Most of the ioctls to net protocols operates directly on userspace
argument (arg). Usually doing get_user()/put_user() directly in the
ioctl callback. This is not flexible, because it is hard to reuse these
functions without passing userspace buffers.
Change the "struct proto" ioctls to avoid touching userspace memory and
operate on kernel buffers, i.e., all protocol's ioctl callbacks is
adapted to operate on a kernel memory other than on userspace (so, no
more {put,get}_user() and friends being called in the ioctl callback).
This changes the "struct proto" ioctl format in the following way:
int (*ioctl)(struct sock *sk, int cmd,
- unsigned long arg);
+ int *karg);
(Important to say that this patch does not touch the "struct proto_ops"
protocols)
So, the "karg" argument, which is passed to the ioctl callback, is a
pointer allocated to kernel space memory (inside a function wrapper).
This buffer (karg) may contain input argument (copied from userspace in
a prep function) and it might return a value/buffer, which is copied
back to userspace if necessary. There is not one-size-fits-all format
(that is I am using 'may' above), but basically, there are three type of
ioctls:
1) Do not read from userspace, returns a result to userspace
2) Read an input parameter from userspace, and does not return anything
to userspace
3) Read an input from userspace, and return a buffer to userspace.
The default case (1) (where no input parameter is given, and an "int" is
returned to userspace) encompasses more than 90% of the cases, but there
are two other exceptions. Here is a list of exceptions:
* Protocol RAW:
* cmd = SIOCGETVIFCNT:
* input and output = struct sioc_vif_req
* cmd = SIOCGETSGCNT
* input and output = struct sioc_sg_req
* Explanation: for the SIOCGETVIFCNT case, userspace passes the input
argument, which is struct sioc_vif_req. Then the callback populates
the struct, which is copied back to userspace.
* Protocol RAW6:
* cmd = SIOCGETMIFCNT_IN6
* input and output = struct sioc_mif_req6
* cmd = SIOCGETSGCNT_IN6
* input and output = struct sioc_sg_req6
* Protocol PHONET:
* cmd == SIOCPNADDRESOURCE | SIOCPNDELRESOURCE
* input int (4 bytes)
* Nothing is copied back to userspace.
For the exception cases, functions sock_sk_ioctl_inout() will
copy the userspace input, and copy it back to kernel space.
The wrapper that prepare the buffer and put the buffer back to user is
sk_ioctl(), so, instead of calling sk->sk_prot->ioctl(), the callee now
calls sk_ioctl(), which will handle all cases.
Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Link: https://lore.kernel.org/r/20230609152800.830401-1-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add an optional method, ->splice_eof(), to allow splice to indicate the
premature termination of a splice to struct file_operations and struct
proto_ops.
This is called if sendfile() or splice() encounters all of the following
conditions inside splice_direct_to_actor():
(1) the user did not set SPLICE_F_MORE (splice only), and
(2) an EOF condition occurred (->splice_read() returned 0), and
(3) we haven't read enough to fulfill the request (ie. len > 0 still), and
(4) we have already spliced at least one byte.
A further patch will modify the behaviour of SPLICE_F_MORE to always be
passed to the actor if either the user set it or we haven't yet read
sufficient data to fulfill the request.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Link: https://lore.kernel.org/r/CAHk-=wh=V579PDYvkpnTobCLGczbgxpMgGmmhqiTyE34Cpi5Gg@mail.gmail.com/
Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Christoph Hellwig <hch@lst.de>
cc: Al Viro <viro@zeniv.linux.org.uk>
cc: Matthew Wilcox <willy@infradead.org>
cc: Jan Kara <jack@suse.cz>
cc: Jeff Layton <jlayton@kernel.org>
cc: David Hildenbrand <david@redhat.com>
cc: Christian Brauner <brauner@kernel.org>
cc: Chuck Lever <chuck.lever@oracle.com>
cc: Boris Pismenny <borisp@nvidia.com>
cc: John Fastabend <john.fastabend@gmail.com>
cc: linux-mm@kvack.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add READ_ONCE()/WRITE_ONCE() on accesses to sk->sk_rxhash.
This also prevents a (smart ?) compiler to remove the condition in:
if (sk->sk_rxhash != newval)
sk->sk_rxhash = newval;
We need the condition to avoid dirtying a shared cache line.
Fixes: fec5e652e5 ("rfs: Receive Flow Steering")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Datacenter kernel builds will very likely not include WIRELESS,
so let them shave 2 bits off the skb by hiding the wifi fields.
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
Commit e48c414ee6 ("[INET]: Generalise the TCP sock ID lookup routines")
commented out the definition of SOCK_REFCNT_DEBUG in 2005 and later another
commit 463c84b97f ("[NET]: Introduce inet_connection_sock") removed it.
Since we could track all of them through bpf and kprobe related tools
and the feature could print loads of information which might not be
that helpful even under a little bit pressure, the whole feature which
has been inactive for many years is no longer supported.
Link: https://lore.kernel.org/lkml/20230211065153.54116-1-kerneljasonxing@gmail.com/
Suggested-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: Jason Xing <kernelxing@tencent.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Acked-by: Wenjia Zhang <wenjia@linux.ibm.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Eric Dumazet pointed out [0] that when we call skb_set_owner_r()
for ipv6_pinfo.pktoptions, sk_rmem_schedule() has not been called,
resulting in a negative sk_forward_alloc.
We add a new helper which clones a skb and sets its owner only
when sk_rmem_schedule() succeeds.
Note that we move skb_set_owner_r() forward in (dccp|tcp)_v6_do_rcv()
because tcp_send_synack() can make sk_forward_alloc negative before
ipv6_opt_accepted() in the crossed SYN-ACK or self-connect() cases.
[0]: https://lore.kernel.org/netdev/CANn89iK9oc20Jdi_41jb9URdF210r7d1Y-+uypbMSbOfY6jqrg@mail.gmail.com/
Fixes: 323fbd0edf ("net: dccp: Add handling of IPV6_PKTOPTIONS to dccp_v6_do_rcv()")
Fixes: 3df80d9320 ("[DCCP]: Introduce DCCPv6")
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add sock_init_data_uid() to explicitly initialize the socket uid.
To initialise the socket uid, sock_init_data() assumes a the struct
socket* sock is always embedded in a struct socket_alloc, used to
access the corresponding inode uid. This may not be true.
Examples are sockets created in tun_chr_open() and tap_open().
Fixes: 86741ec254 ("net: core: Add a UID field to struct sock.")
Signed-off-by: Pietro Borrello <borrello@diag.uniroma1.it>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that in-kernel socket users that may recurse during reclaim have benn
converted to sk_use_task_frag = false, we can have sk_page_frag() simply
check that value.
Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
Reviewed-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Sockets that can be used while recursing into memory reclaim, like
those used by network block devices and file systems, mustn't use
current->task_frag: if the current process is already using it, then
the inner memory reclaim call would corrupt the task_frag structure.
To avoid this, sk_page_frag() uses ->sk_allocation to detect sockets
that mustn't use current->task_frag, assuming that those used during
memory reclaim had their allocation constraints reflected in
->sk_allocation.
This unfortunately doesn't cover all cases: in an attempt to remove all
usage of GFP_NOFS and GFP_NOIO, sunrpc stopped setting these flags in
->sk_allocation, and used memalloc_nofs critical sections instead.
This breaks the sk_page_frag() heuristic since the allocation
constraints are now stored in current->flags, which sk_page_frag()
can't read without risking triggering a cache miss and slowing down
TCP's fast path.
This patch creates a new field in struct sock, named sk_use_task_frag,
which sockets with memory reclaim constraints can set to false if they
can't safely use current->task_frag. In such cases, sk_page_frag() now
always returns the socket's page_frag (->sk_frag). The first user is
sunrpc, which needs to avoid using current->task_frag but can keep
->sk_allocation set to GFP_KERNEL otherwise.
Eventually, it might be possible to simplify sk_page_frag() by only
testing ->sk_use_task_frag and avoid relying on the ->sk_allocation
heuristic entirely (assuming other sockets will set ->sk_use_task_frag
according to their constraints in the future).
The new ->sk_use_task_frag field is placed in a hole in struct sock and
belongs to a cache line shared with ->sk_shutdown. Therefore it should
be hot and shouldn't have negative performance impacts on TCP's fast
path (sk_shutdown is tested just before the while() loop in
tcp_sendmsg_locked()).
Link: https://lore.kernel.org/netdev/b4d8cb09c913d3e34f853736f3f5628abfd7f4b6.1656699567.git.gnault@redhat.com/
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add an option to initialize SOF_TIMESTAMPING_OPT_ID for TCP from
write_seq sockets instead of snd_una.
This should have been the behavior from the start. Because processes
may now exist that rely on the established behavior, do not change
behavior of the existing option, but add the right behavior with a new
flag. It is encouraged to always set SOF_TIMESTAMPING_OPT_ID_TCP on
stream sockets along with the existing SOF_TIMESTAMPING_OPT_ID.
Intuitively the contract is that the counter is zero after the
setsockopt, so that the next write N results in a notification for
the last byte N - 1.
On idle sockets snd_una == write_seq and this holds for both. But on
sockets with data in transmission, snd_una records the unacked offset
in the stream. This depends on the ACK response from the peer. A
process cannot learn this in a race free manner (ioctl SIOCOUTQ is one
racy approach).
write_seq records the offset at the last byte written by the process.
This is a better starting point. It matches the intuitive contract in
all circumstances, unaffected by external behavior.
The new timestamp flag necessitates increasing sk_tsflags to 32 bits.
Move the field in struct sock to avoid growing the socket (for some
common CONFIG variants). The UAPI interface so_timestamping.flags is
already int, so 32 bits wide.
Reported-by: Sotirios Delimanolis <sotodel@meta.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Link: https://lore.kernel.org/r/20221207143701.29861-1-willemdebruijn.kernel@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sk->sk_user_data has multiple users, which are not compatible with each
other. Writers must synchronize by grabbing the sk->sk_callback_lock.
l2tp currently fails to grab the lock when modifying the underlying tunnel
socket fields. Fix it by adding appropriate locking.
We err on the side of safety and grab the sk_callback_lock also inside the
sk_destruct callback overridden by l2tp, even though there should be no
refs allowing access to the sock at the time when sk_destruct gets called.
v4:
- serialize write to sk_user_data in l2tp sk_destruct
v3:
- switch from sock lock to sk_callback_lock
- document write-protection for sk_user_data
v2:
- update Fixes to point to origin of the bug
- use real names in Reported/Tested-by tags
Cc: Tom Parkin <tparkin@katalix.com>
Fixes: 3557baabf2 ("[L2TP]: PPP over L2TP driver core")
Reported-by: Haowei Yan <g1042620637@gmail.com>
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
sockmap replaces ->sk_prot with its own callbacks, we should remove
SOCK_SUPPORT_ZC as the new proto doesn't support msghdr::ubuf_info.
Cc: <stable@vger.kernel.org> # 6.0
Reported-by: Jakub Kicinski <kuba@kernel.org>
Fixes: e993ffe3da ("net: flag sockets supporting msghdr originated zerocopy")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As Shakeel explains the commit under Fixes had the unintended
side-effect of no longer pre-loading the cached memory allowance.
Even tho we previously dropped the first packet received when
over memory limit - the consecutive ones would get thru by using
the cache. The charging was happening in batches of 128kB, so
we'd let in 128kB (truesize) worth of packets per one drop.
After the change we no longer force charge, there will be no
cache filling side effects. This causes significant drops and
connection stalls for workloads which use a lot of page cache,
since we can't reclaim page cache under GFP_NOWAIT.
Some of the latency can be recovered by improving SACK reneg
handling but nowhere near enough to get back to the pre-5.15
performance (the application I'm experimenting with still
sees 5-10x worst latency).
Apply the suggested workaround of using GFP_ATOMIC. We will now
be more permissive than previously as we'll drop _no_ packets
in softirq when under pressure. But I can't think of any good
and simple way to address that within networking.
Link: https://lore.kernel.org/all/20221012163300.795e7b86@kernel.org/
Suggested-by: Shakeel Butt <shakeelb@google.com>
Fixes: 4b1327be9f ("net-memcg: pass in gfp_t mask to mem_cgroup_charge_skmem()")
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://lore.kernel.org/r/20221021160304.1362511-1-kuba@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The parameter 'msg' has never been used by __sock_cmsg_send, so we can remove it
safely.
Reported-by: Zeal Robot <zealci@zte.com.cn>
Signed-off-by: xu xin <xu.xin16@zte.com.cn>
Reviewed-by: Zhang Yunkai <zhang.yunkai@zte.com.cn>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The prandom_u32() function has been a deprecated inline wrapper around
get_random_u32() for several releases now, and compiles down to the
exact same code. Replace the deprecated wrapper with a direct call to
the real function. The same also applies to get_random_int(), which is
just a wrapper around get_random_u32(). This was done as a basic find
and replace.
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Yury Norov <yury.norov@gmail.com>
Reviewed-by: Jan Kara <jack@suse.cz> # for ext4
Acked-by: Toke Høiland-Jørgensen <toke@toke.dk> # for sch_cake
Acked-by: Chuck Lever <chuck.lever@oracle.com> # for nfsd
Acked-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Mika Westerberg <mika.westerberg@linux.intel.com> # for thunderbolt
Acked-by: Darrick J. Wong <djwong@kernel.org> # for xfs
Acked-by: Helge Deller <deller@gmx.de> # for parisc
Acked-by: Heiko Carstens <hca@linux.ibm.com> # for s390
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
All uses of sk_nulls_node_init() have
been removed since commit dbca1596bb ("ping: convert to RCU
lookups, get rid of rwlock"), so remove it.
Signed-off-by: Gaosheng Cui <cuigaosheng1@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Daniel Borkmann says:
====================
pull-request: bpf-next 2022-09-05
The following pull-request contains BPF updates for your *net-next* tree.
We've added 106 non-merge commits during the last 18 day(s) which contain
a total of 159 files changed, 5225 insertions(+), 1358 deletions(-).
There are two small merge conflicts, resolve them as follows:
1) tools/testing/selftests/bpf/DENYLIST.s390x
Commit 27e23836ce ("selftests/bpf: Add lru_bug to s390x deny list") in
bpf tree was needed to get BPF CI green on s390x, but it conflicted with
newly added tests on bpf-next. Resolve by adding both hunks, result:
[...]
lru_bug # prog 'printk': failed to auto-attach: -524
setget_sockopt # attach unexpected error: -524 (trampoline)
cb_refs # expected error message unexpected error: -524 (trampoline)
cgroup_hierarchical_stats # JIT does not support calling kernel function (kfunc)
htab_update # failed to attach: ERROR: strerror_r(-524)=22 (trampoline)
[...]
2) net/core/filter.c
Commit 1227c1771d ("net: Fix data-races around sysctl_[rw]mem_(max|default).")
from net tree conflicts with commit 29003875bd ("bpf: Change bpf_setsockopt(SOL_SOCKET)
to reuse sk_setsockopt()") from bpf-next tree. Take the code as it is from
bpf-next tree, result:
[...]
if (getopt) {
if (optname == SO_BINDTODEVICE)
return -EINVAL;
return sk_getsockopt(sk, SOL_SOCKET, optname,
KERNEL_SOCKPTR(optval),
KERNEL_SOCKPTR(optlen));
}
return sk_setsockopt(sk, SOL_SOCKET, optname,
KERNEL_SOCKPTR(optval), *optlen);
[...]
The main changes are:
1) Add any-context BPF specific memory allocator which is useful in particular for BPF
tracing with bonus of performance equal to full prealloc, from Alexei Starovoitov.
2) Big batch to remove duplicated code from bpf_{get,set}sockopt() helpers as an effort
to reuse the existing core socket code as much as possible, from Martin KaFai Lau.
3) Extend BPF flow dissector for BPF programs to just augment the in-kernel dissector
with custom logic. In other words, allow for partial replacement, from Shmulik Ladkani.
4) Add a new cgroup iterator to BPF with different traversal options, from Hao Luo.
5) Support for BPF to collect hierarchical cgroup statistics efficiently through BPF
integration with the rstat framework, from Yosry Ahmed.
6) Support bpf_{g,s}et_retval() under more BPF cgroup hooks, from Stanislav Fomichev.
7) BPF hash table and local storages fixes under fully preemptible kernel, from Hou Tao.
8) Add various improvements to BPF selftests and libbpf for compilation with gcc BPF
backend, from James Hilliard.
9) Fix verifier helper permissions and reference state management for synchronous
callbacks, from Kumar Kartikeya Dwivedi.
10) Add support for BPF selftest's xskxceiver to also be used against real devices that
support MAC loopback, from Maciej Fijalkowski.
11) Various fixes to the bpf-helpers(7) man page generation script, from Quentin Monnet.
12) Document BPF verifier's tnum_in(tnum_range(), ...) gotchas, from Shung-Hsi Yu.
13) Various minor misc improvements all over the place.
* https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (106 commits)
bpf: Optimize rcu_barrier usage between hash map and bpf_mem_alloc.
bpf: Remove usage of kmem_cache from bpf_mem_cache.
bpf: Remove prealloc-only restriction for sleepable bpf programs.
bpf: Prepare bpf_mem_alloc to be used by sleepable bpf programs.
bpf: Remove tracing program restriction on map types
bpf: Convert percpu hash map to per-cpu bpf_mem_alloc.
bpf: Add percpu allocation support to bpf_mem_alloc.
bpf: Batch call_rcu callbacks instead of SLAB_TYPESAFE_BY_RCU.
bpf: Adjust low/high watermarks in bpf_mem_cache
bpf: Optimize call_rcu in non-preallocated hash map.
bpf: Optimize element count in non-preallocated hash map.
bpf: Relax the requirement to use preallocated hash maps in tracing progs.
samples/bpf: Reduce syscall overhead in map_perf_test.
selftests/bpf: Improve test coverage of test_maps
bpf: Convert hash map to bpf_mem_alloc.
bpf: Introduce any context BPF specific memory allocator.
selftest/bpf: Add test for bpf_getsockopt()
bpf: Change bpf_getsockopt(SOL_IPV6) to reuse do_ipv6_getsockopt()
bpf: Change bpf_getsockopt(SOL_IP) to reuse do_ip_getsockopt()
bpf: Change bpf_getsockopt(SOL_TCP) to reuse do_tcp_getsockopt()
...
====================
Link: https://lore.kernel.org/r/20220905161136.9150-1-daniel@iogearbox.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
This patch changes bpf_getsockopt(SOL_SOCKET) to reuse
sk_getsockopt(). It removes all duplicated code from
bpf_getsockopt(SOL_SOCKET).
Before this patch, there were some optnames available to
bpf_setsockopt(SOL_SOCKET) but missing in bpf_getsockopt(SOL_SOCKET).
It surprises users from time to time. For example, SO_REUSEADDR,
SO_KEEPALIVE, SO_RCVLOWAT, and SO_MAX_PACING_RATE. This patch
automatically closes this gap without duplicating more code.
The only exception is SO_BINDTODEVICE because it needs to acquire a
blocking lock. Thus, SO_BINDTODEVICE is not supported.
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/r/20220902002912.2894040-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The current bind hashtable (bhash) is hashed by port only.
In the socket bind path, we have to check for bind conflicts by
traversing the specified port's inet_bind_bucket while holding the
hashbucket's spinlock (see inet_csk_get_port() and
inet_csk_bind_conflict()). In instances where there are tons of
sockets hashed to the same port at different addresses, the bind
conflict check is time-intensive and can cause softirq cpu lockups,
as well as stops new tcp connections since __inet_inherit_port()
also contests for the spinlock.
This patch adds a second bind table, bhash2, that hashes by
port and sk->sk_rcv_saddr (ipv4) and sk->sk_v6_rcv_saddr (ipv6).
Searching the bhash2 table leads to significantly faster conflict
resolution and less time holding the hashbucket spinlock.
Please note a few things:
* There can be the case where the a socket's address changes after it
has been bound. There are two cases where this happens:
1) The case where there is a bind() call on INADDR_ANY (ipv4) or
IPV6_ADDR_ANY (ipv6) and then a connect() call. The kernel will
assign the socket an address when it handles the connect()
2) In inet_sk_reselect_saddr(), which is called when rebuilding the
sk header and a few pre-conditions are met (eg rerouting fails).
In these two cases, we need to update the bhash2 table by removing the
entry for the old address, and add a new entry reflecting the updated
address.
* The bhash2 table must have its own lock, even though concurrent
accesses on the same port are protected by the bhash lock. Bhash2 must
have its own lock to protect against cases where sockets on different
ports hash to different bhash hashbuckets but to the same bhash2
hashbucket.
This brings up a few stipulations:
1) When acquiring both the bhash and the bhash2 lock, the bhash2 lock
will always be acquired after the bhash lock and released before the
bhash lock is released.
2) There are no nested bhash2 hashbucket locks. A bhash2 lock is always
acquired+released before another bhash2 lock is acquired+released.
* The bhash table cannot be superseded by the bhash2 table because for
bind requests on INADDR_ANY (ipv4) or IPV6_ADDR_ANY (ipv6), every socket
bound to that port must be checked for a potential conflict. The bhash
table is the only source of port->socket associations.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
After the prep work in the previous patches,
this patch removes most of the dup code from bpf_setsockopt(SOL_SOCKET)
and reuses them from sk_setsockopt().
The sock ptr test is added to the SO_RCVLOWAT because
the sk->sk_socket could be NULL in some of the bpf hooks.
The existing optname white-list is refactored into a new
function sol_socket_setsockopt().
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061804.4178920-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When bpf program calling bpf_setsockopt(SOL_SOCKET),
it could be run in softirq and doesn't make sense to do the capable
check. There was a similar situation in bpf_setsockopt(TCP_CONGESTION).
In commit 8d650cdeda ("tcp: fix tcp_set_congestion_control() use from bpf hook"),
tcp_set_congestion_control(..., cap_net_admin) was added to skip
the cap check for bpf prog.
This patch adds sockopt_ns_capable() and sockopt_capable() for
the sk_setsockopt() to use. They will consider the
has_current_bpf_ctx() before doing the ns_capable() and capable() test.
They are in EXPORT_SYMBOL for the ipv6 module to use in a latter patch.
Suggested-by: Stanislav Fomichev <sdf@google.com>
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061723.4175820-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Most of the code in bpf_setsockopt(SOL_SOCKET) are duplicated from
the sk_setsockopt(). The number of supported optnames are
increasing ever and so as the duplicated code.
One issue in reusing sk_setsockopt() is that the bpf prog
has already acquired the sk lock. This patch adds a
has_current_bpf_ctx() to tell if the sk_setsockopt() is called from
a bpf prog. The bpf prog calling bpf_setsockopt() is either running
in_task() or in_serving_softirq(). Both cases have the current->bpf_ctx
initialized. Thus, the has_current_bpf_ctx() only needs to
test !!current->bpf_ctx.
This patch also adds sockopt_{lock,release}_sock() helpers
for sk_setsockopt() to use. These helpers will test
has_current_bpf_ctx() before acquiring/releasing the lock. They are
in EXPORT_SYMBOL for the ipv6 module to use in a latter patch.
Note on the change in sock_setbindtodevice(). sockopt_lock_sock()
is done in sock_setbindtodevice() instead of doing the lock_sock
in sock_bindtoindex(..., lock_sk = true).
Reviewed-by: Stanislav Fomichev <sdf@google.com>
Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Link: https://lore.kernel.org/r/20220817061717.4175589-1-kafai@fb.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_sk_reuseport_detach() calls __rcu_dereference_sk_user_data_with_flags()
to obtain the value of sk->sk_user_data, but that function is only usable
if the RCU read lock is held, and neither that function nor any of its
callers hold it.
Fix this by adding a new helper, __locked_read_sk_user_data_with_flags()
that checks to see if sk->sk_callback_lock() is held and use that here
instead.
Alternatively, making __rcu_dereference_sk_user_data_with_flags() use
rcu_dereference_checked() might suffice.
Without this, the following warning can be occasionally observed:
=============================
WARNING: suspicious RCU usage
6.0.0-rc1-build2+ #563 Not tainted
-----------------------------
include/net/sock.h:592 suspicious rcu_dereference_check() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
5 locks held by locktest/29873:
#0: ffff88812734b550 (&sb->s_type->i_mutex_key#9){+.+.}-{3:3}, at: __sock_release+0x77/0x121
#1: ffff88812f5621b0 (sk_lock-AF_INET){+.+.}-{0:0}, at: tcp_close+0x1c/0x70
#2: ffff88810312f5c8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: inet_unhash+0x76/0x1c0
#3: ffffffff83768bb8 (reuseport_lock){+...}-{2:2}, at: reuseport_detach_sock+0x18/0xdd
#4: ffff88812f562438 (clock-AF_INET){++..}-{2:2}, at: bpf_sk_reuseport_detach+0x24/0xa4
stack backtrace:
CPU: 1 PID: 29873 Comm: locktest Not tainted 6.0.0-rc1-build2+ #563
Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014
Call Trace:
<TASK>
dump_stack_lvl+0x4c/0x5f
bpf_sk_reuseport_detach+0x6d/0xa4
reuseport_detach_sock+0x75/0xdd
inet_unhash+0xa5/0x1c0
tcp_set_state+0x169/0x20f
? lockdep_sock_is_held+0x3a/0x3a
? __lock_release.isra.0+0x13e/0x220
? reacquire_held_locks+0x1bb/0x1bb
? hlock_class+0x31/0x96
? mark_lock+0x9e/0x1af
__tcp_close+0x50/0x4b6
tcp_close+0x28/0x70
inet_release+0x8e/0xa7
__sock_release+0x95/0x121
sock_close+0x14/0x17
__fput+0x20f/0x36a
task_work_run+0xa3/0xcc
exit_to_user_mode_prepare+0x9c/0x14d
syscall_exit_to_user_mode+0x18/0x44
entry_SYSCALL_64_after_hwframe+0x63/0xcd
Fixes: cf8c1e9672 ("net: refactor bpf_sk_reuseport_detach()")
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Hawkins Jiawei <yin31149@gmail.com>
Link: https://lore.kernel.org/r/166064248071.3502205.10036394558814861778.stgit@warthog.procyon.org.uk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Syzkaller reports refcount bug as follows:
------------[ cut here ]------------
refcount_t: saturated; leaking memory.
WARNING: CPU: 1 PID: 3605 at lib/refcount.c:19 refcount_warn_saturate+0xf4/0x1e0 lib/refcount.c:19
Modules linked in:
CPU: 1 PID: 3605 Comm: syz-executor208 Not tainted 5.18.0-syzkaller-03023-g7e062cda7d90 #0
<TASK>
__refcount_add_not_zero include/linux/refcount.h:163 [inline]
__refcount_inc_not_zero include/linux/refcount.h:227 [inline]
refcount_inc_not_zero include/linux/refcount.h:245 [inline]
sk_psock_get+0x3bc/0x410 include/linux/skmsg.h:439
tls_data_ready+0x6d/0x1b0 net/tls/tls_sw.c:2091
tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:4983
tcp_data_queue+0x25f2/0x4c90 net/ipv4/tcp_input.c:5057
tcp_rcv_state_process+0x1774/0x4e80 net/ipv4/tcp_input.c:6659
tcp_v4_do_rcv+0x339/0x980 net/ipv4/tcp_ipv4.c:1682
sk_backlog_rcv include/net/sock.h:1061 [inline]
__release_sock+0x134/0x3b0 net/core/sock.c:2849
release_sock+0x54/0x1b0 net/core/sock.c:3404
inet_shutdown+0x1e0/0x430 net/ipv4/af_inet.c:909
__sys_shutdown_sock net/socket.c:2331 [inline]
__sys_shutdown_sock net/socket.c:2325 [inline]
__sys_shutdown+0xf1/0x1b0 net/socket.c:2343
__do_sys_shutdown net/socket.c:2351 [inline]
__se_sys_shutdown net/socket.c:2349 [inline]
__x64_sys_shutdown+0x50/0x70 net/socket.c:2349
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
</TASK>
During SMC fallback process in connect syscall, kernel will
replaces TCP with SMC. In order to forward wakeup
smc socket waitqueue after fallback, kernel will sets
clcsk->sk_user_data to origin smc socket in
smc_fback_replace_callbacks().
Later, in shutdown syscall, kernel will calls
sk_psock_get(), which treats the clcsk->sk_user_data
as psock type, triggering the refcnt warning.
So, the root cause is that smc and psock, both will use
sk_user_data field. So they will mismatch this field
easily.
This patch solves it by using another bit(defined as
SK_USER_DATA_PSOCK) in PTRMASK, to mark whether
sk_user_data points to a psock object or not.
This patch depends on a PTRMASK introduced in commit f1ff5ce2cd
("net, sk_msg: Clear sk_user_data pointer on clone if tagged").
For there will possibly be more flags in the sk_user_data field,
this patch also refactor sk_user_data flags code to be more generic
to improve its maintainability.
Reported-and-tested-by: syzbot+5f26f85569bd179c18ce@syzkaller.appspotmail.com
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Wen Gu <guwen@linux.alibaba.com>
Signed-off-by: Hawkins Jiawei <yin31149@gmail.com>
Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
While reading these sysctl variables, they can be changed concurrently.
Thus, we need to add READ_ONCE() to their readers.
- .sysctl_rmem
- .sysctl_rwmem
- .sysctl_rmem_offset
- .sysctl_wmem_offset
- sysctl_tcp_rmem[1, 2]
- sysctl_tcp_wmem[1, 2]
- sysctl_decnet_rmem[1]
- sysctl_decnet_wmem[1]
- sysctl_tipc_rmem[1]
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
While reading .sysctl_mem, it can be changed concurrently.
So, we need to add READ_ONCE() to avoid data-races.
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
There are no more users for the mentioned macros, just
drop them.
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Move the len fields manipulation in the skbs to a helper function.
There is a comment specifically requesting this and there are several
other areas in the code displaying the same pattern which can be
refactored.
This improves code readability.
Signed-off-by: Richard Gobert <richardbgobert@gmail.com>
Link: https://lore.kernel.org/r/20220622160853.GA6478@debian
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
sk_memory_allocated_add() has three callers, and returns
to them @memory_allocated.
sk_forced_mem_schedule() is one of them, and ignores
the returned value.
Change sk_memory_allocated_add() to return void.
Change sock_reserve_memory() and __sk_mem_raise_allocated()
to call sk_memory_allocated().
This removes one cache line miss [1] for RPC workloads,
as first skbs in TCP write queue and receive queue go through
sk_forced_mem_schedule().
[1] Cache line holding tcp_memory_allocated.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, tcp_memory_allocated can hit tcp_mem[] limits quite fast.
Each TCP socket can forward allocate up to 2 MB of memory, even after
flow became less active.
10,000 sockets can have reserved 20 GB of memory,
and we have no shrinker in place to reclaim that.
Instead of trying to reclaim the extra allocations in some places,
just keep sk->sk_forward_alloc values as small as possible.
This should not impact performance too much now we have per-cpu
reserves: Changes to tcp_memory_allocated should not be too frequent.
For sockets not using SO_RESERVE_MEM:
- idle sockets (no packets in tx/rx queues) have zero forward alloc.
- non idle sockets have a forward alloc smaller than one page.
Note:
- Removal of SK_RECLAIM_CHUNK and SK_RECLAIM_THRESHOLD
is left to MPTCP maintainers as a follow up.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If sk->sk_forward_alloc is 150000, and we need to schedule 150001 bytes,
we want to allocate 1 byte more (rounded up to one page),
instead of 150001 :/
Fixes: 1da177e4c3 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We plan keeping sk->sk_forward_alloc as small as possible
in future patches.
This means we are going to call sk_memory_allocated_add()
and sk_memory_allocated_sub() more often.
Implement a per-cpu cache of +1/-1 MB, to reduce number
of changes to sk->sk_prot->memory_allocated, which
would otherwise be cause of false sharing.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Each protocol having a ->memory_allocated pointer gets a corresponding
per-cpu reserve, that following patches will use.
Instead of having reserved bytes per socket,
we want to have per-cpu reserves.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Due to memcg interface, SK_MEM_QUANTUM is effectively PAGE_SIZE.
This might change in the future, but it seems better to avoid the
confusion.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This reverts commit bd68a2a854.
This change broke memcg on arches with PAGE_SIZE != 4096
Later, commit 2bb2f5fb21 ("net: add new socket option SO_RESERVE_MEM")
also assumed PAGE_SIZE==SK_MEM_QUANTUM
Following patches in the series will greatly reduce the over allocations
problem.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Soheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Despite these inline functions having full visibility to the compiler
at compile time, they still strip const from passed pointers.
This change allows for functions in various network drivers to be marked as
const that could not be marked const before.
Signed-off-by: Peter Lafreniere <pjlafren@mtu.edu>
Link: https://lore.kernel.org/r/20220606113458.35953-1-pjlafren@mtu.edu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
We currently have one tcp bind table (bhash) which hashes by port
number only. In the socket bind path, we check for bind conflicts by
traversing the specified port's inet_bind2_bucket while holding the
bucket's spinlock (see inet_csk_get_port() and inet_csk_bind_conflict()).
In instances where there are tons of sockets hashed to the same port
at different addresses, checking for a bind conflict is time-intensive
and can cause softirq cpu lockups, as well as stops new tcp connections
since __inet_inherit_port() also contests for the spinlock.
This patch proposes adding a second bind table, bhash2, that hashes by
port and ip address. Searching the bhash2 table leads to significantly
faster conflict resolution and less time holding the spinlock.
Signed-off-by: Joanne Koong <joannelkoong@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: Kuniyuki Iwashima <kuniyu@amazon.co.jp>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
UDP sendmsg() is lockless, and reads sk->sk_bound_dev_if while
this field can be changed by another thread.
Adds minimal annotations to avoid KCSAN splats for UDP.
Following patches will add more annotations to potential lockless readers.
BUG: KCSAN: data-race in __ip6_datagram_connect / udpv6_sendmsg
write to 0xffff888136d47a94 of 4 bytes by task 7681 on cpu 0:
__ip6_datagram_connect+0x6e2/0x930 net/ipv6/datagram.c:221
ip6_datagram_connect+0x2a/0x40 net/ipv6/datagram.c:272
inet_dgram_connect+0x107/0x190 net/ipv4/af_inet.c:576
__sys_connect_file net/socket.c:1900 [inline]
__sys_connect+0x197/0x1b0 net/socket.c:1917
__do_sys_connect net/socket.c:1927 [inline]
__se_sys_connect net/socket.c:1924 [inline]
__x64_sys_connect+0x3d/0x50 net/socket.c:1924
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x50 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
read to 0xffff888136d47a94 of 4 bytes by task 7670 on cpu 1:
udpv6_sendmsg+0xc60/0x16e0 net/ipv6/udp.c:1436
inet6_sendmsg+0x5f/0x80 net/ipv6/af_inet6.c:652
sock_sendmsg_nosec net/socket.c:705 [inline]
sock_sendmsg net/socket.c:725 [inline]
____sys_sendmsg+0x39a/0x510 net/socket.c:2413
___sys_sendmsg net/socket.c:2467 [inline]
__sys_sendmmsg+0x267/0x4c0 net/socket.c:2553
__do_sys_sendmmsg net/socket.c:2582 [inline]
__se_sys_sendmmsg net/socket.c:2579 [inline]
__x64_sys_sendmmsg+0x53/0x60 net/socket.c:2579
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x2b/0x50 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
value changed: 0x00000000 -> 0xffffff9b
Reported by Kernel Concurrency Sanitizer on:
CPU: 1 PID: 7670 Comm: syz-executor.3 Tainted: G W 5.18.0-rc1-syzkaller-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
I chose to not add Fixes: tag because race has minor consequences
and stable teams busy enough.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
