commit 3bc0bb36fa30e95ca829e9cf480e1ef7f7638333 upstream.

The test_cgcore_no_internal_process_constraint_on_threads selftest when
running with subsystem controlling noise triggers two warnings:

> [  597.443115] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3131 cgroup_apply_control_enable+0xe0/0x3f0
> [  597.443413] WARNING: CPU: 1 PID: 28167 at kernel/cgroup/cgroup.c:3177 cgroup_apply_control_disable+0xa6/0x160

Both stem from a call to cgroup_type_write. The first warning was also
triggered by syzkaller.

When we're switching cgroup to threaded mode shortly after a subsystem
was disabled on it, we can see the respective subsystem css dying there.

The warning in cgroup_apply_control_enable is harmless in this case
since we're not adding new subsys anyway.
The warning in cgroup_apply_control_disable indicates an attempt to kill
css of recently disabled subsystem repeatedly.

The commit prevents these situations by making cgroup_type_write wait
for all dying csses to go away before re-applying subtree controls.
When at it, the locations of WARN_ON_ONCE calls are moved so that
warning is triggered only when we are about to misuse the dying css.

Reported-by: syzbot+5493b2a54d31d6aea629@syzkaller.appspotmail.com
Reported-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

commit 87c9366e17259040a9118e06b6dc8de986e5d3d1 upstream.

This reverts commit 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS").

There are two issues with this commit, uncovered by Anton in tests
on some (Debian) systems:

1) I completely forgot to call any constructors if CONFIG_CONSTRUCTORS
   isn't set. Don't recall now if it just wasn't needed on my system, or
   if I never tested this case.

2) With that fixed, it works - with CONFIG_CONSTRUCTORS *unset*. If I
   set CONFIG_CONSTRUCTORS, it fails again, which isn't totally
   unexpected since whatever wanted to run is likely to have to run
   before the kernel init etc. that calls the constructors in this case.

Basically, some constructors that gcc emits (libc has?) need to run
very early during init; the failure mode otherwise was that the ptrace
fork test already failed:

----------------------
$ ./linux mem=512M
Core dump limits :
	soft - 0
	hard - NONE
Checking that ptrace can change system call numbers...check_ptrace : child exited with exitcode 6, while expecting 0; status 0x67f
Aborted
----------------------

Thinking more about this, it's clear that we simply cannot support
CONFIG_CONSTRUCTORS in UML. All the cases we need now (gcov, kasan)
involve not use of the __attribute__((constructor)), but instead
some constructor code/entry generated by gcc. Therefore, we cannot
distinguish between kernel constructors and system constructors.

Thus, revert this commit.

Cc: stable@vger.kernel.org [5.4+]
Fixes: 786b2384bf1c ("um: Enable CONFIG_CONSTRUCTORS")
Reported-by: Anton Ivanov <anton.ivanov@cambridgegreys.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Anton Ivanov <anton.ivanov@cambridgegreys.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Signed-off-by: Richard Weinberger <richard@nod.at>

Pull tracing fixes from Steven Rostedt:
 "Various tracing fixes:

   - Fix a function comparison warning for a xen trace event macro

   - Fix a double perf_event linking to a trace_uprobe_filter for
     multiple events

   - Fix suspicious RCU warnings in trace event code for using
     list_for_each_entry_rcu() when the "_rcu" portion wasn't needed.

   - Fix a bug in the histogram code when using the same variable

   - Fix a NULL pointer dereference when tracefs lockdown enabled and
     calling trace_set_default_clock()

   - A fix to a bug found with the double perf_event linking patch"

* tag 'trace-v5.5-rc6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace:
  tracing/uprobe: Fix to make trace_uprobe_filter alignment safe
  tracing: Do not set trace clock if tracefs lockdown is in effect
  tracing: Fix histogram code when expression has same var as value
  tracing: trigger: Replace unneeded RCU-list traversals
  tracing/uprobe: Fix double perf_event linking on multiprobe uprobe
  tracing: xen: Ordered comparison of function pointers

Pull power management fix from Rafael Wysocki:
 "Prevent the kernel from crashing during resume from hibernation if
  free pages contain leftover data from the restore kernel and
  init_on_free is set (Alexander Potapenko)"

* tag 'pm-5.5-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  PM: hibernate: fix crashes with init_on_free=1

Commit 99c9a923e97a ("tracing/uprobe: Fix double perf_event
linking on multiprobe uprobe") moved trace_uprobe_filter on
trace_probe_event. However, since it introduced a flexible
data structure with char array and type casting, the
alignment of trace_uprobe_filter can be broken.

This changes the type of the array to trace_uprobe_filter
data strucure to fix it.

Link: http://lore.kernel.org/r/20200120124022.GA14897@hirez.programming.kicks-ass.net
Link: http://lkml.kernel.org/r/157966340499.5107.10978352478952144902.stgit@devnote2

Fixes: 99c9a923e97a ("tracing/uprobe: Fix double perf_event linking on multiprobe uprobe")
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

When trace_clock option is not set and unstable clcok detected,
tracing_set_default_clock() sets trace_clock(ThinkPad A285 is one of
case). In that case, if lockdown is in effect, null pointer
dereference error happens in ring_buffer_set_clock().

Link: http://lkml.kernel.org/r/20200116131236.3866925-1-masami256@gmail.com

Cc: stable@vger.kernel.org
Fixes: 17911ff38aa58 ("tracing: Add locked_down checks to the open calls of files created for tracefs")
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1788488
Signed-off-by: Masami Ichikawa <masami256@gmail.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

While working on a tool to convert SQL syntex into the histogram language of
the kernel, I discovered the following bug:

 # echo 'first u64 start_time u64 end_time pid_t pid u64 delta' >> synthetic_events
 # echo 'hist:keys=pid:start=common_timestamp' > events/sched/sched_waking/trigger
 # echo 'hist:keys=next_pid:delta=common_timestamp-$start,start2=$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger

Would not display any histograms in the sched_switch histogram side.

But if I were to swap the location of

  "delta=common_timestamp-$start" with "start2=$start"

Such that the last line had:

 # echo 'hist:keys=next_pid:start2=$start,delta=common_timestamp-$start:onmatch(sched.sched_waking).trace(first,$start2,common_timestamp,next_pid,$delta)' > events/sched/sched_switch/trigger

The histogram works as expected.

What I found out is that the expressions clear out the value once it is
resolved. As the variables are resolved in the order listed, when
processing:

  delta=common_timestamp-$start

The $start is cleared. When it gets to "start2=$start", it errors out with
"unresolved symbol" (which is silent as this happens at the location of the
trace), and the histogram is dropped.

When processing the histogram for variable references, instead of adding a
new reference for a variable used twice, use the same reference. That way,
not only is it more efficient, but the order will no longer matter in
processing of the variables.

From Tom Zanussi:

 "Just to clarify some more about what the problem was is that without
  your patch, we would have two separate references to the same variable,
  and during resolve_var_refs(), they'd both want to be resolved
  separately, so in this case, since the first reference to start wasn't
  part of an expression, it wouldn't get the read-once flag set, so would
  be read normally, and then the second reference would do the read-once
  read and also be read but using read-once.  So everything worked and
  you didn't see a problem:

   from: start2=$start,delta=common_timestamp-$start

  In the second case, when you switched them around, the first reference
  would be resolved by doing the read-once, and following that the second
  reference would try to resolve and see that the variable had already
  been read, so failed as unset, which caused it to short-circuit out and
  not do the trigger action to generate the synthetic event:

   to: delta=common_timestamp-$start,start2=$start

  With your patch, we only have the single resolution which happens
  correctly the one time it's resolved, so this can't happen."

Link: https://lore.kernel.org/r/20200116154216.58ca08eb@gandalf.local.home

Cc: stable@vger.kernel.org
Fixes: 067fe038e70f6 ("tracing: Add variable reference handling to hist triggers")
Reviewed-by: Tom Zanuss <zanussi@kernel.org>
Tested-by: Tom Zanussi <zanussi@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

Pull networking fixes from David Miller:

 1) Fix non-blocking connect() in x25, from Martin Schiller.

 2) Fix spurious decryption errors in kTLS, from Jakub Kicinski.

 3) Netfilter use-after-free in mtype_destroy(), from Cong Wang.

 4) Limit size of TSO packets properly in lan78xx driver, from Eric
    Dumazet.

 5) r8152 probe needs an endpoint sanity check, from Johan Hovold.

 6) Prevent looping in tcp_bpf_unhash() during sockmap/tls free, from
    John Fastabend.

 7) hns3 needs short frames padded on transmit, from Yunsheng Lin.

 8) Fix netfilter ICMP header corruption, from Eyal Birger.

 9) Fix soft lockup when low on memory in hns3, from Yonglong Liu.

10) Fix NTUPLE firmware command failures in bnxt_en, from Michael Chan.

11) Fix memory leak in act_ctinfo, from Eric Dumazet.

* git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (91 commits)
  cxgb4: reject overlapped queues in TC-MQPRIO offload
  cxgb4: fix Tx multi channel port rate limit
  net: sched: act_ctinfo: fix memory leak
  bnxt_en: Do not treat DSN (Digital Serial Number) read failure as fatal.
  bnxt_en: Fix ipv6 RFS filter matching logic.
  bnxt_en: Fix NTUPLE firmware command failures.
  net: systemport: Fixed queue mapping in internal ring map
  net: dsa: bcm_sf2: Configure IMP port for 2Gb/sec
  net: dsa: sja1105: Don't error out on disabled ports with no phy-mode
  net: phy: dp83867: Set FORCE_LINK_GOOD to default after reset
  net: hns: fix soft lockup when there is not enough memory
  net: avoid updating qdisc_xmit_lock_key in netdev_update_lockdep_key()
  net/sched: act_ife: initalize ife->metalist earlier
  netfilter: nat: fix ICMP header corruption on ICMP errors
  net: wan: lapbether.c: Use built-in RCU list checking
  netfilter: nf_tables: fix flowtable list del corruption
  netfilter: nf_tables: fix memory leak in nf_tables_parse_netdev_hooks()
  netfilter: nf_tables: remove WARN and add NLA_STRING upper limits
  netfilter: nft_tunnel: ERSPAN_VERSION must not be null
  netfilter: nft_tunnel: fix null-attribute check
  ...

Pull timer fixes from Ingo Molnar:
 "Three fixes: fix link failure on Alpha, fix a Sparse warning and
  annotate/robustify a lockless access in the NOHZ code"

* 'timers-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick/sched: Annotate lockless access to last_jiffies_update
  lib/vdso: Make __cvdso_clock_getres() static
  time/posix-stubs: Provide compat itimer supoprt for alpha

Pull cpu/SMT fix from Ingo Molnar:
 "Fix a build bug on CONFIG_HOTPLUG_SMT=y && !CONFIG_SYSFS kernels"

* 'smp-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  cpu/SMT: Fix x86 link error without CONFIG_SYSFS