kernel/linux.git/net/core/sysctl_net_core.c, branch v6.6.131

net: set the minimum for net_hotdata.netdev_budget_usecs

2025-03-07T15:45:38+00:00

[ Upstream commit c180188ec02281126045414e90d08422a80f75b4 ] Commit 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") added a possibility to set net_hotdata.netdev_budget_usecs, but added no lower bound checking. Commit a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") made the *initial* value HZ-dependent, so the initial value is at least 2 jiffies even for lower HZ values (2 ms for 1000 Hz, 8ms for 250 Hz, 20 ms for 100 Hz). But a user still can set improper values by a sysctl. Set .extra1 (the lower bound) for net_hotdata.netdev_budget_usecs to the same value as in the latter commit. That is to 2 jiffies. Fixes: a4837980fd9f ("net: revert default NAPI poll timeout to 2 jiffies") Fixes: 7acf8a1e8a28 ("Replace 2 jiffies with sysctl netdev_budget_usecs to enable softirq tuning") Signed-off-by: Jiri Slaby (SUSE) Cc: Dmitry Yakunin Cc: Konstantin Khlebnikov Link: https://patch.msgid.link/20250220110752.137639-1-jirislaby@kernel.org Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: let net.core.dev_weight always be non-zero

2025-02-08T08:52:02+00:00

[ Upstream commit d1f9f79fa2af8e3b45cffdeef66e05833480148a ] The following problem was encountered during stability test: (NULL net_device): NAPI poll function process_backlog+0x0/0x530 \ returned 1, exceeding its budget of 0. ------------[ cut here ]------------ list_add double add: new=ffff88905f746f48, prev=ffff88905f746f48, \ next=ffff88905f746e40. WARNING: CPU: 18 PID: 5462 at lib/list_debug.c:35 \ __list_add_valid_or_report+0xf3/0x130 CPU: 18 UID: 0 PID: 5462 Comm: ping Kdump: loaded Not tainted 6.13.0-rc7+ RIP: 0010:__list_add_valid_or_report+0xf3/0x130 Call Trace: ? __warn+0xcd/0x250 ? __list_add_valid_or_report+0xf3/0x130 enqueue_to_backlog+0x923/0x1070 netif_rx_internal+0x92/0x2b0 __netif_rx+0x15/0x170 loopback_xmit+0x2ef/0x450 dev_hard_start_xmit+0x103/0x490 __dev_queue_xmit+0xeac/0x1950 ip_finish_output2+0x6cc/0x1620 ip_output+0x161/0x270 ip_push_pending_frames+0x155/0x1a0 raw_sendmsg+0xe13/0x1550 __sys_sendto+0x3bf/0x4e0 __x64_sys_sendto+0xdc/0x1b0 do_syscall_64+0x5b/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e The reproduction command is as follows: sysctl -w net.core.dev_weight=0 ping 127.0.0.1 This is because when the napi's weight is set to 0, process_backlog() may return 0 and clear the NAPI_STATE_SCHED bit of napi->state, causing this napi to be re-polled in net_rx_action() until __do_softirq() times out. Since the NAPI_STATE_SCHED bit has been cleared, napi_schedule_rps() can be retriggered in enqueue_to_backlog(), causing this issue. Making the napi's weight always non-zero solves this problem. Triggering this issue requires system-wide admin (setting is not namespaced). Fixes: e38766054509 ("[NET]: Fix sysctl net.core.dev_weight") Fixes: 3d48b53fb2ae ("net: dev_weight: TX/RX orthogonality") Signed-off-by: Liu Jian Link: https://patch.msgid.link/20250116143053.4146855-1-liujian56@huawei.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: make SK_MEMORY_PCPU_RESERV tunable

2024-05-02T14:32:36+00:00

[ Upstream commit 12a686c2e761f1f1f6e6e2117a9ab9c6de2ac8a7 ] This patch adds /proc/sys/net/core/mem_pcpu_rsv sysctl file, to make SK_MEMORY_PCPU_RESERV tunable. Commit 3cd3399dd7a8 ("net: implement per-cpu reserves for memory_allocated") introduced per-cpu forward alloc cache: "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." sk_prot->memory_allocated points to global atomic variable: atomic_long_t tcp_memory_allocated ____cacheline_aligned_in_smp; If increasing the per-cpu cache size from 1MB to e.g. 16MB, changes to sk->sk_prot->memory_allocated can be further reduced. Performance may be improved on system with many cores. Signed-off-by: Adam Li Reviewed-by: Christoph Lameter (Ampere) Signed-off-by: David S. Miller Stable-dep-of: 3584718cf2ec ("net: fix sk_memory_allocated_{add|sub} vs softirqs") Signed-off-by: Sasha Levin

networking: Update to register_net_sysctl_sz

2023-08-15T22:26:18+00:00

Move from register_net_sysctl to register_net_sysctl_sz for all the networking related files. Do this while making sure to mirror the NULL assignments with a table_size of zero for the unprivileged users. We need to move to the new function in preparation for when we change SIZE_MAX to ARRAY_SIZE() in the register_net_sysctl macro. Failing to do so would erroneously allow ARRAY_SIZE() to be called on a pointer. We hold off the SIZE_MAX to ARRAY_SIZE change until we have migrated all the relevant net sysctl registering functions to register_net_sysctl_sz in subsequent commits. An additional size function was added to the following files in order to calculate the size of an array that is defined in another file: include/net/ipv6.h net/ipv6/icmp.c net/ipv6/route.c net/ipv6/sysctl_net_ipv6.c Signed-off-by: Joel Granados Signed-off-by: Luis Chamberlain

net/sysctl: Rename kvfree_rcu() to kvfree_rcu_mightsleep()

2023-04-05T13:48:04+00:00

The kfree_rcu() and kvfree_rcu() macros' single-argument forms are deprecated. Therefore switch to the new kfree_rcu_mightsleep() and kvfree_rcu_mightsleep() variants. The goal is to avoid accidental use of the single-argument forms, which can introduce functionality bugs in atomic contexts and latency bugs in non-atomic contexts. Acked-by: Jakub Kicinski Cc: Eric Dumazet Cc: David S. Miller Signed-off-by: Uladzislau Rezki (Sony) Signed-off-by: Paul E. McKenney Signed-off-by: Joel Fernandes (Google)

net: make default_rps_mask a per netns attribute

2023-02-20T11:22:54+00:00

That really was meant to be a per netns attribute from the beginning. The idea is that once proper isolation is in place in the main namespace, additional demux in the child namespaces will be redundant. Let's make child netns default rps mask empty by default. To avoid bloating the netns with a possibly large cpumask, allocate it on-demand during the first write operation. Signed-off-by: Paolo Abeni Signed-off-by: David S. Miller

net: introduce default_rps_mask netns attribute

2023-02-10T01:45:55+00:00

If RPS is enabled, this allows configuring a default rps mask, which is effective since receive queue creation time. A default RPS mask allows the system admin to ensure proper isolation, avoiding races at network namespace or device creation time. The default RPS mask is initially empty, and can be modified via a newly added sysctl entry. Signed-off-by: Paolo Abeni Reviewed-by: Simon Horman Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski

net-sysctl: factor out cpumask parsing helper

2023-02-10T01:45:55+00:00

Will be used by the following patch to avoid code duplication. No functional changes intended. The only difference is that now flow_limit_cpu_sysctl() will always compute the flow limit mask on each read operation, even when read() will not return any byte to user-space. Note that the new helper is placed under a new #ifdef at the file start to better fit the usage in the later patch Signed-off-by: Paolo Abeni Reviewed-by: Simon Horman Reviewed-by: Eric Dumazet Signed-off-by: Jakub Kicinski

sysctl: expose all net/core sysctls inside netns

2023-01-06T12:41:52+00:00

All were not visible to the non-priv users inside netns. However, with 4ecb90090c84 ("sysctl: allow override of /proc/sys/net with CAP_NET_ADMIN"), these vars are protected from getting modified. A proc with capable(CAP_NET_ADMIN) can change the values so not having them visible inside netns is just causing nuisance to process that check certain values (e.g. net.core.somaxconn) and see different behavior in root-netns vs. other-netns Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Soheil Hassas Yeganeh Signed-off-by: Mahesh Bandewar Acked-by: Soheil Hassas Yeganeh Signed-off-by: David S. Miller

net: sysctl: remove unused variable long_max

2022-09-07T14:31:19+00:00

The variable long_max is replaced by bpf_jit_limit_max and no longer be used. So remove it. No functional change. Signed-off-by: Liu Shixin Signed-off-by: David S. Miller