Merge tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Don't destroy user event fields when removal fails

   User event fields are destroyed before the event is removed from
   visibility. But that can fail leaving the still visible event with no
   fields. Move the destroying of the fields to after the event is
   successfully removed from visibility.

 - Initialize function graph state is fork before calling
   copy_exec_state()

   For non-CLONE_VM forks, copy_exec_state() allocates a new
   task_exec_state. If that allocation fails, ftrace_graph_exit_task()
   will free the tasks ret_stack pointer. Since that pointer is still
   using the parent's ret_stack, it mistakenly frees the parent's
   pointer too.

   Call ftrace_graph_init() on the task first which will NULL out the
   new tasks's ret_stack and if the copy fails, it will not free
   anything.

 - Remove FGRAPH_MAX_INDEX

   The macro FGRAPH_MAX_INDEX was added but never used. Remove it.

 - Save ent_size in function graph printing of nested functions

   The function graph tracer needs to look at the next event to see if
   the next event is the return of the current function entry. If it is,
   it prints a single line:

	ktime_get();

   Otherwise it prints it like a nested function:

	tick_nohz_irq_exit() {
	    ktime_get();
	    kcpustat_irq_exit();
	}

   In order to look at the next event, it must save the current event so
   that it has the information to print from it. It saves the event in
   the iterator descriptor called "ent". What it doesn't save is the
   ent_size of the event which is now used to know if the function graph
   arguments are to be printed. The peek doesn't save the size so the
   size used happens to be that of the size of the last event that was
   seen.

   Save the entry event size in the iterator descriptor so that the
   correct size is used.

 - Fix several errors with freeing data in the histogram code

   The histogram code had a lot of leaked or or incorrect accounting
   when failures happen. Correct them.

 - Fix histogram regression of .percent and .graph modifiers

   Up until 6.3 histogram values could have "percent" or "graph"
   modifiers that changed how they were printed. But a change that added
   restricting histograms values from being strings, stack traces and
   other modifiers inadvertently prevented them from using the percent
   and graph modifiers, which were legal use cases for values.

   Put back the percent and graph modifiers.

 - Fix various typos in the comments

 - Set the trace_clock before initializing a histogram with clock
   argument

   The histogram API allows the user to specific which trace clock to
   use via a "clock=" string. The histogram is set up first before the
   clock is checked. If the passed in clock is not valid, it exits
   without fully fixing up the histogram leaving it on the list and a
   use-after-free can trigger.

   Update the clock argument first and if it fails then exit gracefully
   before the histogram trigger is placed on any lists.

 - Restore :mod: trailer after parsing in ftrace_set_clr_event

   The function ftrace_set_clr_event() modifies the parse string and
   needs to put it back to what was passed in. It searches for ":mod:"
   via a strsep() but fails to put back the first ':' in the string.

   Add back the ':' in the passed in string.

 - Take trace_array reference when opening a tracer options file

   The options files are dynamically created and some tracers add their
   own options. When a tracer adds their own list of options, the
   trace_array holding them has an array to hold the list of options for
   each tracer. This array increases in size via a krealloc(), and the
   new entry gets a newly allocated array to hold the options of the new
   tracer being added.

   The element in each entry of the tracer's option array holds a
   pointer back to the trace_array, a pointer to the tracer it is
   associated to, a pointer to the flags of the option.

   The issue is that these arrays are freed when the trace_array is
   freed when its instance it represents is removed from the instances
   directory. There's a race that an open of one of these options files
   can happen when the instance is being removed.

   Add a new helper function to be called by the open function of the
   options file to iterate all existing trace_arrays under a lock and
   find the one that has the given option element in one of it's tracer
   arrays. If found, then update the associated trace_array's reference
   counter to keep it from being freed. If not found, have the open call
   return -ENODEV.

 - Disable interrupts when acquiring the lock in rb_wake_up_waiters()

   The function rb_wake_up_waiters() assumes it will be called in
   interrupt context and does not disable irqs when taking
   cpu_buffer->reader_lock, which can be called in hard interrupt
   context. The issue is in PREEMPT_RT, this function is called in
   thread context leaving this lock open to a deadlock.

   Take the lock with interrupts disabled.

 - Use rcu_assign_pointer() for tmp_ops filter hash

   The tmp_ops used in update_ftrace_direct_mod() assigns its
   filter_hash field directly, but that field is annotated as __rcu and
   sparse complains. Assign it with rcu_assign_pointer()

 - Fix use-after-free in enable_trigger_private_data_free()

   The trace_event_call is accessed through the event_trigger_data's
   trace_event_file pointer to put the trace_event_call on freeing. The
   issue is that the trace_event_file data may have been freed already
   causing a use-after-free. Add a field to the event_trigger_data that
   points directly to the trace_event_call so that it can decrement its
   reference directly without needing to go through the
   trace_event_file.

 - Fix accounting of buffer data remote headers

   trace_buffer_desc_size() and trace_remote_alloc_buffer() undercount
   the number of pages is needed for the asked for size as it doesn't
   take into account the meta data on each page. Add a helper function
   to do the calculation properly and use that in these functions.

 - Catch nr_page_va overflow in ring_buffer_desc sizing

   The number of pages per remote ring buffer is capped by
   ring_buffer_desc::nr_page_va (32 bits). A buffer_size large enough to
   overflow that field would silently allocate a descriptor smaller than
   what was asked for.

 - Do not resize the subbuf order if any per_cpu buffer is disabled

   The mmapping of ring buffers disables resizing the subbuffers, but it
   is done per-cpu whereas the subbuf size change is done for all the
   per_cpu buffers under the buffer->mutex. It could change the size of
   some while the mapping is happening on others. Have the resize of the
   subbuf order check all the per_cpu buffers under the lock to see if
   any of them is disabled before starting and causing an inconsistency
   between buffers that are being mapped.

* tag 'trace-v7.3-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (25 commits)
  ring-buffer: Check resize_disabled before publishing the new subbuf order
  tracing/remotes: Catch nr_page_va overflow in ring_buffer_desc sizing
  tracing/remotes: Account for ring buffer page header in size calculation
  tracing: Don't dereference trace_event_file in deferred trigger free
  ftrace: Use rcu_assign_pointer() for tmp_ops filter hash
  ring-buffer: Acquire the lock with irqsave in rb_wake_up_waiters()
  tracing: Take trace_array reference when opening a tracer options file
  tracing: Fix ring_buffer_read_page_size() kernel-doc
  tracing: Restore :mod: trailer after parsing in ftrace_set_clr_event()
  tracing: Fix memory corruption from a "STACKTRACE" histogram key
  tracing: Fix memory corruption from the histogram stacktrace modifier
  tracing: Undo the registration when enabling the histogram trigger fails
  tracing: Take the reference before publishing the named histogram trigger
  tracing: Set the trace clock before registering the histogram trigger
  tracing: Fix typo "preceeded" in comment
  tracing: Fix typo "availabe" in comment
  tracing: Let histogram values keep the percent and graph modifiers
  tracing: Keep the entry count when the histogram stats allocation fails
  tracing: Free histogram the field rejected for a bad modifier
  tracing: Free histogram the var ref when its initialization fails
  ...

1 files changed, 310 insertions, 0 deletions

diff --git a/include/net/nsh.h b/include/net/nsh.h
new file mode 100644
index 000000000..15a26c590
--- /dev/null
+++ b/include/net/nsh.h
@@ -0,0 +1,310 @@
+#ifndef __NET_NSH_H
+#define __NET_NSH_H 1
+
+#include <linux/skbuff.h>
+
+/*
+ * Network Service Header:
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |Ver|O|U|    TTL    |   Length  |U|U|U|U|MD Type| Next Protocol |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Service Path Identifier (SPI)        | Service Index |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                                                               |
+ * ~               Mandatory/Optional Context Headers              ~
+ * |                                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Version: The version field is used to ensure backward compatibility
+ * going forward with future NSH specification updates.  It MUST be set
+ * to 0x0 by the sender, in this first revision of NSH.  Given the
+ * widespread implementation of existing hardware that uses the first
+ * nibble after an MPLS label stack for ECMP decision processing, this
+ * document reserves version 01b and this value MUST NOT be used in
+ * future versions of the protocol.  Please see [RFC7325] for further
+ * discussion of MPLS-related forwarding requirements.
+ *
+ * O bit: Setting this bit indicates an Operations, Administration, and
+ * Maintenance (OAM) packet.  The actual format and processing of SFC
+ * OAM packets is outside the scope of this specification (see for
+ * example [I-D.ietf-sfc-oam-framework] for one approach).
+ *
+ * The O bit MUST be set for OAM packets and MUST NOT be set for non-OAM
+ * packets.  The O bit MUST NOT be modified along the SFP.
+ *
+ * SF/SFF/SFC Proxy/Classifier implementations that do not support SFC
+ * OAM procedures SHOULD discard packets with O bit set, but MAY support
+ * a configurable parameter to enable forwarding received SFC OAM
+ * packets unmodified to the next element in the chain.  Forwarding OAM
+ * packets unmodified by SFC elements that do not support SFC OAM
+ * procedures may be acceptable for a subset of OAM functions, but can
+ * result in unexpected outcomes for others, thus it is recommended to
+ * analyze the impact of forwarding an OAM packet for all OAM functions
+ * prior to enabling this behavior.  The configurable parameter MUST be
+ * disabled by default.
+ *
+ * TTL: Indicates the maximum SFF hops for an SFP.  This field is used
+ * for service plane loop detection.  The initial TTL value SHOULD be
+ * configurable via the control plane; the configured initial value can
+ * be specific to one or more SFPs.  If no initial value is explicitly
+ * provided, the default initial TTL value of 63 MUST be used.  Each SFF
+ * involved in forwarding an NSH packet MUST decrement the TTL value by
+ * 1 prior to NSH forwarding lookup.  Decrementing by 1 from an incoming
+ * value of 0 shall result in a TTL value of 63.  The packet MUST NOT be
+ * forwarded if TTL is, after decrement, 0.
+ *
+ * All other flag fields, marked U, are unassigned and available for
+ * future use, see Section 11.2.1.  Unassigned bits MUST be set to zero
+ * upon origination, and MUST be ignored and preserved unmodified by
+ * other NSH supporting elements.  Elements which do not understand the
+ * meaning of any of these bits MUST NOT modify their actions based on
+ * those unknown bits.
+ *
+ * Length: The total length, in 4-byte words, of NSH including the Base
+ * Header, the Service Path Header, the Fixed Length Context Header or
+ * Variable Length Context Header(s).  The length MUST be 0x6 for MD
+ * Type equal to 0x1, and MUST be 0x2 or greater for MD Type equal to
+ * 0x2.  The length of the NSH header MUST be an integer multiple of 4
+ * bytes, thus variable length metadata is always padded out to a
+ * multiple of 4 bytes.
+ *
+ * MD Type: Indicates the format of NSH beyond the mandatory Base Header
+ * and the Service Path Header.  MD Type defines the format of the
+ * metadata being carried.
+ *
+ * 0x0 - This is a reserved value.  Implementations SHOULD silently
+ * discard packets with MD Type 0x0.
+ *
+ * 0x1 - This indicates that the format of the header includes a fixed
+ * length Context Header (see Figure 4 below).
+ *
+ * 0x2 - This does not mandate any headers beyond the Base Header and
+ * Service Path Header, but may contain optional variable length Context
+ * Header(s).  The semantics of the variable length Context Header(s)
+ * are not defined in this document.  The format of the optional
+ * variable length Context Headers is provided in Section 2.5.1.
+ *
+ * 0xF - This value is reserved for experimentation and testing, as per
+ * [RFC3692].  Implementations not explicitly configured to be part of
+ * an experiment SHOULD silently discard packets with MD Type 0xF.
+ *
+ * Next Protocol: indicates the protocol type of the encapsulated data.
+ * NSH does not alter the inner payload, and the semantics on the inner
+ * protocol remain unchanged due to NSH service function chaining.
+ * Please see the IANA Considerations section below, Section 11.2.5.
+ *
+ * This document defines the following Next Protocol values:
+ *
+ * 0x1: IPv4
+ * 0x2: IPv6
+ * 0x3: Ethernet
+ * 0x4: NSH
+ * 0x5: MPLS
+ * 0xFE: Experiment 1
+ * 0xFF: Experiment 2
+ *
+ * Packets with Next Protocol values not supported SHOULD be silently
+ * dropped by default, although an implementation MAY provide a
+ * configuration parameter to forward them.  Additionally, an
+ * implementation not explicitly configured for a specific experiment
+ * [RFC3692] SHOULD silently drop packets with Next Protocol values 0xFE
+ * and 0xFF.
+ *
+ * Service Path Identifier (SPI): Identifies a service path.
+ * Participating nodes MUST use this identifier for Service Function
+ * Path selection.  The initial classifier MUST set the appropriate SPI
+ * for a given classification result.
+ *
+ * Service Index (SI): Provides location within the SFP.  The initial
+ * classifier for a given SFP SHOULD set the SI to 255, however the
+ * control plane MAY configure the initial value of SI as appropriate
+ * (i.e., taking into account the length of the service function path).
+ * The Service Index MUST be decremented by a value of 1 by Service
+ * Functions or by SFC Proxy nodes after performing required services
+ * and the new decremented SI value MUST be used in the egress packet's
+ * NSH.  The initial Classifier MUST send the packet to the first SFF in
+ * the identified SFP for forwarding along an SFP.  If re-classification
+ * occurs, and that re-classification results in a new SPI, the
+ * (re)classifier is, in effect, the initial classifier for the
+ * resultant SPI.
+ *
+ * The SI is used in conjunction the with Service Path Identifier for
+ * Service Function Path Selection and for determining the next SFF/SF
+ * in the path.  The SI is also valuable when troubleshooting or
+ * reporting service paths.  Additionally, while the TTL field is the
+ * main mechanism for service plane loop detection, the SI can also be
+ * used for detecting service plane loops.
+ *
+ * When the Base Header specifies MD Type = 0x1, a Fixed Length Context
+ * Header (16-bytes) MUST be present immediately following the Service
+ * Path Header. The value of a Fixed Length Context
+ * Header that carries no metadata MUST be set to zero.
+ *
+ * When the base header specifies MD Type = 0x2, zero or more Variable
+ * Length Context Headers MAY be added, immediately following the
+ * Service Path Header (see Figure 5).  Therefore, Length = 0x2,
+ * indicates that only the Base Header followed by the Service Path
+ * Header are present.  The optional Variable Length Context Headers
+ * MUST be of an integer number of 4-bytes.  The base header Length
+ * field MUST be used to determine the offset to locate the original
+ * packet or frame for SFC nodes that require access to that
+ * information.
+ *
+ * The format of the optional variable length Context Headers
+ *
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |          Metadata Class       |      Type     |U|    Length   |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                      Variable Metadata                        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ *
+ * Metadata Class (MD Class): Defines the scope of the 'Type' field to
+ * provide a hierarchical namespace.  The IANA Considerations
+ * Section 11.2.4 defines how the MD Class values can be allocated to
+ * standards bodies, vendors, and others.
+ *
+ * Type: Indicates the explicit type of metadata being carried.  The
+ * definition of the Type is the responsibility of the MD Class owner.
+ *
+ * Unassigned bit: One unassigned bit is available for future use. This
+ * bit MUST NOT be set, and MUST be ignored on receipt.
+ *
+ * Length: Indicates the length of the variable metadata, in bytes.  In
+ * case the metadata length is not an integer number of 4-byte words,
+ * the sender MUST add pad bytes immediately following the last metadata
+ * byte to extend the metadata to an integer number of 4-byte words.
+ * The receiver MUST round up the length field to the nearest 4-byte
+ * word boundary, to locate and process the next field in the packet.
+ * The receiver MUST access only those bytes in the metadata indicated
+ * by the length field (i.e., actual number of bytes) and MUST ignore
+ * the remaining bytes up to the nearest 4-byte word boundary.  The
+ * Length may be 0 or greater.
+ *
+ * A value of 0 denotes a Context Header without a Variable Metadata
+ * field.
+ *
+ * [0] https://datatracker.ietf.org/doc/draft-ietf-sfc-nsh/
+ */
+
+/**
+ * struct nsh_md1_ctx - Keeps track of NSH context data
+ * @context: NSH Contexts.
+ */
+struct nsh_md1_ctx {
+	__be32 context[4];
+};
+
+struct nsh_md2_tlv {
+	__be16 md_class;
+	u8 type;
+	u8 length;
+	u8 md_value[];
+};
+
+struct nshhdr {
+	__be16 ver_flags_ttl_len;
+	u8 mdtype;
+	u8 np;
+	__be32 path_hdr;
+	union {
+	    struct nsh_md1_ctx md1;
+	    struct nsh_md2_tlv md2;
+	};
+};
+
+/* Masking NSH header fields. */
+#define NSH_VER_MASK       0xc000
+#define NSH_VER_SHIFT      14
+#define NSH_FLAGS_MASK     0x3000
+#define NSH_FLAGS_SHIFT    12
+#define NSH_TTL_MASK       0x0fc0
+#define NSH_TTL_SHIFT      6
+#define NSH_LEN_MASK       0x003f
+#define NSH_LEN_SHIFT      0
+
+#define NSH_MDTYPE_MASK    0x0f
+#define NSH_MDTYPE_SHIFT   0
+
+#define NSH_SPI_MASK       0xffffff00
+#define NSH_SPI_SHIFT      8
+#define NSH_SI_MASK        0x000000ff
+#define NSH_SI_SHIFT       0
+
+/* MD Type Registry. */
+#define NSH_M_TYPE1     0x01
+#define NSH_M_TYPE2     0x02
+#define NSH_M_EXP1      0xFE
+#define NSH_M_EXP2      0xFF
+
+/* NSH Base Header Length */
+#define NSH_BASE_HDR_LEN  8
+
+/* NSH MD Type 1 header Length. */
+#define NSH_M_TYPE1_LEN   24
+
+/* NSH header maximum Length. */
+#define NSH_HDR_MAX_LEN ((NSH_LEN_MASK >> NSH_LEN_SHIFT) * 4)
+
+/* NSH context headers maximum Length. */
+#define NSH_CTX_HDRS_MAX_LEN (NSH_HDR_MAX_LEN - NSH_BASE_HDR_LEN)
+
+static inline struct nshhdr *nsh_hdr(struct sk_buff *skb)
+{
+	return (struct nshhdr *)skb_network_header(skb);
+}
+
+static inline u16 nsh_hdr_len(const struct nshhdr *nsh)
+{
+	return ((ntohs(nsh->ver_flags_ttl_len) & NSH_LEN_MASK)
+		>> NSH_LEN_SHIFT) << 2;
+}
+
+static inline u8 nsh_get_ver(const struct nshhdr *nsh)
+{
+	return (ntohs(nsh->ver_flags_ttl_len) & NSH_VER_MASK)
+		>> NSH_VER_SHIFT;
+}
+
+static inline u8 nsh_get_flags(const struct nshhdr *nsh)
+{
+	return (ntohs(nsh->ver_flags_ttl_len) & NSH_FLAGS_MASK)
+		>> NSH_FLAGS_SHIFT;
+}
+
+static inline u8 nsh_get_ttl(const struct nshhdr *nsh)
+{
+	return (ntohs(nsh->ver_flags_ttl_len) & NSH_TTL_MASK)
+		>> NSH_TTL_SHIFT;
+}
+
+static inline void __nsh_set_xflag(struct nshhdr *nsh, u16 xflag, u16 xmask)
+{
+	nsh->ver_flags_ttl_len
+		= (nsh->ver_flags_ttl_len & ~htons(xmask)) | htons(xflag);
+}
+
+static inline void nsh_set_flags_and_ttl(struct nshhdr *nsh, u8 flags, u8 ttl)
+{
+	__nsh_set_xflag(nsh, ((flags << NSH_FLAGS_SHIFT) & NSH_FLAGS_MASK) |
+			     ((ttl << NSH_TTL_SHIFT) & NSH_TTL_MASK),
+			NSH_FLAGS_MASK | NSH_TTL_MASK);
+}
+
+static inline void nsh_set_flags_ttl_len(struct nshhdr *nsh, u8 flags,
+					 u8 ttl, u8 len)
+{
+	len = len >> 2;
+	__nsh_set_xflag(nsh, ((flags << NSH_FLAGS_SHIFT) & NSH_FLAGS_MASK) |
+			     ((ttl << NSH_TTL_SHIFT) & NSH_TTL_MASK) |
+			     ((len << NSH_LEN_SHIFT) & NSH_LEN_MASK),
+			NSH_FLAGS_MASK | NSH_TTL_MASK | NSH_LEN_MASK);
+}
+
+int nsh_push(struct sk_buff *skb, const struct nshhdr *pushed_nh);
+int nsh_pop(struct sk_buff *skb);
+
+#endif /* __NET_NSH_H */