d ]

Add missing READ_ONCE() when reading sysctl values.

Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20260115094141.3124990-5-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>ipv6: fix a race in ip6_sock_set_v6only()</title>
<updated>2026-03-04T12:19:51Z</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2026-02-16T10:22:02Z</published>
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<id>urn:sha1:79a813acfeb15f3d918596d12ba6841672532efc</id>
<content type='text'>
[ Upstream commit 452a3eee22c57a5786ae6db5c97f3b0ec13bb3b7 ]

It is unlikely that this function will be ever called
with isk-&gt;inet_num being not zero.

Perform the check on isk-&gt;inet_num inside the locked section
for complete safety.

Fixes: 9b115749acb24 ("ipv6: add ip6_sock_set_v6only")
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Reviewed-by: Fernando Fernandez Mancera &lt;fmancera@suse.de&gt;
Link: https://patch.msgid.link/20260216102202.3343588-1-edumazet@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>netfilter: nf_conncount: increase the connection clean up limit to 64</title>
<updated>2026-03-04T12:19:34Z</updated>
<author>
<name>Fernando Fernandez Mancera</name>
<email>fmancera@suse.de</email>
</author>
<published>2025-12-17T14:46:41Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=13eede458fdf231f1bf96a398feea4ad1553f14c'/>
<id>urn:sha1:13eede458fdf231f1bf96a398feea4ad1553f14c</id>
<content type='text'>
[ Upstream commit 21d033e472735ecec677f1ae46d6740b5e47a4f3 ]

After the optimization to only perform one GC per jiffy, a new problem
was introduced. If more than 8 new connections are tracked per jiffy the
list won't be cleaned up fast enough possibly reaching the limit
wrongly.

In order to prevent this issue, only skip the GC if it was already
triggered during the same jiffy and the increment is lower than the
clean up limit. In addition, increase the clean up limit to 64
connections to avoid triggering GC too often and do more effective GCs.

This has been tested using a HTTP server and several
performance tools while having nft_connlimit/xt_connlimit or OVS limit
configured.

Output of slowhttptest + OVS limit at 52000 connections:

 slow HTTP test status on 340th second:
 initializing:        0
 pending:             432
 connected:           51998
 error:               0
 closed:              0
 service available:   YES

Fixes: d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC")
Reported-by: Aleksandra Rukomoinikova &lt;ARukomoinikova@k2.cloud&gt;
Closes: https://lore.kernel.org/netfilter/b2064e7b-0776-4e14-adb6-c68080987471@k2.cloud/
Signed-off-by: Fernando Fernandez Mancera &lt;fmancera@suse.de&gt;
Signed-off-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>wifi: cfg80211: add a work abstraction with special semantics</title>
<updated>2026-02-06T15:42:04Z</updated>
<author>
<name>Johannes Berg</name>
<email>johannes.berg@intel.com</email>
</author>
<published>2026-02-02T16:50:36Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=ddb1bfbf4ab5c753954d0cd728253b642934a9f2'/>
<id>urn:sha1:ddb1bfbf4ab5c753954d0cd728253b642934a9f2</id>
<content type='text'>
[ Upstream commit a3ee4dc84c4e9d14cb34dad095fd678127aca5b6 ]

Add a work abstraction at the cfg80211 level that will always
hold the wiphy_lock() for any work executed and therefore also
can be canceled safely (without waiting) while holding that.
This improves on what we do now as with the new wiphy works we
don't have to worry about locking while cancelling them safely.

Also, don't let such works run while the device is suspended,
since they'll likely need to interact with the device. Flush
them before suspend though.

Signed-off-by: Johannes Berg &lt;johannes.berg@intel.com&gt;
Signed-off-by: Hanne-Lotta Mäenpää &lt;hannelotta@gmail.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>net: Add locking to protect skb-&gt;dev access in ip_output</title>
<updated>2026-02-06T15:42:01Z</updated>
<author>
<name>Sharath Chandra Vurukala</name>
<email>quic_sharathv@quicinc.com</email>
</author>
<published>2025-07-30T10:51:18Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=10d1b3cf657d57afa9d7ff2c7ac5f40363d927dc'/>
<id>urn:sha1:10d1b3cf657d57afa9d7ff2c7ac5f40363d927dc</id>
<content type='text'>
commit 1dbf1d590d10a6d1978e8184f8dfe20af22d680a upstream.

In ip_output() skb-&gt;dev is updated from the skb_dst(skb)-&gt;dev
this can become invalid when the interface is unregistered and freed,

Introduced new skb_dst_dev_rcu() function to be used instead of
skb_dst_dev() within rcu_locks in ip_output.This will ensure that
all the skb's associated with the dev being deregistered will
be transnmitted out first, before freeing the dev.

Given that ip_output() is called within an rcu_read_lock()
critical section or from a bottom-half context, it is safe to introduce
an RCU read-side critical section within it.

Multiple panic call stacks were observed when UL traffic was run
in concurrency with device deregistration from different functions,
pasting one sample for reference.

[496733.627565][T13385] Call trace:
[496733.627570][T13385] bpf_prog_ce7c9180c3b128ea_cgroupskb_egres+0x24c/0x7f0
[496733.627581][T13385] __cgroup_bpf_run_filter_skb+0x128/0x498
[496733.627595][T13385] ip_finish_output+0xa4/0xf4
[496733.627605][T13385] ip_output+0x100/0x1a0
[496733.627613][T13385] ip_send_skb+0x68/0x100
[496733.627618][T13385] udp_send_skb+0x1c4/0x384
[496733.627625][T13385] udp_sendmsg+0x7b0/0x898
[496733.627631][T13385] inet_sendmsg+0x5c/0x7c
[496733.627639][T13385] __sys_sendto+0x174/0x1e4
[496733.627647][T13385] __arm64_sys_sendto+0x28/0x3c
[496733.627653][T13385] invoke_syscall+0x58/0x11c
[496733.627662][T13385] el0_svc_common+0x88/0xf4
[496733.627669][T13385] do_el0_svc+0x2c/0xb0
[496733.627676][T13385] el0_svc+0x2c/0xa4
[496733.627683][T13385] el0t_64_sync_handler+0x68/0xb4
[496733.627689][T13385] el0t_64_sync+0x1a4/0x1a8

Changes in v3:
- Replaced WARN_ON() with  WARN_ON_ONCE(), as suggested by Willem de Bruijn.
- Dropped legacy lines mistakenly pulled in from an outdated branch.

Changes in v2:
- Addressed review comments from Eric Dumazet
- Used READ_ONCE() to prevent potential load/store tearing
- Added skb_dst_dev_rcu() and used along with rcu_read_lock() in ip_output

Signed-off-by: Sharath Chandra Vurukala &lt;quic_sharathv@quicinc.com&gt;
Reviewed-by: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://patch.msgid.link/20250730105118.GA26100@hu-sharathv-hyd.qualcomm.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
[ Keerthana: Backported the patch to v5.15-v6.1 ]
Signed-off-by: Keerthana K &lt;keerthana.kalyanasundaram@broadcom.com&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
</entry>
<entry>
<title>nfc: nci: Fix race between rfkill and nci_unregister_device().</title>
<updated>2026-02-06T15:42:00Z</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@google.com</email>
</author>
<published>2026-01-27T04:03:59Z</published>
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<id>urn:sha1:eaa5da5130deda26420273d4610cf6e4f794ed75</id>
<content type='text'>
[ Upstream commit d2492688bb9fed6ab6e313682c387ae71a66ebae ]

syzbot reported the splat below [0] without a repro.

It indicates that struct nci_dev.cmd_wq had been destroyed before
nci_close_device() was called via rfkill.

nci_dev.cmd_wq is only destroyed in nci_unregister_device(), which
(I think) was called from virtual_ncidev_close() when syzbot close()d
an fd of virtual_ncidev.

The problem is that nci_unregister_device() destroys nci_dev.cmd_wq
first and then calls nfc_unregister_device(), which removes the
device from rfkill by rfkill_unregister().

So, the device is still visible via rfkill even after nci_dev.cmd_wq
is destroyed.

Let's unregister the device from rfkill first in nci_unregister_device().

Note that we cannot call nfc_unregister_device() before
nci_close_device() because

  1) nfc_unregister_device() calls device_del() which frees
     all memory allocated by devm_kzalloc() and linked to
     ndev-&gt;conn_info_list

  2) nci_rx_work() could try to queue nci_conn_info to
     ndev-&gt;conn_info_list which could be leaked

Thus, nfc_unregister_device() is split into two functions so we
can remove rfkill interfaces only before nci_close_device().

[0]:
DEBUG_LOCKS_WARN_ON(1)
WARNING: kernel/locking/lockdep.c:238 at hlock_class kernel/locking/lockdep.c:238 [inline], CPU#0: syz.0.8675/6349
WARNING: kernel/locking/lockdep.c:238 at check_wait_context kernel/locking/lockdep.c:4854 [inline], CPU#0: syz.0.8675/6349
WARNING: kernel/locking/lockdep.c:238 at __lock_acquire+0x39d/0x2cf0 kernel/locking/lockdep.c:5187, CPU#0: syz.0.8675/6349
Modules linked in:
CPU: 0 UID: 0 PID: 6349 Comm: syz.0.8675 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
RIP: 0010:hlock_class kernel/locking/lockdep.c:238 [inline]
RIP: 0010:check_wait_context kernel/locking/lockdep.c:4854 [inline]
RIP: 0010:__lock_acquire+0x3a4/0x2cf0 kernel/locking/lockdep.c:5187
Code: 18 00 4c 8b 74 24 08 75 27 90 e8 17 f2 fc 02 85 c0 74 1c 83 3d 50 e0 4e 0e 00 75 13 48 8d 3d 43 f7 51 0e 48 c7 c6 8b 3a de 8d &lt;67&gt; 48 0f b9 3a 90 31 c0 0f b6 98 c4 00 00 00 41 8b 45 20 25 ff 1f
RSP: 0018:ffffc9000c767680 EFLAGS: 00010046
RAX: 0000000000000001 RBX: 0000000000040000 RCX: 0000000000080000
RDX: ffffc90013080000 RSI: ffffffff8dde3a8b RDI: ffffffff8ff24ca0
RBP: 0000000000000003 R08: ffffffff8fef35a3 R09: 1ffffffff1fde6b4
R10: dffffc0000000000 R11: fffffbfff1fde6b5 R12: 00000000000012a2
R13: ffff888030338ba8 R14: ffff888030338000 R15: ffff888030338b30
FS:  00007fa5995f66c0(0000) GS:ffff8881256f8000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f7e72f842d0 CR3: 00000000485a0000 CR4: 00000000003526f0
Call Trace:
 &lt;TASK&gt;
 lock_acquire+0x106/0x330 kernel/locking/lockdep.c:5868
 touch_wq_lockdep_map+0xcb/0x180 kernel/workqueue.c:3940
 __flush_workqueue+0x14b/0x14f0 kernel/workqueue.c:3982
 nci_close_device+0x302/0x630 net/nfc/nci/core.c:567
 nci_dev_down+0x3b/0x50 net/nfc/nci/core.c:639
 nfc_dev_down+0x152/0x290 net/nfc/core.c:161
 nfc_rfkill_set_block+0x2d/0x100 net/nfc/core.c:179
 rfkill_set_block+0x1d2/0x440 net/rfkill/core.c:346
 rfkill_fop_write+0x461/0x5a0 net/rfkill/core.c:1301
 vfs_write+0x29a/0xb90 fs/read_write.c:684
 ksys_write+0x150/0x270 fs/read_write.c:738
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fa59b39acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 &lt;48&gt; 3d 01 f0 ff ff 73 01 c3 48 c7 c1 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fa5995f6028 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007fa59b615fa0 RCX: 00007fa59b39acb9
RDX: 0000000000000008 RSI: 0000200000000080 RDI: 0000000000000007
RBP: 00007fa59b408bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fa59b616038 R14: 00007fa59b615fa0 R15: 00007ffc82218788
 &lt;/TASK&gt;

Fixes: 6a2968aaf50c ("NFC: basic NCI protocol implementation")
Reported-by: syzbot+f9c5fd1a0874f9069dce@syzkaller.appspotmail.com
Closes: https://lore.kernel.org/all/695e7f56.050a0220.1c677c.036c.GAE@google.com/
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@google.com&gt;
Reviewed-by: Simon Horman &lt;horms@kernel.org&gt;
Link: https://patch.msgid.link/20260127040411.494931-1-kuniyu@google.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>netfilter: nf_conncount: rework API to use sk_buff directly</title>
<updated>2026-01-19T12:09:35Z</updated>
<author>
<name>Fernando Fernandez Mancera</name>
<email>fmancera@suse.de</email>
</author>
<published>2025-11-21T00:14:30Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=b160895d6bc9690459b16ef87799c9bd456af3ec'/>
<id>urn:sha1:b160895d6bc9690459b16ef87799c9bd456af3ec</id>
<content type='text'>
[ Upstream commit be102eb6a0e7c03db00e50540622f4e43b2d2844 ]

When using nf_conncount infrastructure for non-confirmed connections a
duplicated track is possible due to an optimization introduced since
commit d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC").

In order to fix this introduce a new conncount API that receives
directly an sk_buff struct.  It fetches the tuple and zone and the
corresponding ct from it. It comes with both existing conncount variants
nf_conncount_count_skb() and nf_conncount_add_skb(). In addition remove
the old API and adjust all the users to use the new one.

This way, for each sk_buff struct it is possible to check if there is a
ct present and already confirmed. If so, skip the add operation.

Fixes: d265929930e2 ("netfilter: nf_conncount: reduce unnecessary GC")
Signed-off-by: Fernando Fernandez Mancera &lt;fmancera@suse.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Stable-dep-of: 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
<entry>
<title>netfilter: nf_conncount: reduce unnecessary GC</title>
<updated>2026-01-19T12:09:35Z</updated>
<author>
<name>William Tu</name>
<email>u9012063@gmail.com</email>
</author>
<published>2022-05-04T15:35:59Z</published>
<link rel='alternate' type='text/html' href='https://universe.0xinfinity.dev/distro/kernel/commit/?id=be69850b461e7b491d87a22e33ab76fdd04b725e'/>
<id>urn:sha1:be69850b461e7b491d87a22e33ab76fdd04b725e</id>
<content type='text'>
[ Upstream commit d265929930e2ffafc744c0ae05fb70acd53be1ee ]

Currently nf_conncount can trigger garbage collection (GC)
at multiple places. Each GC process takes a spin_lock_bh
to traverse the nf_conncount_list. We found that when testing
port scanning use two parallel nmap, because the number of
connection increase fast, the nf_conncount_count and its
subsequent call to __nf_conncount_add take too much time,
causing several CPU lockup. This happens when user set the
conntrack limit to +20,000, because the larger the limit,
the longer the list that GC has to traverse.

The patch mitigate the performance issue by avoiding unnecessary
GC with a timestamp. Whenever nf_conncount has done a GC,
a timestamp is updated, and beforce the next time GC is
triggered, we make sure it's more than a jiffies.
By doin this we can greatly reduce the CPU cycles and
avoid the softirq lockup.

To reproduce it in OVS,
$ ovs-appctl dpctl/ct-set-limits zone=1,limit=20000
$ ovs-appctl dpctl/ct-get-limits

At another machine, runs two nmap
$ nmap -p1- &lt;IP&gt;
$ nmap -p1- &lt;IP&gt;

Signed-off-by: William Tu &lt;u9012063@gmail.com&gt;
Co-authored-by: Yifeng Sun &lt;pkusunyifeng@gmail.com&gt;
Reported-by: Greg Rose &lt;gvrose8192@gmail.com&gt;
Suggested-by: Florian Westphal &lt;fw@strlen.de&gt;
Signed-off-by: Pablo Neira Ayuso &lt;pablo@netfilter.org&gt;
Stable-dep-of: 69894e5b4c5e ("netfilter: nft_connlimit: update the count if add was skipped")
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
</entry>
</feed>
