From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- drivers/net/netdevsim/psample.c | 265 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 265 insertions(+) create mode 100644 drivers/net/netdevsim/psample.c (limited to 'drivers/net/netdevsim/psample.c') diff --git a/drivers/net/netdevsim/psample.c b/drivers/net/netdevsim/psample.c new file mode 100644 index 000000000..1e71c3da4 --- /dev/null +++ b/drivers/net/netdevsim/psample.c @@ -0,0 +1,265 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Mellanox Technologies. All rights reserved */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "netdevsim.h" + +#define NSIM_PSAMPLE_REPORT_INTERVAL_MS 100 +#define NSIM_PSAMPLE_INVALID_TC 0xFFFF +#define NSIM_PSAMPLE_L4_DATA_LEN 100 + +struct nsim_dev_psample { + struct delayed_work psample_dw; + struct dentry *ddir; + struct psample_group *group; + u32 rate; + u32 group_num; + u32 trunc_size; + int in_ifindex; + int out_ifindex; + u16 out_tc; + u64 out_tc_occ_max; + u64 latency_max; + bool is_active; +}; + +static struct sk_buff *nsim_dev_psample_skb_build(void) +{ + int tot_len, data_len = NSIM_PSAMPLE_L4_DATA_LEN; + struct sk_buff *skb; + struct udphdr *udph; + struct ethhdr *eth; + struct iphdr *iph; + + skb = alloc_skb(NLMSG_GOODSIZE, GFP_KERNEL); + if (!skb) + return NULL; + tot_len = sizeof(struct iphdr) + sizeof(struct udphdr) + data_len; + + skb_reset_mac_header(skb); + eth = skb_put(skb, sizeof(struct ethhdr)); + eth_random_addr(eth->h_dest); + eth_random_addr(eth->h_source); + eth->h_proto = htons(ETH_P_IP); + skb->protocol = htons(ETH_P_IP); + + skb_set_network_header(skb, skb->len); + iph = skb_put(skb, sizeof(struct iphdr)); + iph->protocol = IPPROTO_UDP; + iph->saddr = in_aton("192.0.2.1"); + iph->daddr = in_aton("198.51.100.1"); + iph->version = 0x4; + iph->frag_off = 0; + iph->ihl = 0x5; + iph->tot_len = htons(tot_len); + iph->id = 0; + iph->ttl = 100; + iph->check = 0; + iph->check = ip_fast_csum((unsigned char *)iph, iph->ihl); + + skb_set_transport_header(skb, skb->len); + udph = skb_put_zero(skb, sizeof(struct udphdr) + data_len); + get_random_bytes(&udph->source, sizeof(u16)); + get_random_bytes(&udph->dest, sizeof(u16)); + udp_set_len_short(udph, sizeof(struct udphdr) + data_len); + + return skb; +} + +static void nsim_dev_psample_md_prepare(const struct nsim_dev_psample *psample, + struct psample_metadata *md, + unsigned int len) +{ + md->trunc_size = psample->trunc_size ? psample->trunc_size : len; + md->in_ifindex = psample->in_ifindex; + md->out_ifindex = psample->out_ifindex; + + if (psample->out_tc != NSIM_PSAMPLE_INVALID_TC) { + md->out_tc = psample->out_tc; + md->out_tc_valid = 1; + } + + if (psample->out_tc_occ_max) { + u64 out_tc_occ; + + out_tc_occ = get_random_u64(); + md->out_tc_occ = out_tc_occ & (psample->out_tc_occ_max - 1); + md->out_tc_occ_valid = 1; + } + + if (psample->latency_max) { + u64 latency; + + latency = get_random_u64(); + md->latency = latency & (psample->latency_max - 1); + md->latency_valid = 1; + } +} + +static void nsim_dev_psample_report_work(struct work_struct *work) +{ + struct nsim_dev_psample *psample; + struct psample_metadata md = {}; + struct sk_buff *skb; + unsigned long delay; + + psample = container_of(work, struct nsim_dev_psample, psample_dw.work); + + skb = nsim_dev_psample_skb_build(); + if (!skb) + goto out; + + nsim_dev_psample_md_prepare(psample, &md, skb->len); + psample_sample_packet(psample->group, skb, psample->rate, &md); + consume_skb(skb); + +out: + delay = msecs_to_jiffies(NSIM_PSAMPLE_REPORT_INTERVAL_MS); + schedule_delayed_work(&psample->psample_dw, delay); +} + +static int nsim_dev_psample_enable(struct nsim_dev *nsim_dev) +{ + struct nsim_dev_psample *psample = nsim_dev->psample; + struct devlink *devlink; + unsigned long delay; + + if (psample->is_active) + return -EBUSY; + + devlink = priv_to_devlink(nsim_dev); + psample->group = psample_group_get(devlink_net(devlink), + psample->group_num); + if (!psample->group) + return -EINVAL; + + delay = msecs_to_jiffies(NSIM_PSAMPLE_REPORT_INTERVAL_MS); + schedule_delayed_work(&psample->psample_dw, delay); + + psample->is_active = true; + + return 0; +} + +static int nsim_dev_psample_disable(struct nsim_dev *nsim_dev) +{ + struct nsim_dev_psample *psample = nsim_dev->psample; + + if (!psample->is_active) + return -EINVAL; + + psample->is_active = false; + + cancel_delayed_work_sync(&psample->psample_dw); + psample_group_put(psample->group); + + return 0; +} + +static ssize_t nsim_dev_psample_enable_write(struct file *file, + const char __user *data, + size_t count, loff_t *ppos) +{ + struct nsim_dev *nsim_dev = file->private_data; + bool enable; + int err; + + err = kstrtobool_from_user(data, count, &enable); + if (err) + return err; + + if (enable) + err = nsim_dev_psample_enable(nsim_dev); + else + err = nsim_dev_psample_disable(nsim_dev); + + return err ? err : count; +} + +static const struct file_operations nsim_psample_enable_fops = { + .open = simple_open, + .write = nsim_dev_psample_enable_write, + .llseek = generic_file_llseek, + .owner = THIS_MODULE, +}; + +int nsim_dev_psample_init(struct nsim_dev *nsim_dev) +{ + struct nsim_dev_psample *psample; + int err; + + psample = kzalloc_obj(*psample); + if (!psample) + return -ENOMEM; + nsim_dev->psample = psample; + + INIT_DELAYED_WORK(&psample->psample_dw, nsim_dev_psample_report_work); + + psample->ddir = debugfs_create_dir("psample", nsim_dev->ddir); + if (IS_ERR(psample->ddir)) { + err = PTR_ERR(psample->ddir); + goto err_psample_free; + } + + /* Populate sampling parameters with sane defaults. */ + psample->rate = 100; + debugfs_create_u32("rate", 0600, psample->ddir, &psample->rate); + + psample->group_num = 10; + debugfs_create_u32("group_num", 0600, psample->ddir, + &psample->group_num); + + psample->trunc_size = 0; + debugfs_create_u32("trunc_size", 0600, psample->ddir, + &psample->trunc_size); + + psample->in_ifindex = 1; + debugfs_create_u32("in_ifindex", 0600, psample->ddir, + &psample->in_ifindex); + + psample->out_ifindex = 2; + debugfs_create_u32("out_ifindex", 0600, psample->ddir, + &psample->out_ifindex); + + psample->out_tc = 0; + debugfs_create_u16("out_tc", 0600, psample->ddir, &psample->out_tc); + + psample->out_tc_occ_max = 10000; + debugfs_create_u64("out_tc_occ_max", 0600, psample->ddir, + &psample->out_tc_occ_max); + + psample->latency_max = 50; + debugfs_create_u64("latency_max", 0600, psample->ddir, + &psample->latency_max); + + debugfs_create_file("enable", 0200, psample->ddir, nsim_dev, + &nsim_psample_enable_fops); + + return 0; + +err_psample_free: + kfree(nsim_dev->psample); + return err; +} + +void nsim_dev_psample_exit(struct nsim_dev *nsim_dev) +{ + debugfs_remove_recursive(nsim_dev->psample->ddir); + if (nsim_dev->psample->is_active) { + cancel_delayed_work_sync(&nsim_dev->psample->psample_dw); + psample_group_put(nsim_dev->psample->group); + } + kfree(nsim_dev->psample); +} -- cgit v1.3.1