Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 413 insertions, 0 deletions

diff --git a/Documentation/networking/ipvs-sysctl.rst b/Documentation/networking/ipvs-sysctl.rst
new file mode 100644
index 000000000..fe36f4fcd
--- /dev/null
+++ b/Documentation/networking/ipvs-sysctl.rst
@@ -0,0 +1,413 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+===========
+IPvs-sysctl
+===========
+
+/proc/sys/net/ipv4/vs/* Variables:
+==================================
+
+am_droprate - INTEGER
+	default 10
+
+	It sets the always mode drop rate, which is used in the mode 3
+	of the drop_rate defense.
+
+amemthresh - INTEGER
+	default 1024
+
+	It sets the available memory threshold (in pages), which is
+	used in the automatic modes of defense. When there is no
+	enough available memory, the respective strategy will be
+	enabled and the variable is automatically set to 2, otherwise
+	the strategy is disabled and the variable is  set  to 1.
+
+backup_only - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	If set, disable the director function while the server is
+	in backup mode to avoid packet loops for DR/TUN methods.
+
+conn_lfactor - INTEGER
+	Possible values: -8 (larger table) .. 8 (smaller table)
+
+	Default: -4
+
+	Controls the sizing of the connection hash table based on the
+	load factor (number of connections per table buckets):
+
+		2^conn_lfactor = nodes / buckets
+
+	As result, the table grows if load increases and shrinks when
+	load decreases in the range of 2^8 - 2^conn_tab_bits (module
+	parameter).
+	The value is a shift count where negative values select
+	buckets = (connection hash nodes << -value) while positive
+	values select buckets = (connection hash nodes >> value). The
+	negative values reduce the collisions and reduce the time for
+	lookups but increase the table size. Positive values will
+	tolerate load above 100% when using smaller table is
+	preferred with the cost of more collisions. If using NAT
+	connections consider decreasing the value with one because
+	they add two nodes in the hash table.
+
+	Example:
+	-4: grow if load goes above 6% (buckets = nodes * 16)
+	2: grow if load goes above 400% (buckets = nodes / 4)
+
+conn_max - INTEGER
+	Limit for number of connections, per netns.
+
+	Controls the soft and hard limit for number of connections.
+	Initially, the platform specific limit is assigned for init_net.
+	The value can be changed and later the soft limit propagated
+	to other networking namespaces.
+
+	Privileged admin can change both limits up to the value of the
+	platform limit while the unprivileged admin can change only the
+	soft limit up to the value of the hard limit.
+
+	For setups using conntrack=1 (CONFIG_IP_VS_NFCT for
+	Netfilter connection tracking) the connections can be
+	limited also by nf_conntrack_max.
+
+	Limits for init_net:
+
+	======================= =============== =============
+	\			soft limit	hard limit
+	======================= =============== =============
+	create netns		platform	platform
+	priv admin		0 .. platform	0 .. platform
+	======================= =============== =============
+
+	Limits for new netns:
+
+	======================= =============== =============
+	\			soft limit	hard limit
+	======================= =============== =============
+	create netns		init_net:soft	init_net:soft
+	priv admin		0 .. platform	0 .. platform
+	unpriv admin		0 .. hard	N/A
+	======================= =============== =============
+
+	Limits per platform:
+
+	- 1,073,741,824 (2^30 for 64-bit)
+	- 16,777,216 (2^24 for 32-bit)
+
+	Possible values: 0 .. platform limit
+
+	Default: platform limit
+
+conn_reuse_mode - INTEGER
+	1 - default
+
+	Controls how ipvs will deal with connections that are detected
+	port reuse. It is a bitmap, with the values being:
+
+	0: disable any special handling on port reuse. The new
+	connection will be delivered to the same real server that was
+	servicing the previous connection.
+
+	bit 1: enable rescheduling of new connections when it is safe.
+	That is, whenever expire_nodest_conn and for TCP sockets, when
+	the connection is in TIME_WAIT state (which is only possible if
+	you use NAT mode).
+
+	bit 2: it is bit 1 plus, for TCP connections, when connections
+	are in FIN_WAIT state, as this is the last state seen by load
+	balancer in Direct Routing mode. This bit helps on adding new
+	real servers to a very busy cluster.
+
+conntrack - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	If set, maintain connection tracking entries for
+	connections handled by IPVS.
+
+	This should be enabled if connections handled by IPVS are to be
+	also handled by stateful firewall rules. That is, iptables rules
+	that make use of connection tracking.  It is a performance
+	optimisation to disable this setting otherwise.
+
+	Connections handled by the IPVS FTP application module
+	will have connection tracking entries regardless of this setting.
+
+	Only available when IPVS is compiled with CONFIG_IP_VS_NFCT enabled.
+
+cache_bypass - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	If it is enabled, forward packets to the original destination
+	directly when no cache server is available and destination
+	address is not local (iph->daddr is RTN_UNICAST). It is mostly
+	used in transparent web cache cluster.
+
+debug_level - INTEGER
+	- 0          - transmission error messages (default)
+	- 1          - non-fatal error messages
+	- 2          - configuration
+	- 3          - destination trash
+	- 4          - drop entry
+	- 5          - service lookup
+	- 6          - scheduling
+	- 7          - connection new/expire, lookup and synchronization
+	- 8          - state transition
+	- 9          - binding destination, template checks and applications
+	- 10         - IPVS packet transmission
+	- 11         - IPVS packet handling (ip_vs_in/ip_vs_out)
+	- 12 or more - packet traversal
+
+	Only available when IPVS is compiled with CONFIG_IP_VS_DEBUG enabled.
+
+	Higher debugging levels include the messages for lower debugging
+	levels, so setting debug level 2, includes level 0, 1 and 2
+	messages. Thus, logging becomes more and more verbose the higher
+	the level.
+
+drop_entry - INTEGER
+	- 0  - disabled (default)
+
+	The drop_entry defense is to randomly drop entries in the
+	connection hash table, just in order to collect back some
+	memory for new connections. In the current code, the
+	drop_entry procedure can be activated every second, then it
+	randomly scans 1/32 of the whole and drops entries that are in
+	the SYN-RECV/SYNACK state, which should be effective against
+	syn-flooding attack.
+
+	The valid values of drop_entry are from 0 to 3, where 0 means
+	that this strategy is always disabled, 1 and 2 mean automatic
+	modes (when there is no enough available memory, the strategy
+	is enabled and the variable is automatically set to 2,
+	otherwise the strategy is disabled and the variable is set to
+	1), and 3 means that the strategy is always enabled.
+
+drop_packet - INTEGER
+	- 0  - disabled (default)
+
+	The drop_packet defense is designed to drop 1/rate packets
+	before forwarding them to real servers. If the rate is 1, then
+	drop all the incoming packets.
+
+	The value definition is the same as that of the drop_entry. In
+	the automatic mode, the rate is determined by the follow
+	formula: rate = amemthresh / (amemthresh - available_memory)
+	when available memory is less than the available memory
+	threshold. When the mode 3 is set, the always mode drop rate
+	is controlled by the /proc/sys/net/ipv4/vs/am_droprate.
+
+est_cpulist - CPULIST
+	Allowed	CPUs for estimation kthreads
+
+	Syntax: standard cpulist format
+	empty list - stop kthread tasks and estimation
+	default - the system's housekeeping CPUs for kthreads
+
+	Example:
+	"all": all possible CPUs
+	"0-N": all possible CPUs, N denotes last CPU number
+	"0,1-N:1/2": first and all CPUs with odd number
+	"": empty list
+
+est_nice - INTEGER
+	default 0
+	Valid range: -20 (more favorable) .. 19 (less favorable)
+
+	Niceness value to use for the estimation kthreads (scheduling
+	priority)
+
+expire_nodest_conn - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	The default value is 0, the load balancer will silently drop
+	packets when its destination server is not available. It may
+	be useful, when user-space monitoring program deletes the
+	destination server (because of server overload or wrong
+	detection) and add back the server later, and the connections
+	to the server can continue.
+
+	If this feature is enabled, the load balancer will expire the
+	connection immediately when a packet arrives and its
+	destination server is not available, then the client program
+	will be notified that the connection is closed. This is
+	equivalent to the feature some people requires to flush
+	connections when its destination is not available.
+
+expire_quiescent_template - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	When set to a non-zero value, the load balancer will expire
+	persistent templates when the destination server is quiescent.
+	This may be useful, when a user makes a destination server
+	quiescent by setting its weight to 0 and it is desired that
+	subsequent otherwise persistent connections are sent to a
+	different destination server.  By default new persistent
+	connections are allowed to quiescent destination servers.
+
+	If this feature is enabled, the load balancer will expire the
+	persistence template if it is to be used to schedule a new
+	connection and the destination server is quiescent.
+
+ignore_tunneled - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	If set, ipvs will set the ipvs_property on all packets which are of
+	unrecognized protocols.  This prevents us from routing tunneled
+	protocols like ipip, which is useful to prevent rescheduling
+	packets that have been tunneled to the ipvs host (i.e. to prevent
+	ipvs routing loops when ipvs is also acting as a real server).
+
+nat_icmp_send - BOOLEAN
+	- 0 - disabled (default)
+	- not 0 - enabled
+
+	It controls sending icmp error messages (ICMP_DEST_UNREACH)
+	for VS/NAT when the load balancer receives packets from real
+	servers but the connection entries don't exist.
+
+pmtu_disc - BOOLEAN
+	- 0 - disabled
+	- not 0 - enabled (default)
+
+	By default, reject with FRAG_NEEDED all DF packets that exceed
+	the PMTU, irrespective of the forwarding method. For TUN method
+	the flag can be disabled to fragment such packets.
+
+secure_tcp - INTEGER
+	- 0  - disabled (default)
+
+	The secure_tcp defense is to use a more complicated TCP state
+	transition table. For VS/NAT, it also delays entering the
+	TCP ESTABLISHED state until the three way handshake is completed.
+
+	The value definition is the same as that of drop_entry and
+	drop_packet.
+
+svc_lfactor - INTEGER
+	Possible values: -8 (larger table) .. 8 (smaller table)
+
+	Default: -3
+
+	Controls the sizing of the service hash table based on the
+	load factor (number of services per table buckets). The table
+	will grow and shrink in the range of 2^4 - 2^20.
+	See conn_lfactor for explanation.
+
+sync_threshold - vector of 2 INTEGERs: sync_threshold, sync_period
+	default 3 50
+
+	It sets synchronization threshold, which is the minimum number
+	of incoming packets that a connection needs to receive before
+	the connection will be synchronized. A connection will be
+	synchronized, every time the number of its incoming packets
+	modulus sync_period equals the threshold. The range of the
+	threshold is from 0 to sync_period.
+
+	When sync_period and sync_refresh_period are 0, send sync only
+	for state changes or only once when pkts matches sync_threshold
+
+sync_refresh_period - UNSIGNED INTEGER
+	default 0
+
+	In seconds, difference in reported connection timer that triggers
+	new sync message. It can be used to avoid sync messages for the
+	specified period (or half of the connection timeout if it is lower)
+	if connection state is not changed since last sync.
+
+	This is useful for normal connections with high traffic to reduce
+	sync rate. Additionally, retry sync_retries times with period of
+	sync_refresh_period/8.
+
+sync_retries - INTEGER
+	default 0
+
+	Defines sync retries with period of sync_refresh_period/8. Useful
+	to protect against loss of sync messages. The range of the
+	sync_retries is from 0 to 3.
+
+sync_qlen_max - UNSIGNED LONG
+
+	Hard limit for queued sync messages that are not sent yet. It
+	defaults to 1/32 of the memory pages but actually represents
+	number of messages. It will protect us from allocating large
+	parts of memory when the sending rate is lower than the queuing
+	rate.
+
+sync_sock_size - INTEGER
+	default 0
+
+	Configuration of SNDBUF (master) or RCVBUF (slave) socket limit.
+	Default value is 0 (preserve system defaults).
+
+sync_ports - INTEGER
+	default 1
+
+	The number of threads that master and backup servers can use for
+	sync traffic. Every thread will use single UDP port, thread 0 will
+	use the default port 8848 while last thread will use port
+	8848+sync_ports-1.
+
+snat_reroute - BOOLEAN
+	- 0 - disabled
+	- not 0 - enabled (default)
+
+	If enabled, recalculate the route of SNATed packets from
+	realservers so that they are routed as if they originate from the
+	director. Otherwise they are routed as if they are forwarded by the
+	director.
+
+	If policy routing is in effect then it is possible that the route
+	of a packet originating from a director is routed differently to a
+	packet being forwarded by the director.
+
+	If policy routing is not in effect then the recalculated route will
+	always be the same as the original route so it is an optimisation
+	to disable snat_reroute and avoid the recalculation.
+
+sync_persist_mode - INTEGER
+	default 0
+
+	Controls the synchronisation of connections when using persistence
+
+	0: All types of connections are synchronised
+
+	1: Attempt to reduce the synchronisation traffic depending on
+	the connection type. For persistent services avoid synchronisation
+	for normal connections, do it only for persistence templates.
+	In such case, for TCP and SCTP it may need enabling sloppy_tcp and
+	sloppy_sctp flags on backup servers. For non-persistent services
+	such optimization is not applied, mode 0 is assumed.
+
+sync_version - INTEGER
+	default 1
+
+	The version of the synchronisation protocol used when sending
+	synchronisation messages.
+
+	0 selects the original synchronisation protocol (version 0). This
+	should be used when sending synchronisation messages to a legacy
+	system that only understands the original synchronisation protocol.
+
+	1 selects the current synchronisation protocol (version 1). This
+	should be used where possible.
+
+	Kernels with this sync_version entry are able to receive messages
+	of both version 1 and version 2 of the synchronisation protocol.
+
+run_estimation - BOOLEAN
+	0 - disabled
+	not 0 - enabled (default)
+
+	If disabled, the estimation will be suspended and kthread tasks
+	stopped.
+
+	You can always re-enable estimation by setting this value to 1.
+	But be careful, the first estimation after re-enable is not
+	accurate.