Pull bpf updates from Alexei Starovoitov:
 "Major changes:

   - Recover from BPF arena page faults using a scratch page and add
     ptep_try_set() for lockless empty-slot installs on x86 and arm64.

     This allows BPF kfuncs to access arena pointers directly.

     The 'arena_direct_access' stable branch was created for this work
     and was pulled into sched-ext and bpf-next trees (Tejun Heo, Kumar
     Kartikeya Dwivedi)

   - Lift old restriction and support 6+ arguments in BPF programs and
     kfuncs on x86 and arm64 (Yonghong Song, Puranjay Mohan)

  Other features and fixes:

   - Add 24-bit BTF vlen and reclaim unused bits in the BTF UAPI to ease
     addition of new BTF kinds (Alan Maguire)

   - Raise the maximum BPF call chain depth from 8 to 16 frames (Alexei
     Starovoitov)

   - Refactor object relationship tracking in the verifier and fix a
     dynptr use-after-free bug (Amery Hung)

   - Harden the signed program loader and reject exclusive maps as inner
     maps (Daniel Borkmann)

   - Replace the verifier min/max bounds fields with a circular number
     (cnum) representation and improve 32->64 bit range refinements
     (Eduard Zingerman)

   - Introduce the arena library and runtime (libarena) with a buddy
     allocator, rbtree and SPMC queue data structures, ASAN support and
     a parallel test harness. Allow subprograms to return arena pointers
     and switch to a BTF type-tag based __arena annotation (Emil
     Tsalapatis)

   - Cache build IDs in the sleepable stackmap path and avoid faultable
     build ID reads under mm locks (Ihor Solodrai)

   - Introduce the tracing_multi link to attach a single BPF program to
     many kernel functions at once. Allow specifying the uprobe_multi
     target via FD (Jiri Olsa)

   - Extend the bpf_list family of kfuncs with bpf_list_add/del(), and
     bpf_list_is_first/is_last/empty() (Kaitao Cheng)

   - Extend the BPF syscall with common attributes support for
     prog_load, btf_load and map_create (Leon Hwang)

   - Wrap rhashtable as BPF map (Mykyta Yatsenko, Herbert Xu)

   - Add sleepable support for tracepoint programs and fix deadlocks in
     LRU map due to NMI reentry (Mykyta Yatsenko)

   - Fix OOB access in bpf_flow_keys, fix nullness analysis of inner
     arrays, enforce write checks for global subprograms (Nuoqi Gui)

   - Report the maximum combined stack depth and print a breakdown of
     instructions processed per subprogram (Paul Chaignon)

   - Add an XDP load-balancer benchmark and arm64 JIT support for stack
     arguments (Puranjay Mohan)

   - Add kfuncs to traverse over wakeup_sources (Samuel Wu)

   - Allow sleepable BPF programs to use LPM trie maps directly (Vlad
     Poenaru)

   - Many more fixes and cleanups across the verifier, BTF, sockmap,
     devmap, bpffs, security hooks, s390/riscv/loongarch JITs,
     rqspinlock, libbpf, bpftool, selftests"

* tag 'bpf-next-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next: (336 commits)
  selftests/bpf: Work around llvm stack overflow in crypto progs
  selftests/bpf: add test for bpf_msg_pop_data() overflow
  bpf, sockmap: fix integer overflow in bpf_msg_pop_data() bounds check
  sockmap: Fix use-after-free in udp_bpf_recvmsg()
  bpf, sockmap: keep sk_msg copy state in sync
  bpf, sockmap: Fix wrong rsge offset in bpf_msg_push_data()
  bpf, sockmap: reject overflowing copy + len in bpf_msg_push_data()
  selftsets/bpf: Retry map update on helper_fill_hashmap()
  selftests/bpf: Add test for sleepable lsm_cgroup rejection
  selftests/bpf: Add test to verify the fix for bpf_setsockopt() helper
  bpf: Fix bpf_get/setsockopt to tos for ipv4-mapped ipv6 socket
  selftests/bpf: Avoid static LLVM linking for cross builds
  selftests/bpf: Use common CFLAGS for urandom_read
  selftests/bpf: Initialize operation name before use
  tools/bpf: build: Append extra cflags
  libbpf: Initialize CFLAGS before including Makefile.include
  bpftool: Append extra host flags
  bpftool: Avoid adding EXTRA_CFLAGS to HOST_CFLAGS
  bpftool: Pass host flags to bootstrap libbpf
  selftests/bpf: correct CONFIG_PPC64 macro name in comment
  ...

Pull simple_xattr updates from Christian Brauner:
 "This reworks the simple xattr api to make it more efficient and easier
  to use for all consumers.

  The simple_xattr hash table moves from the inode into a per-superblock
  cache, removing the per-inode overhead for the common case of few or
  no xattrs. The interface now passes struct simple_xattrs ** so lazy
  allocation is handled internally instead of by every caller, kernfs
  xattr operations on kernfs nodes shared between multiple superblocks
  are properly serialized, and tmpfs constructs "security.foo" xattr
  names with kasprintf() instead of kmalloc() plus two memcpy()s.

  A follow-up fix links kernfs nodes to their parent before the LSM init
  hook runs: with the per-sb cache kernfs_xattr_set() computes the cache
  via kernfs_root(kn), which faulted on a freshly allocated node when
  selinux_kernfs_init_security() called into it - reproducible as a NULL
  pointer dereference on the first cgroup mkdir on SELinux-enabled
  systems.

  On top of this bpffs gains support for trusted.* and security.* xattrs
  so that user space and BPF LSM programs can attach metadata - for
  example a content hash or a security label - to pinned objects and
  directories and inspect it uniformly like on other filesystems. The
  store is in-memory and non-persistent, living only for the lifetime of
  the mount like everything else in bpffs"

* tag 'vfs-7.2-rc1.xattr' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs:
  bpf: Add simple xattr support to bpffs
  kernfs: link kn to its parent before the LSM init hook
  simpe_xattr: use per-sb cache
  simple_xattr: change interface to pass struct simple_xattrs **
  tmpfs: simplify constructing "security.foo" xattr names
  kernfs: fix xattr race condition with multiple superblocks

Map update and delete paths currently call bpf_obj_free_fields() when a
value is being replaced or recycled. That makes field destruction depend
on the context of the update/delete operation. For tracing programs this
can include NMI context, where referenced kptr destructors, uptr
unpinning, and graph root destruction are not generally safe.

Introduce bpf_obj_cancel_fields() for the reusable-value path. It only
performs NMI-safe cleanup for timer, workqueue, and task_work fields.
Fields that need full destruction are left attached to the recycled value
and are destroyed by the final cleanup path instead.

Switch array and hashtab update/delete/recycle paths to this cancel
helper. Keep bpf_obj_free_fields() for final map destruction and for
bpf_mem_alloc destructors. Preallocated hashtabs do not have allocator
destructors, so teardown continues to walk the normal and extra elements
and fully destroy their fields.

This deliberately relaxes the eager-free semantics of map update/delete
for special fields. Programs that relied on a recycled map slot becoming
empty immediately after update/delete were relying on behavior that
cannot be implemented safely from every BPF execution context without
offloading arbitrary destructors.

There is a chance this change breaks programs making assumptions
regarding the eager freeing of fields. If so, we can relax semantics to
cancellation only when irqs_disabled() is true in the future. However,
theoretically, map values that get reused eagerly already have weaker
guarantees as parallel users can recreate freed fields before the new
element becomes visible again.

Fixes: 14a324f6a67e ("bpf: Wire up freeing of referenced kptr")
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260609202548.3571690-3-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

bpf_obj_drop() runs bpf_obj_free_fields() synchronously for
program-allocated objects. When such an object contains NMI unsafe
fields, tracing programs that can run from arbitrary instrumented
context can reach that destruction from unsafe contexts, including NMI.

NMI is likely one instance of this problem, and other instances would
include possible unsafe reentrancy. Deferring bpf_obj_drop() is not
appealing either: it would add delayed-free machinery to a release
operation that otherwise has straightforward synchronous ownership
semantics.

Reject bpf_obj_drop() and bpf_percpu_obj_drop() from tracing programs
that may run from unsafe contexts unless every field in the object's BTF
record is explicitly NMI safe. Do not reject sleepable
BPF_PROG_TYPE_TRACING programs, since they are not the arbitrary/NMI
contexts that motivate the restriction.

Note that while bpf_rb_root and bpf_list_head would be NMI safe on their
own to free, the objects recursively held by them may not be; be
conservative and just mark them as not NMI safe for now.

Use a whitelist for the NMI-safe field set instead of listing only known
NMI unsafe fields. Locks, async fields, unreferenced kptrs, and
refcounts are known to be NMI safe because their destruction is either a
no-op, simple state reset, or async cancellation. Referenced kptrs,
percpu referenced kptrs, uptrs, graph roots, graph nodes, and any future
field type are rejected until audited for arbitrary tracing and NMI
contexts. This is less susceptible to future changes in fields that were
previously safe by exclusion, and to new fields being added without
updating this check.

Convert the existing recursive local-object drop success case to a
syscall program in the same commit, since this verifier change makes the
old tracing program form invalid. The test still exercises
bpf_obj_drop() releasing a referenced task kptr from a safe program
type.

Fixes: ac9f06050a35 ("bpf: Introduce bpf_obj_drop")
Signed-off-by: Justin Suess <utilityemal77@gmail.com>
Co-developed-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260609202548.3571690-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding support to use session attachment with tracing_multi link.

Adding new BPF_TRACE_FSESSION_MULTI program attach type, that follows
the BPF_TRACE_FSESSION behaviour but on the tracing_multi link.

Such program is called on entry and exit of the attached function
and allows to pass cookie value from entry to exit execution.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-16-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Add support to specify cookies for tracing_multi link.

Cookies are provided in array where each value is paired with provided
BTF ID value with the same array index.

Such cookie can be retrieved by bpf program with bpf_get_attach_cookie
helper call.

We need to sort cookies array together with ids array in check_dup_ids,
to keep the id->cookie relation.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-15-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding bpf_trampoline_multi_attach/detach functions that allows to
attach/detach tracing program to multiple functions/trampolines.

The attachment is defined with bpf_program and array of BTF ids of
functions to attach the bpf program to.

Adding bpf_tracing_multi_link object that holds all the attached
trampolines and is initialized in attach and used in detach.

The attachment allocates or uses currently existing trampoline
for each function to attach and links it with the bpf program.

The attach works as follows:
- we get all the needed trampolines
- lock them and add the bpf program to each (__bpf_trampoline_link_prog)
- the trampoline_multi_ops passed in __bpf_trampoline_link_prog gathers
  ftrace_hash (ip -> trampoline) objects
- we call update_ftrace_direct_add/mod to update needed locations
- we unlock all the trampolines

The detach works as follows:
- we lock all the needed trampolines
- remove the program from each (__bpf_trampoline_unlink_prog)
- the trampoline_multi_ops passed in __bpf_trampoline_unlink_prog gathers
  ftrace_hash (ip -> trampoline) objects
- we call update_ftrace_direct_del/mod to update needed locations
- we unlock and put all the trampolines

We store the old image/flags in the trampoline before the update
and use it in case we need to rollback the attachment.

We keep the ftrace_hash objects allocated during attach in the link
so they can be used for detach as well.

Adding trampoline_(un)lock_all functions to (un)lock all trampolines
to gate the tracing_multi attachment.

Note this is supported only for archs (x86_64) with ftrace direct and
have single ops support.

  CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS &&
  CONFIG_HAVE_SINGLE_FTRACE_DIRECT_OPS

It also needs CONFIG_BPF_SYSCALL enabled.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-13-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding new program attach types multi tracing attachment:
  BPF_TRACE_FENTRY_MULTI
  BPF_TRACE_FEXIT_MULTI

and their base support in verifier code.

Programs with such attach type will use specific link attachment
interface coming in following changes.

This was suggested by Andrii some (long) time ago and turned out
to be easier than having special program flag for that.

Bpf programs with such types have 'bpf_multi_func' function set as
their attach_btf_id and keep module reference when it's specified
by attach_prog_fd.

They are also accepted as sleepable programs during verification,
and the real validation for specific BTF_IDs/functions will happen
during the multi link attachment in following changes.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-11-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Now that we split trampoline attachment object (bpf_tramp_node) from
the link object (bpf_tramp_link) we can use bpf_tramp_node as fsession's
fexit attachment object and get rid of the bpf_fsession_link object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-10-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Adding struct bpf_tramp_node to decouple the link out of the trampoline
attachment info.

At the moment the object for attaching bpf program to the trampoline is
'struct bpf_tramp_link':

  struct bpf_tramp_link {
       struct bpf_link link;
       struct hlist_node tramp_hlist;
       u64 cookie;
  }

The link holds the bpf_prog pointer and forces one link - one program
binding logic. In following changes we want to attach program to multiple
trampolines but we want to keep just one bpf_link object.

Splitting struct bpf_tramp_link into:

  struct bpf_tramp_link {
       struct bpf_link link;
       struct bpf_tramp_node node;
  };

  struct bpf_tramp_node {
       struct bpf_link *link;
       struct hlist_node tramp_hlist;
       u64 cookie;
  };

The 'struct bpf_tramp_link' defines standard single trampoline link
and 'struct bpf_tramp_node' is the attachment trampoline object with
pointer to the bpf_link object.

This will allow us to define link for multiple trampolines, like:

  struct bpf_tracing_multi_link {
       struct bpf_link link;
       ...
       int nodes_cnt;
       struct bpf_tracing_multi_node nodes[] __counted_by(nodes_cnt);
  };

Cc: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260606123955.345967-9-jolsa@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>