<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/net/core, branch v6.0.6</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>net: Fix return value of qdisc ingress handling on success</title>
<updated>2022-10-29T08:08:35+00:00</updated>
<author>
<name>Paul Blakey</name>
<email>paulb@nvidia.com</email>
</author>
<published>2022-10-18T07:34:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9d7f7277df6e4be9a7621d84fe35cb2da76c3b5d'/>
<id>9d7f7277df6e4be9a7621d84fe35cb2da76c3b5d</id>
<content type='text'>
[ Upstream commit 672e97ef689a38cb20c2cc6a1814298fea34461e ]

Currently qdisc ingress handling (sch_handle_ingress()) doesn't
set a return value and it is left to the old return value of
the caller (__netif_receive_skb_core()) which is RX drop, so if
the packet is consumed, caller will stop and return this value
as if the packet was dropped.

This causes a problem in the kernel tcp stack when having a
egress tc rule forwarding to a ingress tc rule.
The tcp stack sending packets on the device having the egress rule
will see the packets as not successfully transmitted (although they
actually were), will not advance it's internal state of sent data,
and packets returning on such tcp stream will be dropped by the tcp
stack with reason ack-of-unsent-data. See reproduction in [0] below.

Fix that by setting the return value to RX success if
the packet was handled successfully.

[0] Reproduction steps:
 $ ip link add veth1 type veth peer name peer1
 $ ip link add veth2 type veth peer name peer2
 $ ifconfig peer1 5.5.5.6/24 up
 $ ip netns add ns0
 $ ip link set dev peer2 netns ns0
 $ ip netns exec ns0 ifconfig peer2 5.5.5.5/24 up
 $ ifconfig veth2 0 up
 $ ifconfig veth1 0 up

 #ingress forwarding veth1 &lt;-&gt; veth2
 $ tc qdisc add dev veth2 ingress
 $ tc qdisc add dev veth1 ingress
 $ tc filter add dev veth2 ingress prio 1 proto all flower \
   action mirred egress redirect dev veth1
 $ tc filter add dev veth1 ingress prio 1 proto all flower \
   action mirred egress redirect dev veth2

 #steal packet from peer1 egress to veth2 ingress, bypassing the veth pipe
 $ tc qdisc add dev peer1 clsact
 $ tc filter add dev peer1 egress prio 20 proto ip flower \
   action mirred ingress redirect dev veth1

 #run iperf and see connection not running
 $ iperf3 -s&amp;
 $ ip netns exec ns0 iperf3 -c 5.5.5.6 -i 1

 #delete egress rule, and run again, now should work
 $ tc filter del dev peer1 egress
 $ ip netns exec ns0 iperf3 -c 5.5.5.6 -i 1

Fixes: f697c3e8b35c ("[NET]: Avoid unnecessary cloning for ingress filtering")
Signed-off-by: Paul Blakey &lt;paulb@nvidia.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 672e97ef689a38cb20c2cc6a1814298fea34461e ]

Currently qdisc ingress handling (sch_handle_ingress()) doesn't
set a return value and it is left to the old return value of
the caller (__netif_receive_skb_core()) which is RX drop, so if
the packet is consumed, caller will stop and return this value
as if the packet was dropped.

This causes a problem in the kernel tcp stack when having a
egress tc rule forwarding to a ingress tc rule.
The tcp stack sending packets on the device having the egress rule
will see the packets as not successfully transmitted (although they
actually were), will not advance it's internal state of sent data,
and packets returning on such tcp stream will be dropped by the tcp
stack with reason ack-of-unsent-data. See reproduction in [0] below.

Fix that by setting the return value to RX success if
the packet was handled successfully.

[0] Reproduction steps:
 $ ip link add veth1 type veth peer name peer1
 $ ip link add veth2 type veth peer name peer2
 $ ifconfig peer1 5.5.5.6/24 up
 $ ip netns add ns0
 $ ip link set dev peer2 netns ns0
 $ ip netns exec ns0 ifconfig peer2 5.5.5.5/24 up
 $ ifconfig veth2 0 up
 $ ifconfig veth1 0 up

 #ingress forwarding veth1 &lt;-&gt; veth2
 $ tc qdisc add dev veth2 ingress
 $ tc qdisc add dev veth1 ingress
 $ tc filter add dev veth2 ingress prio 1 proto all flower \
   action mirred egress redirect dev veth1
 $ tc filter add dev veth1 ingress prio 1 proto all flower \
   action mirred egress redirect dev veth2

 #steal packet from peer1 egress to veth2 ingress, bypassing the veth pipe
 $ tc qdisc add dev peer1 clsact
 $ tc filter add dev peer1 egress prio 20 proto ip flower \
   action mirred ingress redirect dev veth1

 #run iperf and see connection not running
 $ iperf3 -s&amp;
 $ ip netns exec ns0 iperf3 -c 5.5.5.6 -i 1

 #delete egress rule, and run again, now should work
 $ tc filter del dev peer1 egress
 $ ip netns exec ns0 iperf3 -c 5.5.5.6 -i 1

Fixes: f697c3e8b35c ("[NET]: Avoid unnecessary cloning for ingress filtering")
Signed-off-by: Paul Blakey &lt;paulb@nvidia.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>udp: Update reuse-&gt;has_conns under reuseport_lock.</title>
<updated>2022-10-29T08:08:33+00:00</updated>
<author>
<name>Kuniyuki Iwashima</name>
<email>kuniyu@amazon.com</email>
</author>
<published>2022-10-14T18:26:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=1fb3a672317fba2a54f1bc8a6401235c6f11f883'/>
<id>1fb3a672317fba2a54f1bc8a6401235c6f11f883</id>
<content type='text'>
[ Upstream commit 69421bf98482d089e50799f45e48b25ce4a8d154 ]

When we call connect() for a UDP socket in a reuseport group, we have
to update sk-&gt;sk_reuseport_cb-&gt;has_conns to 1.  Otherwise, the kernel
could select a unconnected socket wrongly for packets sent to the
connected socket.

However, the current way to set has_conns is illegal and possible to
trigger that problem.  reuseport_has_conns() changes has_conns under
rcu_read_lock(), which upgrades the RCU reader to the updater.  Then,
it must do the update under the updater's lock, reuseport_lock, but
it doesn't for now.

For this reason, there is a race below where we fail to set has_conns
resulting in the wrong socket selection.  To avoid the race, let's split
the reader and updater with proper locking.

 cpu1                               cpu2
+----+                             +----+

__ip[46]_datagram_connect()        reuseport_grow()
.                                  .
|- reuseport_has_conns(sk, true)   |- more_reuse = __reuseport_alloc(more_socks_size)
|  .                               |
|  |- rcu_read_lock()
|  |- reuse = rcu_dereference(sk-&gt;sk_reuseport_cb)
|  |
|  |                               |  /* reuse-&gt;has_conns == 0 here */
|  |                               |- more_reuse-&gt;has_conns = reuse-&gt;has_conns
|  |- reuse-&gt;has_conns = 1         |  /* more_reuse-&gt;has_conns SHOULD BE 1 HERE */
|  |                               |
|  |                               |- rcu_assign_pointer(reuse-&gt;socks[i]-&gt;sk_reuseport_cb,
|  |                               |                     more_reuse)
|  `- rcu_read_unlock()            `- kfree_rcu(reuse, rcu)
|
|- sk-&gt;sk_state = TCP_ESTABLISHED

Note the likely(reuse) in reuseport_has_conns_set() is always true,
but we put the test there for ease of review.  [0]

For the record, usually, sk_reuseport_cb is changed under lock_sock().
The only exception is reuseport_grow() &amp; TCP reqsk migration case.

  1) shutdown() TCP listener, which is moved into the latter part of
     reuse-&gt;socks[] to migrate reqsk.

  2) New listen() overflows reuse-&gt;socks[] and call reuseport_grow().

  3) reuse-&gt;max_socks overflows u16 with the new listener.

  4) reuseport_grow() pops the old shutdown()ed listener from the array
     and update its sk-&gt;sk_reuseport_cb as NULL without lock_sock().

shutdown()ed TCP sk-&gt;sk_reuseport_cb can be changed without lock_sock(),
but, reuseport_has_conns_set() is called only for UDP under lock_sock(),
so likely(reuse) never be false in reuseport_has_conns_set().

[0]: https://lore.kernel.org/netdev/CANn89iLja=eQHbsM_Ta2sQF0tOGU8vAGrh_izRuuHjuO1ouUag@mail.gmail.com/

Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20221014182625.89913-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 69421bf98482d089e50799f45e48b25ce4a8d154 ]

When we call connect() for a UDP socket in a reuseport group, we have
to update sk-&gt;sk_reuseport_cb-&gt;has_conns to 1.  Otherwise, the kernel
could select a unconnected socket wrongly for packets sent to the
connected socket.

However, the current way to set has_conns is illegal and possible to
trigger that problem.  reuseport_has_conns() changes has_conns under
rcu_read_lock(), which upgrades the RCU reader to the updater.  Then,
it must do the update under the updater's lock, reuseport_lock, but
it doesn't for now.

For this reason, there is a race below where we fail to set has_conns
resulting in the wrong socket selection.  To avoid the race, let's split
the reader and updater with proper locking.

 cpu1                               cpu2
+----+                             +----+

__ip[46]_datagram_connect()        reuseport_grow()
.                                  .
|- reuseport_has_conns(sk, true)   |- more_reuse = __reuseport_alloc(more_socks_size)
|  .                               |
|  |- rcu_read_lock()
|  |- reuse = rcu_dereference(sk-&gt;sk_reuseport_cb)
|  |
|  |                               |  /* reuse-&gt;has_conns == 0 here */
|  |                               |- more_reuse-&gt;has_conns = reuse-&gt;has_conns
|  |- reuse-&gt;has_conns = 1         |  /* more_reuse-&gt;has_conns SHOULD BE 1 HERE */
|  |                               |
|  |                               |- rcu_assign_pointer(reuse-&gt;socks[i]-&gt;sk_reuseport_cb,
|  |                               |                     more_reuse)
|  `- rcu_read_unlock()            `- kfree_rcu(reuse, rcu)
|
|- sk-&gt;sk_state = TCP_ESTABLISHED

Note the likely(reuse) in reuseport_has_conns_set() is always true,
but we put the test there for ease of review.  [0]

For the record, usually, sk_reuseport_cb is changed under lock_sock().
The only exception is reuseport_grow() &amp; TCP reqsk migration case.

  1) shutdown() TCP listener, which is moved into the latter part of
     reuse-&gt;socks[] to migrate reqsk.

  2) New listen() overflows reuse-&gt;socks[] and call reuseport_grow().

  3) reuse-&gt;max_socks overflows u16 with the new listener.

  4) reuseport_grow() pops the old shutdown()ed listener from the array
     and update its sk-&gt;sk_reuseport_cb as NULL without lock_sock().

shutdown()ed TCP sk-&gt;sk_reuseport_cb can be changed without lock_sock(),
but, reuseport_has_conns_set() is called only for UDP under lock_sock(),
so likely(reuse) never be false in reuseport_has_conns_set().

[0]: https://lore.kernel.org/netdev/CANn89iLja=eQHbsM_Ta2sQF0tOGU8vAGrh_izRuuHjuO1ouUag@mail.gmail.com/

Fixes: acdcecc61285 ("udp: correct reuseport selection with connected sockets")
Signed-off-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20221014182625.89913-1-kuniyu@amazon.com
Signed-off-by: Paolo Abeni &lt;pabeni@redhat.com&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>skmsg: pass gfp argument to alloc_sk_msg()</title>
<updated>2022-10-29T08:08:32+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-10-15T21:24:41+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=693ddd6ffc05b228ea1638f9d757c5d3541f9446'/>
<id>693ddd6ffc05b228ea1638f9d757c5d3541f9446</id>
<content type='text'>
[ Upstream commit 2d1f274b95c6e4ba6a813b3b8e7a1a38d54a0a08 ]

syzbot found that alloc_sk_msg() could be called from a
non sleepable context. sk_psock_verdict_recv() uses
rcu_read_lock() protection.

We need the callers to pass a gfp_t argument to avoid issues.

syzbot report was:

BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 3613, name: syz-executor414
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
INFO: lockdep is turned off.
CPU: 0 PID: 3613 Comm: syz-executor414 Not tainted 6.0.0-syzkaller-09589-g55be6084c8e0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
&lt;TASK&gt;
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
__might_resched+0x538/0x6a0 kernel/sched/core.c:9877
might_alloc include/linux/sched/mm.h:274 [inline]
slab_pre_alloc_hook mm/slab.h:700 [inline]
slab_alloc_node mm/slub.c:3162 [inline]
slab_alloc mm/slub.c:3256 [inline]
kmem_cache_alloc_trace+0x59/0x310 mm/slub.c:3287
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
alloc_sk_msg net/core/skmsg.c:507 [inline]
sk_psock_skb_ingress_self+0x5c/0x330 net/core/skmsg.c:600
sk_psock_verdict_apply+0x395/0x440 net/core/skmsg.c:1014
sk_psock_verdict_recv+0x34d/0x560 net/core/skmsg.c:1201
tcp_read_skb+0x4a1/0x790 net/ipv4/tcp.c:1770
tcp_rcv_established+0x129d/0x1a10 net/ipv4/tcp_input.c:5971
tcp_v4_do_rcv+0x479/0xac0 net/ipv4/tcp_ipv4.c:1681
sk_backlog_rcv include/net/sock.h:1109 [inline]
__release_sock+0x1d8/0x4c0 net/core/sock.c:2906
release_sock+0x5d/0x1c0 net/core/sock.c:3462
tcp_sendmsg+0x36/0x40 net/ipv4/tcp.c:1483
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
__sys_sendto+0x46d/0x5f0 net/socket.c:2117
__do_sys_sendto net/socket.c:2129 [inline]
__se_sys_sendto net/socket.c:2125 [inline]
__x64_sys_sendto+0xda/0xf0 net/socket.c:2125
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 43312915b5ba ("skmsg: Get rid of unncessary memset()")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Cong Wang &lt;cong.wang@bytedance.com&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 2d1f274b95c6e4ba6a813b3b8e7a1a38d54a0a08 ]

syzbot found that alloc_sk_msg() could be called from a
non sleepable context. sk_psock_verdict_recv() uses
rcu_read_lock() protection.

We need the callers to pass a gfp_t argument to avoid issues.

syzbot report was:

BUG: sleeping function called from invalid context at include/linux/sched/mm.h:274
in_atomic(): 0, irqs_disabled(): 0, non_block: 0, pid: 3613, name: syz-executor414
preempt_count: 0, expected: 0
RCU nest depth: 1, expected: 0
INFO: lockdep is turned off.
CPU: 0 PID: 3613 Comm: syz-executor414 Not tainted 6.0.0-syzkaller-09589-g55be6084c8e0 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
&lt;TASK&gt;
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
__might_resched+0x538/0x6a0 kernel/sched/core.c:9877
might_alloc include/linux/sched/mm.h:274 [inline]
slab_pre_alloc_hook mm/slab.h:700 [inline]
slab_alloc_node mm/slub.c:3162 [inline]
slab_alloc mm/slub.c:3256 [inline]
kmem_cache_alloc_trace+0x59/0x310 mm/slub.c:3287
kmalloc include/linux/slab.h:600 [inline]
kzalloc include/linux/slab.h:733 [inline]
alloc_sk_msg net/core/skmsg.c:507 [inline]
sk_psock_skb_ingress_self+0x5c/0x330 net/core/skmsg.c:600
sk_psock_verdict_apply+0x395/0x440 net/core/skmsg.c:1014
sk_psock_verdict_recv+0x34d/0x560 net/core/skmsg.c:1201
tcp_read_skb+0x4a1/0x790 net/ipv4/tcp.c:1770
tcp_rcv_established+0x129d/0x1a10 net/ipv4/tcp_input.c:5971
tcp_v4_do_rcv+0x479/0xac0 net/ipv4/tcp_ipv4.c:1681
sk_backlog_rcv include/net/sock.h:1109 [inline]
__release_sock+0x1d8/0x4c0 net/core/sock.c:2906
release_sock+0x5d/0x1c0 net/core/sock.c:3462
tcp_sendmsg+0x36/0x40 net/ipv4/tcp.c:1483
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
__sys_sendto+0x46d/0x5f0 net/socket.c:2117
__do_sys_sendto net/socket.c:2129 [inline]
__se_sys_sendto net/socket.c:2125 [inline]
__x64_sys_sendto+0xda/0xf0 net/socket.c:2125
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

Fixes: 43312915b5ba ("skmsg: Get rid of unncessary memset()")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Cong Wang &lt;cong.wang@bytedance.com&gt;
Cc: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Cc: John Fastabend &lt;john.fastabend@gmail.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: If sock is dead don't access sock's sk_wq in sk_stream_wait_memory</title>
<updated>2022-10-21T10:39:11+00:00</updated>
<author>
<name>Liu Jian</name>
<email>liujian56@huawei.com</email>
</author>
<published>2022-08-23T13:37:54+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=435f5aa4421782af197b98d8525263977be4af5c'/>
<id>435f5aa4421782af197b98d8525263977be4af5c</id>
<content type='text'>
[ Upstream commit 3f8ef65af927db247418d4e1db49164d7a158fc5 ]

Fixes the below NULL pointer dereference:

  [...]
  [   14.471200] Call Trace:
  [   14.471562]  &lt;TASK&gt;
  [   14.471882]  lock_acquire+0x245/0x2e0
  [   14.472416]  ? remove_wait_queue+0x12/0x50
  [   14.473014]  ? _raw_spin_lock_irqsave+0x17/0x50
  [   14.473681]  _raw_spin_lock_irqsave+0x3d/0x50
  [   14.474318]  ? remove_wait_queue+0x12/0x50
  [   14.474907]  remove_wait_queue+0x12/0x50
  [   14.475480]  sk_stream_wait_memory+0x20d/0x340
  [   14.476127]  ? do_wait_intr_irq+0x80/0x80
  [   14.476704]  do_tcp_sendpages+0x287/0x600
  [   14.477283]  tcp_bpf_push+0xab/0x260
  [   14.477817]  tcp_bpf_sendmsg_redir+0x297/0x500
  [   14.478461]  ? __local_bh_enable_ip+0x77/0xe0
  [   14.479096]  tcp_bpf_send_verdict+0x105/0x470
  [   14.479729]  tcp_bpf_sendmsg+0x318/0x4f0
  [   14.480311]  sock_sendmsg+0x2d/0x40
  [   14.480822]  ____sys_sendmsg+0x1b4/0x1c0
  [   14.481390]  ? copy_msghdr_from_user+0x62/0x80
  [   14.482048]  ___sys_sendmsg+0x78/0xb0
  [   14.482580]  ? vmf_insert_pfn_prot+0x91/0x150
  [   14.483215]  ? __do_fault+0x2a/0x1a0
  [   14.483738]  ? do_fault+0x15e/0x5d0
  [   14.484246]  ? __handle_mm_fault+0x56b/0x1040
  [   14.484874]  ? lock_is_held_type+0xdf/0x130
  [   14.485474]  ? find_held_lock+0x2d/0x90
  [   14.486046]  ? __sys_sendmsg+0x41/0x70
  [   14.486587]  __sys_sendmsg+0x41/0x70
  [   14.487105]  ? intel_pmu_drain_pebs_core+0x350/0x350
  [   14.487822]  do_syscall_64+0x34/0x80
  [   14.488345]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [...]

The test scenario has the following flow:

thread1                               thread2
-----------                           ---------------
 tcp_bpf_sendmsg
  tcp_bpf_send_verdict
   tcp_bpf_sendmsg_redir              sock_close
    tcp_bpf_push_locked                 __sock_release
     tcp_bpf_push                         //inet_release
      do_tcp_sendpages                    sock-&gt;ops-&gt;release
       sk_stream_wait_memory          	   // tcp_close
          sk_wait_event                      sk-&gt;sk_prot-&gt;close
           release_sock(__sk);
            ***
                                                lock_sock(sk);
                                                  __tcp_close
                                                    sock_orphan(sk)
                                                      sk-&gt;sk_wq  = NULL
                                                release_sock
            ****
           lock_sock(__sk);
          remove_wait_queue(sk_sleep(sk), &amp;wait);
             sk_sleep(sk)
             //NULL pointer dereference
             &amp;rcu_dereference_raw(sk-&gt;sk_wq)-&gt;wait

While waiting for memory in thread1, the socket is released with its wait
queue because thread2 has closed it. This caused by tcp_bpf_send_verdict
didn't increase the f_count of psock-&gt;sk_redir-&gt;sk_socket-&gt;file in thread1.

We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory
before accessing the wait queue.

Suggested-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/bpf/20220823133755.314697-2-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 3f8ef65af927db247418d4e1db49164d7a158fc5 ]

Fixes the below NULL pointer dereference:

  [...]
  [   14.471200] Call Trace:
  [   14.471562]  &lt;TASK&gt;
  [   14.471882]  lock_acquire+0x245/0x2e0
  [   14.472416]  ? remove_wait_queue+0x12/0x50
  [   14.473014]  ? _raw_spin_lock_irqsave+0x17/0x50
  [   14.473681]  _raw_spin_lock_irqsave+0x3d/0x50
  [   14.474318]  ? remove_wait_queue+0x12/0x50
  [   14.474907]  remove_wait_queue+0x12/0x50
  [   14.475480]  sk_stream_wait_memory+0x20d/0x340
  [   14.476127]  ? do_wait_intr_irq+0x80/0x80
  [   14.476704]  do_tcp_sendpages+0x287/0x600
  [   14.477283]  tcp_bpf_push+0xab/0x260
  [   14.477817]  tcp_bpf_sendmsg_redir+0x297/0x500
  [   14.478461]  ? __local_bh_enable_ip+0x77/0xe0
  [   14.479096]  tcp_bpf_send_verdict+0x105/0x470
  [   14.479729]  tcp_bpf_sendmsg+0x318/0x4f0
  [   14.480311]  sock_sendmsg+0x2d/0x40
  [   14.480822]  ____sys_sendmsg+0x1b4/0x1c0
  [   14.481390]  ? copy_msghdr_from_user+0x62/0x80
  [   14.482048]  ___sys_sendmsg+0x78/0xb0
  [   14.482580]  ? vmf_insert_pfn_prot+0x91/0x150
  [   14.483215]  ? __do_fault+0x2a/0x1a0
  [   14.483738]  ? do_fault+0x15e/0x5d0
  [   14.484246]  ? __handle_mm_fault+0x56b/0x1040
  [   14.484874]  ? lock_is_held_type+0xdf/0x130
  [   14.485474]  ? find_held_lock+0x2d/0x90
  [   14.486046]  ? __sys_sendmsg+0x41/0x70
  [   14.486587]  __sys_sendmsg+0x41/0x70
  [   14.487105]  ? intel_pmu_drain_pebs_core+0x350/0x350
  [   14.487822]  do_syscall_64+0x34/0x80
  [   14.488345]  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  [...]

The test scenario has the following flow:

thread1                               thread2
-----------                           ---------------
 tcp_bpf_sendmsg
  tcp_bpf_send_verdict
   tcp_bpf_sendmsg_redir              sock_close
    tcp_bpf_push_locked                 __sock_release
     tcp_bpf_push                         //inet_release
      do_tcp_sendpages                    sock-&gt;ops-&gt;release
       sk_stream_wait_memory          	   // tcp_close
          sk_wait_event                      sk-&gt;sk_prot-&gt;close
           release_sock(__sk);
            ***
                                                lock_sock(sk);
                                                  __tcp_close
                                                    sock_orphan(sk)
                                                      sk-&gt;sk_wq  = NULL
                                                release_sock
            ****
           lock_sock(__sk);
          remove_wait_queue(sk_sleep(sk), &amp;wait);
             sk_sleep(sk)
             //NULL pointer dereference
             &amp;rcu_dereference_raw(sk-&gt;sk_wq)-&gt;wait

While waiting for memory in thread1, the socket is released with its wait
queue because thread2 has closed it. This caused by tcp_bpf_send_verdict
didn't increase the f_count of psock-&gt;sk_redir-&gt;sk_socket-&gt;file in thread1.

We should check if SOCK_DEAD flag is set on wakeup in sk_stream_wait_memory
before accessing the wait queue.

Suggested-by: Jakub Sitnicki &lt;jakub@cloudflare.com&gt;
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Cc: Eric Dumazet &lt;edumazet@google.com&gt;
Link: https://lore.kernel.org/bpf/20220823133755.314697-2-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>skmsg: Schedule psock work if the cached skb exists on the psock</title>
<updated>2022-10-21T10:38:17+00:00</updated>
<author>
<name>Liu Jian</name>
<email>liujian56@huawei.com</email>
</author>
<published>2022-09-07T07:13:11+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=83efae58143b80bf764c75d0d3a051465f906585'/>
<id>83efae58143b80bf764c75d0d3a051465f906585</id>
<content type='text'>
[ Upstream commit bec217197b412d74168c6a42fc0f76d0cc9cad00 ]

In sk_psock_backlog function, for ingress direction skb, if no new data
packet arrives after the skb is cached, the cached skb does not have a
chance to be added to the receive queue of psock. As a result, the cached
skb cannot be received by the upper-layer application. Fix this by reschedule
the psock work to dispose the cached skb in sk_msg_recvmsg function.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20220907071311.60534-1-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit bec217197b412d74168c6a42fc0f76d0cc9cad00 ]

In sk_psock_backlog function, for ingress direction skb, if no new data
packet arrives after the skb is cached, the cached skb does not have a
chance to be added to the receive queue of psock. As a result, the cached
skb cannot be received by the upper-layer application. Fix this by reschedule
the psock work to dispose the cached skb in sk_msg_recvmsg function.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Liu Jian &lt;liujian56@huawei.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Acked-by: John Fastabend &lt;john.fastabend@gmail.com&gt;
Link: https://lore.kernel.org/bpf/20220907071311.60534-1-liujian56@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>flow_dissector: Do not count vlan tags inside tunnel payload</title>
<updated>2022-10-21T10:38:12+00:00</updated>
<author>
<name>Qingqing Yang</name>
<email>qingqing.yang@broadcom.com</email>
</author>
<published>2022-09-19T07:48:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=7520d82c5f8894d4941cbd6a6df75918986c0454'/>
<id>7520d82c5f8894d4941cbd6a6df75918986c0454</id>
<content type='text'>
[ Upstream commit 9f87eb4246994e32a4e4ea88476b20ab3b412840 ]

We've met the problem that when there is a vlan tag inside
GRE encapsulation, the match of num_of_vlans fails.
It is caused by the vlan tag inside GRE payload has been
counted into num_of_vlans, which is not expected.

One example packet is like this:
Ethernet II, Src: Broadcom_68:56:07 (00:10:18:68:56:07)
                   Dst: Broadcom_68:56:08 (00:10:18:68:56:08)
802.1Q Virtual LAN, PRI: 0, DEI: 0, ID: 100
Internet Protocol Version 4, Src: 192.168.1.4, Dst: 192.168.1.200
Generic Routing Encapsulation (Transparent Ethernet bridging)
Ethernet II, Src: Broadcom_68:58:07 (00:10:18:68:58:07)
                   Dst: Broadcom_68:58:08 (00:10:18:68:58:08)
802.1Q Virtual LAN, PRI: 0, DEI: 0, ID: 200
...
It should match the (num_of_vlans 1) rule, but it matches
the (num_of_vlans 2) rule.

The vlan tags inside the GRE or other tunnel encapsulated payload
should not be taken into num_of_vlans.
The fix is to stop counting the vlan number when the encapsulation
bit is set.

Fixes: 34951fcf26c5 ("flow_dissector: Add number of vlan tags dissector")
Signed-off-by: Qingqing Yang &lt;qingqing.yang@broadcom.com&gt;
Reviewed-by: Boris Sukholitko &lt;boris.sukholitko@broadcom.com&gt;
Link: https://lore.kernel.org/r/20220919074808.136640-1-qingqing.yang@broadcom.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 9f87eb4246994e32a4e4ea88476b20ab3b412840 ]

We've met the problem that when there is a vlan tag inside
GRE encapsulation, the match of num_of_vlans fails.
It is caused by the vlan tag inside GRE payload has been
counted into num_of_vlans, which is not expected.

One example packet is like this:
Ethernet II, Src: Broadcom_68:56:07 (00:10:18:68:56:07)
                   Dst: Broadcom_68:56:08 (00:10:18:68:56:08)
802.1Q Virtual LAN, PRI: 0, DEI: 0, ID: 100
Internet Protocol Version 4, Src: 192.168.1.4, Dst: 192.168.1.200
Generic Routing Encapsulation (Transparent Ethernet bridging)
Ethernet II, Src: Broadcom_68:58:07 (00:10:18:68:58:07)
                   Dst: Broadcom_68:58:08 (00:10:18:68:58:08)
802.1Q Virtual LAN, PRI: 0, DEI: 0, ID: 200
...
It should match the (num_of_vlans 1) rule, but it matches
the (num_of_vlans 2) rule.

The vlan tags inside the GRE or other tunnel encapsulated payload
should not be taken into num_of_vlans.
The fix is to stop counting the vlan number when the encapsulation
bit is set.

Fixes: 34951fcf26c5 ("flow_dissector: Add number of vlan tags dissector")
Signed-off-by: Qingqing Yang &lt;qingqing.yang@broadcom.com&gt;
Reviewed-by: Boris Sukholitko &lt;boris.sukholitko@broadcom.com&gt;
Link: https://lore.kernel.org/r/20220919074808.136640-1-qingqing.yang@broadcom.com
Signed-off-by: Jakub Kicinski &lt;kuba@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Revert "net: set proper memcg for net_init hooks allocations"</title>
<updated>2022-09-28T16:20:37+00:00</updated>
<author>
<name>Shakeel Butt</name>
<email>shakeelb@google.com</email>
</author>
<published>2022-09-26T19:59:31+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=b1cab78ba392162a5ef11173d02db6e182e04edd'/>
<id>b1cab78ba392162a5ef11173d02db6e182e04edd</id>
<content type='text'>
This reverts commit 1d0403d20f6c281cb3d14c5f1db5317caeec48e9.

Anatoly Pugachev reported that the commit 1d0403d20f6c ("net: set proper
memcg for net_init hooks allocations") is somehow causing the sparc64
VMs failed to boot and the VMs boot fine with that patch reverted. So,
revert the patch for now and later we can debug the issue.

Link: https://lore.kernel.org/all/20220918092849.GA10314@u164.east.ru/
Reported-by: Anatoly Pugachev &lt;matorola@gmail.com&gt;
Signed-off-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Vasily Averin &lt;vvs@openvz.org&gt;
Cc: Jakub Kicinski &lt;kuba@kernel.org&gt;
Cc: Michal Koutný &lt;mkoutny@suse.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: cgroups@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Tested-by: Anatoly Pugachev &lt;matorola@gmail.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Fixes: 1d0403d20f6c ("net: set proper memcg for net_init hooks allocations")
Reviewed-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Acked-by: Roman Gushchin &lt;roman.gushchin@linux.dev&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
This reverts commit 1d0403d20f6c281cb3d14c5f1db5317caeec48e9.

Anatoly Pugachev reported that the commit 1d0403d20f6c ("net: set proper
memcg for net_init hooks allocations") is somehow causing the sparc64
VMs failed to boot and the VMs boot fine with that patch reverted. So,
revert the patch for now and later we can debug the issue.

Link: https://lore.kernel.org/all/20220918092849.GA10314@u164.east.ru/
Reported-by: Anatoly Pugachev &lt;matorola@gmail.com&gt;
Signed-off-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Cc: Vasily Averin &lt;vvs@openvz.org&gt;
Cc: Jakub Kicinski &lt;kuba@kernel.org&gt;
Cc: Michal Koutný &lt;mkoutny@suse.com&gt;
Cc: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Cc: cgroups@vger.kernel.org
Cc: sparclinux@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: linux-kernel@vger.kernel.org
Tested-by: Anatoly Pugachev &lt;matorola@gmail.com&gt;
Acked-by: Johannes Weiner &lt;hannes@cmpxchg.org&gt;
Fixes: 1d0403d20f6c ("net: set proper memcg for net_init hooks allocations")
Reviewed-by: Muchun Song &lt;songmuchun@bytedance.com&gt;
Acked-by: Roman Gushchin &lt;roman.gushchin@linux.dev&gt;
Signed-off-by: Linus Torvalds &lt;torvalds@linux-foundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: core: fix flow symmetric hash</title>
<updated>2022-09-09T11:48:00+00:00</updated>
<author>
<name>Ludovic Cintrat</name>
<email>ludovic.cintrat@gatewatcher.com</email>
</author>
<published>2022-09-07T10:08:13+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=64ae13ed478428135cddc2f1113dff162d8112d4'/>
<id>64ae13ed478428135cddc2f1113dff162d8112d4</id>
<content type='text'>
__flow_hash_consistentify() wrongly swaps ipv4 addresses in few cases.
This function is indirectly used by __skb_get_hash_symmetric(), which is
used to fanout packets in AF_PACKET.
Intrusion detection systems may be impacted by this issue.

__flow_hash_consistentify() computes the addresses difference then swaps
them if the difference is negative. In few cases src - dst and dst - src
are both negative.

The following snippet mimics __flow_hash_consistentify():

```
 #include &lt;stdio.h&gt;
 #include &lt;stdint.h&gt;

 int main(int argc, char** argv) {

     int diffs_d, diffd_s;
     uint32_t dst  = 0xb225a8c0; /* 178.37.168.192 --&gt; 192.168.37.178 */
     uint32_t src  = 0x3225a8c0; /*  50.37.168.192 --&gt; 192.168.37.50  */
     uint32_t dst2 = 0x3325a8c0; /*  51.37.168.192 --&gt; 192.168.37.51  */

     diffs_d = src - dst;
     diffd_s = dst - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst, diffs_d, diffs_d, diffd_s, diffd_s);

     diffs_d = src - dst2;
     diffd_s = dst2 - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst2, diffs_d, diffs_d, diffd_s, diffd_s);

     return 0;
 }
```

Results:

src:3225a8c0 dst:b225a8c0, \
    diff(s-d)=-2147483648(0x80000000) \
    diff(d-s)=-2147483648(0x80000000)

src:3225a8c0 dst:3325a8c0, \
    diff(s-d)=-16777216(0xff000000) \
    diff(d-s)=16777216(0x1000000)

In the first case the addresses differences are always &lt; 0, therefore
__flow_hash_consistentify() always swaps, thus dst-&gt;src and src-&gt;dst
packets have differents hashes.

Fixes: c3f8324188fa8 ("net: Add full IPv6 addresses to flow_keys")
Signed-off-by: Ludovic Cintrat &lt;ludovic.cintrat@gatewatcher.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
__flow_hash_consistentify() wrongly swaps ipv4 addresses in few cases.
This function is indirectly used by __skb_get_hash_symmetric(), which is
used to fanout packets in AF_PACKET.
Intrusion detection systems may be impacted by this issue.

__flow_hash_consistentify() computes the addresses difference then swaps
them if the difference is negative. In few cases src - dst and dst - src
are both negative.

The following snippet mimics __flow_hash_consistentify():

```
 #include &lt;stdio.h&gt;
 #include &lt;stdint.h&gt;

 int main(int argc, char** argv) {

     int diffs_d, diffd_s;
     uint32_t dst  = 0xb225a8c0; /* 178.37.168.192 --&gt; 192.168.37.178 */
     uint32_t src  = 0x3225a8c0; /*  50.37.168.192 --&gt; 192.168.37.50  */
     uint32_t dst2 = 0x3325a8c0; /*  51.37.168.192 --&gt; 192.168.37.51  */

     diffs_d = src - dst;
     diffd_s = dst - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst, diffs_d, diffs_d, diffd_s, diffd_s);

     diffs_d = src - dst2;
     diffd_s = dst2 - src;

     printf("src:%08x dst:%08x, diff(s-d)=%d(0x%x) diff(d-s)=%d(0x%x)\n",
             src, dst2, diffs_d, diffs_d, diffd_s, diffd_s);

     return 0;
 }
```

Results:

src:3225a8c0 dst:b225a8c0, \
    diff(s-d)=-2147483648(0x80000000) \
    diff(d-s)=-2147483648(0x80000000)

src:3225a8c0 dst:3325a8c0, \
    diff(s-d)=-16777216(0xff000000) \
    diff(d-s)=16777216(0x1000000)

In the first case the addresses differences are always &lt; 0, therefore
__flow_hash_consistentify() always swaps, thus dst-&gt;src and src-&gt;dst
packets have differents hashes.

Fixes: c3f8324188fa8 ("net: Add full IPv6 addresses to flow_keys")
Signed-off-by: Ludovic Cintrat &lt;ludovic.cintrat@gatewatcher.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>net: skb: export skb drop reaons to user by TRACE_DEFINE_ENUM</title>
<updated>2022-09-07T14:28:08+00:00</updated>
<author>
<name>Menglong Dong</name>
<email>imagedong@tencent.com</email>
</author>
<published>2022-09-05T03:50:15+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=9cb252c4c1c53ae58bc565bab76e98133288f23a'/>
<id>9cb252c4c1c53ae58bc565bab76e98133288f23a</id>
<content type='text'>
As Eric reported, the 'reason' field is not presented when trace the
kfree_skb event by perf:

$ perf record -e skb:kfree_skb -a sleep 10
$ perf script
  ip_defrag 14605 [021]   221.614303:   skb:kfree_skb:
  skbaddr=0xffff9d2851242700 protocol=34525 location=0xffffffffa39346b1
  reason:

The cause seems to be passing kernel address directly to TP_printk(),
which is not right. As the enum 'skb_drop_reason' is not exported to
user space through TRACE_DEFINE_ENUM(), perf can't get the drop reason
string from the 'reason' field, which is a number.

Therefore, we introduce the macro DEFINE_DROP_REASON(), which is used
to define the trace enum by TRACE_DEFINE_ENUM(). With the help of
DEFINE_DROP_REASON(), now we can remove the auto-generate that we
introduced in the commit ec43908dd556
("net: skb: use auto-generation to convert skb drop reason to string"),
and define the string array 'drop_reasons'.

Hmmmm...now we come back to the situation that have to maintain drop
reasons in both enum skb_drop_reason and DEFINE_DROP_REASON. But they
are both in dropreason.h, which makes it easier.

After this commit, now the format of kfree_skb is like this:

$ cat /tracing/events/skb/kfree_skb/format
name: kfree_skb
ID: 1524
format:
        field:unsigned short common_type;       offset:0;       size:2; signed:0;
        field:unsigned char common_flags;       offset:2;       size:1; signed:0;
        field:unsigned char common_preempt_count;       offset:3;       size:1; signed:0;
        field:int common_pid;   offset:4;       size:4; signed:1;

        field:void * skbaddr;   offset:8;       size:8; signed:0;
        field:void * location;  offset:16;      size:8; signed:0;
        field:unsigned short protocol;  offset:24;      size:2; signed:0;
        field:enum skb_drop_reason reason;      offset:28;      size:4; signed:0;

print fmt: "skbaddr=%p protocol=%u location=%p reason: %s", REC-&gt;skbaddr, REC-&gt;protocol, REC-&gt;location, __print_symbolic(REC-&gt;reason, { 1, "NOT_SPECIFIED" }, { 2, "NO_SOCKET" } ......

Fixes: ec43908dd556 ("net: skb: use auto-generation to convert skb drop reason to string")
Link: https://lore.kernel.org/netdev/CANn89i+bx0ybvE55iMYf5GJM48WwV1HNpdm9Q6t-HaEstqpCSA@mail.gmail.com/
Reported-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Menglong Dong &lt;imagedong@tencent.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
As Eric reported, the 'reason' field is not presented when trace the
kfree_skb event by perf:

$ perf record -e skb:kfree_skb -a sleep 10
$ perf script
  ip_defrag 14605 [021]   221.614303:   skb:kfree_skb:
  skbaddr=0xffff9d2851242700 protocol=34525 location=0xffffffffa39346b1
  reason:

The cause seems to be passing kernel address directly to TP_printk(),
which is not right. As the enum 'skb_drop_reason' is not exported to
user space through TRACE_DEFINE_ENUM(), perf can't get the drop reason
string from the 'reason' field, which is a number.

Therefore, we introduce the macro DEFINE_DROP_REASON(), which is used
to define the trace enum by TRACE_DEFINE_ENUM(). With the help of
DEFINE_DROP_REASON(), now we can remove the auto-generate that we
introduced in the commit ec43908dd556
("net: skb: use auto-generation to convert skb drop reason to string"),
and define the string array 'drop_reasons'.

Hmmmm...now we come back to the situation that have to maintain drop
reasons in both enum skb_drop_reason and DEFINE_DROP_REASON. But they
are both in dropreason.h, which makes it easier.

After this commit, now the format of kfree_skb is like this:

$ cat /tracing/events/skb/kfree_skb/format
name: kfree_skb
ID: 1524
format:
        field:unsigned short common_type;       offset:0;       size:2; signed:0;
        field:unsigned char common_flags;       offset:2;       size:1; signed:0;
        field:unsigned char common_preempt_count;       offset:3;       size:1; signed:0;
        field:int common_pid;   offset:4;       size:4; signed:1;

        field:void * skbaddr;   offset:8;       size:8; signed:0;
        field:void * location;  offset:16;      size:8; signed:0;
        field:unsigned short protocol;  offset:24;      size:2; signed:0;
        field:enum skb_drop_reason reason;      offset:28;      size:4; signed:0;

print fmt: "skbaddr=%p protocol=%u location=%p reason: %s", REC-&gt;skbaddr, REC-&gt;protocol, REC-&gt;location, __print_symbolic(REC-&gt;reason, { 1, "NOT_SPECIFIED" }, { 2, "NO_SOCKET" } ......

Fixes: ec43908dd556 ("net: skb: use auto-generation to convert skb drop reason to string")
Link: https://lore.kernel.org/netdev/CANn89i+bx0ybvE55iMYf5GJM48WwV1HNpdm9Q6t-HaEstqpCSA@mail.gmail.com/
Reported-by: Eric Dumazet &lt;edumazet@google.com&gt;
Signed-off-by: Menglong Dong &lt;imagedong@tencent.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tcp: TX zerocopy should not sense pfmemalloc status</title>
<updated>2022-09-02T11:29:02+00:00</updated>
<author>
<name>Eric Dumazet</name>
<email>edumazet@google.com</email>
</author>
<published>2022-08-31T23:38:09+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3261400639463a853ba2b3be8bd009c2a8089775'/>
<id>3261400639463a853ba2b3be8bd009c2a8089775</id>
<content type='text'>
We got a recent syzbot report [1] showing a possible misuse
of pfmemalloc page status in TCP zerocopy paths.

Indeed, for pages coming from user space or other layers,
using page_is_pfmemalloc() is moot, and possibly could give
false positives.

There has been attempts to make page_is_pfmemalloc() more robust,
but not using it in the first place in this context is probably better,
removing cpu cycles.

Note to stable teams :

You need to backport 84ce071e38a6 ("net: introduce
__skb_fill_page_desc_noacc") as a prereq.

Race is more probable after commit c07aea3ef4d4
("mm: add a signature in struct page") because page_is_pfmemalloc()
is now using low order bit from page-&gt;lru.next, which can change
more often than page-&gt;index.

Low order bit should never be set for lru.next (when used as an anchor
in LRU list), so KCSAN report is mostly a false positive.

Backporting to older kernel versions seems not necessary.

[1]
BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag

write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:105 [inline]
lru_add_fn+0x440/0x520 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
folio_batch_add_and_move mm/swap.c:263 [inline]
folio_add_lru+0xf1/0x140 mm/swap.c:490
filemap_add_folio+0xf8/0x150 mm/filemap.c:948
__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981
pagecache_get_page+0x26/0x190 mm/folio-compat.c:104
grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116
ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988
generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738
ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270
ext4_file_write_iter+0x2e3/0x1210
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x468/0x760 fs/read_write.c:578
ksys_write+0xe8/0x1a0 fs/read_write.c:631
__do_sys_write fs/read_write.c:643 [inline]
__se_sys_write fs/read_write.c:640 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:640
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1740 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]
skb_fill_page_desc include/linux/skbuff.h:2443 [inline]
tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018
do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075
tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]
tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150
inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64 fs/read_write.c:1303 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -&gt; 0xffffea0004a1d288

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

Fixes: c07aea3ef4d4 ("mm: add a signature in struct page")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Reviewed-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
We got a recent syzbot report [1] showing a possible misuse
of pfmemalloc page status in TCP zerocopy paths.

Indeed, for pages coming from user space or other layers,
using page_is_pfmemalloc() is moot, and possibly could give
false positives.

There has been attempts to make page_is_pfmemalloc() more robust,
but not using it in the first place in this context is probably better,
removing cpu cycles.

Note to stable teams :

You need to backport 84ce071e38a6 ("net: introduce
__skb_fill_page_desc_noacc") as a prereq.

Race is more probable after commit c07aea3ef4d4
("mm: add a signature in struct page") because page_is_pfmemalloc()
is now using low order bit from page-&gt;lru.next, which can change
more often than page-&gt;index.

Low order bit should never be set for lru.next (when used as an anchor
in LRU list), so KCSAN report is mostly a false positive.

Backporting to older kernel versions seems not necessary.

[1]
BUG: KCSAN: data-race in lru_add_fn / tcp_build_frag

write to 0xffffea0004a1d2c8 of 8 bytes by task 18600 on cpu 0:
__list_add include/linux/list.h:73 [inline]
list_add include/linux/list.h:88 [inline]
lruvec_add_folio include/linux/mm_inline.h:105 [inline]
lru_add_fn+0x440/0x520 mm/swap.c:228
folio_batch_move_lru+0x1e1/0x2a0 mm/swap.c:246
folio_batch_add_and_move mm/swap.c:263 [inline]
folio_add_lru+0xf1/0x140 mm/swap.c:490
filemap_add_folio+0xf8/0x150 mm/filemap.c:948
__filemap_get_folio+0x510/0x6d0 mm/filemap.c:1981
pagecache_get_page+0x26/0x190 mm/folio-compat.c:104
grab_cache_page_write_begin+0x2a/0x30 mm/folio-compat.c:116
ext4_da_write_begin+0x2dd/0x5f0 fs/ext4/inode.c:2988
generic_perform_write+0x1d4/0x3f0 mm/filemap.c:3738
ext4_buffered_write_iter+0x235/0x3e0 fs/ext4/file.c:270
ext4_file_write_iter+0x2e3/0x1210
call_write_iter include/linux/fs.h:2187 [inline]
new_sync_write fs/read_write.c:491 [inline]
vfs_write+0x468/0x760 fs/read_write.c:578
ksys_write+0xe8/0x1a0 fs/read_write.c:631
__do_sys_write fs/read_write.c:643 [inline]
__se_sys_write fs/read_write.c:640 [inline]
__x64_sys_write+0x3e/0x50 fs/read_write.c:640
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

read to 0xffffea0004a1d2c8 of 8 bytes by task 18611 on cpu 1:
page_is_pfmemalloc include/linux/mm.h:1740 [inline]
__skb_fill_page_desc include/linux/skbuff.h:2422 [inline]
skb_fill_page_desc include/linux/skbuff.h:2443 [inline]
tcp_build_frag+0x613/0xb20 net/ipv4/tcp.c:1018
do_tcp_sendpages+0x3e8/0xaf0 net/ipv4/tcp.c:1075
tcp_sendpage_locked net/ipv4/tcp.c:1140 [inline]
tcp_sendpage+0x89/0xb0 net/ipv4/tcp.c:1150
inet_sendpage+0x7f/0xc0 net/ipv4/af_inet.c:833
kernel_sendpage+0x184/0x300 net/socket.c:3561
sock_sendpage+0x5a/0x70 net/socket.c:1054
pipe_to_sendpage+0x128/0x160 fs/splice.c:361
splice_from_pipe_feed fs/splice.c:415 [inline]
__splice_from_pipe+0x222/0x4d0 fs/splice.c:559
splice_from_pipe fs/splice.c:594 [inline]
generic_splice_sendpage+0x89/0xc0 fs/splice.c:743
do_splice_from fs/splice.c:764 [inline]
direct_splice_actor+0x80/0xa0 fs/splice.c:931
splice_direct_to_actor+0x305/0x620 fs/splice.c:886
do_splice_direct+0xfb/0x180 fs/splice.c:974
do_sendfile+0x3bf/0x910 fs/read_write.c:1249
__do_sys_sendfile64 fs/read_write.c:1317 [inline]
__se_sys_sendfile64 fs/read_write.c:1303 [inline]
__x64_sys_sendfile64+0x10c/0x150 fs/read_write.c:1303
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x70 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd

value changed: 0x0000000000000000 -&gt; 0xffffea0004a1d288

Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 18611 Comm: syz-executor.4 Not tainted 6.0.0-rc2-syzkaller-00248-ge022620b5d05-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022

Fixes: c07aea3ef4d4 ("mm: add a signature in struct page")
Reported-by: syzbot &lt;syzkaller@googlegroups.com&gt;
Signed-off-by: Eric Dumazet &lt;edumazet@google.com&gt;
Cc: Shakeel Butt &lt;shakeelb@google.com&gt;
Reviewed-by: Shakeel Butt &lt;shakeelb@google.com&gt;
Signed-off-by: David S. Miller &lt;davem@davemloft.net&gt;
</pre>
</div>
</content>
</entry>
</feed>
