From 5b7c4cabbb65f5c469464da6c5f614cbd7f730f2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 21 Feb 2023 18:24:12 -0800 Subject: Merge tag 'net-next-6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net-next 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(). ... --- Documentation/admin-guide/dynamic-debug-howto.rst | 376 ++++++++++++++++++++++ 1 file changed, 376 insertions(+) create mode 100644 Documentation/admin-guide/dynamic-debug-howto.rst (limited to 'Documentation/admin-guide/dynamic-debug-howto.rst') diff --git a/Documentation/admin-guide/dynamic-debug-howto.rst b/Documentation/admin-guide/dynamic-debug-howto.rst new file mode 100644 index 000000000..faa22f778 --- /dev/null +++ b/Documentation/admin-guide/dynamic-debug-howto.rst @@ -0,0 +1,376 @@ +Dynamic debug ++++++++++++++ + + +Introduction +============ + +Dynamic debug allows you to dynamically enable/disable kernel +debug-print code to obtain additional kernel information. + +If ``/proc/dynamic_debug/control`` exists, your kernel has dynamic +debug. You'll need root access (sudo su) to use this. + +Dynamic debug provides: + + * a Catalog of all *prdbgs* in your kernel. + ``cat /proc/dynamic_debug/control`` to see them. + + * a Simple query/command language to alter *prdbgs* by selecting on + any combination of 0 or 1 of: + + - source filename + - function name + - line number (including ranges of line numbers) + - module name + - format string + - class name (as known/declared by each module) + +Viewing Dynamic Debug Behaviour +=============================== + +You can view the currently configured behaviour in the *prdbg* catalog:: + + :#> head -n7 /proc/dynamic_debug/control + # filename:lineno [module]function flags format + init/main.c:1179 [main]initcall_blacklist =_ "blacklisting initcall %s\012 + init/main.c:1218 [main]initcall_blacklisted =_ "initcall %s blacklisted\012" + init/main.c:1424 [main]run_init_process =_ " with arguments:\012" + init/main.c:1426 [main]run_init_process =_ " %s\012" + init/main.c:1427 [main]run_init_process =_ " with environment:\012" + init/main.c:1429 [main]run_init_process =_ " %s\012" + +The 3rd space-delimited column shows the current flags, preceded by +a ``=`` for easy use with grep/cut. ``=p`` shows enabled callsites. + +Controlling dynamic debug Behaviour +=================================== + +The behaviour of *prdbg* sites are controlled by writing +query/commands to the control file. Example:: + + # grease the interface + :#> alias ddcmd='echo $* > /proc/dynamic_debug/control' + + :#> ddcmd '-p; module main func run* +p' + :#> grep =p /proc/dynamic_debug/control + init/main.c:1424 [main]run_init_process =p " with arguments:\012" + init/main.c:1426 [main]run_init_process =p " %s\012" + init/main.c:1427 [main]run_init_process =p " with environment:\012" + init/main.c:1429 [main]run_init_process =p " %s\012" + +Error messages go to console/syslog:: + + :#> ddcmd mode foo +p + dyndbg: unknown keyword "mode" + dyndbg: query parse failed + bash: echo: write error: Invalid argument + +If debugfs is also enabled and mounted, ``dynamic_debug/control`` is +also under the mount-dir, typically ``/sys/kernel/debug/``. + +Command Language Reference +========================== + +At the basic lexical level, a command is a sequence of words separated +by spaces or tabs. So these are all equivalent:: + + :#> ddcmd file svcsock.c line 1603 +p + :#> ddcmd "file svcsock.c line 1603 +p" + :#> ddcmd ' file svcsock.c line 1603 +p ' + +Command submissions are bounded by a write() system call. +Multiple commands can be written together, separated by ``;`` or ``\n``:: + + :#> ddcmd "func pnpacpi_get_resources +p; func pnp_assign_mem +p" + :#> ddcmd <<"EOC" + func pnpacpi_get_resources +p + func pnp_assign_mem +p + EOC + :#> cat query-batch-file > /proc/dynamic_debug/control + +You can also use wildcards in each query term. The match rule supports +``*`` (matches zero or more characters) and ``?`` (matches exactly one +character). For example, you can match all usb drivers:: + + :#> ddcmd file "drivers/usb/*" +p # "" to suppress shell expansion + +Syntactically, a command is pairs of keyword values, followed by a +flags change or setting:: + + command ::= match-spec* flags-spec + +The match-spec's select *prdbgs* from the catalog, upon which to apply +the flags-spec, all constraints are ANDed together. An absent keyword +is the same as keyword "*". + + +A match specification is a keyword, which selects the attribute of +the callsite to be compared, and a value to compare against. Possible +keywords are::: + + match-spec ::= 'func' string | + 'file' string | + 'module' string | + 'format' string | + 'class' string | + 'line' line-range + + line-range ::= lineno | + '-'lineno | + lineno'-' | + lineno'-'lineno + + lineno ::= unsigned-int + +.. note:: + + ``line-range`` cannot contain space, e.g. + "1-30" is valid range but "1 - 30" is not. + + +The meanings of each keyword are: + +func + The given string is compared against the function name + of each callsite. Example:: + + func svc_tcp_accept + func *recv* # in rfcomm, bluetooth, ping, tcp + +file + The given string is compared against either the src-root relative + pathname, or the basename of the source file of each callsite. + Examples:: + + file svcsock.c + file kernel/freezer.c # ie column 1 of control file + file drivers/usb/* # all callsites under it + file inode.c:start_* # parse :tail as a func (above) + file inode.c:1-100 # parse :tail as a line-range (above) + +module + The given string is compared against the module name + of each callsite. The module name is the string as + seen in ``lsmod``, i.e. without the directory or the ``.ko`` + suffix and with ``-`` changed to ``_``. Examples:: + + module sunrpc + module nfsd + module drm* # both drm, drm_kms_helper + +format + The given string is searched for in the dynamic debug format + string. Note that the string does not need to match the + entire format, only some part. Whitespace and other + special characters can be escaped using C octal character + escape ``\ooo`` notation, e.g. the space character is ``\040``. + Alternatively, the string can be enclosed in double quote + characters (``"``) or single quote characters (``'``). + Examples:: + + format svcrdma: // many of the NFS/RDMA server pr_debugs + format readahead // some pr_debugs in the readahead cache + format nfsd:\040SETATTR // one way to match a format with whitespace + format "nfsd: SETATTR" // a neater way to match a format with whitespace + format 'nfsd: SETATTR' // yet another way to match a format with whitespace + +class + The given class_name is validated against each module, which may + have declared a list of known class_names. If the class_name is + found for a module, callsite & class matching and adjustment + proceeds. Examples:: + + class DRM_UT_KMS # a DRM.debug category + class JUNK # silent non-match + // class TLD_* # NOTICE: no wildcard in class names + +line + The given line number or range of line numbers is compared + against the line number of each ``pr_debug()`` callsite. A single + line number matches the callsite line number exactly. A + range of line numbers matches any callsite between the first + and last line number inclusive. An empty first number means + the first line in the file, an empty last line number means the + last line number in the file. Examples:: + + line 1603 // exactly line 1603 + line 1600-1605 // the six lines from line 1600 to line 1605 + line -1605 // the 1605 lines from line 1 to line 1605 + line 1600- // all lines from line 1600 to the end of the file + +The flags specification comprises a change operation followed +by one or more flag characters. The change operation is one +of the characters:: + + - remove the given flags + + add the given flags + = set the flags to the given flags + +The flags are:: + + p enables the pr_debug() callsite. + _ enables no flags. + + Decorator flags add to the message-prefix, in order: + t Include thread ID, or + m Include module name + f Include the function name + l Include line number + +For ``print_hex_dump_debug()`` and ``print_hex_dump_bytes()``, only +the ``p`` flag has meaning, other flags are ignored. + +Note the regexp ``^[-+=][flmpt_]+$`` matches a flags specification. +To clear all flags at once, use ``=_`` or ``-flmpt``. + + +Debug messages during Boot Process +================================== + +To activate debug messages for core code and built-in modules during +the boot process, even before userspace and debugfs exists, use +``dyndbg="QUERY"`` or ``module.dyndbg="QUERY"``. QUERY follows +the syntax described above, but must not exceed 1023 characters. Your +bootloader may impose lower limits. + +These ``dyndbg`` params are processed just after the ddebug tables are +processed, as part of the early_initcall. Thus you can enable debug +messages in all code run after this early_initcall via this boot +parameter. + +On an x86 system for example ACPI enablement is a subsys_initcall and:: + + dyndbg="file ec.c +p" + +will show early Embedded Controller transactions during ACPI setup if +your machine (typically a laptop) has an Embedded Controller. +PCI (or other devices) initialization also is a hot candidate for using +this boot parameter for debugging purposes. + +If ``foo`` module is not built-in, ``foo.dyndbg`` will still be processed at +boot time, without effect, but will be reprocessed when module is +loaded later. Bare ``dyndbg=`` is only processed at boot. + + +Debug Messages at Module Initialization Time +============================================ + +When ``modprobe foo`` is called, modprobe scans ``/proc/cmdline`` for +``foo.params``, strips ``foo.``, and passes them to the kernel along with +params given in modprobe args or ``/etc/modprob.d/*.conf`` files, +in the following order: + +1. parameters given via ``/etc/modprobe.d/*.conf``:: + + options foo dyndbg=+pt + options foo dyndbg # defaults to +p + +2. ``foo.dyndbg`` as given in boot args, ``foo.`` is stripped and passed:: + + foo.dyndbg=" func bar +p; func buz +mp" + +3. args to modprobe:: + + modprobe foo dyndbg==pmf # override previous settings + +These ``dyndbg`` queries are applied in order, with last having final say. +This allows boot args to override or modify those from ``/etc/modprobe.d`` +(sensible, since 1 is system wide, 2 is kernel or boot specific), and +modprobe args to override both. + +In the ``foo.dyndbg="QUERY"`` form, the query must exclude ``module foo``. +``foo`` is extracted from the param-name, and applied to each query in +``QUERY``, and only 1 match-spec of each type is allowed. + +The ``dyndbg`` option is a "fake" module parameter, which means: + +- modules do not need to define it explicitly +- every module gets it tacitly, whether they use pr_debug or not +- it doesn't appear in ``/sys/module/$module/parameters/`` + To see it, grep the control file, or inspect ``/proc/cmdline.`` + +For ``CONFIG_DYNAMIC_DEBUG`` kernels, any settings given at boot-time (or +enabled by ``-DDEBUG`` flag during compilation) can be disabled later via +the debugfs interface if the debug messages are no longer needed:: + + echo "module module_name -p" > /proc/dynamic_debug/control + +Examples +======== + +:: + + // enable the message at line 1603 of file svcsock.c + :#> ddcmd 'file svcsock.c line 1603 +p' + + // enable all the messages in file svcsock.c + :#> ddcmd 'file svcsock.c +p' + + // enable all the messages in the NFS server module + :#> ddcmd 'module nfsd +p' + + // enable all 12 messages in the function svc_process() + :#> ddcmd 'func svc_process +p' + + // disable all 12 messages in the function svc_process() + :#> ddcmd 'func svc_process -p' + + // enable messages for NFS calls READ, READLINK, READDIR and READDIR+. + :#> ddcmd 'format "nfsd: READ" +p' + + // enable messages in files of which the paths include string "usb" + :#> ddcmd 'file *usb* +p' > /proc/dynamic_debug/control + + // enable all messages + :#> ddcmd '+p' > /proc/dynamic_debug/control + + // add module, function to all enabled messages + :#> ddcmd '+mf' > /proc/dynamic_debug/control + + // boot-args example, with newlines and comments for readability + Kernel command line: ... + // see whats going on in dyndbg=value processing + dynamic_debug.verbose=3 + // enable pr_debugs in the btrfs module (can be builtin or loadable) + btrfs.dyndbg="+p" + // enable pr_debugs in all files under init/ + // and the function parse_one, #cmt is stripped + dyndbg="file init/* +p #cmt ; func parse_one +p" + // enable pr_debugs in 2 functions in a module loaded later + pc87360.dyndbg="func pc87360_init_device +p; func pc87360_find +p" + +Kernel Configuration +==================== + +Dynamic Debug is enabled via kernel config items:: + + CONFIG_DYNAMIC_DEBUG=y # build catalog, enables CORE + CONFIG_DYNAMIC_DEBUG_CORE=y # enable mechanics only, skip catalog + +If you do not want to enable dynamic debug globally (i.e. in some embedded +system), you may set ``CONFIG_DYNAMIC_DEBUG_CORE`` as basic support of dynamic +debug and add ``ccflags := -DDYNAMIC_DEBUG_MODULE`` into the Makefile of any +modules which you'd like to dynamically debug later. + + +Kernel *prdbg* API +================== + +The following functions are cataloged and controllable when dynamic +debug is enabled:: + + pr_debug() + dev_dbg() + print_hex_dump_debug() + print_hex_dump_bytes() + +Otherwise, they are off by default; ``ccflags += -DDEBUG`` or +``#define DEBUG`` in a source file will enable them appropriately. + +If ``CONFIG_DYNAMIC_DEBUG`` is not set, ``print_hex_dump_debug()`` is +just a shortcut for ``print_hex_dump(KERN_DEBUG)``. + +For ``print_hex_dump_debug()``/``print_hex_dump_bytes()``, format string is +its ``prefix_str`` argument, if it is constant string; or ``hexdump`` +in case ``prefix_str`` is built dynamically. -- cgit v1.2.3