In ip_output() skb->dev is updated from the skb_dst(skb)->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- Dropped legacy lines mistakenly pulled in from an outdated branch.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 <quic_sharathv@quicinc.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250730105118.GA26100@hu-sharathv-hyd.qualcomm.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
dst->dev is read locklessly in many contexts,
and written in dst_dev_put().
Fixing all the races is going to need many changes.
We probably will have to add full RCU protection.
Add three helpers to ease this painful process.
static inline struct net_device *dst_dev(const struct dst_entry *dst)
{
return READ_ONCE(dst->dev);
}
static inline struct net_device *skb_dst_dev(const struct sk_buff *skb)
{
return dst_dev(skb_dst(skb));
}
static inline struct net *skb_dst_dev_net(const struct sk_buff *skb)
{
return dev_net(skb_dst_dev(skb));
}
static inline struct net *skb_dst_dev_net_rcu(const struct sk_buff *skb)
{
return dev_net_rcu(skb_dst_dev(skb));
}
Fixes: 4a6ce2b6f2 ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-7-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
dst_dev_put() can overwrite dst->output while other
cpus might read this field (for instance from dst_output())
Add READ_ONCE()/WRITE_ONCE() annotations to suppress
potential issues.
We will likely need RCU protection in the future.
Fixes: 4a6ce2b6f2 ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-6-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
dst_dev_put() can overwrite dst->input while other
cpus might read this field (for instance from dst_input())
Add READ_ONCE()/WRITE_ONCE() annotations to suppress
potential issues.
We will likely need full RCU protection later.
Fixes: 4a6ce2b6f2 ("net: introduce a new function dst_dev_put()")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-5-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(dst_entry)->lastuse is read and written locklessly,
add corresponding annotations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-4-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
(dst_entry)->expires is read and written locklessly,
add corresponding annotations.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>
Link: https://patch.msgid.link/20250630121934.3399505-3-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
kernel-doc -Wall warns about missing Return: statement for non-void
functions. We have a number of kdocs in our headers which are missing
the colon, IOW they use
* Return some value
or
* Returns some value
Having the colon makes some sense, it should help kdoc parser avoid
false positives. So add them. This is mostly done with a sed script,
and removing the unnecessary cases (mostly the comments which aren't
kdoc).
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Acked-by: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Reviewed-by: Edward Cree <ecree.xilinx@gmail.com>
Acked-by: Alexandra Winter <wintera@linux.ibm.com>
Acked-by: Pablo Neira Ayuso <pablo@netfilter.org>
Link: https://patch.msgid.link/20241205165914.1071102-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add static inline dst_dev_overhead() function to include/net/dst.h. This
helper function is used by ioam6_iptunnel, rpl_iptunnel and
seg6_iptunnel to get the dev's overhead based on a cache entry
(dst_entry). If the cache is empty, the default and generic value
skb->mac_len is returned. Otherwise, LL_RESERVED_SPACE() over dst's dev
is returned.
Signed-off-by: Justin Iurman <justin.iurman@uliege.be>
Cc: Alexander Lobakin <aleksander.lobakin@intel.com>
Cc: Vadim Fedorenko <vadim.fedorenko@linux.dev>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Since commit 52df157f17 ("xfrm: take refcnt of dst when creating
struct xfrm_dst bundle") dst_destroy() returns only NULL and no caller
cares about the return value.
There are no in in-tree users of dst_destroy() outside of the file.
Make dst_destroy() static and return void.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240202163746.2489150-1-bigeasy@linutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
RTAX_FEATURE_ALLFRAG was added before the first git commit:
https://www.mail-archive.com/bk-commits-head@vger.kernel.org/msg03399.html
The feature would send packets to the fragmentation path if a box
receives a PMTU value with less than 1280 byte. However, since commit
9d289715eb ("ipv6: stop sending PTB packets for MTU < 1280"), such
message would be simply discarded. The feature flag is neither supported
in iproute2 utility. In theory one can still manipulate it with direct
netlink message, but it is not ideal because it was based on obsoleted
guidance of RFC-2460 (replaced by RFC-8200).
The feature would always test false at the moment, so remove related
code or mark them as unused.
Signed-off-by: Yan Zhai <yan@cloudflare.com>
Reviewed-by: Florian Westphal <fw@strlen.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/d78e44dcd9968a252143ffe78460446476a472a1.1698156966.git.yan@cloudflare.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Since commit 1202cdd66531("Remove DECnet support from kernel") has been
merged, all callers pass in the initial_ref value of 1 when they call
dst_alloc(). Therefore, remove initial_ref when the dst_alloc() is
declared and replace initial_ref with 1 in dst_alloc().
Also when all callers call dst_init(), the value of initial_ref is 1.
Therefore, remove the input parameter initial_ref of the dst_init() and
replace initial_ref with the value 1 in dst_init.
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20230911125045.346390-1-shaozhengchao@huawei.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Under high contention dst_entry::__refcnt becomes a significant bottleneck.
atomic_inc_not_zero() is implemented with a cmpxchg() loop, which goes into
high retry rates on contention.
Switch the reference count to rcuref_t which results in a significant
performance gain. Rename the reference count member to __rcuref to reflect
the change.
The gain depends on the micro-architecture and the number of concurrent
operations and has been measured in the range of +25% to +130% with a
localhost memtier/memcached benchmark which amplifies the problem
massively.
Running the memtier/memcached benchmark over a real (1Gb) network
connection the conversion on top of the false sharing fix for struct
dst_entry::__refcnt results in a total gain in the 2%-5% range over the
upstream baseline.
Reported-by: Wangyang Guo <wangyang.guo@intel.com>
Reported-by: Arjan Van De Ven <arjan.van.de.ven@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20230307125538.989175656@linutronix.de
Link: https://lore.kernel.org/r/20230323102800.215027837@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
dst_entry::__refcnt is highly contended in scenarios where many connections
happen from and to the same IP. The reference count is an atomic_t, so the
reference count operations have to take the cache-line exclusive.
Aside of the unavoidable reference count contention there is another
significant problem which is caused by that: False sharing.
perf top identified two affected read accesses. dst_entry::lwtstate and
rtable::rt_genid.
dst_entry:__refcnt is located at offset 64 of dst_entry, which puts it into
a seperate cacheline vs. the read mostly members located at the beginning
of the struct.
That prevents false sharing vs. the struct members in the first 64
bytes of the structure, but there is also
dst_entry::lwtstate
which is located after the reference count and in the same cache line. This
member is read after a reference count has been acquired.
struct rtable embeds a struct dst_entry at offset 0. struct dst_entry has a
size of 112 bytes, which means that the struct members of rtable which
follow the dst member share the same cache line as dst_entry::__refcnt.
Especially
rtable::rt_genid
is also read by the contexts which have a reference count acquired
already.
When dst_entry:__refcnt is incremented or decremented via an atomic
operation these read accesses stall. This was found when analysing the
memtier benchmark in 1:100 mode, which amplifies the problem extremly.
Move the rt[6i]_uncached[_list] members out of struct rtable and struct
rt6_info into struct dst_entry to provide padding and move the lwtstate
member after that so it ends up in the same cache line.
The resulting improvement depends on the micro-architecture and the number
of CPUs. It ranges from +20% to +120% with a localhost memtier/memcached
benchmark.
[ tglx: Rearrange struct ]
Signed-off-by: Wangyang Guo <wangyang.guo@intel.com>
Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://lore.kernel.org/r/20230323102800.042297517@linutronix.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Long standing KCSAN issues are caused by data-race around
some dev->stats changes.
Most performance critical paths already use per-cpu
variables, or per-queue ones.
It is reasonable (and more correct) to use atomic operations
for the slow paths.
This patch adds an union for each field of net_device_stats,
so that we can convert paths that are not yet protected
by a spinlock or a mutex.
netdev_stats_to_stats64() no longer has an #if BITS_PER_LONG==64
Note that the memcpy() we were using on 64bit arches
had no provision to avoid load-tearing,
while atomic_long_read() is providing the needed protection
at no cost.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All uses of dst_hold_and_use() have
been removed since commit 1202cdd665 ("Remove DECnet support
from kernel"), so remove it.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We want to track all dev_hold()/dev_put() to ease leak hunting.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Similar to the previous patch, but covering the dst field:
the slow_gro flag is additionally set when a dst is attached
to the skb
RFC -> v1:
- use the existing flag instead of adding a new one
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move generic blackhole dst ops to the core and use them from both
ipv4_dst_blackhole_ops and ip6_dst_blackhole_ops where possible. No
functional change otherwise. We need these also in other locations
and having to define them over and over again is not great.
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch avoids the indirect call for the common case:
ip6_dst_check and ipv4_dst_check
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch avoids the indirect call for the common case:
ip6_mtu and ipv4_mtu
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch avoids the indirect call for the common case:
ip6_output and ip_output
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This patch avoids the indirect call for the common case:
ip_local_deliver and ip6_input
Signed-off-by: Brian Vazquez <brianvv@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Commit 394de110a7 ("net: Added pointer check for
dst->ops->neigh_lookup in dst_neigh_lookup_skb") added a test in
dst_neigh_lookup_skb() to avoid a NULL pointer dereference. The root
cause was the MPLS forwarding code, which doesn't call skb_dst_drop()
on incoming packets. That is, if the packet is received from a
collect_md device, it has a metadata_dst attached to it that doesn't
implement any dst_ops function.
To align the MPLS behaviour with IPv4 and IPv6, let's drop the dst in
mpls_forward(). This way, dst_neigh_lookup_skb() doesn't need to test
->neigh_lookup any more. Let's keep a WARN condition though, to
document the precondition and to ease detection of such problems in the
future.
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Link: https://lore.kernel.org/r/f8c2784c13faa54469a2aac339470b1049ca6b63.1604102750.git.gnault@redhat.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is a pure codestyle cleanup patch. No functional change intended.
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
It's currently possible to bridge Ethernet tunnels carrying IP
packets directly to external interfaces without assigning them
addresses and routes on the bridged network itself: this is the case
for UDP tunnels bridged with a standard bridge or by Open vSwitch.
PMTU discovery is currently broken with those configurations, because
the encapsulation effectively decreases the MTU of the link, and
while we are able to account for this using PMTU discovery on the
lower layer, we don't have a way to relay ICMP or ICMPv6 messages
needed by the sender, because we don't have valid routes to it.
On the other hand, as a tunnel endpoint, we can't fragment packets
as a general approach: this is for instance clearly forbidden for
VXLAN by RFC 7348, section 4.3:
VTEPs MUST NOT fragment VXLAN packets. Intermediate routers may
fragment encapsulated VXLAN packets due to the larger frame size.
The destination VTEP MAY silently discard such VXLAN fragments.
The same paragraph recommends that the MTU over the physical network
accomodates for encapsulations, but this isn't a practical option for
complex topologies, especially for typical Open vSwitch use cases.
Further, it states that:
Other techniques like Path MTU discovery (see [RFC1191] and
[RFC1981]) MAY be used to address this requirement as well.
Now, PMTU discovery already works for routed interfaces, we get
route exceptions created by the encapsulation device as they receive
ICMP Fragmentation Needed and ICMPv6 Packet Too Big messages, and
we already rebuild those messages with the appropriate MTU and route
them back to the sender.
Add the missing bits for bridged cases:
- checks in skb_tunnel_check_pmtu() to understand if it's appropriate
to trigger a reply according to RFC 1122 section 3.2.2 for ICMP and
RFC 4443 section 2.4 for ICMPv6. This function is already called by
UDP tunnels
- a new function generating those ICMP or ICMPv6 replies. We can't
reuse icmp_send() and icmp6_send() as we don't see the sender as a
valid destination. This doesn't need to be generic, as we don't
cover any other type of ICMP errors given that we only provide an
encapsulation function to the sender
While at it, make the MTU check in skb_tunnel_check_pmtu() accurate:
we might receive GSO buffers here, and the passed headroom already
includes the inner MAC length, so we don't have to account for it
a second time (that would imply three MAC headers on the wire, but
there are just two).
This issue became visible while bridging IPv6 packets with 4500 bytes
of payload over GENEVE using IPv4 with a PMTU of 4000. Given the 50
bytes of encapsulation headroom, we would advertise MTU as 3950, and
we would reject fragmented IPv6 datagrams of 3958 bytes size on the
wire. We're exclusively dealing with network MTU here, though, so we
could get Ethernet frames up to 3964 octets in that case.
v2:
- moved skb_tunnel_check_pmtu() to ip_tunnel_core.c (David Ahern)
- split IPv4/IPv6 functions (David Ahern)
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Previous changes to the IP routing code have removed all the
tests for the DS_HOST route flag.
Remove the flags and all the code that sets it.
Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When do IPv6 tunnel PMTU update and calls __ip6_rt_update_pmtu() in the end,
we should not call dst_confirm_neigh() as there is no two-way communication.
So disable the neigh confirm for vxlan and geneve pmtu update.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
Fixes: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Tested-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Add a new function skb_dst_update_pmtu_no_confirm() for callers who need
update pmtu but should not do neighbor confirm.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The MTU update code is supposed to be invoked in response to real
networking events that update the PMTU. In IPv6 PMTU update function
__ip6_rt_update_pmtu() we called dst_confirm_neigh() to update neighbor
confirmed time.
But for tunnel code, it will call pmtu before xmit, like:
- tnl_update_pmtu()
- skb_dst_update_pmtu()
- ip6_rt_update_pmtu()
- __ip6_rt_update_pmtu()
- dst_confirm_neigh()
If the tunnel remote dst mac address changed and we still do the neigh
confirm, we will not be able to update neigh cache and ping6 remote
will failed.
So for this ip_tunnel_xmit() case, _EVEN_ if the MTU is changed, we
should not be invoking dst_confirm_neigh() as we have no evidence
of successful two-way communication at this point.
On the other hand it is also important to keep the neigh reachability fresh
for TCP flows, so we cannot remove this dst_confirm_neigh() call.
To fix the issue, we have to add a new bool parameter for dst_ops.update_pmtu
to choose whether we should do neigh update or not. I will add the parameter
in this patch and set all the callers to true to comply with the previous
way, and fix the tunnel code one by one on later patches.
v5: No change.
v4: No change.
v3: Do not remove dst_confirm_neigh, but add a new bool parameter in
dst_ops.update_pmtu to control whether we should do neighbor confirm.
Also split the big patch to small ones for each area.
v2: Remove dst_confirm_neigh in __ip6_rt_update_pmtu.
Suggested-by: David Miller <davem@davemloft.net>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Acked-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Hangbin Liu <liuhangbin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When storing a pointer to a dst_metrics structure in dst_entry._metrics,
two flags are added in the least significant bits of the pointer value.
Hence this assumes all pointers to dst_metrics structures have at least
4-byte alignment.
However, on m68k, the minimum alignment of 32-bit values is 2 bytes, not
4 bytes. Hence in some kernel builds, dst_default_metrics may be only
2-byte aligned, leading to obscure boot warnings like:
WARNING: CPU: 0 PID: 7 at lib/refcount.c:28 refcount_warn_saturate+0x44/0x9a
refcount_t: underflow; use-after-free.
Modules linked in:
CPU: 0 PID: 7 Comm: ksoftirqd/0 Tainted: G W 5.5.0-rc2-atari-01448-g114a1a1038af891d-dirty #261
Stack from 10835e6c:
10835e6c 0038134f 00023fa6 00394b0f 0000001c 00000009 00321560 00023fea
00394b0f 0000001c 001a70f8 00000009 00000000 10835eb4 00000001 00000000
04208040 0000000a 00394b4a 10835ed4 00043aa8 001a70f8 00394b0f 0000001c
00000009 00394b4a 0026aba8 003215a4 00000003 00000000 0026d5a8 00000001
003215a4 003a4361 003238d6 000001f0 00000000 003215a4 10aa3b00 00025e84
003ddb00 10834000 002416a8 10aa3b00 00000000 00000080 000aa038 0004854a
Call Trace: [<00023fa6>] __warn+0xb2/0xb4
[<00023fea>] warn_slowpath_fmt+0x42/0x64
[<001a70f8>] refcount_warn_saturate+0x44/0x9a
[<00043aa8>] printk+0x0/0x18
[<001a70f8>] refcount_warn_saturate+0x44/0x9a
[<0026aba8>] refcount_sub_and_test.constprop.73+0x38/0x3e
[<0026d5a8>] ipv4_dst_destroy+0x5e/0x7e
[<00025e84>] __local_bh_enable_ip+0x0/0x8e
[<002416a8>] dst_destroy+0x40/0xae
Fix this by forcing 4-byte alignment of all dst_metrics structures.
Fixes: e5fd387ad5 ("ipv6: do not overwrite inetpeer metrics prematurely")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Fix DST_FEATURE_ECN_CA to use "U" cast to avoid shifting signed
32-bit value by 31 bits problem.
Signed-off-by: Vandana BN <bnvandana@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
netfilter did not expect that skb_dst_force() can cause skb to lose its
dst entry.
I got a bug report with a skb->dst NULL dereference in netfilter
output path. The backtrace contains nf_reinject(), so the dst might have
been cleared when skb got queued to userspace.
Other users were fixed via
if (skb_dst(skb)) {
skb_dst_force(skb);
if (!skb_dst(skb))
goto handle_err;
}
But I think its preferable to make the 'dst might be cleared' part
of the function explicit.
In netfilter case, skb with a null dst is expected when queueing in
prerouting hook, so drop skb for the other hooks.
v2:
v1 of this patch returned true in case skb had no dst entry.
Eric said:
Say if we have two skb_dst_force() calls for some reason
on the same skb, only the first one will return false.
This now returns false even when skb had no dst, as per Erics
suggestion, so callers might need to check skb_dst() first before
skb_dst_force().
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Get rid of some obsolete gc-related documentation and macros that were
missed in commit 5b7c9a8ff8 ("net: remove dst gc related code").
CC: Wei Wang <weiwan@google.com>
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Acked-by: Wei Wang <weiwan@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We shouldn't abuse exceptions: if the destination MTU is already higher
than what we're transmitting, no exception should be created.
Fixes: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
Reviewed-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
In order to remove performance impact of having the extra u32 in every
single flowi, this change removes the flowi_xfrm struct, prefering to
take the if_id as a method parameter where needed.
In the inbound direction, if_id is only needed during the
__xfrm_check_policy() function, and the if_id can be determined at that
point based on the skb. As such, xfrmi_decode_session() is only called
with the skb in __xfrm_check_policy().
In the outbound direction, the only place where if_id is needed is the
xfrm_lookup() call in xfrmi_xmit2(). With this change, the if_id is
directly passed into the xfrm_lookup_with_ifid() call. All existing
callers can still call xfrm_lookup(), which uses a default if_id of 0.
This change does not change any behavior of XFRMIs except for improving
overall system performance via flowi size reduction.
This change has been tested against the Android Kernel Networking Tests:
https://android.googlesource.com/kernel/tests/+/master/net/test
Signed-off-by: Benedict Wong <benedictwong@google.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>
This fixes the following kernel-doc warning:
./include/net/dst.h:366: warning: Function parameter or member 'net' not described in 'skb_tunnel_rx'
Fixes: ea23192e8e ("tunnels: harmonize cleanup done on skb on rx path")
Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Some dst_ops (e.g. md_dst_ops)) doesn't set this handler. It may result to:
"BUG: unable to handle kernel NULL pointer dereference at (null)"
Let's add a helper to check if update_pmtu is available before calling it.
Fixes: 52a589d51f ("geneve: update skb dst pmtu on tx path")
Fixes: a93bf0ff44 ("vxlan: update skb dst pmtu on tx path")
CC: Roman Kapl <code@rkapl.cz>
CC: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We have padding to try and align the refcount on a separate cache
line. But after several simplifications the padding has increased
substantially.
So now it's easy to change the layout to get rid of the padding
entirely.
We group the write-heavy __refcnt and __use with less often used
items such as the rcu_head and the error code.
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
The first member of an IPSEC route bundle chain sets it's dst->path to
the underlying ipv4/ipv6 route that carries the bundle.
Stated another way, if one were to follow the xfrm_dst->child chain of
the bundle, the final non-NULL pointer would be the path and point to
either an ipv4 or an ipv6 route.
This is largely used to make sure that PMTU events propagate down to
the correct ipv4 or ipv6 route.
When we don't have the top of an IPSEC bundle 'dst->path == dst'.
Move it down into xfrm_dst and key off of dst->xfrm.
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
The dst->from value is only used by ipv6 routes to track where
a route "came from".
Any time we clone or copy a core ipv6 route in the ipv6 routing
tables, we have the copy/clone's ->from point to the base route.
This is used to handle route expiration properly.
Only ipv6 uses this mechanism, and only ipv6 code references
it. So it is safe to move it into rt6_info.
Signed-off-by: David S. Miller <davem@davemloft.net>
Reviewed-by: Eric Dumazet <edumazet@google.com>
XFRM bundle child chains look like this:
xdst1 --> xdst2 --> xdst3 --> path_dst
All of xdstN are xfrm_dst objects and xdst->u.dst.xfrm is non-NULL.
The final child pointer in the chain, here called 'path_dst', is some
other kind of route such as an ipv4 or ipv6 one.
The xfrm output path pops routes, one at a time, via the child
pointer, until we hit one which has a dst->xfrm pointer which
is NULL.
We can easily preserve the above mechanisms with child sitting
only in the xfrm_dst structure. All children in the chain
before we break out of the xfrm_output() loop have dst->xfrm
non-NULL and are therefore xfrm_dst objects.
Since we break out of the loop when we find dst->xfrm NULL, we
will not try to dereference 'dst' as if it were an xfrm_dst.
Signed-off-by: David S. Miller <davem@davemloft.net>
Files removed in 'net-next' had their license header updated
in 'net'. We take the remove from 'net-next'.
Signed-off-by: David S. Miller <davem@davemloft.net>
