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authorLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
committerLibravatar Linus Torvalds <torvalds@linux-foundation.org>2023-02-21 18:24:12 -0800
commit5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 (patch)
treecc5c2d0a898769fd59549594fedb3ee6f84e59a0 /samples/kprobes
downloadlinux-5b7c4cabbb65f5c469464da6c5f614cbd7f730f2.tar.gz
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Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-nextgrafted
Pull networking updates from Jakub Kicinski: "Core: - Add dedicated kmem_cache for typical/small skb->head, avoid having to access struct page at kfree time, and improve memory use. - Introduce sysctl to set default RPS configuration for new netdevs. - Define Netlink protocol specification format which can be used to describe messages used by each family and auto-generate parsers. Add tools for generating kernel data structures and uAPI headers. - Expose all net/core sysctls inside netns. - Remove 4s sleep in netpoll if carrier is instantly detected on boot. - Add configurable limit of MDB entries per port, and port-vlan. - Continue populating drop reasons throughout the stack. - Retire a handful of legacy Qdiscs and classifiers. Protocols: - Support IPv4 big TCP (TSO frames larger than 64kB). - Add IP_LOCAL_PORT_RANGE socket option, to control local port range on socket by socket basis. - Track and report in procfs number of MPTCP sockets used. - Support mixing IPv4 and IPv6 flows in the in-kernel MPTCP path manager. - IPv6: don't check net.ipv6.route.max_size and rely on garbage collection to free memory (similarly to IPv4). - Support Penultimate Segment Pop (PSP) flavor in SRv6 (RFC8986). - ICMP: add per-rate limit counters. - Add support for user scanning requests in ieee802154. - Remove static WEP support. - Support minimal Wi-Fi 7 Extremely High Throughput (EHT) rate reporting. - WiFi 7 EHT channel puncturing support (client & AP). BPF: - Add a rbtree data structure following the "next-gen data structure" precedent set by recently added linked list, that is, by using kfunc + kptr instead of adding a new BPF map type. - Expose XDP hints via kfuncs with initial support for RX hash and timestamp metadata. - Add BPF_F_NO_TUNNEL_KEY extension to bpf_skb_set_tunnel_key to better support decap on GRE tunnel devices not operating in collect metadata. - Improve x86 JIT's codegen for PROBE_MEM runtime error checks. - Remove the need for trace_printk_lock for bpf_trace_printk and bpf_trace_vprintk helpers. - Extend libbpf's bpf_tracing.h support for tracing arguments of kprobes/uprobes and syscall as a special case. - Significantly reduce the search time for module symbols by livepatch and BPF. - Enable cpumasks to be used as kptrs, which is useful for tracing programs tracking which tasks end up running on which CPUs in different time intervals. - Add support for BPF trampoline on s390x and riscv64. - Add capability to export the XDP features supported by the NIC. - Add __bpf_kfunc tag for marking kernel functions as kfuncs. - Add cgroup.memory=nobpf kernel parameter option to disable BPF memory accounting for container environments. Netfilter: - Remove the CLUSTERIP target. It has been marked as obsolete for years, and we still have WARN splats wrt races of the out-of-band /proc interface installed by this target. - Add 'destroy' commands to nf_tables. They are identical to the existing 'delete' commands, but do not return an error if the referenced object (set, chain, rule...) did not exist. Driver API: - Improve cpumask_local_spread() locality to help NICs set the right IRQ affinity on AMD platforms. - Separate C22 and C45 MDIO bus transactions more clearly. - Introduce new DCB table to control DSCP rewrite on egress. - Support configuration of Physical Layer Collision Avoidance (PLCA) Reconciliation Sublayer (RS) (802.3cg-2019). Modern version of shared medium Ethernet. - Support for MAC Merge layer (IEEE 802.3-2018 clause 99). Allowing preemption of low priority frames by high priority frames. - Add support for controlling MACSec offload using netlink SET. - Rework devlink instance refcounts to allow registration and de-registration under the instance lock. Split the code into multiple files, drop some of the unnecessarily granular locks and factor out common parts of netlink operation handling. - Add TX frame aggregation parameters (for USB drivers). - Add a new attr TCA_EXT_WARN_MSG to report TC (offload) warning messages with notifications for debug. - Allow offloading of UDP NEW connections via act_ct. - Add support for per action HW stats in TC. - Support hardware miss to TC action (continue processing in SW from a specific point in the action chain). - Warn if old Wireless Extension user space interface is used with modern cfg80211/mac80211 drivers. Do not support Wireless Extensions for Wi-Fi 7 devices at all. Everyone should switch to using nl80211 interface instead. - Improve the CAN bit timing configuration. Use extack to return error messages directly to user space, update the SJW handling, including the definition of a new default value that will benefit CAN-FD controllers, by increasing their oscillator tolerance. New hardware / drivers: - Ethernet: - nVidia BlueField-3 support (control traffic driver) - Ethernet support for imx93 SoCs - Motorcomm yt8531 gigabit Ethernet PHY - onsemi NCN26000 10BASE-T1S PHY (with support for PLCA) - Microchip LAN8841 PHY (incl. cable diagnostics and PTP) - Amlogic gxl MDIO mux - WiFi: - RealTek RTL8188EU (rtl8xxxu) - Qualcomm Wi-Fi 7 devices (ath12k) - CAN: - Renesas R-Car V4H Drivers: - Bluetooth: - Set Per Platform Antenna Gain (PPAG) for Intel controllers. - Ethernet NICs: - Intel (1G, igc): - support TSN / Qbv / packet scheduling features of i226 model - Intel (100G, ice): - use GNSS subsystem instead of TTY - multi-buffer XDP support - extend support for GPIO pins to E823 devices - nVidia/Mellanox: - update the shared buffer configuration on PFC commands - implement PTP adjphase function for HW offset control - TC support for Geneve and GRE with VF tunnel offload - more efficient crypto key management method - multi-port eswitch support - Netronome/Corigine: - add DCB IEEE support - support IPsec offloading for NFP3800 - Freescale/NXP (enetc): - support XDP_REDIRECT for XDP non-linear buffers - improve reconfig, avoid link flap and waiting for idle - support MAC Merge layer - Other NICs: - sfc/ef100: add basic devlink support for ef100 - ionic: rx_push mode operation (writing descriptors via MMIO) - bnxt: use the auxiliary bus abstraction for RDMA - r8169: disable ASPM and reset bus in case of tx timeout - cpsw: support QSGMII mode for J721e CPSW9G - cpts: support pulse-per-second output - ngbe: add an mdio bus driver - usbnet: optimize usbnet_bh() by avoiding unnecessary queuing - r8152: handle devices with FW with NCM support - amd-xgbe: support 10Mbps, 2.5GbE speeds and rx-adaptation - virtio-net: support multi buffer XDP - virtio/vsock: replace virtio_vsock_pkt with sk_buff - tsnep: XDP support - Ethernet high-speed switches: - nVidia/Mellanox (mlxsw): - add support for latency TLV (in FW control messages) - Microchip (sparx5): - separate explicit and implicit traffic forwarding rules, make the implicit rules always active - add support for egress DSCP rewrite - IS0 VCAP support (Ingress Classification) - IS2 VCAP filters (protos, L3 addrs, L4 ports, flags, ToS etc.) - ES2 VCAP support (Egress Access Control) - support for Per-Stream Filtering and Policing (802.1Q, 8.6.5.1) - Ethernet embedded switches: - Marvell (mv88e6xxx): - add MAB (port auth) offload support - enable PTP receive for mv88e6390 - NXP (ocelot): - support MAC Merge layer - support for the the vsc7512 internal copper phys - Microchip: - lan9303: convert to PHYLINK - lan966x: support TC flower filter statistics - lan937x: PTP support for KSZ9563/KSZ8563 and LAN937x - lan937x: support Credit Based Shaper configuration - ksz9477: support Energy Efficient Ethernet - other: - qca8k: convert to regmap read/write API, use bulk operations - rswitch: Improve TX timestamp accuracy - Intel WiFi (iwlwifi): - EHT (Wi-Fi 7) rate reporting - STEP equalizer support: transfer some STEP (connection to radio on platforms with integrated wifi) related parameters from the BIOS to the firmware. - Qualcomm 802.11ax WiFi (ath11k): - IPQ5018 support - Fine Timing Measurement (FTM) responder role support - channel 177 support - MediaTek WiFi (mt76): - per-PHY LED support - mt7996: EHT (Wi-Fi 7) support - Wireless Ethernet Dispatch (WED) reset support - switch to using page pool allocator - RealTek WiFi (rtw89): - support new version of Bluetooth co-existance - Mobile: - rmnet: support TX aggregation" * tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next: (1872 commits) page_pool: add a comment explaining the fragment counter usage net: ethtool: fix __ethtool_dev_mm_supported() implementation ethtool: pse-pd: Fix double word in comments xsk: add linux/vmalloc.h to xsk.c sefltests: netdevsim: wait for devlink instance after netns removal selftest: fib_tests: Always cleanup before exit net/mlx5e: Align IPsec ASO result memory to be as required by hardware net/mlx5e: TC, Set CT miss to the specific ct action instance net/mlx5e: Rename CHAIN_TO_REG to MAPPED_OBJ_TO_REG net/mlx5: Refactor tc miss handling to a single function net/mlx5: Kconfig: Make tc offload depend on tc skb extension net/sched: flower: Support hardware miss to tc action net/sched: flower: Move filter handle initialization earlier net/sched: cls_api: Support hardware miss to tc action net/sched: Rename user cookie and act cookie sfc: fix builds without CONFIG_RTC_LIB sfc: clean up some inconsistent indentings net/mlx4_en: Introduce flexible array to silence overflow warning net: lan966x: Fix possible deadlock inside PTP net/ulp: Remove redundant ->clone() test in inet_clone_ulp(). ...
Diffstat (limited to 'samples/kprobes')
-rw-r--r--samples/kprobes/Makefile6
-rw-r--r--samples/kprobes/kprobe_example.c120
-rw-r--r--samples/kprobes/kretprobe_example.c107
3 files changed, 233 insertions, 0 deletions
diff --git a/samples/kprobes/Makefile b/samples/kprobes/Makefile
new file mode 100644
index 000000000..e77459271
--- /dev/null
+++ b/samples/kprobes/Makefile
@@ -0,0 +1,6 @@
+# SPDX-License-Identifier: GPL-2.0-only
+# builds the kprobes example kernel modules;
+# then to use one (as root): insmod <module_name.ko>
+
+obj-$(CONFIG_SAMPLE_KPROBES) += kprobe_example.o
+obj-$(CONFIG_SAMPLE_KRETPROBES) += kretprobe_example.o
diff --git a/samples/kprobes/kprobe_example.c b/samples/kprobes/kprobe_example.c
new file mode 100644
index 000000000..fd346f58d
--- /dev/null
+++ b/samples/kprobes/kprobe_example.c
@@ -0,0 +1,120 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Here's a sample kernel module showing the use of kprobes to dump a
+ * stack trace and selected registers when kernel_clone() is called.
+ *
+ * For more information on theory of operation of kprobes, see
+ * Documentation/trace/kprobes.rst
+ *
+ * You will see the trace data in /var/log/messages and on the console
+ * whenever kernel_clone() is invoked to create a new process.
+ */
+
+#define pr_fmt(fmt) "%s: " fmt, __func__
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+
+static char symbol[KSYM_NAME_LEN] = "kernel_clone";
+module_param_string(symbol, symbol, KSYM_NAME_LEN, 0644);
+
+/* For each probe you need to allocate a kprobe structure */
+static struct kprobe kp = {
+ .symbol_name = symbol,
+};
+
+/* kprobe pre_handler: called just before the probed instruction is executed */
+static int __kprobes handler_pre(struct kprobe *p, struct pt_regs *regs)
+{
+#ifdef CONFIG_X86
+ pr_info("<%s> p->addr = 0x%p, ip = %lx, flags = 0x%lx\n",
+ p->symbol_name, p->addr, regs->ip, regs->flags);
+#endif
+#ifdef CONFIG_PPC
+ pr_info("<%s> p->addr = 0x%p, nip = 0x%lx, msr = 0x%lx\n",
+ p->symbol_name, p->addr, regs->nip, regs->msr);
+#endif
+#ifdef CONFIG_MIPS
+ pr_info("<%s> p->addr = 0x%p, epc = 0x%lx, status = 0x%lx\n",
+ p->symbol_name, p->addr, regs->cp0_epc, regs->cp0_status);
+#endif
+#ifdef CONFIG_ARM64
+ pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, pstate = 0x%lx\n",
+ p->symbol_name, p->addr, (long)regs->pc, (long)regs->pstate);
+#endif
+#ifdef CONFIG_ARM
+ pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, cpsr = 0x%lx\n",
+ p->symbol_name, p->addr, (long)regs->ARM_pc, (long)regs->ARM_cpsr);
+#endif
+#ifdef CONFIG_RISCV
+ pr_info("<%s> p->addr = 0x%p, pc = 0x%lx, status = 0x%lx\n",
+ p->symbol_name, p->addr, regs->epc, regs->status);
+#endif
+#ifdef CONFIG_S390
+ pr_info("<%s> p->addr, 0x%p, ip = 0x%lx, flags = 0x%lx\n",
+ p->symbol_name, p->addr, regs->psw.addr, regs->flags);
+#endif
+
+ /* A dump_stack() here will give a stack backtrace */
+ return 0;
+}
+
+/* kprobe post_handler: called after the probed instruction is executed */
+static void __kprobes handler_post(struct kprobe *p, struct pt_regs *regs,
+ unsigned long flags)
+{
+#ifdef CONFIG_X86
+ pr_info("<%s> p->addr = 0x%p, flags = 0x%lx\n",
+ p->symbol_name, p->addr, regs->flags);
+#endif
+#ifdef CONFIG_PPC
+ pr_info("<%s> p->addr = 0x%p, msr = 0x%lx\n",
+ p->symbol_name, p->addr, regs->msr);
+#endif
+#ifdef CONFIG_MIPS
+ pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n",
+ p->symbol_name, p->addr, regs->cp0_status);
+#endif
+#ifdef CONFIG_ARM64
+ pr_info("<%s> p->addr = 0x%p, pstate = 0x%lx\n",
+ p->symbol_name, p->addr, (long)regs->pstate);
+#endif
+#ifdef CONFIG_ARM
+ pr_info("<%s> p->addr = 0x%p, cpsr = 0x%lx\n",
+ p->symbol_name, p->addr, (long)regs->ARM_cpsr);
+#endif
+#ifdef CONFIG_RISCV
+ pr_info("<%s> p->addr = 0x%p, status = 0x%lx\n",
+ p->symbol_name, p->addr, regs->status);
+#endif
+#ifdef CONFIG_S390
+ pr_info("<%s> p->addr, 0x%p, flags = 0x%lx\n",
+ p->symbol_name, p->addr, regs->flags);
+#endif
+}
+
+static int __init kprobe_init(void)
+{
+ int ret;
+ kp.pre_handler = handler_pre;
+ kp.post_handler = handler_post;
+
+ ret = register_kprobe(&kp);
+ if (ret < 0) {
+ pr_err("register_kprobe failed, returned %d\n", ret);
+ return ret;
+ }
+ pr_info("Planted kprobe at %p\n", kp.addr);
+ return 0;
+}
+
+static void __exit kprobe_exit(void)
+{
+ unregister_kprobe(&kp);
+ pr_info("kprobe at %p unregistered\n", kp.addr);
+}
+
+module_init(kprobe_init)
+module_exit(kprobe_exit)
+MODULE_LICENSE("GPL");
diff --git a/samples/kprobes/kretprobe_example.c b/samples/kprobes/kretprobe_example.c
new file mode 100644
index 000000000..cbf16542d
--- /dev/null
+++ b/samples/kprobes/kretprobe_example.c
@@ -0,0 +1,107 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * kretprobe_example.c
+ *
+ * Here's a sample kernel module showing the use of return probes to
+ * report the return value and total time taken for probed function
+ * to run.
+ *
+ * usage: insmod kretprobe_example.ko func=<func_name>
+ *
+ * If no func_name is specified, kernel_clone is instrumented
+ *
+ * For more information on theory of operation of kretprobes, see
+ * Documentation/trace/kprobes.rst
+ *
+ * Build and insert the kernel module as done in the kprobe example.
+ * You will see the trace data in /var/log/messages and on the console
+ * whenever the probed function returns. (Some messages may be suppressed
+ * if syslogd is configured to eliminate duplicate messages.)
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/kprobes.h>
+#include <linux/ktime.h>
+#include <linux/sched.h>
+
+static char func_name[KSYM_NAME_LEN] = "kernel_clone";
+module_param_string(func, func_name, KSYM_NAME_LEN, 0644);
+MODULE_PARM_DESC(func, "Function to kretprobe; this module will report the"
+ " function's execution time");
+
+/* per-instance private data */
+struct my_data {
+ ktime_t entry_stamp;
+};
+
+/* Here we use the entry_hanlder to timestamp function entry */
+static int entry_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+ struct my_data *data;
+
+ if (!current->mm)
+ return 1; /* Skip kernel threads */
+
+ data = (struct my_data *)ri->data;
+ data->entry_stamp = ktime_get();
+ return 0;
+}
+NOKPROBE_SYMBOL(entry_handler);
+
+/*
+ * Return-probe handler: Log the return value and duration. Duration may turn
+ * out to be zero consistently, depending upon the granularity of time
+ * accounting on the platform.
+ */
+static int ret_handler(struct kretprobe_instance *ri, struct pt_regs *regs)
+{
+ unsigned long retval = regs_return_value(regs);
+ struct my_data *data = (struct my_data *)ri->data;
+ s64 delta;
+ ktime_t now;
+
+ now = ktime_get();
+ delta = ktime_to_ns(ktime_sub(now, data->entry_stamp));
+ pr_info("%s returned %lu and took %lld ns to execute\n",
+ func_name, retval, (long long)delta);
+ return 0;
+}
+NOKPROBE_SYMBOL(ret_handler);
+
+static struct kretprobe my_kretprobe = {
+ .handler = ret_handler,
+ .entry_handler = entry_handler,
+ .data_size = sizeof(struct my_data),
+ /* Probe up to 20 instances concurrently. */
+ .maxactive = 20,
+};
+
+static int __init kretprobe_init(void)
+{
+ int ret;
+
+ my_kretprobe.kp.symbol_name = func_name;
+ ret = register_kretprobe(&my_kretprobe);
+ if (ret < 0) {
+ pr_err("register_kretprobe failed, returned %d\n", ret);
+ return ret;
+ }
+ pr_info("Planted return probe at %s: %p\n",
+ my_kretprobe.kp.symbol_name, my_kretprobe.kp.addr);
+ return 0;
+}
+
+static void __exit kretprobe_exit(void)
+{
+ unregister_kretprobe(&my_kretprobe);
+ pr_info("kretprobe at %p unregistered\n", my_kretprobe.kp.addr);
+
+ /* nmissed > 0 suggests that maxactive was set too low. */
+ pr_info("Missed probing %d instances of %s\n",
+ my_kretprobe.nmissed, my_kretprobe.kp.symbol_name);
+}
+
+module_init(kretprobe_init)
+module_exit(kretprobe_exit)
+MODULE_LICENSE("GPL");