Dave Marchevsky says:

====================

This series adds support for refcounted local kptrs to the verifier. A local
kptr is 'refcounted' if its type contains a struct bpf_refcount field:

  struct refcounted_node {
    long data;
    struct bpf_list_node ll;
    struct bpf_refcount ref;
  };

bpf_refcount is used to implement shared ownership for local kptrs.

Motivating usecase
==================

If a struct has two collection node fields, e.g.:

  struct node {
    long key;
    long val;
    struct bpf_rb_node rb;
    struct bpf_list_node ll;
  };

It's not currently possible to add a node to both the list and rbtree:

  long bpf_prog(void *ctx)
  {
    struct node *n = bpf_obj_new(typeof(*n));
    if (!n) { /* ... */ }

    bpf_spin_lock(&lock);

    bpf_list_push_back(&head, &n->ll);
    bpf_rbtree_add(&root, &n->rb, less); /* Assume a resonable less() */
    bpf_spin_unlock(&lock);
  }

The above program will fail verification due to current owning / non-owning ref
logic: after bpf_list_push_back, n is a non-owning reference and thus cannot be
passed to bpf_rbtree_add. The only way to get an owning reference for the node
that was added is to bpf_list_pop_{front,back} it.

More generally, verifier ownership semantics expect that a node has one
owner (program, collection, or stashed in map) with exclusive ownership
of the node's lifetime. The owner free's the node's underlying memory when it
itself goes away.

Without a shared ownership concept it's impossible to express many real-world
usecases such that they pass verification.

Semantic Changes
================

Before this series, the verifier could make this statement: "whoever has the
owning reference has exclusive ownership of the referent's lifetime". As
demonstrated in the previous section, this implies that a BPF program can't
have an owning reference to some node if that node is in a collection. If
such a state were possible, the node would have multiple owners, each thinking
they have exclusive ownership. In order to support shared ownership it's
necessary to modify the exclusive ownership semantic.

After this series' changes, an owning reference has ownership of the referent's
lifetime, but it's not necessarily exclusive. The referent's underlying memory
is guaranteed to be valid (i.e. not free'd) until the reference is dropped or
used for collection insert.

This change doesn't affect UX of owning or non-owning references much:

  * insert kfuncs (bpf_rbtree_add, bpf_list_push_{front,back}) still require
    an owning reference arg, as ownership still must be passed to the
    collection in a shared-ownership world.

  * non-owning references still refer to valid memory without claiming
    any ownership.

One important conclusion that followed from "exclusive ownership" statement
is no longer valid, though. In exclusive-ownership world, if a BPF prog has
an owning reference to a node, the verifier can conclude that no collection has
ownership of it. This conclusion was used to avoid runtime checking in the
implementations of insert and remove operations (""has the node already been
{inserted, removed}?").

In a shared-ownership world the aforementioned conclusion is no longer valid,
which necessitates doing runtime checking in insert and remove operation
kfuncs, and those functions possibly failing to insert or remove anything.

Luckily the verifier changes necessary to go from exclusive to shared ownership
were fairly minimal. Patches in this series which do change verifier semantics
generally have some summary dedicated to explaining why certain usecases
Just Work for shared ownership without verifier changes.

Implementation
==============

The changes in this series can be categorized as follows:

  * struct bpf_refcount opaque field + plumbing
  * support for refcounted kptrs in bpf_obj_new and bpf_obj_drop
  * bpf_refcount_acquire kfunc
    * enables shared ownershp by bumping refcount + acquiring owning ref
  * support for possibly-failing collection insertion and removal
    * insertion changes are more complex

If a patch's changes have some nuance to their effect - or lack of effect - on
verifier behavior, the patch summary talks about it at length.

Patch contents:
  * Patch 1 removes btf_field_offs struct
  * Patch 2 adds struct bpf_refcount and associated plumbing
  * Patch 3 modifies semantics of bpf_obj_drop and bpf_obj_new to handle
    refcounted kptrs
  * Patch 4 adds bpf_refcount_acquire
  * Patches 5-7 add support for possibly-failing collection insert and remove
  * Patch 8 centralizes constructor-like functionality for local kptr types
  * Patch 9 adds tests for new functionality

base-commit: 4a1e885c

Changelog:

v1 -> v2: lore.kernel.org/bpf/20230410190753.2012798-1-davemarchevsky@fb.com

Patch #s used below refer to the patch's position in v1 unless otherwise
specified.

  * General
    * Rebase onto latest bpf-next (base-commit updated above)

  * Patch 4 - "bpf: Add bpf_refcount_acquire kfunc"
    * Fix typo in summary (Alexei)
  * Patch 7 - "Migrate bpf_rbtree_remove to possibly fail"
    * Modify a paragraph in patch summary to more clearly state that only
      bpf_rbtree_remove's non-owning ref clobbering behavior is changed by the
      patch (Alexei)
    * refcount_off == -1 -> refcount_off < 0  in "node type w/ both list
      and rb_node fields" check, since any negative value means "no
      bpf_refcount field found", and furthermore refcount_off is never
      explicitly set to -1, but rather -EINVAL. (Alexei)
    * Instead of just changing "btf: list_node and rb_node in same struct" test
      expectation to pass instead of fail, do some refactoring to test both
      "list_node, rb_node, and bpf_refcount" (success) and "list_node, rb_node,
      _no_ bpf_refcount" (failure) cases. This ensures that logic change in
      previous bullet point is correct.
      * v1's "btf: list_node and rb_node in same struct" test changes didn't
        add bpf_refcount, so the fact that btf load succeeded w/ list and
        rb_nodes but no bpf_refcount field is further proof that this logic
        was incorrect in v1.
  * Patch 8 - "bpf: Centralize btf_field-specific initialization logic"
    * Instead of doing __init_field_infer_size in kfuncs when taking
      bpf_list_head type input which might've been 0-initialized in map, go
      back to simple oneliner initialization. Add short comment explaining why
      this is necessary. (Alexei)
  * Patch 9 - "selftests/bpf: Add refcounted_kptr tests"
    * Don't __always_inline helper fns in progs/refcounted_kptr.c (Alexei)
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Test refcounted local kptr functionality added in previous patches in
the series.

Usecases which pass verification:

* Add refcounted local kptr to both tree and list. Then, read and -
  possibly, depending on test variant - delete from tree, then list.
  * Also test doing read-and-maybe-delete in opposite order
* Stash a refcounted local kptr in a map_value, then add it to a
  rbtree. Read from both, possibly deleting after tree read.
* Add refcounted local kptr to both tree and list. Then, try reading and
  deleting twice from one of the collections.
* bpf_refcount_acquire of just-added non-owning ref should work, as
  should bpf_refcount_acquire of owning ref just out of bpf_obj_new

Usecases which fail verification:

* The simple successful bpf_refcount_acquire cases from above should
  both fail to verify if the newly-acquired owning ref is not dropped
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-10-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

All btf_fields in an object are 0-initialized by memset in
bpf_obj_init. This might not be a valid initial state for some field
types, in which case kfuncs that use the type will properly initialize
their input if it's been 0-initialized. Some BPF graph collection types
and kfuncs do this: bpf_list_{head,node} and bpf_rb_node.

An earlier patch in this series added the bpf_refcount field, for which
the 0 state indicates that the refcounted object should be free'd.
bpf_obj_init treats this field specially, setting refcount to 1 instead
of relying on scattered "refcount is 0? Must have just been initialized,
let's set to 1" logic in kfuncs.

This patch extends this treatment to list and rbtree field types,
allowing most scattered initialization logic in kfuncs to be removed.

Note that bpf_{list_head,rb_root} may be inside a BPF map, in which case
they'll be 0-initialized without passing through the newly-added logic,
so scattered initialization logic must remain for these collection root
types.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-9-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

This patch modifies bpf_rbtree_remove to account for possible failure
due to the input rb_node already not being in any collection.
The function can now return NULL, and does when the aforementioned
scenario occurs. As before, on successful removal an owning reference to
the removed node is returned.

Adding KF_RET_NULL to bpf_rbtree_remove's kfunc flags - now KF_RET_NULL |
KF_ACQUIRE - provides the desired verifier semantics:

  * retval must be checked for NULL before use
  * if NULL, retval's ref_obj_id is released
  * retval is a "maybe acquired" owning ref, not a non-owning ref,
    so it will live past end of critical section (bpf_spin_unlock), and
    thus can be checked for NULL after the end of the CS

BPF programs must add checks
============================

This does change bpf_rbtree_remove's verifier behavior. BPF program
writers will need to add NULL checks to their programs, but the
resulting UX looks natural:

  bpf_spin_lock(&glock);

  n = bpf_rbtree_first(&ghead);
  if (!n) { /* ... */}
  res = bpf_rbtree_remove(&ghead, &n->node);

  bpf_spin_unlock(&glock);

  if (!res)  /* Newly-added check after this patch */
    return 1;

  n = container_of(res, /* ... */);
  /* Do something else with n */
  bpf_obj_drop(n);
  return 0;

The "if (!res)" check above is the only addition necessary for the above
program to pass verification after this patch.

bpf_rbtree_remove no longer clobbers non-owning refs
====================================================

An issue arises when bpf_rbtree_remove fails, though. Consider this
example:

  struct node_data {
    long key;
    struct bpf_list_node l;
    struct bpf_rb_node r;
    struct bpf_refcount ref;
  };

  long failed_sum;

  void bpf_prog()
  {
    struct node_data *n = bpf_obj_new(/* ... */);
    struct bpf_rb_node *res;
    n->key = 10;

    bpf_spin_lock(&glock);

    bpf_list_push_back(&some_list, &n->l); /* n is now a non-owning ref */
    res = bpf_rbtree_remove(&some_tree, &n->r, /* ... */);
    if (!res)
      failed_sum += n->key;  /* not possible */

    bpf_spin_unlock(&glock);
    /* if (res) { do something useful and drop } ... */
  }

The bpf_rbtree_remove in this example will always fail. Similarly to
bpf_spin_unlock, bpf_rbtree_remove is a non-owning reference
invalidation point. The verifier clobbers all non-owning refs after a
bpf_rbtree_remove call, so the "failed_sum += n->key" line will fail
verification, and in fact there's no good way to get information about
the node which failed to add after the invalidation. This patch removes
non-owning reference invalidation from bpf_rbtree_remove to allow the
above usecase to pass verification. The logic for why this is now
possible is as follows:

Before this series, bpf_rbtree_add couldn't fail and thus assumed that
its input, a non-owning reference, was in the tree. But it's easy to
construct an example where two non-owning references pointing to the same
underlying memory are acquired and passed to rbtree_remove one after
another (see rbtree_api_release_aliasing in
selftests/bpf/progs/rbtree_fail.c).

So it was necessary to clobber non-owning refs to prevent this
case and, more generally, to enforce "non-owning ref is definitely
in some collection" invariant. This series removes that invariant and
the failure / runtime checking added in this patch provide a clean way
to deal with the aliasing issue - just fail to remove.

Because the aliasing issue prevented by clobbering non-owning refs is no
longer an issue, this patch removes the invalidate_non_owning_refs
call from verifier handling of bpf_rbtree_remove. Note that
bpf_spin_unlock - the other caller of invalidate_non_owning_refs -
clobbers non-owning refs for a different reason, so its clobbering
behavior remains unchanged.

No BPF program changes are necessary for programs to remain valid as a
result of this clobbering change. A valid program before this patch
passed verification with its non-owning refs having shorter (or equal)
lifetimes due to more aggressive clobbering.

Also, update existing tests to check bpf_rbtree_remove retval for NULL
where necessary, and move rbtree_api_release_aliasing from
progs/rbtree_fail.c to progs/rbtree.c since it's now expected to pass
verification.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-8-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

The linked_list tests use macros and function pointers to reduce code
duplication. Earlier in the series, bpf_list_push_{front,back} were
modified to be macros, expanding to invoke actual kfuncs
bpf_list_push_{front,back}_impl. Due to this change, a code snippet
like:

  void (*p)(void *, void *) = (void *)&bpf_list_##op;
  p(hexpr, nexpr);

meant to do bpf_list_push_{front,back}(hexpr, nexpr), will no longer
work as it's no longer valid to do &bpf_list_push_{front,back} since
they're no longer functions.

This patch fixes issues of this type, along with two other minor changes
- one improvement and one fix - both related to the node argument to
list_push_{front,back}.

  * The fix: migration of list_push tests away from (void *, void *)
    func ptr uncovered that some tests were incorrectly passing pointer
    to node, not pointer to struct bpf_list_node within the node. This
    patch fixes such issues (CHECK(..., f) -> CHECK(..., &f->node))

  * The improvement: In linked_list tests, the struct foo type has two
    list_node fields: node and node2, at byte offsets 0 and 40 within
    the struct, respectively. Currently node is used in ~all tests
    involving struct foo and lists. The verifier needs to do some work
    to account for the offset of bpf_list_node within the node type, so
    using node2 instead of node exercises that logic more in the tests.
    This patch migrates linked_list tests to use node2 instead of node.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-7-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Consider this code snippet:

  struct node {
    long key;
    bpf_list_node l;
    bpf_rb_node r;
    bpf_refcount ref;
  }

  int some_bpf_prog(void *ctx)
  {
    struct node *n = bpf_obj_new(/*...*/), *m;

    bpf_spin_lock(&glock);

    bpf_rbtree_add(&some_tree, &n->r, /* ... */);
    m = bpf_refcount_acquire(n);
    bpf_rbtree_add(&other_tree, &m->r, /* ... */);

    bpf_spin_unlock(&glock);

    /* ... */
  }

After bpf_refcount_acquire, n and m point to the same underlying memory,
and that node's bpf_rb_node field is being used by the some_tree insert,
so overwriting it as a result of the second insert is an error. In order
to properly support refcounted nodes, the rbtree and list insert
functions must be allowed to fail. This patch adds such support.

The kfuncs bpf_rbtree_add, bpf_list_push_{front,back} are modified to
return an int indicating success/failure, with 0 -> success, nonzero ->
failure.

bpf_obj_drop on failure
=======================

Currently the only reason an insert can fail is the example above: the
bpf_{list,rb}_node is already in use. When such a failure occurs, the
insert kfuncs will bpf_obj_drop the input node. This allows the insert
operations to logically fail without changing their verifier owning ref
behavior, namely the unconditional release_reference of the input
owning ref.

With insert that always succeeds, ownership of the node is always passed
to the collection, since the node always ends up in the collection.

With a possibly-failed insert w/ bpf_obj_drop, ownership of the node
is always passed either to the collection (success), or to bpf_obj_drop
(failure). Regardless, it's correct to continue unconditionally
releasing the input owning ref, as something is always taking ownership
from the calling program on insert.

Keeping owning ref behavior unchanged results in a nice default UX for
insert functions that can fail. If the program's reaction to a failed
insert is "fine, just get rid of this owning ref for me and let me go
on with my business", then there's no reason to check for failure since
that's default behavior. e.g.:

  long important_failures = 0;

  int some_bpf_prog(void *ctx)
  {
    struct node *n, *m, *o; /* all bpf_obj_new'd */

    bpf_spin_lock(&glock);
    bpf_rbtree_add(&some_tree, &n->node, /* ... */);
    bpf_rbtree_add(&some_tree, &m->node, /* ... */);
    if (bpf_rbtree_add(&some_tree, &o->node, /* ... */)) {
      important_failures++;
    }
    bpf_spin_unlock(&glock);
  }

If we instead chose to pass ownership back to the program on failed
insert - by returning NULL on success or an owning ref on failure -
programs would always have to do something with the returned ref on
failure. The most likely action is probably "I'll just get rid of this
owning ref and go about my business", which ideally would look like:

  if (n = bpf_rbtree_add(&some_tree, &n->node, /* ... */))
    bpf_obj_drop(n);

But bpf_obj_drop isn't allowed in a critical section and inserts must
occur within one, so in reality error handling would become a
hard-to-parse mess.

For refcounted nodes, we can replicate the "pass ownership back to
program on failure" logic with this patch's semantics, albeit in an ugly
way:

  struct node *n = bpf_obj_new(/* ... */), *m;

  bpf_spin_lock(&glock);

  m = bpf_refcount_acquire(n);
  if (bpf_rbtree_add(&some_tree, &n->node, /* ... */)) {
    /* Do something with m */
  }

  bpf_spin_unlock(&glock);
  bpf_obj_drop(m);

bpf_refcount_acquire is used to simulate "return owning ref on failure".
This should be an uncommon occurrence, though.

Addition of two verifier-fixup'd args to collection inserts
===========================================================

The actual bpf_obj_drop kfunc is
bpf_obj_drop_impl(void *, struct btf_struct_meta *), with bpf_obj_drop
macro populating the second arg with 0 and the verifier later filling in
the arg during insn fixup.

Because bpf_rbtree_add and bpf_list_push_{front,back} now might do
bpf_obj_drop, these kfuncs need a btf_struct_meta parameter that can be
passed to bpf_obj_drop_impl.

Similarly, because the 'node' param to those insert functions is the
bpf_{list,rb}_node within the node type, and bpf_obj_drop expects a
pointer to the beginning of the node, the insert functions need to be
able to find the beginning of the node struct. A second
verifier-populated param is necessary: the offset of {list,rb}_node within the
node type.

These two new params allow the insert kfuncs to correctly call
__bpf_obj_drop_impl:

  beginning_of_node = bpf_rb_node_ptr - offset
  if (already_inserted)
    __bpf_obj_drop_impl(beginning_of_node, btf_struct_meta->record);

Similarly to other kfuncs with "hidden" verifier-populated params, the
insert functions are renamed with _impl prefix and a macro is provided
for common usage. For example, bpf_rbtree_add kfunc is now
bpf_rbtree_add_impl and bpf_rbtree_add is now a macro which sets
"hidden" args to 0.

Due to the two new args BPF progs will need to be recompiled to work
with the new _impl kfuncs.

This patch also rewrites the "hidden argument" explanation to more
directly say why the BPF program writer doesn't need to populate the
arguments with anything meaningful.

How does this new logic affect non-owning references?
=====================================================

Currently, non-owning refs are valid until the end of the critical
section in which they're created. We can make this guarantee because, if
a non-owning ref exists, the referent was added to some collection. The
collection will drop() its nodes when it goes away, but it can't go away
while our program is accessing it, so that's not a problem. If the
referent is removed from the collection in the same CS that it was added
in, it can't be bpf_obj_drop'd until after CS end. Those are the only
two ways to free the referent's memory and neither can happen until
after the non-owning ref's lifetime ends.

On first glance, having these collection insert functions potentially
bpf_obj_drop their input seems like it breaks the "can't be
bpf_obj_drop'd until after CS end" line of reasoning. But we care about
the memory not being _freed_ until end of CS end, and a previous patch
in the series modified bpf_obj_drop such that it doesn't free refcounted
nodes until refcount == 0. So the statement can be more accurately
rewritten as "can't be free'd until after CS end".

We can prove that this rewritten statement holds for any non-owning
reference produced by collection insert functions:

* If the input to the insert function is _not_ refcounted
  * We have an owning reference to the input, and can conclude it isn't
    in any collection
    * Inserting a node in a collection turns owning refs into
      non-owning, and since our input type isn't refcounted, there's no
      way to obtain additional owning refs to the same underlying
      memory
  * Because our node isn't in any collection, the insert operation
    cannot fail, so bpf_obj_drop will not execute
  * If bpf_obj_drop is guaranteed not to execute, there's no risk of
    memory being free'd

* Otherwise, the input to the insert function is refcounted
  * If the insert operation fails due to the node's list_head or rb_root
    already being in some collection, there was some previous successful
    insert which passed refcount to the collection
  * We have an owning reference to the input, it must have been
    acquired via bpf_refcount_acquire, which bumped the refcount
  * refcount must be >= 2 since there's a valid owning reference and the
    node is already in a collection
  * Insert triggering bpf_obj_drop will decr refcount to >= 1, never
    resulting in a free

So although we may do bpf_obj_drop during the critical section, this
will never result in memory being free'd, and no changes to non-owning
ref logic are needed in this patch.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-6-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Currently, BPF programs can interact with the lifetime of refcounted
local kptrs in the following ways:

  bpf_obj_new  - Initialize refcount to 1 as part of new object creation
  bpf_obj_drop - Decrement refcount and free object if it's 0
  collection add - Pass ownership to the collection. No change to
                   refcount but collection is responsible for
		   bpf_obj_dropping it

In order to be able to add a refcounted local kptr to multiple
collections we need to be able to increment the refcount and acquire a
new owning reference. This patch adds a kfunc, bpf_refcount_acquire,
implementing such an operation.

bpf_refcount_acquire takes a refcounted local kptr and returns a new
owning reference to the same underlying memory as the input. The input
can be either owning or non-owning. To reinforce why this is safe,
consider the following code snippets:

  struct node *n = bpf_obj_new(typeof(*n)); // A
  struct node *m = bpf_refcount_acquire(n); // B

In the above snippet, n will be alive with refcount=1 after (A), and
since nothing changes that state before (B), it's obviously safe. If
n is instead added to some rbtree, we can still safely refcount_acquire
it:

  struct node *n = bpf_obj_new(typeof(*n));
  struct node *m;

  bpf_spin_lock(&glock);
  bpf_rbtree_add(&groot, &n->node, less);   // A
  m = bpf_refcount_acquire(n);              // B
  bpf_spin_unlock(&glock);

In the above snippet, after (A) n is a non-owning reference, and after
(B) m is an owning reference pointing to the same memory as n. Although
n has no ownership of that memory's lifetime, it's guaranteed to be
alive until the end of the critical section, and n would be clobbered if
we were past the end of the critical section, so it's safe to bump
refcount.

Implementation details:

* From verifier's perspective, bpf_refcount_acquire handling is similar
  to bpf_obj_new and bpf_obj_drop. Like the former, it returns a new
  owning reference matching input type, although like the latter, type
  can be inferred from concrete kptr input. Verifier changes in
  {check,fixup}_kfunc_call and check_kfunc_args are largely copied from
  aforementioned functions' verifier changes.

* An exception to the above is the new KF_ARG_PTR_TO_REFCOUNTED_KPTR
  arg, indicated by new "__refcounted_kptr" kfunc arg suffix. This is
  necessary in order to handle both owning and non-owning input without
  adding special-casing to "__alloc" arg handling. Also a convenient
  place to confirm that input type has bpf_refcount field.

* The implemented kfunc is actually bpf_refcount_acquire_impl, with
  'hidden' second arg that the verifier sets to the type's struct_meta
  in fixup_kfunc_call.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-5-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

A local kptr is considered 'refcounted' when it is of a type that has a
bpf_refcount field. When such a kptr is created, its refcount should be
initialized to 1; when destroyed, the object should be free'd only if a
refcount decr results in 0 refcount.

Existing logic always frees the underlying memory when destroying a
local kptr, and 0-initializes all btf_record fields. This patch adds
checks for "is local kptr refcounted?" and new logic for that case in
the appropriate places.

This patch focuses on changing existing semantics and thus conspicuously
does _not_ provide a way for BPF programs in increment refcount. That
follows later in the series.

__bpf_obj_drop_impl is modified to do the right thing when it sees a
refcounted type. Container types for graph nodes (list, tree, stashed in
map) are migrated to use __bpf_obj_drop_impl as a destructor for their
nodes instead of each having custom destruction code in their _free
paths. Now that "drop" isn't a synonym for "free" when the type is
refcounted it makes sense to centralize this logic.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-4-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

A 'struct bpf_refcount' is added to the set of opaque uapi/bpf.h types
meant for use in BPF programs. Similarly to other opaque types like
bpf_spin_lock and bpf_rbtree_node, the verifier needs to know where in
user-defined struct types a bpf_refcount can be located, so necessary
btf_record plumbing is added to enable this. bpf_refcount is sized to
hold a refcount_t.

Similarly to bpf_spin_lock, the offset of a bpf_refcount is cached in
btf_record as refcount_off in addition to being in the field array.
Caching refcount_off makes sense for this field because further patches
in the series will modify functions that take local kptrs (e.g.
bpf_obj_drop) to change their behavior if the type they're operating on
is refcounted. So enabling fast "is this type refcounted?" checks is
desirable.

No such verifier behavior changes are introduced in this patch, just
logic to recognize 'struct bpf_refcount' in btf_record.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-3-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

The btf_field_offs struct contains (offset, size) for btf_record fields,
sorted by offset. btf_field_offs is always used in conjunction with
btf_record, which has btf_field 'fields' array with (offset, type), the
latter of which btf_field_offs' size is derived from via
btf_field_type_size.

This patch adds a size field to struct btf_field and sorts btf_record's
fields by offset, making it possible to get rid of btf_field_offs. Less
data duplication and less code complexity results.

Since btf_field_offs' lifetime closely followed the btf_record used to
populate it, most complexity wins are from removal of initialization
code like:

  if (btf_record_successfully_initialized) {
    foffs = btf_parse_field_offs(rec);
    if (IS_ERR_OR_NULL(foffs))
      // free the btf_record and return err
  }

Other changes in this patch are pretty mechanical:

  * foffs->field_off[i] -> rec->fields[i].offset
  * foffs->field_sz[i] -> rec->fields[i].size
  * Sort rec->fields in btf_parse_fields before returning
    * It's possible that this is necessary independently of other
      changes in this patch. btf_record_find in syscall.c expects
      btf_record's fields to be sorted by offset, yet there's no
      explicit sorting of them before this patch, record's fields are
      populated in the order they're read from BTF struct definition.
      BTF docs don't say anything about the sortedness of struct fields.
  * All functions taking struct btf_field_offs * input now instead take
    struct btf_record *. All callsites of these functions already have
    access to the correct btf_record.
Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
Link: https://lore.kernel.org/r/20230415201811.343116-2-davemarchevsky@fb.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Macro PAGE_OFFSET(0xffff880000000000) in sampleip_user.c is inaccurate,
for example, in aarch64 architecture, this value depends on the
CONFIG_ARM64_VA_BITS compilation configuration, this value defaults to 48,
the corresponding PAGE_OFFSET is 0xffff800000000000, if we use the value
defined in sampleip_user.c, then all KSYMs obtained by sampleip are (user)

Symbol error due to PAGE_OFFSET error:

    $ sudo ./sampleip 1
    Sampling at 99 Hertz for 1 seconds. Ctrl-C also ends.
    ADDR                KSYM                             COUNT
    0xffff80000810ceb8  (user)                           1
    0xffffb28ec880      (user)                           1
    0xffff8000080c82b8  (user)                           1
    0xffffb23fed24      (user)                           1
    0xffffb28944fc      (user)                           1
    0xffff8000084628bc  (user)                           1
    0xffffb2a935c0      (user)                           1
    0xffff80000844677c  (user)                           1
    0xffff80000857a3a4  (user)                           1
    ...

A few examples of addresses in the CONFIG_ARM64_VA_BITS=48 environment in
the aarch64 environment:

    $ sudo head /proc/kallsyms
    ffff8000080a0000 T _text
    ffff8000080b0000 t gic_handle_irq
    ffff8000080b0000 T _stext
    ffff8000080b0000 T __irqentry_text_start
    ffff8000080b00b0 t gic_handle_irq
    ffff8000080b0230 t gic_handle_irq
    ffff8000080b03b4 T __irqentry_text_end
    ffff8000080b03b8 T __softirqentry_text_start
    ffff8000080b03c0 T __do_softirq
    ffff8000080b0718 T __entry_text_start

We just need to replace the PAGE_OFFSET with the address _text in
/proc/kallsyms to solve this problem:

    $ sudo ./sampleip 1
    Sampling at 99 Hertz for 1 seconds. Ctrl-C also ends.
    ADDR                KSYM                             COUNT
    0xffffb2892ab0      (user)                           1
    0xffffb2b1edfc      (user)                           1
    0xffff800008462834  __arm64_sys_ppoll                1
    0xffff8000084b87f4  eventfd_read                     1
    0xffffb28e6788      (user)                           1
    0xffff8000081e96d8  rcu_all_qs                       1
    0xffffb2ada878      (user)                           1
    ...
Signed-off-by: Rong Tao <rongtao@cestc.cn>
Link: https://lore.kernel.org/r/tencent_A0E82E0BEE925285F8156D540731DF805F05@qq.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

test_ksyms_module fails to emit a kfunc call targeting a module on
s390x, because the verifier stores the difference between kfunc
address and __bpf_call_base in bpf_insn.imm, which is s32, and modules
are roughly (1 << 42) bytes away from the kernel on s390x.

Fix by keeping BTF id in bpf_insn.imm for BPF_PSEUDO_KFUNC_CALLs,
and storing the absolute address in bpf_kfunc_desc.

Introduce bpf_jit_supports_far_kfunc_call() in order to limit this new
behavior to the s390x JIT. Otherwise other JITs need to be modified,
which is not desired.

Introduce bpf_get_kfunc_addr() instead of exposing both
find_kfunc_desc() and struct bpf_kfunc_desc.

In addition to sorting kfuncs by imm, also sort them by offset, in
order to handle conflicting imms from different modules. Do this on
all architectures in order to simplify code.

Factor out resolving specialized kfuncs (XPD and dynptr) from
fixup_kfunc_call(). This was required in the first place, because
fixup_kfunc_call() uses find_kfunc_desc(), which returns a const
pointer, so it's not possible to modify kfunc addr without stripping
const, which is not nice. It also removes repetition of code like:

	if (bpf_jit_supports_far_kfunc_call())
		desc->addr = func;
	else
		insn->imm = BPF_CALL_IMM(func);

and separates kfunc_desc_tab fixups from kfunc_call fixups.
Suggested-by: Jiri Olsa <olsajiri@gmail.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20230412230632.885985-1-iii@linux.ibm.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

The recursion check in __bpf_prog_enter* and __bpf_prog_exit*
leave preempt_count_{sub,add} unprotected. When attaching trampoline to
them we get panic as follows,

[  867.843050] BUG: TASK stack guard page was hit at 0000000009d325cf (stack is 0000000046a46a15..00000000537e7b28)
[  867.843064] stack guard page: 0000 [#1] PREEMPT SMP NOPTI
[  867.843067] CPU: 8 PID: 11009 Comm: trace Kdump: loaded Not tainted 6.2.0+ #4
[  867.843100] Call Trace:
[  867.843101]  <TASK>
[  867.843104]  asm_exc_int3+0x3a/0x40
[  867.843108] RIP: 0010:preempt_count_sub+0x1/0xa0
[  867.843135]  __bpf_prog_enter_recur+0x17/0x90
[  867.843148]  bpf_trampoline_6442468108_0+0x2e/0x1000
[  867.843154]  ? preempt_count_sub+0x1/0xa0
[  867.843157]  preempt_count_sub+0x5/0xa0
[  867.843159]  ? migrate_enable+0xac/0xf0
[  867.843164]  __bpf_prog_exit_recur+0x2d/0x40
[  867.843168]  bpf_trampoline_6442468108_0+0x55/0x1000
...
[  867.843788]  preempt_count_sub+0x5/0xa0
[  867.843793]  ? migrate_enable+0xac/0xf0
[  867.843829]  __bpf_prog_exit_recur+0x2d/0x40
[  867.843837] BUG: IRQ stack guard page was hit at 0000000099bd8228 (stack is 00000000b23e2bc4..000000006d95af35)
[  867.843841] BUG: IRQ stack guard page was hit at 000000005ae07924 (stack is 00000000ffd69623..0000000014eb594c)
[  867.843843] BUG: IRQ stack guard page was hit at 00000000028320f0 (stack is 00000000034b6438..0000000078d1bcec)
[  867.843842]  bpf_trampoline_6442468108_0+0x55/0x1000
...

That is because in __bpf_prog_exit_recur, the preempt_count_{sub,add} are
called after prog->active is decreased.

Fixing this by adding these two functions into btf ids deny list.
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Yafang <laoar.shao@gmail.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jiri Olsa <olsajiri@gmail.com>
Acked-by: Hao Luo <haoluo@google.com>
Link: https://lore.kernel.org/r/20230413025248.79764-1-laoar.shao@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Some distros ship with older vm_sockets.h that doesn't have VMADDR_CID_LOCAL
which causes selftests build to fail:
/tmp/work/bpf/bpf/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c:261:18: error: ‘VMADDR_CID_LOCAL’ undeclared (first use in this function); did you mean ‘VMADDR_CID_HOST’?
    261 |  addr->svm_cid = VMADDR_CID_LOCAL;
        |                  ^~~~~~~~~~~~~~~~
        |                  VMADDR_CID_HOST

Workaround this issue by defining it on demand.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Fix merge conflict between bpf/bpf-next trees due to change of arguments in SYS() macro.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

====================
pull-request: bpf-next 2023-04-13

We've added 260 non-merge commits during the last 36 day(s) which contain
a total of 356 files changed, 21786 insertions(+), 11275 deletions(-).

The main changes are:

1) Rework BPF verifier log behavior and implement it as a rotating log
   by default with the option to retain old-style fixed log behavior,
   from Andrii Nakryiko.

2) Adds support for using {FOU,GUE} encap with an ipip device operating
   in collect_md mode and add a set of BPF kfuncs for controlling encap
   params, from Christian Ehrig.

3) Allow BPF programs to detect at load time whether a particular kfunc
   exists or not, and also add support for this in light skeleton,
   from Alexei Starovoitov.

4) Optimize hashmap lookups when key size is multiple of 4,
   from Anton Protopopov.

5) Enable RCU semantics for task BPF kptrs and allow referenced kptr
   tasks to be stored in BPF maps, from David Vernet.

6) Add support for stashing local BPF kptr into a map value via
   bpf_kptr_xchg(). This is useful e.g. for rbtree node creation
   for new cgroups, from Dave Marchevsky.

7) Fix BTF handling of is_int_ptr to skip modifiers to work around
   tracing issues where a program cannot be attached, from Feng Zhou.

8) Migrate a big portion of test_verifier unit tests over to
   test_progs -a verifier_* via inline asm to ease {read,debug}ability,
   from Eduard Zingerman.

9) Several updates to the instruction-set.rst documentation
   which is subject to future IETF standardization
   (https://lwn.net/Articles/926882/), from Dave Thaler.

10) Fix BPF verifier in the __reg_bound_offset's 64->32 tnum sub-register
    known bits information propagation, from Daniel Borkmann.

11) Add skb bitfield compaction work related to BPF with the overall goal
    to make more of the sk_buff bits optional, from Jakub Kicinski.

12) BPF selftest cleanups for build id extraction which stand on its own
    from the upcoming integration work of build id into struct file object,
    from Jiri Olsa.

13) Add fixes and optimizations for xsk descriptor validation and several
    selftest improvements for xsk sockets, from Kal Conley.

14) Add BPF links for struct_ops and enable switching implementations
    of BPF TCP cong-ctls under a given name by replacing backing
    struct_ops map, from Kui-Feng Lee.

15) Remove a misleading BPF verifier env->bypass_spec_v1 check on variable
    offset stack read as earlier Spectre checks cover this,
    from Luis Gerhorst.

16) Fix issues in copy_from_user_nofault() for BPF and other tracers
    to resemble copy_from_user_nmi() from safety PoV, from Florian Lehner
    and Alexei Starovoitov.

17) Add --json-summary option to test_progs in order for CI tooling to
    ease parsing of test results, from Manu Bretelle.

18) Batch of improvements and refactoring to prep for upcoming
    bpf_local_storage conversion to bpf_mem_cache_{alloc,free} allocator,
    from Martin KaFai Lau.

19) Improve bpftool's visual program dump which produces the control
    flow graph in a DOT format by adding C source inline annotations,
    from Quentin Monnet.

20) Fix attaching fentry/fexit/fmod_ret/lsm to modules by extracting
    the module name from BTF of the target and searching kallsyms of
    the correct module, from Viktor Malik.

21) Improve BPF verifier handling of '<const> <cond> <non_const>'
    to better detect whether in particular jmp32 branches are taken,
    from Yonghong Song.

22) Allow BPF TCP cong-ctls to write app_limited of struct tcp_sock.
    A built-in cc or one from a kernel module is already able to write
    to app_limited, from Yixin Shen.

Conflicts:

Documentation/bpf/bpf_devel_QA.rst
  b7abcd9c ("bpf, doc: Link to submitting-patches.rst for general patch submission info")
  0f10f647 ("bpf, docs: Use internal linking for link to netdev subsystem doc")
https://lore.kernel.org/all/20230307095812.236eb1be@canb.auug.org.au/

include/net/ip_tunnels.h
  bc9d003d ("ip_tunnel: Preserve pointer const in ip_tunnel_info_opts")
  ac931d4c ("ipip,ip_tunnel,sit: Add FOU support for externally controlled ipip devices")
https://lore.kernel.org/all/20230413161235.4093777-1-broonie@kernel.org/

net/bpf/test_run.c
  e5995bc7 ("bpf, test_run: fix crashes due to XDP frame overwriting/corruption")
  294635a8 ("bpf, test_run: fix &xdp_frame misplacement for LIVE_FRAMES")
https://lore.kernel.org/all/20230320102619.05b80a98@canb.auug.org.au/
====================

Link: https://lore.kernel.org/r/20230413191525.7295-1-daniel@iogearbox.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Conflicts:

tools/testing/selftests/net/config
  62199e3f ("selftests: net: Add VXLAN MDB test")
  3a0385be ("selftests: add the missing CONFIG_IP_SCTP in net config")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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

  Not all that quiet given spring celebrations, but "current" fixes are
  thinning out, which is encouraging. One outstanding regression in the
  mlx5 driver when using old FW, not blocking but we're pushing for a
  fix.

  Current release - new code bugs:

   - eth: enetc: workaround for unresponsive pMAC after receiving
     express traffic

  Previous releases - regressions:

   - rtnetlink: restore RTM_NEW/DELLINK notification behavior, keep the
     pid/seq fields 0 for backward compatibility

  Previous releases - always broken:

   - sctp: fix a potential overflow in sctp_ifwdtsn_skip

   - mptcp:
      - use mptcp_schedule_work instead of open-coding it and make the
        worker check stricter, to avoid scheduling work on closed
        sockets
      - fix NULL pointer dereference on fastopen early fallback

   - skbuff: fix memory corruption due to a race between skb coalescing
     and releasing clones confusing page_pool reference counting

   - bonding: fix neighbor solicitation validation on backup slaves

   - bpf: tcp: use sock_gen_put instead of sock_put in bpf_iter_tcp

   - bpf: arm64: fixed a BTI error on returning to patched function

   - openvswitch: fix race on port output leading to inf loop

   - sfp: initialize sfp->i2c_block_size at sfp allocation to avoid
     returning a different errno than expected

   - phy: nxp-c45-tja11xx: unregister PTP, purge queues on remove

   - Bluetooth: fix printing errors if LE Connection times out

   - Bluetooth: assorted UaF, deadlock and data race fixes

   - eth: macb: fix memory corruption in extended buffer descriptor mode

  Misc:

   - adjust the XDP Rx flow hash API to also include the protocol layers
     over which the hash was computed"

* tag 'net-6.3-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net: (50 commits)
  selftests/bpf: Adjust bpf_xdp_metadata_rx_hash for new arg
  mlx4: bpf_xdp_metadata_rx_hash add xdp rss hash type
  veth: bpf_xdp_metadata_rx_hash add xdp rss hash type
  mlx5: bpf_xdp_metadata_rx_hash add xdp rss hash type
  xdp: rss hash types representation
  selftests/bpf: xdp_hw_metadata remove bpf_printk and add counters
  skbuff: Fix a race between coalescing and releasing SKBs
  net: macb: fix a memory corruption in extended buffer descriptor mode
  selftests: add the missing CONFIG_IP_SCTP in net config
  udp6: fix potential access to stale information
  selftests: openvswitch: adjust datapath NL message declaration
  selftests: mptcp: userspace pm: uniform verify events
  mptcp: fix NULL pointer dereference on fastopen early fallback
  mptcp: stricter state check in mptcp_worker
  mptcp: use mptcp_schedule_work instead of open-coding it
  net: enetc: workaround for unresponsive pMAC after receiving express traffic
  sctp: fix a potential overflow in sctp_ifwdtsn_skip
  net: qrtr: Fix an uninit variable access bug in qrtr_tx_resume()
  rtnetlink: Restore RTM_NEW/DELLINK notification behavior
  net: ti/cpsw: Add explicit platform_device.h and of_platform.h includes
  ...

Pull devicetree fixes from Rob Herring:

 - Fix interaction between fw_devlink and DT overlays causing devices to
   not be probed

 - Fix the compatible string for loongson,cpu-interrupt-controller

* tag 'devicetree-fixes-for-6.2-3' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux:
  treewide: Fix probing of devices in DT overlays
  dt-bindings: interrupt-controller: loongarch: Fix mismatched compatible

Pull pin control fix from Linus Walleij:
 "This is just a revert of the AMD fix, because the fix broke some
  laptops. We are working on a proper solution"

* tag 'pinctrl-v6.3-3' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl:
  Revert "pinctrl: amd: Disable and mask interrupts on resume"

Pull drm fixes from Daniel Vetter:

 - two fbcon regressions

 - amdgpu: dp mst, smu13

 - i915: dual link dsi for tgl+

 - armada, nouveau, drm/sched, fbmem

* tag 'drm-fixes-2023-04-13' of git://anongit.freedesktop.org/drm/drm:
  fbcon: set_con2fb_map needs to set con2fb_map!
  fbcon: Fix error paths in set_con2fb_map
  drm/amd/pm: correct the pcie link state check for SMU13
  drm/amd/pm: correct SMU13.0.7 max shader clock reporting
  drm/amd/pm: correct SMU13.0.7 pstate profiling clock settings
  drm/amd/display: Pass the right info to drm_dp_remove_payload
  drm/armada: Fix a potential double free in an error handling path
  fbmem: Reject FB_ACTIVATE_KD_TEXT from userspace
  drm/nouveau/fb: add missing sysmen flush callbacks
  drm/i915/dsi: fix DSS CTL register offsets for TGL+
  drm/scheduler: Fix UAF race in drm_sched_entity_push_job()

Daniel Borkmann says:

====================
pull-request: bpf 2023-04-13

We've added 6 non-merge commits during the last 1 day(s) which contain
a total of 14 files changed, 205 insertions(+), 38 deletions(-).

The main changes are:

1) One late straggler fix on the XDP hints side which fixes
   bpf_xdp_metadata_rx_hash kfunc API before the release goes out
   in order to provide information on the RSS hash type,
   from Jesper Dangaard Brouer.

* tag 'for-netdev' of https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
  selftests/bpf: Adjust bpf_xdp_metadata_rx_hash for new arg
  mlx4: bpf_xdp_metadata_rx_hash add xdp rss hash type
  veth: bpf_xdp_metadata_rx_hash add xdp rss hash type
  mlx5: bpf_xdp_metadata_rx_hash add xdp rss hash type
  xdp: rss hash types representation
  selftests/bpf: xdp_hw_metadata remove bpf_printk and add counters
====================

Link: https://lore.kernel.org/r/20230413192939.10202-1-daniel@iogearbox.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Short summary of fixes pull:

 * armada: Fix double free
 * fb: Clear FB_ACTIVATE_KD_TEXT in ioctl
 * nouveau: Add missing callbacks
 * scheduler: Fix use-after-free error
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
From: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20230413184233.GA8148@linux-uq9g

syzbot reported a splat and bisected it to recent commit ed17aa92 ("bpf,
sockmap: fix deadlocks in the sockhash and sockmap"):

  [...]
  WARNING: CPU: 1 PID: 9280 at kernel/softirq.c:376 __local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376
  Modules linked in:
  CPU: 1 PID: 9280 Comm: syz-executor.1 Not tainted 6.2.0-syzkaller-13249-gd319f344 #0
  Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023
  RIP: 0010:__local_bh_enable_ip+0xbe/0x130 kernel/softirq.c:376
  [...]
  Call Trace:
  <TASK>
  spin_unlock_bh include/linux/spinlock.h:395 [inline]
  sock_map_del_link+0x2ea/0x510 net/core/sock_map.c:165
  sock_map_unref+0xb0/0x1d0 net/core/sock_map.c:184
  sock_hash_delete_elem+0x1ec/0x2a0 net/core/sock_map.c:945
  map_delete_elem kernel/bpf/syscall.c:1536 [inline]
  __sys_bpf+0x2edc/0x53e0 kernel/bpf/syscall.c:5053
  __do_sys_bpf kernel/bpf/syscall.c:5166 [inline]
  __se_sys_bpf kernel/bpf/syscall.c:5164 [inline]
  __x64_sys_bpf+0x79/0xc0 kernel/bpf/syscall.c:5164
  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
  do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  RIP: 0033:0x7fe8f7c8c169
  </TASK>
  [...]

Revert for now until we have a proper solution.

Fixes: ed17aa92 ("bpf, sockmap: fix deadlocks in the sockhash and sockmap")
Reported-by: syzbot+49f6cef45247ff249498@syzkaller.appspotmail.com
Cc: Hsin-Wei Hung <hsinweih@uci.edu>
Cc: Xin Liu <liuxin350@huawei.com>
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/000000000000f1db9605f939720e@google.com/

Jesper Dangaard Brouer says:

====================

Current API for bpf_xdp_metadata_rx_hash() returns the raw RSS hash value,
but doesn't provide information on the RSS hash type (part of 6.3-rc).

This patchset proposal is to change the function call signature via adding
a pointer value argument for providing the RSS hash type.

Patchset also removes all bpf_printk's from xdp_hw_metadata program
that we expect driver developers to use. Instead counters are introduced
for relaying e.g. skip and fail info.
====================
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Update BPF selftests to use the new RSS type argument for kfunc
bpf_xdp_metadata_rx_hash.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132894068.340624.8914711185697163690.stgit@firesoulSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Update API for bpf_xdp_metadata_rx_hash() with arg for xdp rss hash type
via matching individual Completion Queue Entry (CQE) status bits.

Fixes: ab46182d ("net/mlx4_en: Support RX XDP metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132893562.340624.12779118462402031248.stgit@firesoulSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Update API for bpf_xdp_metadata_rx_hash() with arg for xdp rss hash type.

The veth driver currently only support XDP-hints based on SKB code path.
The SKB have lost information about the RSS hash type, by compressing
the information down to a single bitfield skb->l4_hash, that only knows
if this was a L4 hash value.

In preparation for veth, the xdp_rss_hash_type have an L4 indication
bit that allow us to return a meaningful L4 indication when working
with SKB based packets.

Fixes: 306531f0 ("veth: Support RX XDP metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132893055.340624.16209448340644513469.stgit@firesoulSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Update API for bpf_xdp_metadata_rx_hash() with arg for xdp rss hash type
via mapping table.

The mlx5 hardware can also identify and RSS hash IPSEC.  This indicate
hash includes SPI (Security Parameters Index) as part of IPSEC hash.

Extend xdp core enum xdp_rss_hash_type with IPSEC hash type.

Fixes: bc8d405b ("net/mlx5e: Support RX XDP metadata")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132892548.340624.11185734579430124869.stgit@firesoulSigned-off-by: Alexei Starovoitov <ast@kernel.org>

The RSS hash type specifies what portion of packet data NIC hardware used
when calculating RSS hash value. The RSS types are focused on Internet
traffic protocols at OSI layers L3 and L4. L2 (e.g. ARP) often get hash
value zero and no RSS type. For L3 focused on IPv4 vs. IPv6, and L4
primarily TCP vs UDP, but some hardware supports SCTP.

Hardware RSS types are differently encoded for each hardware NIC. Most
hardware represent RSS hash type as a number. Determining L3 vs L4 often
requires a mapping table as there often isn't a pattern or sorting
according to ISO layer.

The patch introduce a XDP RSS hash type (enum xdp_rss_hash_type) that
contains both BITs for the L3/L4 types, and combinations to be used by
drivers for their mapping tables. The enum xdp_rss_type_bits get exposed
to BPF via BTF, and it is up to the BPF-programmer to match using these
defines.

This proposal change the kfunc API bpf_xdp_metadata_rx_hash() adding
a pointer value argument for provide the RSS hash type.
Change signature for all xmo_rx_hash calls in drivers to make it compile.

The RSS type implementations for each driver comes as separate patches.

Fixes: 3d76a4d3 ("bpf: XDP metadata RX kfuncs")
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Toke Høiland-Jørgensen <toke@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132892042.340624.582563003880565460.stgit@firesoulSigned-off-by: Alexei Starovoitov <ast@kernel.org>

The tool xdp_hw_metadata can be used by driver developers
implementing XDP-hints metadata kfuncs.

Remove all bpf_printk calls, as the tool already transfers all the
XDP-hints related information via metadata area to AF_XDP
userspace process.

Add counters for providing remaining information about failure and
skipped packet events.
Signed-off-by: Jesper Dangaard Brouer <brouer@redhat.com>
Acked-by: Stanislav Fomichev <sdf@google.com>
Link: https://lore.kernel.org/r/168132891533.340624.7313781245316405141.stgit@firesoulSigned-off-by: Alexei Starovoitov <ast@kernel.org>

I got really badly confused in d443d938 ("fbcon: move more common
code into fb_open()") because we set the con2fb_map before the failure
points, which didn't look good.

But in trying to fix that I moved the assignment into the wrong path -
we need to do it for _all_ vc we take over, not just the first one
(which additionally requires the call to con2fb_acquire_newinfo).

I've figured this out because of a KASAN bug report, where the
fbcon_registered_fb and fbcon_display arrays went out of sync in
fbcon_mode_deleted() because the con2fb_map pointed at the old
fb_info, but the modes and everything was updated for the new one.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Tested-by: Xingyuan Mo <hdthky0@gmail.com>
Fixes: d443d938 ("fbcon: move more common code into fb_open()")
Reported-by: Xingyuan Mo <hdthky0@gmail.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Xingyuan Mo <hdthky0@gmail.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.19+

This is a regressoin introduced in b07db395 ("fbcon: Ditch error
handling for con2fb_release_oldinfo"). I failed to realize what the if
(!err) checks. The mentioned commit was dropping the
con2fb_release_oldinfo() return value but the if (!err) was also
checking whether the con2fb_acquire_newinfo() function call above
failed or not.

Fix this with an early return statement.

Note that there's still a difference compared to the orginal state of
the code, the below lines are now also skipped on error:

	if (!search_fb_in_map(info_idx))
		info_idx = newidx;

These are only needed when we've actually thrown out an old fb_info
from the console mappings, which only happens later on.

Also move the fbcon_add_cursor_work() call into the same if block,
it's all protected by console_lock so doesn't matter when we set up
the blinking cursor delayed work anyway. This further simplifies the
control flow and allows us to ditch the found local variable.

v2: Clarify commit message (Javier)
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Acked-by: Helge Deller <deller@gmx.de>
Tested-by: Xingyuan Mo <hdthky0@gmail.com>
Fixes: b07db395 ("fbcon: Ditch error handling for con2fb_release_oldinfo")
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Xingyuan Mo <hdthky0@gmail.com>
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Cc: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.19+

Commit 1effe8ca ("skbuff: fix coalescing for page_pool fragment
recycling") allowed coalescing to proceed with non page pool page and page
pool page when @from is cloned, i.e.

to->pp_recycle    --> false
from->pp_recycle  --> true
skb_cloned(from)  --> true

However, it actually requires skb_cloned(@from) to hold true until
coalescing finishes in this situation. If the other cloned SKB is
released while the merging is in process, from_shinfo->nr_frags will be
set to 0 toward the end of the function, causing the increment of frag
page _refcount to be unexpectedly skipped resulting in inconsistent
reference counts. Later when SKB(@to) is released, it frees the page
directly even though the page pool page is still in use, leading to
use-after-free or double-free errors. So it should be prohibited.

The double-free error message below prompted us to investigate:
BUG: Bad page state in process swapper/1  pfn:0e0d1
page:00000000c6548b28 refcount:-1 mapcount:0 mapping:0000000000000000
index:0x2 pfn:0xe0d1
flags: 0xfffffc0000000(node=0|zone=1|lastcpupid=0x1fffff)
raw: 000fffffc0000000 0000000000000000 ffffffff00000101 0000000000000000
raw: 0000000000000002 0000000000000000 ffffffffffffffff 0000000000000000
page dumped because: nonzero _refcount

CPU: 1 PID: 0 Comm: swapper/1 Tainted: G            E      6.2.0+
Call Trace:
 <IRQ>
dump_stack_lvl+0x32/0x50
bad_page+0x69/0xf0
free_pcp_prepare+0x260/0x2f0
free_unref_page+0x20/0x1c0
skb_release_data+0x10b/0x1a0
napi_consume_skb+0x56/0x150
net_rx_action+0xf0/0x350
? __napi_schedule+0x79/0x90
__do_softirq+0xc8/0x2b1
__irq_exit_rcu+0xb9/0xf0
common_interrupt+0x82/0xa0
</IRQ>
<TASK>
asm_common_interrupt+0x22/0x40
RIP: 0010:default_idle+0xb/0x20

Fixes: 53e0961d ("page_pool: add frag page recycling support in page pool")
Signed-off-by: Liang Chen <liangchen.linux@gmail.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20230413090353.14448-1-liangchen.linux@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

For quite some time we were chasing a bug which looked like a sudden
permanent failure of networking and mmc on some of our devices.
The bug was very sensitive to any software changes and even more to
any kernel debug options.

Finally we got a setup where the problem was reproducible with
CONFIG_DMA_API_DEBUG=y and it revealed the issue with the rx dma:

[   16.992082] ------------[ cut here ]------------
[   16.996779] DMA-API: macb ff0b0000.ethernet: device driver tries to free DMA memory it has not allocated [device address=0x0000000875e3e244] [size=1536 bytes]
[   17.011049] WARNING: CPU: 0 PID: 85 at kernel/dma/debug.c:1011 check_unmap+0x6a0/0x900
[   17.018977] Modules linked in: xxxxx
[   17.038823] CPU: 0 PID: 85 Comm: irq/55-8000f000 Not tainted 5.4.0 #28
[   17.045345] Hardware name: xxxxx
[   17.049528] pstate: 60000005 (nZCv daif -PAN -UAO)
[   17.054322] pc : check_unmap+0x6a0/0x900
[   17.058243] lr : check_unmap+0x6a0/0x900
[   17.062163] sp : ffffffc010003c40
[   17.065470] x29: ffffffc010003c40 x28: 000000004000c03c
[   17.070783] x27: ffffffc010da7048 x26: ffffff8878e38800
[   17.076095] x25: ffffff8879d22810 x24: ffffffc010003cc8
[   17.081407] x23: 0000000000000000 x22: ffffffc010a08750
[   17.086719] x21: ffffff8878e3c7c0 x20: ffffffc010acb000
[   17.092032] x19: 0000000875e3e244 x18: 0000000000000010
[   17.097343] x17: 0000000000000000 x16: 0000000000000000
[   17.102647] x15: ffffff8879e4a988 x14: 0720072007200720
[   17.107959] x13: 0720072007200720 x12: 0720072007200720
[   17.113261] x11: 0720072007200720 x10: 0720072007200720
[   17.118565] x9 : 0720072007200720 x8 : 000000000000022d
[   17.123869] x7 : 0000000000000015 x6 : 0000000000000098
[   17.129173] x5 : 0000000000000000 x4 : 0000000000000000
[   17.134475] x3 : 00000000ffffffff x2 : ffffffc010a1d370
[   17.139778] x1 : b420c9d75d27bb00 x0 : 0000000000000000
[   17.145082] Call trace:
[   17.147524]  check_unmap+0x6a0/0x900
[   17.151091]  debug_dma_unmap_page+0x88/0x90
[   17.155266]  gem_rx+0x114/0x2f0
[   17.158396]  macb_poll+0x58/0x100
[   17.161705]  net_rx_action+0x118/0x400
[   17.165445]  __do_softirq+0x138/0x36c
[   17.169100]  irq_exit+0x98/0xc0
[   17.172234]  __handle_domain_irq+0x64/0xc0
[   17.176320]  gic_handle_irq+0x5c/0xc0
[   17.179974]  el1_irq+0xb8/0x140
[   17.183109]  xiic_process+0x5c/0xe30
[   17.186677]  irq_thread_fn+0x28/0x90
[   17.190244]  irq_thread+0x208/0x2a0
[   17.193724]  kthread+0x130/0x140
[   17.196945]  ret_from_fork+0x10/0x20
[   17.200510] ---[ end trace 7240980785f81d6f ]---

[  237.021490] ------------[ cut here ]------------
[  237.026129] DMA-API: exceeded 7 overlapping mappings of cacheline 0x0000000021d79e7b
[  237.033886] WARNING: CPU: 0 PID: 0 at kernel/dma/debug.c:499 add_dma_entry+0x214/0x240
[  237.041802] Modules linked in: xxxxx
[  237.061637] CPU: 0 PID: 0 Comm: swapper/0 Tainted: G        W         5.4.0 #28
[  237.068941] Hardware name: xxxxx
[  237.073116] pstate: 80000085 (Nzcv daIf -PAN -UAO)
[  237.077900] pc : add_dma_entry+0x214/0x240
[  237.081986] lr : add_dma_entry+0x214/0x240
[  237.086072] sp : ffffffc010003c30
[  237.089379] x29: ffffffc010003c30 x28: ffffff8878a0be00
[  237.094683] x27: 0000000000000180 x26: ffffff8878e387c0
[  237.099987] x25: 0000000000000002 x24: 0000000000000000
[  237.105290] x23: 000000000000003b x22: ffffffc010a0fa00
[  237.110594] x21: 0000000021d79e7b x20: ffffffc010abe600
[  237.115897] x19: 00000000ffffffef x18: 0000000000000010
[  237.121201] x17: 0000000000000000 x16: 0000000000000000
[  237.126504] x15: ffffffc010a0fdc8 x14: 0720072007200720
[  237.131807] x13: 0720072007200720 x12: 0720072007200720
[  237.137111] x11: 0720072007200720 x10: 0720072007200720
[  237.142415] x9 : 0720072007200720 x8 : 0000000000000259
[  237.147718] x7 : 0000000000000001 x6 : 0000000000000000
[  237.153022] x5 : ffffffc010003a20 x4 : 0000000000000001
[  237.158325] x3 : 0000000000000006 x2 : 0000000000000007
[  237.163628] x1 : 8ac721b3a7dc1c00 x0 : 0000000000000000
[  237.168932] Call trace:
[  237.171373]  add_dma_entry+0x214/0x240
[  237.175115]  debug_dma_map_page+0xf8/0x120
[  237.179203]  gem_rx_refill+0x190/0x280
[  237.182942]  gem_rx+0x224/0x2f0
[  237.186075]  macb_poll+0x58/0x100
[  237.189384]  net_rx_action+0x118/0x400
[  237.193125]  __do_softirq+0x138/0x36c
[  237.196780]  irq_exit+0x98/0xc0
[  237.199914]  __handle_domain_irq+0x64/0xc0
[  237.204000]  gic_handle_irq+0x5c/0xc0
[  237.207654]  el1_irq+0xb8/0x140
[  237.210789]  arch_cpu_idle+0x40/0x200
[  237.214444]  default_idle_call+0x18/0x30
[  237.218359]  do_idle+0x200/0x280
[  237.221578]  cpu_startup_entry+0x20/0x30
[  237.225493]  rest_init+0xe4/0xf0
[  237.228713]  arch_call_rest_init+0xc/0x14
[  237.232714]  start_kernel+0x47c/0x4a8
[  237.236367] ---[ end trace 7240980785f81d70 ]---

Lars was fast to find an explanation: according to the datasheet
bit 2 of the rx buffer descriptor entry has a different meaning in the
extended mode:
  Address [2] of beginning of buffer, or
  in extended buffer descriptor mode (DMA configuration register [28] = 1),
  indicates a valid timestamp in the buffer descriptor entry.

The macb driver didn't mask this bit while getting an address and it
eventually caused a memory corruption and a dma failure.

The problem is resolved by explicitly clearing the problematic bit
if hw timestamping is used.

Fixes: 7b429614 ("net: macb: Add support for PTP timestamps in DMA descriptors")
Signed-off-by: Roman Gushchin <roman.gushchin@linux.dev>
Co-developed-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Acked-by: Nicolas Ferre <nicolas.ferre@microchip.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://lore.kernel.org/r/20230412232144.770336-1-roman.gushchin@linux.devSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The selftest sctp_vrf needs CONFIG_IP_SCTP set in config
when building the kernel, so add it.

Fixes: a61bd7b9 ("selftests: add a selftest for sctp vrf")
Reported-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Sridhar Samudrala <sridhar.samudrala@intel.com>
Link: https://lore.kernel.org/r/61dddebc4d2dd98fe7fb145e24d4b2430e42b572.1681312386.git.lucien.xin@gmail.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

lena wang reported an issue caused by udpv6_sendmsg()
mangling msg->msg_name and msg->msg_namelen, which
are later read from ____sys_sendmsg() :

	/*
	 * If this is sendmmsg() and sending to current destination address was
	 * successful, remember it.
	 */
	if (used_address && err >= 0) {
		used_address->name_len = msg_sys->msg_namelen;
		if (msg_sys->msg_name)
			memcpy(&used_address->name, msg_sys->msg_name,
			       used_address->name_len);
	}

udpv6_sendmsg() wants to pretend the remote address family
is AF_INET in order to call udp_sendmsg().

A fix would be to modify the address in-place, instead
of using a local variable, but this could have other side effects.

Instead, restore initial values before we return from udpv6_sendmsg().

Fixes: c71d8ebe ("net: Fix security_socket_sendmsg() bypass problem.")
Reported-by: lena wang <lena.wang@mediatek.com>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Maciej Żenczykowski <maze@google.com>
Link: https://lore.kernel.org/r/20230412130308.1202254-1-edumazet@google.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

The netlink message for creating a new datapath takes an array
of ports for the PID creation.  This shouldn't cause much issue
but correct it for future cases where we need to do decode of
datapath information that could include the per-cpu PID map.

Fixes: 25f16c87 ("selftests: add openvswitch selftest suite")
Signed-off-by: Aaron Conole <aconole@redhat.com>
Link: https://lore.kernel.org/r/20230412115828.3991806-1-aconole@redhat.comSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Matthieu Baerts says:

====================
mptcp: more fixes for 6.3

Patch 1 avoids scheduling the MPTCP worker on a closed socket on some
edge cases. It fixes issues that can be visible from v5.11.

Patch 2 makes sure the MPTCP worker doesn't try to manipulate
disconnected sockets. This is also a fix for an issue that can be
visible from v5.11.

Patch 3 fixes a NULL pointer dereference when MPTCP FastOpen is used
and an early fallback is done. A fix for v6.2.

Patch 4 improves the stability of the userspace PM selftest for a
subtest added in v6.2.
====================

Link: https://lore.kernel.org/r/20230411-upstream-net-20230411-mptcp-fixes-v1-0-ca540f3ef986@tessares.netSigned-off-by: Jakub Kicinski <kuba@kernel.org>

Simply adding a "sleep" before checking something is usually not a good
idea because the time that has been picked can not be enough or too
much. The best is to wait for events with a timeout.

In this selftest, 'sleep 0.5' is used more than 40 times. It is always
used before calling a 'verify_*' function except for this
verify_listener_events which has been added later.

At the end, using all these 'sleep 0.5' seems to work: the slow CIs
don't complain so far. Also because it doesn't take too much time, we
can just add two more 'sleep 0.5' to uniform what is done before calling
a 'verify_*' function. For the same reasons, we can also delay a bigger
refactoring to replace all these 'sleep 0.5' by functions waiting for
events instead of waiting for a fix time and hope for the best.

Fixes: 6c73008a ("selftests: mptcp: listener test for userspace PM")
Cc: stable@vger.kernel.org
Suggested-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>