memcg_write_event_control() accesses the dentry->d_name of the specified
control fd to route the write call.  As a cgroup interface file can't be
renamed, it's safe to access d_name as long as the specified file is a
regular cgroup file.  Also, as these cgroup interface files can't be
removed before the directory, it's safe to access the parent too.

Prior to 347c4a874710 ("memcg: remove cgroup_event->cft"), there was a
call to __file_cft() which verified that the specified file is a regular
cgroupfs file before further accesses.  The cftype pointer returned from
__file_cft() was no longer necessary and the commit inadvertently
dropped the file type check with it allowing any file to slip through.
With the invarients broken, the d_name and parent accesses can now race
against renames and removals of arbitrary files and cause
use-after-free's.

Fix the bug by resurrecting the file type check in __file_cft().  Now
that cgroupfs is implemented through kernfs, checking the file
operations needs to go through a layer of indirection.  Instead, let's
check the superblock and dentry type.

Signed-off-by: Tejun Heo <tj@kernel.org>
Fixes: 347c4a874710 ("memcg: remove cgroup_event->cft")
Cc: stable@kernel.org # v3.14+
Reported-by: Jann Horn <jannh@google.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc_skip_spaces() seems to think it is working on C strings, and ends
up being just a wrapper around skip_spaces() with a really odd calling
convention.

Instead of basing it on skip_spaces(), it should have looked more like
proc_skip_char(), which really is the exact same function (except it
skips a particular character, rather than whitespace).  So use that as
inspiration, odd coding and all.

Now the calling convention actually makes sense and works for the
intended purpose.

Reported-and-tested-by: Kyle Zeng <zengyhkyle@gmail.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

proc_get_long() is passed a size_t, but then assigns it to an 'int'
variable for the length.  Let's not do that, even if our IO paths are
limited to MAX_RW_COUNT (exactly because of these kinds of type errors).

So do the proper test in the rigth type.

Reported-by: Kyle Zeng <zengyhkyle@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull perf fix from Borislav Petkov:

 - Fix a use-after-free case where the perf pending task callback would
   see an already freed event

* tag 'perf_urgent_for_v6.1_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix perf_pending_task() UaF

Pull networking fixes from Jakub Kicinski:
 "Including fixes from bpf, can and wifi.

  Current release - new code bugs:

   - eth: mlx5e:
      - use kvfree() in mlx5e_accel_fs_tcp_create()
      - MACsec, fix RX data path 16 RX security channel limit
      - MACsec, fix memory leak when MACsec device is deleted
      - MACsec, fix update Rx secure channel active field
      - MACsec, fix add Rx security association (SA) rule memory leak

  Previous releases - regressions:

   - wifi: cfg80211: don't allow multi-BSSID in S1G

   - stmmac: set MAC's flow control register to reflect current settings

   - eth: mlx5:
      - E-switch, fix duplicate lag creation
      - fix use-after-free when reverting termination table

  Previous releases - always broken:

   - ipv4: fix route deletion when nexthop info is not specified

   - bpf: fix a local storage BPF map bug where the value's spin lock
     field can get initialized incorrectly

   - tipc: re-fetch skb cb after tipc_msg_validate

   - wifi: wilc1000: fix Information Element parsing

   - packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE

   - sctp: fix memory leak in sctp_stream_outq_migrate()

   - can: can327: fix potential skb leak when netdev is down

   - can: add number of missing netdev freeing on error paths

   - aquantia: do not purge addresses when setting the number of rings

   - wwan: iosm:
      - fix incorrect skb length leading to truncated packet
      - fix crash in peek throughput test due to skb UAF"

* tag 'net-6.1-rc8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (79 commits)
  net: ethernet: renesas: ravb: Fix promiscuous mode after system resumed
  MAINTAINERS: Update maintainer list for chelsio drivers
  ionic: update MAINTAINERS entry
  sctp: fix memory leak in sctp_stream_outq_migrate()
  packet: do not set TP_STATUS_CSUM_VALID on CHECKSUM_COMPLETE
  net/mlx5: Lag, Fix for loop when checking lag
  Revert "net/mlx5e: MACsec, remove replay window size limitation in offload path"
  net: marvell: prestera: Fix a NULL vs IS_ERR() check in some functions
  net: tun: Fix use-after-free in tun_detach()
  net: mdiobus: fix unbalanced node reference count
  net: hsr: Fix potential use-after-free
  tipc: re-fetch skb cb after tipc_msg_validate
  mptcp: fix sleep in atomic at close time
  mptcp: don't orphan ssk in mptcp_close()
  dsa: lan9303: Correct stat name
  ipv4: Fix route deletion when nexthop info is not specified
  net: wwan: iosm: fix incorrect skb length
  net: wwan: iosm: fix crash in peek throughput test
  net: wwan: iosm: fix dma_alloc_coherent incompatible pointer type
  net: wwan: iosm: fix kernel test robot reported error
  ...

Per syzbot it is possible for perf_pending_task() to run after the
event is free()'d. There are two related but distinct cases:

 - the task_work was already queued before destroying the event;
 - destroying the event itself queues the task_work.

The first cannot be solved using task_work_cancel() since
perf_release() itself might be called from a task_work (____fput),
which means the current->task_works list is already empty and
task_work_cancel() won't be able to find the perf_pending_task()
entry.

The simplest alternative is extending the perf_event lifetime to cover
the task_work.

The second is just silly, queueing a task_work while you know the
event is going away makes no sense and is easily avoided by
re-arranging how the event is marked STATE_DEAD and ensuring it goes
through STATE_OFF on the way down.

Reported-by: syzbot+9228d6098455bb209ec8@syzkaller.appspotmail.com
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Marco Elver <elver@google.com>

Pull tracing fixes from Steven Rostedt:

 - Fix osnoise duration type to 64bit not 32bit

 - Have histogram triggers be able to handle an unexpected NULL pointer
   for the record event, which can happen when the histogram first
   starts up

 - Clear out ring buffers when dynamic events are removed, as the type
   that is saved in the ring buffer is used to read the event, and a
   stale type that is reused by another event could cause use after free
   issues

 - Trivial comment fix

 - Fix memory leak in user_event_create()

* tag 'trace-v6.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  tracing: Free buffers when a used dynamic event is removed
  tracing: Add tracing_reset_all_online_cpus_unlocked() function
  tracing: Fix race where histograms can be called before the event
  tracing/osnoise: Fix duration type
  tracing/user_events: Fix memory leak in user_event_create()
  tracing/hist: add in missing * in comment blocks

Pull perf fixes from Borislav Petkov:
 "Two more fixes to the perf sigtrap handling:

   - output the address in the sample only when it has been requested

   - handle the case where user-only events can hit in kernel and thus
     upset the sigtrap sanity checking"

* tag 'perf_urgent_for_v6.1_rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Consider OS filter fail
  perf: Fixup SIGTRAP and sample_flags interaction

Pull power management fixes from Rafael Wysocki:
 "These revert a recent change in the schedutil cpufreq governor that
  had not been expected to make any functional difference, but turned
  out to introduce a performance regression, fix an initialization issue
  in the amd-pstate driver and make it actually replace the venerable
  ACPI cpufreq driver on the supported systems by default.

  Specifics:

   - Revert a recent schedutil cpufreq governor change that introduced a
     performace regression on Pixel 6 (Sam Wu)

   - Fix amd-pstate driver initialization after running the kernel via
     kexec (Wyes Karny)

   - Turn amd-pstate into a built-in driver which allows it to take
     precedence over acpi-cpufreq by default on supported systems and
     amend it with a mechanism to disable this behavior (Perry Yuan)

   - Update amd-pstate documentation in accordance with the other
     changes made to it (Perry Yuan)"

* tag 'pm-6.1-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
  Documentation: add amd-pstate kernel command line options
  Documentation: amd-pstate: add driver working mode introduction
  cpufreq: amd-pstate: add amd-pstate driver parameter for mode selection
  cpufreq: amd-pstate: change amd-pstate driver to be built-in type
  cpufreq: amd-pstate: cpufreq: amd-pstate: reset MSR_AMD_PERF_CTL register at init
  Revert "cpufreq: schedutil: Move max CPU capacity to sugov_policy"

Pull hotfixes from Andrew Morton:
 "24 MM and non-MM hotfixes. 8 marked cc:stable and 16 for post-6.0
  issues.

  There have been a lot of hotfixes this cycle, and this is quite a
  large batch given how far we are into the -rc cycle. Presumably a
  reflection of the unusually large amount of MM material which went
  into 6.1-rc1"

* tag 'mm-hotfixes-stable-2022-11-24' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (24 commits)
  test_kprobes: fix implicit declaration error of test_kprobes
  nilfs2: fix nilfs_sufile_mark_dirty() not set segment usage as dirty
  mm/cgroup/reclaim: fix dirty pages throttling on cgroup v1
  mm: fix unexpected changes to {failslab|fail_page_alloc}.attr
  swapfile: fix soft lockup in scan_swap_map_slots
  hugetlb: fix __prep_compound_gigantic_page page flag setting
  kfence: fix stack trace pruning
  proc/meminfo: fix spacing in SecPageTables
  mm: multi-gen LRU: retry folios written back while isolated
  mailmap: update email address for Satya Priya
  mm/migrate_device: return number of migrating pages in args->cpages
  kbuild: fix -Wimplicit-function-declaration in license_is_gpl_compatible
  MAINTAINERS: update Alex Hung's email address
  mailmap: update Alex Hung's email address
  mm: mmap: fix documentation for vma_mas_szero
  mm/damon/sysfs-schemes: skip stats update if the scheme directory is removed
  mm/memory: return vm_fault_t result from migrate_to_ram() callback
  mm: correctly charge compressed memory to its memcg
  ipc/shm: call underlying open/close vm_ops
  gcov: clang: fix the buffer overflow issue
  ...