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2022-09-15tcp: TX zerocopy should not sense pfmemalloc statusEric Dumazet1-1/+1
[ Upstream commit 3261400639463a853ba2b3be8bd009c2a8089775 ] 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->lru.next, which can change more often than page->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 -> 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 <syzkaller@googlegroups.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Shakeel Butt <shakeelb@google.com> Reviewed-by: Shakeel Butt <shakeelb@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-15net/core/skbuff: Check the return value of skb_copy_bits()lily1-3/+2
[ Upstream commit c624c58e08b15105662b9ab9be23d14a6b945a49 ] skb_copy_bits() could fail, which requires a check on the return value. Signed-off-by: Li Zhong <floridsleeves@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-08skmsg: Fix wrong last sg check in sk_msg_recvmsg()Liu Jian1-2/+2
[ Upstream commit 583585e48d965338e73e1eb383768d16e0922d73 ] Fix one kernel NULL pointer dereference as below: [ 224.462334] Call Trace: [ 224.462394] __tcp_bpf_recvmsg+0xd3/0x380 [ 224.462441] ? sock_has_perm+0x78/0xa0 [ 224.462463] tcp_bpf_recvmsg+0x12e/0x220 [ 224.462494] inet_recvmsg+0x5b/0xd0 [ 224.462534] __sys_recvfrom+0xc8/0x130 [ 224.462574] ? syscall_trace_enter+0x1df/0x2e0 [ 224.462606] ? __do_page_fault+0x2de/0x500 [ 224.462635] __x64_sys_recvfrom+0x24/0x30 [ 224.462660] do_syscall_64+0x5d/0x1d0 [ 224.462709] entry_SYSCALL_64_after_hwframe+0x65/0xca In commit 9974d37ea75f ("skmsg: Fix invalid last sg check in sk_msg_recvmsg()"), we change last sg check to sg_is_last(), but in sockmap redirection case (without stream_parser/stream_verdict/ skb_verdict), we did not mark the end of the scatterlist. Check the sk_msg_alloc, sk_msg_page_add, and bpf_msg_push_data functions, they all do not mark the end of sg. They are expected to use sg.end for end judgment. So the judgment of '(i != msg_rx->sg.end)' is added back here. Fixes: 9974d37ea75f ("skmsg: Fix invalid last sg check in sk_msg_recvmsg()") Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Acked-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/bpf/20220809094915.150391-1-liujian56@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-05net: neigh: don't call kfree_skb() under spin_lock_irqsave()Yang Yingliang1-2/+8
commit d5485d9dd24e1d04e5509916515260186eb1455c upstream. It is not allowed to call kfree_skb() from hardware interrupt context or with interrupts being disabled. So add all skb to a tmp list, then free them after spin_unlock_irqrestore() at once. Fixes: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop") Suggested-by: Denis V. Lunev <den@openvz.org> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-05neigh: fix possible DoS due to net iface start/stop loopDenis V. Lunev1-8/+17
[ Upstream commit 66ba215cb51323e4e55e38fd5f250e0fae0cbc94 ] Normal processing of ARP request (usually this is Ethernet broadcast packet) coming to the host is looking like the following: * the packet comes to arp_process() call and is passed through routing procedure * the request is put into the queue using pneigh_enqueue() if corresponding ARP record is not local (common case for container records on the host) * the request is processed by timer (within 80 jiffies by default) and ARP reply is sent from the same arp_process() using NEIGH_CB(skb)->flags & LOCALLY_ENQUEUED condition (flag is set inside pneigh_enqueue()) And here the problem comes. Linux kernel calls pneigh_queue_purge() which destroys the whole queue of ARP requests on ANY network interface start/stop event through __neigh_ifdown(). This is actually not a problem within the original world as network interface start/stop was accessible to the host 'root' only, which could do more destructive things. But the world is changed and there are Linux containers available. Here container 'root' has an access to this API and could be considered as untrusted user in the hosting (container's) world. Thus there is an attack vector to other containers on node when container's root will endlessly start/stop interfaces. We have observed similar situation on a real production node when docker container was doing such activity and thus other containers on the node become not accessible. The patch proposed doing very simple thing. It drops only packets from the same namespace in the pneigh_queue_purge() where network interface state change is detected. This is enough to prevent the problem for the whole node preserving original semantics of the code. v2: - do del_timer_sync() if queue is empty after pneigh_queue_purge() v3: - rebase to net tree Cc: "David S. Miller" <davem@davemloft.net> Cc: Eric Dumazet <edumazet@google.com> Cc: Jakub Kicinski <kuba@kernel.org> Cc: Paolo Abeni <pabeni@redhat.com> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: David Ahern <dsahern@kernel.org> Cc: Yajun Deng <yajun.deng@linux.dev> Cc: Roopa Prabhu <roopa@nvidia.com> Cc: Christian Brauner <brauner@kernel.org> Cc: netdev@vger.kernel.org Cc: linux-kernel@vger.kernel.org Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Cc: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> Cc: Konstantin Khorenko <khorenko@virtuozzo.com> Cc: kernel@openvz.org Cc: devel@openvz.org Investigated-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> Signed-off-by: Denis V. Lunev <den@openvz.org> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-09-05bpf: Don't redirect packets with invalid pkt_lenZhengchao Shao1-0/+1
commit fd1894224407c484f652ad456e1ce423e89bb3eb upstream. Syzbot found an issue [1]: fq_codel_drop() try to drop a flow whitout any skbs, that is, the flow->head is null. The root cause, as the [2] says, is because that bpf_prog_test_run_skb() run a bpf prog which redirects empty skbs. So we should determine whether the length of the packet modified by bpf prog or others like bpf_prog_test is valid before forwarding it directly. LINK: [1] https://syzkaller.appspot.com/bug?id=0b84da80c2917757915afa89f7738a9d16ec96c5 LINK: [2] https://www.spinics.net/lists/netdev/msg777503.html Reported-by: syzbot+7a12909485b94426aceb@syzkaller.appspotmail.com Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> Reviewed-by: Stanislav Fomichev <sdf@google.com> Link: https://lore.kernel.org/r/20220715115559.139691-1-shaozhengchao@huawei.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-09-05net: fix refcount bug in sk_psock_get (2)Hawkins Jiawei1-1/+3
commit 2a0133723f9ebeb751cfce19f74ec07e108bef1f upstream. 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 f1ff5ce2cd5e ("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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-31net: Fix a data-race around netdev_unregister_timeout_secs.Kuniyuki Iwashima1-1/+1
[ Upstream commit 05e49cfc89e4f325eebbc62d24dd122e55f94c23 ] While reading netdev_unregister_timeout_secs, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 5aa3afe107d9 ("net: make unregister netdev warning timeout configurable") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Acked-by: Dmitry Vyukov <dvyukov@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix a data-race around netdev_budget_usecs.Kuniyuki Iwashima1-1/+1
[ Upstream commit fa45d484c52c73f79db2c23b0cdfc6c6455093ad ] While reading netdev_budget_usecs, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix a data-race around netdev_budget.Kuniyuki Iwashima1-1/+1
[ Upstream commit 2e0c42374ee32e72948559d2ae2f7ba3dc6b977c ] While reading netdev_budget, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 51b0bdedb8e7 ("[NET]: Separate two usages of netdev_max_backlog.") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix a data-race around sysctl_net_busy_read.Kuniyuki Iwashima1-1/+1
[ Upstream commit e59ef36f0795696ab229569c153936bfd068d21c ] While reading sysctl_net_busy_read, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: 2d48d67fa8cd ("net: poll/select low latency socket support") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix a data-race around sysctl_tstamp_allow_data.Kuniyuki Iwashima1-1/+1
[ Upstream commit d2154b0afa73c0159b2856f875c6b4fe7cf6a95e ] While reading sysctl_tstamp_allow_data, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Fixes: b245be1f4db1 ("net-timestamp: no-payload only sysctl") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix data-races around sysctl_optmem_max.Kuniyuki Iwashima3-9/+13
[ Upstream commit 7de6d09f51917c829af2b835aba8bb5040f8e86a ] While reading sysctl_optmem_max, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix data-races around netdev_tstamp_prequeue.Kuniyuki Iwashima1-4/+4
[ Upstream commit 61adf447e38664447526698872e21c04623afb8e ] While reading netdev_tstamp_prequeue, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 3b098e2d7c69 ("net: Consistent skb timestamping") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix data-races around netdev_max_backlog.Kuniyuki Iwashima2-3/+3
[ Upstream commit 5dcd08cd19912892586c6082d56718333e2d19db ] While reading netdev_max_backlog, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. While at it, we remove the unnecessary spaces in the doc. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix data-races around weight_p and dev_weight_[rt]x_bias.Kuniyuki Iwashima2-7/+10
[ Upstream commit bf955b5ab8f6f7b0632cdef8e36b14e4f6e77829 ] While reading weight_p, it can be changed concurrently. Thus, we need to add READ_ONCE() to its reader. Also, dev_[rt]x_weight can be read/written at the same time. So, we need to use READ_ONCE() and WRITE_ONCE() for its access. Moreover, to use the same weight_p while changing dev_[rt]x_weight, we add a mutex in proc_do_dev_weight(). Fixes: 3d48b53fb2ae ("net: dev_weight: TX/RX orthogonality") Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-31net: Fix data-races around sysctl_[rw]mem_(max|default).Kuniyuki Iwashima2-6/+6
[ Upstream commit 1227c1771dd2ad44318aa3ab9e3a293b3f34ff2a ] While reading sysctl_[rw]mem_(max|default), they can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-25net: sched: fix misuse of qcpu->backlog in gnet_stats_add_queue_cpuZhengchao Shao1-1/+1
commit de64b6b6fb6f369840d171b7c5a9baf31b8b2630 upstream. In the gnet_stats_add_queue_cpu function, the qstats->qlen statistics are incorrectly set to qcpu->backlog. Fixes: 448e163f8b9b ("gen_stats: Add gnet_stats_add_queue()") Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> Link: https://lore.kernel.org/r/20220815030848.276746-1-shaozhengchao@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25net: rtnetlink: fix module reference count leak issue in rtnetlink_rcv_msgZhengchao Shao1-0/+1
commit 5b22f62724a0a09e00d301abf5b57b0c12be8a16 upstream. When bulk delete command is received in the rtnetlink_rcv_msg function, if bulk delete is not supported, module_put is not called to release the reference counting. As a result, module reference count is leaked. Fixes: a6cec0bcd342 ("net: rtnetlink: add bulk delete support flag") Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com> Acked-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://lore.kernel.org/r/20220815024629.240367-1-shaozhengchao@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25devlink: Fix use-after-free after a failed reloadIdo Schimmel1-2/+2
commit 6b4db2e528f650c7fb712961aac36455468d5902 upstream. After a failed devlink reload, devlink parameters are still registered, which means user space can set and get their values. In the case of the mlxsw "acl_region_rehash_interval" parameter, these operations will trigger a use-after-free [1]. Fix this by rejecting set and get operations while in the failed state. Return the "-EOPNOTSUPP" error code which does not abort the parameters dump, but instead causes it to skip over the problematic parameter. Another possible fix is to perform these checks in the mlxsw parameter callbacks, but other drivers might be affected by the same problem and I am not aware of scenarios where these stricter checks will cause a regression. [1] mlxsw_spectrum3 0000:00:10.0: Port 125: Failed to register netdev mlxsw_spectrum3 0000:00:10.0: Failed to create ports ================================================================== BUG: KASAN: use-after-free in mlxsw_sp_acl_tcam_vregion_rehash_intrvl_get+0xbd/0xd0 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c:904 Read of size 4 at addr ffff8880099dcfd8 by task kworker/u4:4/777 CPU: 1 PID: 777 Comm: kworker/u4:4 Not tainted 5.19.0-rc7-custom-126601-gfe26f28c586d #1 Hardware name: QEMU MSN4700, BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 Workqueue: netns cleanup_net Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x92/0xbd lib/dump_stack.c:106 print_address_description mm/kasan/report.c:313 [inline] print_report.cold+0x5e/0x5cf mm/kasan/report.c:429 kasan_report+0xb9/0xf0 mm/kasan/report.c:491 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report_generic.c:306 mlxsw_sp_acl_tcam_vregion_rehash_intrvl_get+0xbd/0xd0 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl_tcam.c:904 mlxsw_sp_acl_region_rehash_intrvl_get+0x49/0x60 drivers/net/ethernet/mellanox/mlxsw/spectrum_acl.c:1106 mlxsw_sp_params_acl_region_rehash_intrvl_get+0x33/0x80 drivers/net/ethernet/mellanox/mlxsw/spectrum.c:3854 devlink_param_get net/core/devlink.c:4981 [inline] devlink_nl_param_fill+0x238/0x12d0 net/core/devlink.c:5089 devlink_param_notify+0xe5/0x230 net/core/devlink.c:5168 devlink_ns_change_notify net/core/devlink.c:4417 [inline] devlink_ns_change_notify net/core/devlink.c:4396 [inline] devlink_reload+0x15f/0x700 net/core/devlink.c:4507 devlink_pernet_pre_exit+0x112/0x1d0 net/core/devlink.c:12272 ops_pre_exit_list net/core/net_namespace.c:152 [inline] cleanup_net+0x494/0xc00 net/core/net_namespace.c:582 process_one_work+0x9fc/0x1710 kernel/workqueue.c:2289 worker_thread+0x675/0x10b0 kernel/workqueue.c:2436 kthread+0x30c/0x3d0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306 </TASK> The buggy address belongs to the physical page: page:ffffea0000267700 refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x99dc flags: 0x100000000000000(node=0|zone=1) raw: 0100000000000000 0000000000000000 dead000000000122 0000000000000000 raw: 0000000000000000 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880099dce80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880099dcf00: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff8880099dcf80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff8880099dd000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff8880099dd080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== Fixes: 98bbf70c1c41 ("mlxsw: spectrum: add "acl_region_rehash_interval" devlink param") Signed-off-by: Ido Schimmel <idosch@nvidia.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25bpf: Check the validity of max_rdwr_access for sock local storage map iteratorHou Tao1-1/+1
commit 52bd05eb7c88e1ad8541a48873188ccebca9da26 upstream. The value of sock local storage map is writable in map iterator, so check max_rdwr_access instead of max_rdonly_access. Fixes: 5ce6e77c7edf ("bpf: Implement bpf iterator for sock local storage map") Signed-off-by: Hou Tao <houtao1@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/20220810080538.1845898-6-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25bpf: Acquire map uref in .init_seq_private for sock{map,hash} iteratorHou Tao1-1/+19
commit f0d2b2716d71778d0b0c8eaa433c073287d69d93 upstream. sock_map_iter_attach_target() acquires a map uref, and the uref may be released before or in the middle of iterating map elements. For example, the uref could be released in sock_map_iter_detach_target() as part of bpf_link_release(), or could be released in bpf_map_put_with_uref() as part of bpf_map_release(). Fixing it by acquiring an extra map uref in .init_seq_private and releasing it in .fini_seq_private. Fixes: 0365351524d7 ("net: Allow iterating sockmap and sockhash") Signed-off-by: Hou Tao <houtao1@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Link: https://lore.kernel.org/r/20220810080538.1845898-5-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-25bpf: Acquire map uref in .init_seq_private for sock local storage map iteratorHou Tao1-1/+9
commit 3c5f6e698b5c538bbb23cd453b22e1e4922cffd8 upstream. bpf_iter_attach_map() acquires a map uref, and the uref may be released before or in the middle of iterating map elements. For example, the uref could be released in bpf_iter_detach_map() as part of bpf_link_release(), or could be released in bpf_map_put_with_uref() as part of bpf_map_release(). So acquiring an extra map uref in bpf_iter_init_sk_storage_map() and releasing it in bpf_iter_fini_sk_storage_map(). Fixes: 5ce6e77c7edf ("bpf: Implement bpf iterator for sock local storage map") Signed-off-by: Hou Tao <houtao1@huawei.com> Acked-by: Yonghong Song <yhs@fb.com> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/r/20220810080538.1845898-4-houtao@huaweicloud.com Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-08-17bpf: Fix bpf_xdp_pointer return pointerJoanne Koong1-1/+1
[ Upstream commit bbd52178e249fe893ef4a9b87cde5b6c473b0a7c ] For the case where offset + len == size, bpf_xdp_pointer should return a valid pointer to the addr because that access is permitted. We should only return NULL in the case where offset + len exceeds size. Fixes: 3f364222d032 ("net: xdp: introduce bpf_xdp_pointer utility routine") Signed-off-by: Joanne Koong <joannelkoong@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Martin KaFai Lau <kafai@fb.com> Acked-by: Lorenzo Bianconi <lorenzo@kernel.org> Link: https://lore.kernel.org/bpf/20220722220105.2065466-1-joannelkoong@gmail.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17bpf: Set flow flag to allow any source IP in bpf_tunnel_keyPaul Chaignon1-0/+1
[ Upstream commit b8fff748521c7178b9a7d32b5a34a81cec8396f3 ] Commit 26101f5ab6bd ("bpf: Add source ip in "struct bpf_tunnel_key"") added support for getting and setting the outer source IP of encapsulated packets via the bpf_skb_{get,set}_tunnel_key BPF helper. This change allows BPF programs to set any IP address as the source, including for example the IP address of a container running on the same host. In that last case, however, the encapsulated packets are dropped when looking up the route because the source IP address isn't assigned to any interface on the host. To avoid this, we need to set the FLOWI_FLAG_ANYSRC flag. Fixes: 26101f5ab6bd ("bpf: Add source ip in "struct bpf_tunnel_key"") Signed-off-by: Paul Chaignon <paul@isovalent.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Acked-by: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/76873d384e21288abe5767551a0799ac93ec07fb.1658759380.git.paul@isovalent.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-08-17skmsg: Fix invalid last sg check in sk_msg_recvmsg()Liu Jian1-2/+2
[ Upstream commit 9974d37ea75f01b47d16072b5dad305bd8d23fcc ] In sk_psock_skb_ingress_enqueue function, if the linear area + nr_frags + frag_list of the SKB has NR_MSG_FRAG_IDS blocks in total, skb_to_sgvec will return NR_MSG_FRAG_IDS, then msg->sg.end will be set to NR_MSG_FRAG_IDS, and in addition, (NR_MSG_FRAG_IDS - 1) is set to the last SG of msg. Recv the msg in sk_msg_recvmsg, when i is (NR_MSG_FRAG_IDS - 1), the sk_msg_iter_var_next(i) will change i to 0 (not NR_MSG_FRAG_IDS), the judgment condition "msg_rx->sg.start==msg_rx->sg.end" and "i != msg_rx->sg.end" can not work. As a result, the processed msg cannot be deleted from ingress_msg list. But the length of all the sge of the msg has changed to 0. Then the next recvmsg syscall will process the msg repeatedly, because the length of sge is 0, the -EFAULT error is always returned. Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface") Signed-off-by: Liu Jian <liujian56@huawei.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: John Fastabend <john.fastabend@gmail.com> Link: https://lore.kernel.org/bpf/20220628123616.186950-1-liujian56@huawei.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-07-20tcp: Fix data-races around sysctl knobs related to SYN option.Kuniyuki Iwashima1-2/+2
While reading these knobs, they can be changed concurrently. Thus, we need to add READ_ONCE() to their readers. - tcp_sack - tcp_window_scaling - tcp_timestamps Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18tcp: Fix data-races around sysctl_tcp_migrate_req.Kuniyuki Iwashima1-2/+2
While reading sysctl_tcp_migrate_req, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: f9ac779f881c ("net: Introduce net.ipv4.tcp_migrate_req.") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-18tcp: Fix data-races around sysctl_tcp_syncookies.Kuniyuki Iwashima1-2/+2
While reading sysctl_tcp_syncookies, it can be changed concurrently. Thus, we need to add READ_ONCE() to its readers. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-07-14seg6: bpf: fix skb checksum in bpf_push_seg6_encap()Andrea Mayer1-1/+0
Both helper functions bpf_lwt_seg6_action() and bpf_lwt_push_encap() use the bpf_push_seg6_encap() to encapsulate the packet in an IPv6 with Segment Routing Header (SRH) or insert an SRH between the IPv6 header and the payload. To achieve this result, such helper functions rely on bpf_push_seg6_encap() which, in turn, leverages seg6_do_srh_{encap,inline}() to perform the required operation (i.e. encap/inline). This patch removes the initialization of the IPv6 header payload length from bpf_push_seg6_encap(), as it is now handled properly by seg6_do_srh_{encap,inline}() to prevent corruption of the skb checksum. Fixes: fe94cc290f53 ("bpf: Add IPv6 Segment Routing helpers") Signed-off-by: Andrea Mayer <andrea.mayer@uniroma2.it> Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-07-06xdp: Fix spurious packet loss in generic XDP TX pathJohan Almbladh1-2/+6
The byte queue limits (BQL) mechanism is intended to move queuing from the driver to the network stack in order to reduce latency caused by excessive queuing in hardware. However, when transmitting or redirecting a packet using generic XDP, the qdisc layer is bypassed and there are no additional queues. Since netif_xmit_stopped() also takes BQL limits into account, but without having any alternative queuing, packets are silently dropped. This patch modifies the drop condition to only consider cases when the driver itself cannot accept any more packets. This is analogous to the condition in __dev_direct_xmit(). Dropped packets are also counted on the device. Bypassing the qdisc layer in the generic XDP TX path means that XDP packets are able to starve other packets going through a qdisc, and DDOS attacks will be more effective. In-driver-XDP use dedicated TX queues, so they do not have this starvation issue. Signed-off-by: Johan Almbladh <johan.almbladh@anyfinetworks.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/bpf/20220705082345.2494312-1-johan.almbladh@anyfinetworks.com
2022-06-23sock: redo the psock vs ULP protection checkJakub Kicinski1-0/+5
Commit 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()") has moved the inet_csk_has_ulp(sk) check from sk_psock_init() to the new tcp_bpf_update_proto() function. I'm guessing that this was done to allow creating psocks for non-inet sockets. Unfortunately the destruction path for psock includes the ULP unwind, so we need to fail the sk_psock_init() itself. Otherwise if ULP is already present we'll notice that later, and call tcp_update_ulp() with the sk_proto of the ULP itself, which will most likely result in the ULP looping its callbacks. Fixes: 8a59f9d1e3d4 ("sock: Introduce sk->sk_prot->psock_update_sk_prot()") Signed-off-by: Jakub Kicinski <kuba@kernel.org> Reviewed-by: John Fastabend <john.fastabend@gmail.com> Reviewed-by: Jakub Sitnicki <jakub@cloudflare.com> Tested-by: Jakub Sitnicki <jakub@cloudflare.com> Link: https://lore.kernel.org/r/20220620191353.1184629-2-kuba@kernel.org Signed-off-by: Paolo Abeni <pabeni@redhat.com>
2022-06-18Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpfJakub Kicinski1-6/+28
Daniel Borkmann says: ==================== pull-request: bpf 2022-06-17 We've added 12 non-merge commits during the last 4 day(s) which contain a total of 14 files changed, 305 insertions(+), 107 deletions(-). The main changes are: 1) Fix x86 JIT tailcall count offset on BPF-2-BPF call, from Jakub Sitnicki. 2) Fix a kprobe_multi link bug which misplaces BPF cookies, from Jiri Olsa. 3) Fix an infinite loop when processing a module's BTF, from Kumar Kartikeya Dwivedi. 4) Fix getting a rethook only in RCU available context, from Masami Hiramatsu. 5) Fix request socket refcount leak in sk lookup helpers, from Jon Maxwell. 6) Fix xsk xmit behavior which wrongly adds skb to already full cq, from Ciara Loftus. * https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf: rethook: Reject getting a rethook if RCU is not watching fprobe, samples: Add use_trace option and show hit/missed counter bpf, docs: Update some of the JIT/maintenance entries selftest/bpf: Fix kprobe_multi bench test bpf: Force cookies array to follow symbols sorting ftrace: Keep address offset in ftrace_lookup_symbols selftests/bpf: Shuffle cookies symbols in kprobe multi test selftests/bpf: Test tail call counting with bpf2bpf and data on stack bpf, x86: Fix tail call count offset calculation on bpf2bpf call bpf: Limit maximum modifier chain length in btf_check_type_tags bpf: Fix request_sock leak in sk lookup helpers xsk: Fix generic transmit when completion queue reservation fails ==================== Link: https://lore.kernel.org/r/20220617202119.2421-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-06-17net: fix data-race in dev_isalive()Eric Dumazet2-10/+16
dev_isalive() is called under RTNL or dev_base_lock protection. This means that changes to dev->reg_state should be done with both locks held. syzbot reported: BUG: KCSAN: data-race in register_netdevice / type_show write to 0xffff888144ecf518 of 1 bytes by task 20886 on cpu 0: register_netdevice+0xb9f/0xdf0 net/core/dev.c:10050 lapbeth_new_device drivers/net/wan/lapbether.c:414 [inline] lapbeth_device_event+0x4a0/0x6c0 drivers/net/wan/lapbether.c:456 notifier_call_chain kernel/notifier.c:87 [inline] raw_notifier_call_chain+0x53/0xb0 kernel/notifier.c:455 __dev_notify_flags+0x1d6/0x3a0 dev_change_flags+0xa2/0xc0 net/core/dev.c:8607 do_setlink+0x778/0x2230 net/core/rtnetlink.c:2780 __rtnl_newlink net/core/rtnetlink.c:3546 [inline] rtnl_newlink+0x114c/0x16a0 net/core/rtnetlink.c:3593 rtnetlink_rcv_msg+0x811/0x8c0 net/core/rtnetlink.c:6089 netlink_rcv_skb+0x13e/0x240 net/netlink/af_netlink.c:2501 rtnetlink_rcv+0x18/0x20 net/core/rtnetlink.c:6107 netlink_unicast_kernel net/netlink/af_netlink.c:1319 [inline] netlink_unicast+0x58a/0x660 net/netlink/af_netlink.c:1345 netlink_sendmsg+0x661/0x750 net/netlink/af_netlink.c:1921 sock_sendmsg_nosec net/socket.c:714 [inline] sock_sendmsg net/socket.c:734 [inline] __sys_sendto+0x21e/0x2c0 net/socket.c:2119 __do_sys_sendto net/socket.c:2131 [inline] __se_sys_sendto net/socket.c:2127 [inline] __x64_sys_sendto+0x74/0x90 net/socket.c:2127 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+0x46/0xb0 read to 0xffff888144ecf518 of 1 bytes by task 20423 on cpu 1: dev_isalive net/core/net-sysfs.c:38 [inline] netdev_show net/core/net-sysfs.c:50 [inline] type_show+0x24/0x90 net/core/net-sysfs.c:112 dev_attr_show+0x35/0x90 drivers/base/core.c:2095 sysfs_kf_seq_show+0x175/0x240 fs/sysfs/file.c:59 kernfs_seq_show+0x75/0x80 fs/kernfs/file.c:162 seq_read_iter+0x2c3/0x8e0 fs/seq_file.c:230 kernfs_fop_read_iter+0xd1/0x2f0 fs/kernfs/file.c:235 call_read_iter include/linux/fs.h:2052 [inline] new_sync_read fs/read_write.c:401 [inline] vfs_read+0x5a5/0x6a0 fs/read_write.c:482 ksys_read+0xe8/0x1a0 fs/read_write.c:620 __do_sys_read fs/read_write.c:630 [inline] __se_sys_read fs/read_write.c:628 [inline] __x64_sys_read+0x3e/0x50 fs/read_write.c:628 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+0x46/0xb0 value changed: 0x00 -> 0x01 Reported by Kernel Concurrency Sanitizer on: CPU: 1 PID: 20423 Comm: udevd Tainted: G W 5.19.0-rc2-syzkaller-dirty #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-06-15bpf: Fix request_sock leak in sk lookup helpersJon Maxwell1-6/+28
A customer reported a request_socket leak in a Calico cloud environment. We found that a BPF program was doing a socket lookup with takes a refcnt on the socket and that it was finding the request_socket but returning the parent LISTEN socket via sk_to_full_sk() without decrementing the child request socket 1st, resulting in request_sock slab object leak. This patch retains the existing behaviour of returning full socks to the caller but it also decrements the child request_socket if one is present before doing so to prevent the leak. Thanks to Curtis Taylor for all the help in diagnosing and testing this. And thanks to Antoine Tenart for the reproducer and patch input. v2 of this patch contains, refactor as per Daniel Borkmann's suggestions to validate RCU flags on the listen socket so that it balances with bpf_sk_release() and update comments as per Martin KaFai Lau's suggestion. One small change to Daniels suggestion, put "sk = sk2" under "if (sk2 != sk)" to avoid an extra instruction. Fixes: f7355a6c0497 ("bpf: Check sk_fullsock() before returning from bpf_sk_lookup()") Fixes: edbf8c01de5a ("bpf: add skc_lookup_tcp helper") Co-developed-by: Antoine Tenart <atenart@kernel.org> Signed-off-by: Antoine Tenart <atenart@kernel.org> Signed-off-by: Jon Maxwell <jmaxwell37@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Tested-by: Curtis Taylor <cutaylor-pub@yahoo.com> Cc: Martin KaFai Lau <kafai@fb.com> Link: https://lore.kernel.org/bpf/56d6f898-bde0-bb25-3427-12a330b29fb8@iogearbox.net Link: https://lore.kernel.org/bpf/20220615011540.813025-1-jmaxwell37@gmail.com
2022-06-06netfilter: nf_tables: bail out early if hardware offload is not supportedPablo Neira Ayuso1-0/+6
If user requests for NFT_CHAIN_HW_OFFLOAD, then check if either device provides the .ndo_setup_tc interface or there is an indirect flow block that has been registered. Otherwise, bail out early from the preparation phase. Moreover, validate that family == NFPROTO_NETDEV and hook is NF_NETDEV_INGRESS. Fixes: c9626a2cbdb2 ("netfilter: nf_tables: add hardware offload support") Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-05-26net, neigh: Set lower cap for neigh_managed_work rearmingDaniel Borkmann1-1/+1
Yuwei reported that plain reuse of DELAY_PROBE_TIME to rearm work queue in neigh_managed_work is problematic if user explicitly configures the DELAY_PROBE_TIME to 0 for a neighbor table. Such misconfig can then hog CPU to 100% processing the system work queue. Instead, set lower interval bound to HZ which is totally sufficient. Yuwei is additionally looking into making the interval separately configurable from DELAY_PROBE_TIME. Reported-by: Yuwei Wang <wangyuweihx@gmail.com> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Link: https://lore.kernel.org/netdev/797c3c53-ce1b-9f60-e253-cda615788f4a@iogearbox.net Reviewed-by: Nikolay Aleksandrov <razor@blackwall.org> Link: https://lore.kernel.org/r/3b8c5aa906c52c3a8c995d1b2e8ccf650ea7c716.1653432794.git.daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-25Merge tag 'net-next-5.19' of ↵Linus Torvalds23-354/+1560
git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next Pull networking updates from Jakub Kicinski: "Core ---- - Support TCPv6 segmentation offload with super-segments larger than 64k bytes using the IPv6 Jumbogram extension header (AKA BIG TCP). - Generalize skb freeing deferral to per-cpu lists, instead of per-socket lists. - Add a netdev statistic for packets dropped due to L2 address mismatch (rx_otherhost_dropped). - Continue work annotating skb drop reasons. - Accept alternative netdev names (ALT_IFNAME) in more netlink requests. - Add VLAN support for AF_PACKET SOCK_RAW GSO. - Allow receiving skb mark from the socket as a cmsg. - Enable memcg accounting for veth queues, sysctl tables and IPv6. BPF --- - Add libbpf support for User Statically-Defined Tracing (USDTs). - Speed up symbol resolution for kprobes multi-link attachments. - Support storing typed pointers to referenced and unreferenced objects in BPF maps. - Add support for BPF link iterator. - Introduce access to remote CPU map elements in BPF per-cpu map. - Allow middle-of-the-road settings for the kernel.unprivileged_bpf_disabled sysctl. - Implement basic types of dynamic pointers e.g. to allow for dynamically sized ringbuf reservations without extra memory copies. Protocols --------- - Retire port only listening_hash table, add a second bind table hashed by port and address. Avoid linear list walk when binding to very popular ports (e.g. 443). - Add bridge FDB bulk flush filtering support allowing user space to remove all FDB entries matching a condition. - Introduce accept_unsolicited_na sysctl for IPv6 to implement router-side changes for RFC9131. - Support for MPTCP path manager in user space. - Add MPTCP support for fallback to regular TCP for connections that have never connected additional subflows or transmitted out-of-sequence data (partial support for RFC8684 fallback). - Avoid races in MPTCP-level window tracking, stabilize and improve throughput. - Support lockless operation of GRE tunnels with seq numbers enabled. - WiFi support for host based BSS color collision detection. - Add support for SO_TXTIME/SCM_TXTIME on CAN sockets. - Support transmission w/o flow control in CAN ISOTP (ISO 15765-2). - Support zero-copy Tx with TLS 1.2 crypto offload (sendfile). - Allow matching on the number of VLAN tags via tc-flower. - Add tracepoint for tcp_set_ca_state(). Driver API ---------- - Improve error reporting from classifier and action offload. - Add support for listing line cards in switches (devlink). - Add helpers for reporting page pool statistics with ethtool -S. - Add support for reading clock cycles when using PTP virtual clocks, instead of having the driver convert to time before reporting. This makes it possible to report time from different vclocks. - Support configuring low-latency Tx descriptor push via ethtool. - Separate Clause 22 and Clause 45 MDIO accesses more explicitly. New hardware / drivers ---------------------- - Ethernet: - Marvell's Octeon NIC PCI Endpoint support (octeon_ep) - Sunplus SP7021 SoC (sp7021_emac) - Add support for Renesas RZ/V2M (in ravb) - Add support for MediaTek mt7986 switches (in mtk_eth_soc) - Ethernet PHYs: - ADIN1100 industrial PHYs (w/ 10BASE-T1L and SQI reporting) - TI DP83TD510 PHY - Microchip LAN8742/LAN88xx PHYs - WiFi: - Driver for pureLiFi X, XL, XC devices (plfxlc) - Driver for Silicon Labs devices (wfx) - Support for WCN6750 (in ath11k) - Support Realtek 8852ce devices (in rtw89) - Mobile: - MediaTek T700 modems (Intel 5G 5000 M.2 cards) - CAN: - ctucanfd: add support for CTU CAN FD open-source IP core from Czech Technical University in Prague Drivers ------- - Delete a number of old drivers still using virt_to_bus(). - Ethernet NICs: - intel: support TSO on tunnels MPLS - broadcom: support multi-buffer XDP - nfp: support VF rate limiting - sfc: use hardware tx timestamps for more than PTP - mlx5: multi-port eswitch support - hyper-v: add support for XDP_REDIRECT - atlantic: XDP support (including multi-buffer) - macb: improve real-time perf by deferring Tx processing to NAPI - High-speed Ethernet switches: - mlxsw: implement basic line card information querying - prestera: add support for traffic policing on ingress and egress - Embedded Ethernet switches: - lan966x: add support for packet DMA (FDMA) - lan966x: add support for PTP programmable pins - ti: cpsw_new: enable bc/mc storm prevention - Qualcomm 802.11ax WiFi (ath11k): - Wake-on-WLAN support for QCA6390 and WCN6855 - device recovery (firmware restart) support - support setting Specific Absorption Rate (SAR) for WCN6855 - read country code from SMBIOS for WCN6855/QCA6390 - enable keep-alive during WoWLAN suspend - implement remain-on-channel support - MediaTek WiFi (mt76): - support Wireless Ethernet Dispatch offloading packet movement between the Ethernet switch and WiFi interfaces - non-standard VHT MCS10-11 support - mt7921 AP mode support - mt7921 IPv6 NS offload support - Ethernet PHYs: - micrel: ksz9031/ksz9131: cabletest support - lan87xx: SQI support for T1 PHYs - lan937x: add interrupt support for link detection" * tag 'net-next-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1809 commits) ptp: ocp: Add firmware header checks ptp: ocp: fix PPS source selector debugfs reporting ptp: ocp: add .init function for sma_op vector ptp: ocp: vectorize the sma accessor functions ptp: ocp: constify selectors ptp: ocp: parameterize input/output sma selectors ptp: ocp: revise firmware display ptp: ocp: add Celestica timecard PCI ids ptp: ocp: Remove #ifdefs around PCI IDs ptp: ocp: 32-bit fixups for pci start address Revert "net/smc: fix listen processing for SMC-Rv2" ath6kl: Use cc-disable-warning to disable -Wdangling-pointer selftests/bpf: Dynptr tests bpf: Add dynptr data slices bpf: Add bpf_dynptr_read and bpf_dynptr_write bpf: Dynptr support for ring buffers bpf: Add bpf_dynptr_from_mem for local dynptrs bpf: Add verifier support for dynptrs bpf: Suppress 'passing zero to PTR_ERR' warning bpf: Introduce bpf_arch_text_invalidate for bpf_prog_pack ...
2022-05-24Merge tag 'random-5.19-rc1-for-linus' of ↵Linus Torvalds1-3/+0
git://git.kernel.org/pub/scm/linux/kernel/git/crng/random Pull random number generator updates from Jason Donenfeld: "These updates continue to refine the work began in 5.17 and 5.18 of modernizing the RNG's crypto and streamlining and documenting its code. New for 5.19, the updates aim to improve entropy collection methods and make some initial decisions regarding the "premature next" problem and our threat model. The cloc utility now reports that random.c is 931 lines of code and 466 lines of comments, not that basic metrics like that mean all that much, but at the very least it tells you that this is very much a manageable driver now. Here's a summary of the various updates: - The random_get_entropy() function now always returns something at least minimally useful. This is the primary entropy source in most collectors, which in the best case expands to something like RDTSC, but prior to this change, in the worst case it would just return 0, contributing nothing. For 5.19, additional architectures are wired up, and architectures that are entirely missing a cycle counter now have a generic fallback path, which uses the highest resolution clock available from the timekeeping subsystem. Some of those clocks can actually be quite good, despite the CPU not having a cycle counter of its own, and going off-core for a stamp is generally thought to increase jitter, something positive from the perspective of entropy gathering. Done very early on in the development cycle, this has been sitting in next getting some testing for a while now and has relevant acks from the archs, so it should be pretty well tested and fine, but is nonetheless the thing I'll be keeping my eye on most closely. - Of particular note with the random_get_entropy() improvements is MIPS, which, on CPUs that lack the c0 count register, will now combine the high-speed but short-cycle c0 random register with the lower-speed but long-cycle generic fallback path. - With random_get_entropy() now always returning something useful, the interrupt handler now collects entropy in a consistent construction. - Rather than comparing two samples of random_get_entropy() for the jitter dance, the algorithm now tests many samples, and uses the amount of differing ones to determine whether or not jitter entropy is usable and how laborious it must be. The problem with comparing only two samples was that if the cycle counter was extremely slow, but just so happened to be on the cusp of a change, the slowness wouldn't be detected. Taking many samples fixes that to some degree. This, combined with the other improvements to random_get_entropy(), should make future unification of /dev/random and /dev/urandom maybe more possible. At the very least, were we to attempt it again today (we're not), it wouldn't break any of Guenter's test rigs that broke when we tried it with 5.18. So, not today, but perhaps down the road, that's something we can revisit. - We attempt to reseed the RNG immediately upon waking up from system suspend or hibernation, making use of the various timestamps about suspend time and such available, as well as the usual inputs such as RDRAND when available. - Batched randomness now falls back to ordinary randomness before the RNG is initialized. This provides more consistent guarantees to the types of random numbers being returned by the various accessors. - The "pre-init injection" code is now gone for good. I suspect you in particular will be happy to read that, as I recall you expressing your distaste for it a few months ago. Instead, to avoid a "premature first" issue, while still allowing for maximal amount of entropy availability during system boot, the first 128 bits of estimated entropy are used immediately as it arrives, with the next 128 bits being buffered. And, as before, after the RNG has been fully initialized, it winds up reseeding anyway a few seconds later in most cases. This resulted in a pretty big simplification of the initialization code and let us remove various ad-hoc mechanisms like the ugly crng_pre_init_inject(). - The RNG no longer pretends to handle the "premature next" security model, something that various academics and other RNG designs have tried to care about in the past. After an interesting mailing list thread, these issues are thought to be a) mainly academic and not practical at all, and b) actively harming the real security of the RNG by delaying new entropy additions after a potential compromise, making a potentially bad situation even worse. As well, in the first place, our RNG never even properly handled the premature next issue, so removing an incomplete solution to a fake problem was particularly nice. This allowed for numerous other simplifications in the code, which is a lot cleaner as a consequence. If you didn't see it before, https://lore.kernel.org/lkml/YmlMGx6+uigkGiZ0@zx2c4.com/ may be a thread worth skimming through. - While the interrupt handler received a separate code path years ago that avoids locks by using per-cpu data structures and a faster mixing algorithm, in order to reduce interrupt latency, input and disk events that are triggered in hardirq handlers were still hitting locks and more expensive algorithms. Those are now redirected to use the faster per-cpu data structures. - Rather than having the fake-crypto almost-siphash-based random32 implementation be used right and left, and in many places where cryptographically secure randomness is desirable, the batched entropy code is now fast enough to replace that. - As usual, numerous code quality and documentation cleanups. For example, the initialization state machine now uses enum symbolic constants instead of just hard coding numbers everywhere. - Since the RNG initializes once, and then is always initialized thereafter, a pretty heavy amount of code used during that initialization is never used again. It is now completely cordoned off using static branches and it winds up in the .text.unlikely section so that it doesn't reduce cache compactness after the RNG is ready. - A variety of functions meant for waiting on the RNG to be initialized were only used by vsprintf, and in not a particularly optimal way. Replacing that usage with a more ordinary setup made it possible to remove those functions. - A cleanup of how we warn userspace about the use of uninitialized /dev/urandom and uninitialized get_random_bytes() usage. Interestingly, with the change you merged for 5.18 that attempts to use jitter (but does not block if it can't), the majority of users should never see those warnings for /dev/urandom at all now, and the one for in-kernel usage is mainly a debug thing. - The file_operations struct for /dev/[u]random now implements .read_iter and .write_iter instead of .read and .write, allowing it to also implement .splice_read and .splice_write, which makes splice(2) work again after it was broken here (and in many other places in the tree) during the set_fs() removal. This was a bit of a last minute arrival from Jens that hasn't had as much time to bake, so I'll be keeping my eye on this as well, but it seems fairly ordinary. Unfortunately, read_iter() is around 3% slower than read() in my tests, which I'm not thrilled about. But Jens and Al, spurred by this observation, seem to be making progress in removing the bottlenecks on the iter paths in the VFS layer in general, which should remove the performance gap for all drivers. - Assorted other bug fixes, cleanups, and optimizations. - A small SipHash cleanup" * tag 'random-5.19-rc1-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/crng/random: (49 commits) random: check for signals after page of pool writes random: wire up fops->splice_{read,write}_iter() random: convert to using fops->write_iter() random: convert to using fops->read_iter() random: unify batched entropy implementations random: move randomize_page() into mm where it belongs random: remove mostly unused async readiness notifier random: remove get_random_bytes_arch() and add rng_has_arch_random() random: move initialization functions out of hot pages random: make consistent use of buf and len random: use proper return types on get_random_{int,long}_wait() random: remove extern from functions in header random: use static branch for crng_ready() random: credit architectural init the exact amount random: handle latent entropy and command line from random_init() random: use proper jiffies comparison macro random: remove ratelimiting for in-kernel unseeded randomness random: move initialization out of reseeding hot path random: avoid initializing twice in credit race random: use symbolic constants for crng_init states ...
2022-05-24Merge https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-nextJakub Kicinski3-9/+46
Daniel Borkmann says: ==================== pull-request: bpf-next 2022-05-23 We've added 113 non-merge commits during the last 26 day(s) which contain a total of 121 files changed, 7425 insertions(+), 1586 deletions(-). The main changes are: 1) Speed up symbol resolution for kprobes multi-link attachments, from Jiri Olsa. 2) Add BPF dynamic pointer infrastructure e.g. to allow for dynamically sized ringbuf reservations without extra memory copies, from Joanne Koong. 3) Big batch of libbpf improvements towards libbpf 1.0 release, from Andrii Nakryiko. 4) Add BPF link iterator to traverse links via seq_file ops, from Dmitrii Dolgov. 5) Add source IP address to BPF tunnel key infrastructure, from Kaixi Fan. 6) Refine unprivileged BPF to disable only object-creating commands, from Alan Maguire. 7) Fix JIT blinding of ld_imm64 when they point to subprogs, from Alexei Starovoitov. 8) Add BPF access to mptcp_sock structures and their meta data, from Geliang Tang. 9) Add new BPF helper for access to remote CPU's BPF map elements, from Feng Zhou. 10) Allow attaching 64-bit cookie to BPF link of fentry/fexit/fmod_ret, from Kui-Feng Lee. 11) Follow-ups to typed pointer support in BPF maps, from Kumar Kartikeya Dwivedi. 12) Add busy-poll test cases to the XSK selftest suite, from Magnus Karlsson. 13) Improvements in BPF selftest test_progs subtest output, from Mykola Lysenko. 14) Fill bpf_prog_pack allocator areas with illegal instructions, from Song Liu. 15) Add generic batch operations for BPF map-in-map cases, from Takshak Chahande. 16) Make bpf_jit_enable more user friendly when permanently on 1, from Tiezhu Yang. 17) Fix an array overflow in bpf_trampoline_get_progs(), from Yuntao Wang. ==================== Link: https://lore.kernel.org/r/20220523223805.27931-1-daniel@iogearbox.net Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-22net: wrap the wireless pointers in struct net_device in an ifdefJakub Kicinski1-8/+13
Most protocol-specific pointers in struct net_device are under a respective ifdef. Wireless is the notable exception. Since there's a sizable number of custom-built kernels for datacenter workloads which don't build wireless it seems reasonable to ifdefy those pointers as well. While at it move IPv4 and IPv6 pointers up, those are special for obvious reasons. Acked-by: Johannes Berg <johannes@sipsolutions.net> Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> # ieee802154 Acked-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-21net: avoid strange behavior with skb_defer_max == 1Jakub Kicinski1-8/+5
When user sets skb_defer_max to 1 the kick threshold is 0 (half of 1). If we increment queue length before the check the kick will never happen, and the skb may get stranded. This is likely harmless but can be avoided by moving the increment after the check. This way skb_defer_max == 1 will always kick. Still a silly config to have, but somehow that feels more correct. While at it drop a comment which seems to be outdated or confusing, and wrap the defer_count write with a WRITE_ONCE() since it's read on the fast path that avoids taking the lock. Reviewed-by: Eric Dumazet <edumazet@google.com> Link: https://lore.kernel.org/r/20220518185522.2038683-1-kuba@kernel.org Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-21bpf: Add bpf_skc_to_mptcp_sock_protoGeliang Tang1-0/+18
This patch implements a new struct bpf_func_proto, named bpf_skc_to_mptcp_sock_proto. Define a new bpf_id BTF_SOCK_TYPE_MPTCP, and a new helper bpf_skc_to_mptcp_sock(), which invokes another new helper bpf_mptcp_sock_from_subflow() in net/mptcp/bpf.c to get struct mptcp_sock from a given subflow socket. v2: Emit BTF type, add func_id checks in verifier.c and bpf_trace.c, remove build check for CONFIG_BPF_JIT v5: Drop EXPORT_SYMBOL (Martin) Co-developed-by: Nicolas Rybowski <nicolas.rybowski@tessares.net> Co-developed-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Nicolas Rybowski <nicolas.rybowski@tessares.net> Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net> Signed-off-by: Geliang Tang <geliang.tang@suse.com> Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20220519233016.105670-2-mathew.j.martineau@linux.intel.com
2022-05-19Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/netJakub Kicinski1-1/+1
drivers/net/ethernet/mellanox/mlx5/core/main.c b33886971dbc ("net/mlx5: Initialize flow steering during driver probe") 40379a0084c2 ("net/mlx5_fpga: Drop INNOVA TLS support") f2b41b32cde8 ("net/mlx5: Remove ipsec_ops function table") https://lore.kernel.org/all/20220519040345.6yrjromcdistu7vh@sx1/ 16d42d313350 ("net/mlx5: Drain fw_reset when removing device") 8324a02c342a ("net/mlx5: Add exit route when waiting for FW") https://lore.kernel.org/all/20220519114119.060ce014@canb.auug.org.au/ tools/testing/selftests/net/mptcp/mptcp_join.sh e274f7154008 ("selftests: mptcp: add subflow limits test-cases") b6e074e171bc ("selftests: mptcp: add infinite map testcase") 5ac1d2d63451 ("selftests: mptcp: Add tests for userspace PM type") https://lore.kernel.org/all/20220516111918.366d747f@canb.auug.org.au/ net/mptcp/options.c ba2c89e0ea74 ("mptcp: fix checksum byte order") 1e39e5a32ad7 ("mptcp: infinite mapping sending") ea66758c1795 ("tcp: allow MPTCP to update the announced window") https://lore.kernel.org/all/20220519115146.751c3a37@canb.auug.org.au/ net/mptcp/pm.c 95d686517884 ("mptcp: fix subflow accounting on close") 4d25247d3ae4 ("mptcp: bypass in-kernel PM restrictions for non-kernel PMs") https://lore.kernel.org/all/20220516111435.72f35dca@canb.auug.org.au/ net/mptcp/subflow.c ae66fb2ba6c3 ("mptcp: Do TCP fallback on early DSS checksum failure") 0348c690ed37 ("mptcp: add the fallback check") f8d4bcacff3b ("mptcp: infinite mapping receiving") https://lore.kernel.org/all/20220519115837.380bb8d4@canb.auug.org.au/ Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2022-05-18random32: use real rng for non-deterministic randomnessJason A. Donenfeld1-3/+0
random32.c has two random number generators in it: one that is meant to be used deterministically, with some predefined seed, and one that does the same exact thing as random.c, except does it poorly. The first one has some use cases. The second one no longer does and can be replaced with calls to random.c's proper random number generator. The relatively recent siphash-based bad random32.c code was added in response to concerns that the prior random32.c was too deterministic. Out of fears that random.c was (at the time) too slow, this code was anonymously contributed. Then out of that emerged a kind of shadow entropy gathering system, with its own tentacles throughout various net code, added willy nilly. Stop👏making👏bespoke👏random👏number👏generators👏. Fortunately, recent advances in random.c mean that we can stop playing with this sketchiness, and just use get_random_u32(), which is now fast enough. In micro benchmarks using RDPMC, I'm seeing the same median cycle count between the two functions, with the mean being _slightly_ higher due to batches refilling (which we can optimize further need be). However, when doing *real* benchmarks of the net functions that actually use these random numbers, the mean cycles actually *decreased* slightly (with the median still staying the same), likely because the additional prandom code means icache misses and complexity, whereas random.c is generally already being used by something else nearby. The biggest benefit of this is that there are many users of prandom who probably should be using cryptographically secure random numbers. This makes all of those accidental cases become secure by just flipping a switch. Later on, we can do a tree-wide cleanup to remove the static inline wrapper functions that this commit adds. There are also some low-ish hanging fruits for making this even faster in the future: a get_random_u16() function for use in the networking stack will give a 2x performance boost there, using SIMD for ChaCha20 will let us compute 4 or 8 or 16 blocks of output in parallel, instead of just one, giving us large buffers for cheap, and introducing a get_random_*_bh() function that assumes irqs are already disabled will shave off a few cycles for ordinary calls. These are things we can chip away at down the road. Acked-by: Jakub Kicinski <kuba@kernel.org> Acked-by: Theodore Ts'o <tytso@mit.edu> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
2022-05-16net: fix dev_fill_forward_path with pppoe + bridgeFelix Fietkau1-1/+1
When calling dev_fill_forward_path on a pppoe device, the provided destination address is invalid. In order for the bridge fdb lookup to succeed, the pppoe code needs to update ctx->daddr to the correct value. Fix this by storing the address inside struct net_device_path_ctx Fixes: f6efc675c9dd ("net: ppp: resolve forwarding path for bridge pppoe devices") Signed-off-by: Felix Fietkau <nbd@nbd.name> Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
2022-05-16net: call skb_defer_free_flush() before each napi_poll()Eric Dumazet1-2/+3
skb_defer_free_flush() can consume cpu cycles, it seems better to call it in the inner loop: - Potentially frees page/skb that will be reallocated while hot. - Account for the cpu cycles in the @time_limit determination. - Keep softnet_data.defer_count small to reduce chances for skb_attempt_defer_free() to send an IPI. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16net: add skb_defer_max sysctlEric Dumazet4-7/+19
commit 68822bdf76f1 ("net: generalize skb freeing deferral to per-cpu lists") added another per-cpu cache of skbs. It was expected to be small, and an IPI was forced whenever the list reached 128 skbs. We might need to be able to control more precisely queue capacity and added latency. An IPI is generated whenever queue reaches half capacity. Default value of the new limit is 64. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16net: use napi_consume_skb() in skb_defer_free_flush()Eric Dumazet1-1/+1
skb_defer_free_flush() runs from softirq context, we have the opportunity to refill the napi_alloc_cache, and/or use kmem_cache_free_bulk() when this cache is full. Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
2022-05-16net: fix possible race in skb_attempt_defer_free()Eric Dumazet2-5/+7
A cpu can observe sd->defer_count reaching 128, and call smp_call_function_single_async() Problem is that the remote CPU can clear sd->defer_count before the IPI is run/acknowledged. Other cpus can queue more packets and also decide to call smp_call_function_single_async() while the pending IPI was not yet delivered. This is a common issue with smp_call_function_single_async(). Callers must ensure correct synchronization and serialization. I triggered this issue while experimenting smaller threshold. Performing the call to smp_call_function_single_async() under sd->defer_lock protection did not solve the problem. Commit 5a18ceca6350 ("smp: Allow smp_call_function_single_async() to insert locked csd") replaced an informative WARN_ON_ONCE() with a return of -EBUSY, which is often ignored. Test of CSD_FLAG_LOCK presence is racy anyway. Fixes: 68822bdf76f1 ("net: generalize skb freeing deferral to per-cpu lists") Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>