__bpf_prog_enter_sleepable_recur does recursion check which is not applicable
to wq callback. The callback function is part of bpf program and bpf prog might
be running on the same cpu. So recursion check would incorrectly prevent
callback from running. The code can call __bpf_prog_enter_sleepable(), but
run_ctx would be fake, hence use explicit rcu_read_lock_trace();
migrate_disable(); to address this problem. Another reason to open code is
__bpf_prog_enter* are not available in !JIT configs.
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202404241719.IIGdpAku-lkp@intel.com/
Closes: https://lore.kernel.org/oe-kbuild-all/202404241811.FFV4Bku3-lkp@intel.com/
Fixes: eb48f6cd ("bpf: wq: add bpf_wq_init")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>

Benjamin Tissoires says:

====================
Introduce bpf_wq

This is a followup of sleepable bpf_timer[0].

When discussing sleepable bpf_timer, it was thought that we should give
a try to bpf_wq, as the 2 APIs are similar but distinct enough to
justify a new one.

So here it is.

I tried to keep as much as possible common code in kernel/bpf/helpers.c
but I couldn't get away with code duplication in kernel/bpf/verifier.c.

This series introduces a basic bpf_wq support:
- creation is supported
- assignment is supported
- running a simple bpf_wq is also supported.

We will probably need to extend the API further with:
- a full delayed_work API (can be piggy backed on top with a correct
  flag)
- bpf_wq_cancel() <- apparently not, this is shooting ourself in the
  foot
- bpf_wq_cancel_sync() (for sleepable programs)
- documentation
---

For reference, the use cases I have in mind:

---

Basically, I need to be able to defer a HID-BPF program for the
following reasons (from the aforementioned patch):
1. defer an event:
   Sometimes we receive an out of proximity event, but the device can not
   be trusted enough, and we need to ensure that we won't receive another
   one in the following n milliseconds. So we need to wait those n
   milliseconds, and eventually re-inject that event in the stack.

2. inject new events in reaction to one given event:
   We might want to transform one given event into several. This is the
   case for macro keys where a single key press is supposed to send
   a sequence of key presses. But this could also be used to patch a
   faulty behavior, if a device forgets to send a release event.

3. communicate with the device in reaction to one event:
   We might want to communicate back to the device after a given event.
   For example a device might send us an event saying that it came back
   from sleeping state and needs to be re-initialized.

Currently we can achieve that by keeping a userspace program around,
raise a bpf event, and let that userspace program inject the events and
commands.
However, we are just keeping that program alive as a daemon for just
scheduling commands. There is no logic in it, so it doesn't really justify
an actual userspace wakeup. So a kernel workqueue seems simpler to handle.

bpf_timers are currently running in a soft IRQ context, this patch
series implements a sleppable context for them.

Cheers,
Benjamin

[0] https://lore.kernel.org/all/20240408-hid-bpf-sleepable-v6-0-0499ddd91b94@kernel.org/

Changes in v2:
- took previous review into account
- mainly dropped BPF_F_WQ_SLEEPABLE
- Link to v1: https://lore.kernel.org/r/20240416-bpf_wq-v1-0-c9e66092f842@kernel.org

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

Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-0-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Allows to test if allocation/free works
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-16-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

again, copy/paste from bpf_timer_start().
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-15-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

We assign the callback and set everything up.
The actual tests of these callbacks will be done when bpf_wq_start() is
available.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-14-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

To support sleepable async callbacks, we need to tell push_async_cb()
whether the cb is sleepable or not.

The verifier now detects that we are in bpf_wq_set_callback_impl and
can allow a sleepable callback to happen.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-13-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Allows to test if allocation/free works
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-12-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

We need to teach the verifier about the second argument which is declared
as void * but which is of type KF_ARG_PTR_TO_MAP. We could have dropped
this extra case if we declared the second argument as struct bpf_map *,
but that means users will have to do extra casting to have their program
compile.

We also need to duplicate the timer code for the checking if the map
argument is matching the provided workqueue.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-11-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

We simply try in all supported map types if we can store/load a bpf_wq.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-10-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Currently bpf_wq_cancel_and_free() is just a placeholder as there is
no memory allocation for bpf_wq just yet.

Again, duplication of the bpf_timer approach
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-9-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Introduce support for KF_ARG_PTR_TO_WORKQUEUE. The kfuncs will use bpf_wq
as argument and that will be recognized as workqueue argument by verifier.
bpf_wq_kern casting can happen inside kfunc, but using bpf_wq in
argument makes life easier for users who work with non-kern type in BPF
progs.

Duplicate process_timer_func into process_wq_func.
meta argument is only needed to ensure bpf_wq_init's workqueue and map
arguments are coming from the same map (map_uid logic is necessary for
correct inner-map handling), so also amend check_kfunc_args() to
match what helpers functions check is doing.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-8-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

When a kfunc is declared with a KF_ARG_PTR_TO_MAP, we should have
reg->map_ptr set to a non NULL value, otherwise, that means that the
underlying type is not a map.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-7-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

cp include/uapi/linux/bpf.h tools/include/uapi/linux/bpf.h
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-6-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Mostly a copy/paste from the bpf_timer API, without the initialization
and free, as they will be done in a separate patch.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-5-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Same reason than most bpf_timer* functions, we need almost the same for
workqueues.
So extract the generic part out of it so bpf_wq_cancel_and_free can reuse
it.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-4-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

In the same way we have a generic __bpf_async_init(), we also need
to share code between timer and workqueue for the set_callback call.

We just add an unused flags parameter, as it will be used for workqueues.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-3-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

No code change except for the new flags argument being stored in the
local data struct.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-2-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

To be able to add workqueues and reuse most of the timer code, we need
to make bpf_hrtimer more generic.

There is no code change except that the new struct gets a new u64 flags
attribute. We are still below 2 cache lines, so this shouldn't impact
the current running codes.

The ordering is also changed. Everything related to async callback
is now on top of bpf_hrtimer.
Signed-off-by: Benjamin Tissoires <bentiss@kernel.org>
Link: https://lore.kernel.org/r/20240420-bpf_wq-v2-1-6c986a5a741f@kernel.orgSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Found the following typos in comments, and fixed them:

s/unpriviledged/unprivileged/
s/reponsible/responsible/
s/possiblities/possibilities/
s/Divison/Division/
s/precsion/precision/
s/havea/have a/
s/reponsible/responsible/
s/responsibile/responsible/
s/tigher/tighter/
s/respecitve/respective/
Signed-off-by: Rafael Passos <rafael@rcpassos.me>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/6af7deb4-bb24-49e8-b3f1-8dd410597337@smtp-relay.sendinblue.com

I found this typo in the save_aux_ptr_type function.
s/allow_trust_missmatch/allow_trust_mismatch/
I did not find this anywhere else in the codebase.
Signed-off-by: Rafael Passos <rafael@rcpassos.me>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/fbe1d636-8172-4698-9a5a-5a3444b55322@smtp-relay.sendinblue.com

Other places that had pseudocode were prefixed with ::
so as to appear in a literal block, but one place was inconsistent.
This patch fixes that inconsistency.
Signed-off-by: Dave Thaler <dthaler1968@googlemail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20240419213826.7301-1-dthaler1968@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Per IETF 119 meeting discussion and mailing list discussion at
https://mailarchive.ietf.org/arch/msg/bpf/2JwWQwFdOeMGv0VTbD0CKWwAOEA/
the following changes are made.

First, say call by "static ID" rather than call by "address"

Second, change "pointer" to "address"
Signed-off-by: Dave Thaler <dthaler1968@gmail.com>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20240419203617.6850-1-dthaler1968@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

Geliang Tang says:

====================
v5:
 - address Martin's comments for v4. (thanks)
 - drop start_server_addr_opts, add opts as a argument of
   start_server_addr.
 - add opts argument for connect_to_addr too.
 - move some patches out of this set, stay with start_server_addr()
   and connect_to_addr() only in it.

v4:
 - add more patches using make_sockaddr and get_socket_local_port
   helpers.

v3:
 - address comments of Martin and Eduard in v2. (thanks)
 - move "int type" to the first argument of start_server_addr and
   connect_to_addr.
 - add start_server_addr_opts.
 - using "sockaddr_storage" instead of "sockaddr".
 - move start_server_setsockopt patches out of this series.

v2:
 - update patch 6 only, fix errors reported by CI.

This patchset uses public helpers start_server_* and connect_to_* defined
in network_helpers.c to drop duplicate code.
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>

This patch uses public helper connect_to_addr() exported in
network_helpers.h instead of the local defined function connect_to_server()
in prog_tests/sk_assign.c. This can avoid duplicate code.

The code that sets SO_SNDTIMEO timeout as timeo_sec (3s) can be dropped,
since connect_to_addr() sets default timeout as 3s.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/98fdd384872bda10b2adb052e900a2212c9047b9.1713427236.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

This patch uses public helper connect_to_addr() exported in
network_helpers.h instead of the local defined function connect_to_server()
in prog_tests/cls_redirect.c. This can avoid duplicate code.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/4a03ac92d2d392f8721f398fa449a83ac75577bc.1713427236.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Move the third argument "int type" of connect_to_addr() to the first one
which is closer to how the socket syscall is doing it. And add a
network_helper_opts argument as the fourth one. Then change its usages in
sock_addr.c too.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/088ea8a95055f93409c5f57d12f0e58d43059ac4.1713427236.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Include network_helpers.h in prog_tests/sk_assign.c, use the newly
added public helper start_server_addr() instead of the local defined
function start_server(). This can avoid duplicate code.

The code that sets SO_RCVTIMEO timeout as timeo_sec (3s) can be dropped,
since start_server_addr() sets default timeout as 3s.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/2af706ffbad63b4f7eaf93a426ed1076eadf1a05.1713427236.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

Include network_helpers.h in prog_tests/cls_redirect.c, use the newly
added public helper start_server_addr() instead of the local defined
function start_server(). This can avoid duplicate code.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/13f336cb4c6680175d50bb963d9532e11528c758.1713427236.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

In order to pair up with connect_to_addr(), this patch adds a new helper
start_server_addr(), which is a wrapper of __start_server(). It accepts
an argument 'addr' of 'struct sockaddr_storage' type instead of a string
type argument like start_server(), and a network_helper_opts argument as
the last one.
Signed-off-by: Geliang Tang <tanggeliang@kylinos.cn>
Link: https://lore.kernel.org/r/2f01d48fa026467926738debe554ac452c19b86f.1713427236.git.tanggeliang@kylinos.cnSigned-off-by: Martin KaFai Lau <martin.lau@kernel.org>

The codegen for is_mov_percpu_addr instruction works for rax/r8 registers
only. Fix it to generate proper x86 byte code for other registers.

Fixes: 7bdbf744 ("bpf: add special internal-only MOV instruction to resolve per-CPU addrs")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240417214406.15788-1-alexei.starovoitov@gmail.com

When dumping a character array, libbpf will watch for a '\0' and set
is_array_terminated=true if found. This prevents libbpf from printing
the remaining characters of the array, treating it as a nul-terminated
string.

However, once this flag is set, it's never reset, leading to subsequent
characters array not being printed properly:

.str_multi = (__u8[2][16])[
    [
        'H',
        'e',
        'l',
    ],
],

This patch saves the is_array_terminated flag and restores its
default (false) value before looping over the elements of an array,
then restores it afterward. This way, libbpf's behavior is unchanged
when dumping the characters of an array, but subsequent arrays are
printed properly:

.str_multi = (__u8[2][16])[
    [
        'H',
        'e',
        'l',
    ],
    [
        'l',
        'o',
    ],
],
Signed-off-by: Quentin Deslandes <qde@naccy.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240413211258.134421-3-qde@naccy.de

In btf_dump_array_data(), libbpf will call btf_dump_dump_type_data() for
each element. For an array of characters, each element will be
processed the following way:

- btf_dump_dump_type_data() is called to print the character
- btf_dump_data_pfx() prefixes the current line with the proper number
  of indentations
- btf_dump_int_data() is called to print the character
- After the last character is printed, btf_dump_dump_type_data() calls
  btf_dump_data_pfx() before writing the closing bracket

However, for an array containing characters, btf_dump_int_data() won't
print any '\0' and subsequent characters. This leads to situations where
the line prefix is written, no character is added, then the prefix is
written again before adding the closing bracket:

(struct sk_metadata){
    .str_array = (__u8[14])[
        'H',
        'e',
        'l',
        'l',
        'o',
                ],

This change solves this issue by printing the '\0' character, which
has two benefits:

- The bracket closing the array is properly aligned
- It's clear from a user point of view that libbpf uses '\0' as a
  terminator for arrays of characters.
Signed-off-by: Quentin Deslandes <qde@naccy.de>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240413211258.134421-2-qde@naccy.de

This commit contains a series of clean-ups and fixes for bpftool's bash
completion file:

- Make sure all local variables are declared as such.
- Make sure variables are initialised before being read.
- Update ELF section ("maps" -> ".maps") for looking up map names in
  object files.
- Fix call to _init_completion.
- Move definition for MAP_TYPE and PROG_TYPE higher up in the scope to
  avoid defining them multiple times, reuse MAP_TYPE where relevant.
- Simplify completion for "duration" keyword in "bpftool prog profile".
- Fix completion for "bpftool struct_ops register" and "bpftool link
  (pin|detach)" where we would repeatedly suggest file names instead of
  suggesting just one name.
- Fix completion for "bpftool iter pin ... map MAP" to account for the
  "map" keyword.
- Add missing "detach" suggestion for "bpftool link".
Signed-off-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240413011427.14402-3-qmo@kernel.org

When using references to BPF programs, bpftool supports passing programs
by name on the command line. The manual pages for "bpftool prog" and
"bpftool map" (for prog_array updates) mention it, but we have a few
additional subcommands that support referencing programs by name but do
not mention it in their documentation. Let's update the pages for
subcommands "btf", "cgroup", and "net".

Similarly, we can reference maps by name when passing them to "bpftool
prog load", so we update the page for "bpftool prog" as well.
Signed-off-by: Quentin Monnet <qmo@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240413011427.14402-2-qmo@kernel.org

This patch addresses a latent unsoundness issue in the
scalar(32)_min_max_and/or/xor functions. While it is not a bugfix,
it ensures that the functions produce sound outputs for all inputs.

The issue occurs in these functions when setting signed bounds. The
following example illustrates the issue for scalar_min_max_and(),
but it applies to the other functions.

In scalar_min_max_and() the following clause is executed when ANDing
positive numbers:

  /* ANDing two positives gives a positive, so safe to
   * cast result into s64.
   */
  dst_reg->smin_value = dst_reg->umin_value;
  dst_reg->smax_value = dst_reg->umax_value;

However, if umin_value and umax_value of dst_reg cross the sign boundary
(i.e., if (s64)dst_reg->umin_value > (s64)dst_reg->umax_value), then we
will end up with smin_value > smax_value, which is unsound.

Previous works [1, 2] have discovered and reported this issue. Our tool
Agni [2, 3] consideres it a false positive. This is because, during the
verification of the abstract operator scalar_min_max_and(), Agni restricts
its inputs to those passing through reg_bounds_sync(). This mimics
real-world verifier behavior, as reg_bounds_sync() is invariably executed
at the tail of every abstract operator. Therefore, such behavior is
unlikely in an actual verifier execution.

However, it is still unsound for an abstract operator to set signed bounds
such that smin_value > smax_value. This patch fixes it, making the abstract
operator sound for all (well-formed) inputs.

It is worth noting that while the previous code updated the signed bounds
(using the output unsigned bounds) only when the *input signed* bounds
were positive, the new code updates them whenever the *output unsigned*
bounds do not cross the sign boundary.

An alternative approach to fix this latent unsoundness would be to
unconditionally set the signed bounds to unbounded [S64_MIN, S64_MAX], and
let reg_bounds_sync() refine the signed bounds using the unsigned bounds
and the tnum. We found that our approach produces more precise (tighter)
bounds.

For example, consider these inputs to BPF_AND:

  /* dst_reg */
  var_off.value: 8608032320201083347
  var_off.mask: 615339716653692460
  smin_value: 8070450532247928832
  smax_value: 8070450532247928832
  umin_value: 13206380674380886586
  umax_value: 13206380674380886586
  s32_min_value: -2110561598
  s32_max_value: -133438816
  u32_min_value: 4135055354
  u32_max_value: 4135055354

  /* src_reg */
  var_off.value: 8584102546103074815
  var_off.mask: 9862641527606476800
  smin_value: 2920655011908158522
  smax_value: 7495731535348625717
  umin_value: 7001104867969363969
  umax_value: 8584102543730304042
  s32_min_value: -2097116671
  s32_max_value: 71704632
  u32_min_value: 1047457619
  u32_max_value: 4268683090

After going through tnum_and() -> scalar32_min_max_and() ->
scalar_min_max_and() -> reg_bounds_sync(), our patch produces the following
bounds for s32:

  s32_min_value: -1263875629
  s32_max_value: -159911942

Whereas, setting the signed bounds to unbounded in scalar_min_max_and()
produces:

  s32_min_value: -1263875629
  s32_max_value: -1

As observed, our patch produces a tighter s32 bound. We also confirmed
using Agni and SMT verification that our patch always produces signed
bounds that are equal to or more precise than setting the signed bounds to
unbounded in scalar_min_max_and().

  [1] https://sanjit-bhat.github.io/assets/pdf/ebpf-verifier-range-analysis22.pdf
  [2] https://link.springer.com/chapter/10.1007/978-3-031-37709-9_12
  [3] https://github.com/bpfverif/agniCo-developed-by: Matan Shachnai <m.shachnai@rutgers.edu>
Signed-off-by: Matan Shachnai <m.shachnai@rutgers.edu>
Co-developed-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Signed-off-by: Srinivas Narayana <srinivas.narayana@rutgers.edu>
Co-developed-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Santosh Nagarakatte <santosh.nagarakatte@rutgers.edu>
Signed-off-by: Harishankar Vishwanathan <harishankar.vishwanathan@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20240402212039.51815-1-harishankar.vishwanathan@gmail.com
Link: https://lore.kernel.org/bpf/20240416115303.331688-1-harishankar.vishwanathan@gmail.com

Currently, there are two comments with same name "64-bit ATOMIC magnitudes",
the second one should be "32-bit ATOMIC magnitudes" based on the context.
Signed-off-by: Chen Pei <cp0613@linux.alibaba.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240415081928.17440-1-cp0613@linux.alibaba.com

If the BTF code is enabled in the build configuration, the start/stop
BTF markers are guaranteed to exist. Only when CONFIG_DEBUG_INFO_BTF=n,
the references in btf_parse_vmlinux() will remain unsatisfied, relying
on the weak linkage of the external references to avoid breaking the
build.

Avoid GOT based relocations to these markers in the final executable by
dropping the weak attribute and instead, make btf_parse_vmlinux() return
ERR_PTR(-ENOENT) directly if CONFIG_DEBUG_INFO_BTF is not enabled to
begin with.  The compiler will drop any subsequent references to
__start_BTF and __stop_BTF in that case, allowing the link to succeed.

Note that Clang will notice that taking the address of __start_BTF can
no longer yield NULL, so testing for that condition becomes unnecessary.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/bpf/20240415162041.2491523-8-ardb+git@google.com

We have two printk tests reading trace_pipe in non blocking way,
with the very same code. Moving that in new read_trace_pipe_iter
function.

Current read_trace_pipe is used from samples/bpf and needs to
do blocking read and printf of the trace_pipe data, using new
read_trace_pipe_iter to implement that.

Both printk tests do early checks for the number of found messages
and can bail earlier, but I did not find any speed difference w/o
that condition, so I did not complicate the change more for that.

Some of the samples/bpf programs use read_trace_pipe function,
so I kept that interface untouched. I did not see any issues with
affected samples/bpf programs other than there's slight change in
read_trace_pipe output. The current code uses puts that adds new
line after the printed string, so we would occasionally see extra
new line. With this patch we read output per lines, so there's no
need to use puts and we can use just printf instead without extra
new line.
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20240410140952.292261-1-jolsa@kernel.org

s/at at/at a/
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Quentin Monnet <qmo@kernel.org>
Link: https://lore.kernel.org/bpf/20240411164258.533063-3-thorsten.blum@toblux.com

Geliang Tang says:

====================
v5:
 - address Martin's comments for v4 (thanks).
 - update patch 2, use 'return err' instead of 'return -1/0'.
 - drop patch 3 in v4.

v4:
 - fix a bug in v3, it should be 'if (err)', not 'if (!err)'.
 - move "selftests/bpf: Use log_err in network_helpers" out of this
   series.

v3:
 - add two more patches.
 - use log_err instead of ASSERT in v3.
 - let send_recv_data return int as Martin suggested.

v2:

Address Martin's comments for v1 (thanks.)
 - drop patch 1, "export send_byte helper".
 - drop "WRITE_ONCE(arg.stop, 0)".
 - rebased.

send_recv_data will be re-used in MPTCP bpf tests, but not included
in this set because it depends on other patches that have not been
in the bpf-next yet. It will be sent as another set soon.
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>