Commit Graph

2767 Commits

Author SHA1 Message Date
Andrii Nakryiko
85d9be97eb sync: latest libbpf changes from kernel
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   6f0b824a61f212e9707ff68abcabfdfa4724b811
Checkpoint bpf-next commit: 08a7491843224f8b96518fbe70d9e48163046054
Baseline bpf commit:        1d528e794f3db5d32279123a89957c44c4406a09
Checkpoint bpf commit:      22cc16c04b7893d8fc22810599f49a305d600b9e

Donglin Peng (4):
  libbpf: Add BTF permutation support for type reordering
  libbpf: Optimize type lookup with binary search for sorted BTF
  libbpf: Verify BTF sorting
  btf: Refactor the code by calling str_is_empty

Emil Tsalapatis (2):
  libbpf: Turn relo_core->sym_off unsigned
  libbpf: Move arena globals to the end of the arena

Ihor Solodrai (1):
  bpf: Migrate bpf_stream_vprintk() to KF_IMPLICIT_ARGS

Leon Hwang (2):
  bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags
  libbpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu maps

Matt Bobrowski (1):
  bpf: add new BPF_CGROUP_ITER_CHILDREN control option

Menglong Dong (2):
  bpf: add fsession support
  libbpf: add fsession support

Thomas Gleixner (1):
  treewide: Update email address

Thomas Weißschuh (1):
  vfs: use UAPI types for new struct delegation definition

Varun R Mallya (1):
  libbpf: Fix OOB read in btf_dump_get_bitfield_value

 include/uapi/linux/bpf.h        |  11 ++
 include/uapi/linux/fcntl.h      |  10 +-
 include/uapi/linux/perf_event.h |   2 +-
 src/bpf.c                       |   1 +
 src/bpf.h                       |   8 +
 src/bpf_helpers.h               |   6 +-
 src/btf.c                       | 276 +++++++++++++++++++++++++++-----
 src/btf.h                       |  42 +++++
 src/btf_dump.c                  |   9 ++
 src/libbpf.c                    |  64 +++++---
 src/libbpf.h                    |  21 +--
 src/libbpf.map                  |   1 +
 12 files changed, 369 insertions(+), 82 deletions(-)

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
v1.6.3.1p_netdata
2026-01-29 14:10:19 -08:00
Andrii Nakryiko
fddf93d20b sync: update .mailmap
Update .mailmap based on libbpf's list of contributors and on the latest
.mailmap version in the upstream repository.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2026-01-29 14:10:19 -08:00
Matt Bobrowski
ed6bb65cf1 bpf: add new BPF_CGROUP_ITER_CHILDREN control option
Currently, the BPF cgroup iterator supports walking descendants in
either pre-order (BPF_CGROUP_ITER_DESCENDANTS_PRE) or post-order
(BPF_CGROUP_ITER_DESCENDANTS_POST). These modes perform an exhaustive
depth-first search (DFS) of the hierarchy. In scenarios where a BPF
program may need to inspect only the direct children of a given parent
cgroup, a full DFS is unnecessarily expensive.

This patch introduces a new BPF cgroup iterator control option,
BPF_CGROUP_ITER_CHILDREN. This control option restricts the traversal
to the immediate children of a specified parent cgroup, allowing for
more targeted and efficient iteration, particularly when exhaustive
depth-first search (DFS) traversal is not required.

Signed-off-by: Matt Bobrowski <mattbobrowski@google.com>
Link: https://lore.kernel.org/r/20260127085112.3608687-1-mattbobrowski@google.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-29 14:10:19 -08:00
Menglong Dong
5ee8863eaf libbpf: add fsession support
Add BPF_TRACE_FSESSION to libbpf.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Link: https://lore.kernel.org/r/20260124062008.8657-9-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-29 14:10:19 -08:00
Menglong Dong
adde4f55b7 bpf: add fsession support
The fsession is something that similar to kprobe session. It allow to
attach a single BPF program to both the entry and the exit of the target
functions.

Introduce the struct bpf_fsession_link, which allows to add the link to
both the fentry and fexit progs_hlist of the trampoline.

Signed-off-by: Menglong Dong <dongml2@chinatelecom.cn>
Co-developed-by: Leon Hwang <leon.hwang@linux.dev>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260124062008.8657-2-dongml2@chinatelecom.cn
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-29 14:10:19 -08:00
Ihor Solodrai
977b1f820c bpf: Migrate bpf_stream_vprintk() to KF_IMPLICIT_ARGS
Implement bpf_stream_vprintk with an implicit bpf_prog_aux argument,
and remote bpf_stream_vprintk_impl from the kernel.

Update the selftests to use the new API with implicit argument.

bpf_stream_vprintk macro is changed to use the new bpf_stream_vprintk
kfunc, and the extern definition of bpf_stream_vprintk_impl is
replaced accordingly.

Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Link: https://lore.kernel.org/r/20260120222638.3976562-11-ihor.solodrai@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-29 14:10:19 -08:00
Thomas Gleixner
5d02120e10 treewide: Update email address
In a vain attempt to consolidate the email zoo switch everything to the
kernel.org account.

Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2026-01-29 14:10:19 -08:00
Donglin Peng
8a090ef1e5 btf: Refactor the code by calling str_is_empty
Calling the str_is_empty function to clarify the code and
no functional changes are introduced.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-12-dolinux.peng@gmail.com
2026-01-29 14:10:19 -08:00
Donglin Peng
ad9c763445 libbpf: Verify BTF sorting
This patch checks whether the BTF is sorted by name in ascending
order. If sorted, binary search will be used when looking up types.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-6-dolinux.peng@gmail.com
2026-01-29 14:10:19 -08:00
Donglin Peng
1c96b72cb0 libbpf: Optimize type lookup with binary search for sorted BTF
This patch introduces binary search optimization for BTF type lookups
when the BTF instance contains sorted types.

The optimization significantly improves performance when searching for
types in large BTF instances with sorted types. For unsorted BTF, the
implementation falls back to the original linear search.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-5-dolinux.peng@gmail.com
2026-01-29 14:10:19 -08:00
Donglin Peng
b7c6c02b5f libbpf: Add BTF permutation support for type reordering
Introduce btf__permute() API to allow in-place rearrangement of BTF types.
This function reorganizes BTF type order according to a provided array of
type IDs, updating all type references to maintain consistency.

Signed-off-by: Donglin Peng <pengdonglin@xiaomi.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260109130003.3313716-2-dolinux.peng@gmail.com
2026-01-29 14:10:19 -08:00
Varun R Mallya
2c5038dcf4 libbpf: Fix OOB read in btf_dump_get_bitfield_value
When dumping bitfield data, btf_dump_get_bitfield_value() reads data
based on the underlying type's size (t->size). However, it does not
verify that the provided data buffer (data_sz) is large enough to
contain these bytes.

If btf_dump__dump_type_data() is called with a buffer smaller than
the type's size, this leads to an out-of-bounds read. This was
confirmed by AddressSanitizer in the linked issue.

Fix this by ensuring we do not read past the provided data_sz limit.

Fixes: a1d3cc3c5eca ("libbpf: Avoid use of __int128 in typed dump display")
Reported-by: Harrison Green <harrisonmichaelgreen@gmail.com>
Suggested-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Varun R Mallya <varunrmallya@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20260106233527.163487-1-varunrmallya@gmail.com

Closes: https://github.com/libbpf/libbpf/issues/928
2026-01-29 14:10:19 -08:00
Leon Hwang
dc8673b28b libbpf: Add BPF_F_CPU and BPF_F_ALL_CPUS flags support for percpu maps
Add libbpf support for the BPF_F_CPU flag for percpu maps by embedding the
cpu info into the high 32 bits of:

1. **flags**: bpf_map_lookup_elem_flags(), bpf_map__lookup_elem(),
   bpf_map_update_elem() and bpf_map__update_elem()
2. **opts->elem_flags**: bpf_map_lookup_batch() and
   bpf_map_update_batch()

And the flag can be BPF_F_ALL_CPUS, but cannot be
'BPF_F_CPU | BPF_F_ALL_CPUS'.

Behavior:

* If the flag is BPF_F_ALL_CPUS, the update is applied across all CPUs.
* If the flag is BPF_F_CPU, it updates value only to the specified CPU.
* If the flag is BPF_F_CPU, lookup value only from the specified CPU.
* lookup does not support BPF_F_ALL_CPUS.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-7-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-29 14:10:19 -08:00
Leon Hwang
a6d7ceaaeb bpf: Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags
Introduce BPF_F_CPU and BPF_F_ALL_CPUS flags and check them for
following APIs:

* 'map_lookup_elem()'
* 'map_update_elem()'
* 'generic_map_lookup_batch()'
* 'generic_map_update_batch()'

And, get the correct value size for these APIs.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20260107022022.12843-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2026-01-29 14:10:19 -08:00
Thomas Weißschuh
e64e125ef6 vfs: use UAPI types for new struct delegation definition
Using libc types and headers from the UAPI headers is problematic as it
introduces a dependency on a full C toolchain.

Use the fixed-width integer types provided by the UAPI headers instead.

Fixes: 1602bad16d7d ("vfs: expose delegation support to userland")
Fixes: 4be9e04ebf75 ("vfs: add needed headers for new struct delegation definition")
Signed-off-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Link: https://patch.msgid.link/20251203-uapi-fcntl-v1-1-490c67bf3425@linutronix.de
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2026-01-29 14:10:19 -08:00
Emil Tsalapatis
9dd6fda504 libbpf: Move arena globals to the end of the arena
Arena globals are currently placed at the beginning of the arena
by libbpf. This is convenient, but prevents users from reserving
guard pages in the beginning of the arena to identify NULL pointer
dereferences. Adjust the load logic to place the globals at the
end of the arena instead.

Also modify bpftool to set the arena pointer in the program's BPF
skeleton to point to the globals. Users now call bpf_map__initial_value()
to find the beginning of the arena mapping and use the arena pointer
in the skeleton to determine which part of the mapping holds the
arena globals and which part is free.

Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251216173325.98465-5-emil@etsalapatis.com
2026-01-29 14:10:19 -08:00
Emil Tsalapatis
2c7fe6ec5d libbpf: Turn relo_core->sym_off unsigned
The symbols' relocation offsets in BPF are stored in an int field,
but cannot actually be negative. When in the next patch libbpf relocates
globals to the end of the arena, it is also possible to have valid
offsets > 2GiB that are used to calculate the final relo offsets.
Avoid accidentally interpreting large offsets as negative by turning
the sym_off field unsigned.

Signed-off-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20251216173325.98465-4-emil@etsalapatis.com
2026-01-29 14:10:19 -08:00
Andrii Nakryiko
160423d498 ci: denylist flaky 'bpf_cookie/perf_event' selftest
It keeps failing. It relies on perf_events so not super reliable.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2026-01-26 13:12:58 -08:00
Andrii Nakryiko
afb8b17bc5 sync: latest libbpf changes from kernel
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   f8c67d8550ee69ce684c7015b2c8c63cda24bbfb
Checkpoint bpf-next commit: 6f0b824a61f212e9707ff68abcabfdfa4724b811
Baseline bpf commit:        e427054ae7bc8b1268cf1989381a43885795616f
Checkpoint bpf commit:      1d528e794f3db5d32279123a89957c44c4406a09

Alan Maguire (1):
  libbpf: Add debug messaging in dedup equivalence/identity matching

Amery Hung (2):
  bpf: Support associating BPF program with struct_ops
  libbpf: Add support for associating BPF program with struct_ops

Asbjørn Sloth Tønnesen (1):
  tools: ynl-gen: add regeneration comment

Heiko Carstens (1):
  tools: Remove s390 compat support

James Clark (1):
  perf: Add perf_event_attr::config4

Jeff Layton (2):
  vfs: expose delegation support to userland
  vfs: add needed headers for new struct delegation definition

Jianyun Gao (1):
  libbpf: Fix some incorrect @param descriptions in the comment of
    libbpf.h

Kuniyuki Iwashima (1):
  bpf: Introduce SK_BPF_BYPASS_PROT_MEM.

Mikhail Gavrilov (1):
  libbpf: Fix -Wdiscarded-qualifiers under C23

Paul Houssel (1):
  libbpf: Fix BTF dedup to support recursive typedef definitions

Peter Zijlstra (1):
  perf: Support deferred user unwind

Samiullah Khawaja (1):
  net: Extend NAPI threaded polling to allow kthread based busy polling

 include/uapi/linux/bpf.h        |  19 ++++++
 include/uapi/linux/fcntl.h      |  16 +++++
 include/uapi/linux/netdev.h     |   2 +
 include/uapi/linux/perf_event.h |  23 +++++++-
 src/bpf.c                       |  19 ++++++
 src/bpf.h                       |  21 +++++++
 src/btf.c                       | 100 +++++++++++++++++++++++++-------
 src/libbpf.c                    |  42 +++++++++++---
 src/libbpf.h                    |  43 ++++++++++----
 src/libbpf.map                  |   2 +
 src/usdt.c                      |   2 -
 11 files changed, 247 insertions(+), 42 deletions(-)

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2025-12-16 09:52:07 -08:00
Mikhail Gavrilov
fda2bfcb7a libbpf: Fix -Wdiscarded-qualifiers under C23
glibc ≥ 2.42 (GCC 15) defaults to -std=gnu23, which promotes
-Wdiscarded-qualifiers to an error.

In C23, strstr() and strchr() return "const char *".

Change variable types to const char * where the pointers are never
modified (res, sym_sfx, next_path).

Suggested-by: Florian Weimer <fweimer@redhat.com>
Suggested-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Link: https://lore.kernel.org/r/20251206092825.1471385-1-mikhail.v.gavrilov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-12-16 09:52:07 -08:00
Amery Hung
5635185147 libbpf: Add support for associating BPF program with struct_ops
Add low-level wrapper and libbpf API for BPF_PROG_ASSOC_STRUCT_OPS
command in the bpf() syscall.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251203233748.668365-4-ameryhung@gmail.com
2025-12-16 09:52:07 -08:00
Amery Hung
1a41b12b4f bpf: Support associating BPF program with struct_ops
Add a new BPF command BPF_PROG_ASSOC_STRUCT_OPS to allow associating
a BPF program with a struct_ops map. This command takes a file
descriptor of a struct_ops map and a BPF program and set
prog->aux->st_ops_assoc to the kdata of the struct_ops map.

The command does not accept a struct_ops program nor a non-struct_ops
map. Programs of a struct_ops map is automatically associated with the
map during map update. If a program is shared between two struct_ops
maps, prog->aux->st_ops_assoc will be poisoned to indicate that the
associated struct_ops is ambiguous. The pointer, once poisoned, cannot
be reset since we have lost track of associated struct_ops. For other
program types, the associated struct_ops map, once set, cannot be
changed later. This restriction may be lifted in the future if there is
a use case.

A kernel helper bpf_prog_get_assoc_struct_ops() can be used to retrieve
the associated struct_ops pointer. The returned pointer, if not NULL, is
guaranteed to be valid and point to a fully updated struct_ops struct.
For struct_ops program reused in multiple struct_ops map, the return
will be NULL.

prog->aux->st_ops_assoc is protected by bumping the refcount for
non-struct_ops programs and RCU for struct_ops programs. Since it would
be inefficient to track programs associated with a struct_ops map, every
non-struct_ops program will bump the refcount of the map to make sure
st_ops_assoc stays valid. For a struct_ops program, it is protected by
RCU as map_free will wait for an RCU grace period before disassociating
the program with the map. The helper must be called in BPF program
context or RCU read-side critical section.

struct_ops implementers should note that the struct_ops returned may not
be initialized nor attached yet. The struct_ops implementer will be
responsible for tracking and checking the state of the associated
struct_ops map if the use case expects an initialized or attached
struct_ops.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Link: https://lore.kernel.org/bpf/20251203233748.668365-3-ameryhung@gmail.com
2025-12-16 09:52:07 -08:00
Alan Maguire
8ffe064aed libbpf: Add debug messaging in dedup equivalence/identity matching
We have seen a number of issues like [1]; failures to deduplicate
key kernel data structures like task_struct.  These are often hard
to debug from pahole even with verbose output, especially when
identity/equivalence checks fail deep in a nested struct comparison.

Here we add debug messages of the form

libbpf: STRUCT 'task_struct' size=2560 vlen=194 cand_id[54222] canon_id[102820] shallow-equal but not equiv for field#23 'sched_class': 0

These will be emitted during dedup from pahole when --verbose/-V
is specified.  This greatly helps identify exactly where dedup
failures are experienced.

[1] https://lore.kernel.org/bpf/b8e8b560-bce5-414b-846d-0da6d22a9983@oracle.com/

Changes since v1:

- updated debug messages to refer to shallow-equal, added ids (Andrii)

Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251203191507.55565-1-alan.maguire@oracle.com
2025-12-16 09:52:07 -08:00
Asbjørn Sloth Tønnesen
7ac4e3a670 tools: ynl-gen: add regeneration comment
Add a comment on regeneration to the generated files.

The comment is placed after the YNL-GEN line[1], as to not interfere
with ynl-regen.sh's detection logic.

[1] and after the optional YNL-ARG line.

Link: https://lore.kernel.org/r/aR5m174O7pklKrMR@zx2c4.com/
Suggested-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Asbjørn Sloth Tønnesen <ast@fiberby.net>
Acked-by: Matthieu Baerts (NGI0) <matttbe@kernel.org>
Link: https://patch.msgid.link/20251120174429.390574-3-ast@fiberby.net
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-16 09:52:07 -08:00
Samiullah Khawaja
cd173d0ea3 net: Extend NAPI threaded polling to allow kthread based busy polling
Add a new state NAPI_STATE_THREADED_BUSY_POLL to the NAPI state enum to
enable and disable threaded busy polling.

When threaded busy polling is enabled for a NAPI, enable
NAPI_STATE_THREADED also.

When the threaded NAPI is scheduled, set NAPI_STATE_IN_BUSY_POLL to
signal napi_complete_done not to rearm interrupts.

Whenever NAPI_STATE_THREADED_BUSY_POLL is unset, the
NAPI_STATE_IN_BUSY_POLL will be unset, napi_complete_done unsets the
NAPI_STATE_SCHED_THREADED bit also, which in turn will make the kthread
go to sleep.

Signed-off-by: Samiullah Khawaja <skhawaja@google.com>
Reviewed-by: Willem de Bruijn <willemb@google.com>
Acked-by: Martin Karsten <mkarsten@uwaterloo.ca>
Tested-by: Martin Karsten <mkarsten@uwaterloo.ca>
Link: https://patch.msgid.link/20251028203007.575686-2-skhawaja@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2025-12-16 09:52:07 -08:00
Kuniyuki Iwashima
3fe0a72123 bpf: Introduce SK_BPF_BYPASS_PROT_MEM.
If a socket has sk->sk_bypass_prot_mem flagged, the socket opts out
of the global protocol memory accounting.

This is easily controlled by net.core.bypass_prot_mem sysctl, but it
lacks flexibility.

Let's support flagging (and clearing) sk->sk_bypass_prot_mem via
bpf_setsockopt() at the BPF_CGROUP_INET_SOCK_CREATE hook.

  int val = 1;

  bpf_setsockopt(ctx, SOL_SOCKET, SK_BPF_BYPASS_PROT_MEM,
                 &val, sizeof(val));

As with net.core.bypass_prot_mem, this is inherited to child sockets,
and BPF always takes precedence over sysctl at socket(2) and accept(2).

SK_BPF_BYPASS_PROT_MEM is only supported at BPF_CGROUP_INET_SOCK_CREATE
and not supported on other hooks for some reasons:

  1. UDP charges memory under sk->sk_receive_queue.lock instead
     of lock_sock()

  2. Modifying the flag after skb is charged to sk requires such
     adjustment during bpf_setsockopt() and complicates the logic
     unnecessarily

We can support other hooks later if a real use case justifies that.

Most changes are inline and hard to trace, but a microbenchmark on
__sk_mem_raise_allocated() during neper/tcp_stream showed that more
samples completed faster with sk->sk_bypass_prot_mem == 1.  This will
be more visible under tcp_mem pressure (but it's not a fair comparison).

  # bpftrace -e 'kprobe:__sk_mem_raise_allocated { @start[tid] = nsecs; }
    kretprobe:__sk_mem_raise_allocated /@start[tid]/
    { @end[tid] = nsecs - @start[tid]; @times = hist(@end[tid]); delete(@start[tid]); }'
  # tcp_stream -6 -F 1000 -N -T 256

Without bpf prog:

  [128, 256)          3846 |                                                    |
  [256, 512)       1505326 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
  [512, 1K)        1371006 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@     |
  [1K, 2K)          198207 |@@@@@@                                              |
  [2K, 4K)           31199 |@                                                   |

With bpf prog in the next patch:
  (must be attached before tcp_stream)
  # bpftool prog load sk_bypass_prot_mem.bpf.o /sys/fs/bpf/test type cgroup/sock_create
  # bpftool cgroup attach /sys/fs/cgroup/test cgroup_inet_sock_create pinned /sys/fs/bpf/test

  [128, 256)          6413 |                                                    |
  [256, 512)       1868425 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@|
  [512, 1K)        1101697 |@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@                      |
  [1K, 2K)          117031 |@@@@                                                |
  [2K, 4K)           11773 |                                                    |

Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev>
Link: https://patch.msgid.link/20251014235604.3057003-6-kuniyu@google.com
2025-12-16 09:52:07 -08:00
Jianyun Gao
f561c42074 libbpf: Fix some incorrect @param descriptions in the comment of libbpf.h
Fix up some of missing or incorrect @param descriptions for libbpf public APIs
in libbpf.h.

Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251118033025.11804-1-jianyungao89@gmail.com
2025-12-16 09:52:07 -08:00
Paul Houssel
370271441c libbpf: Fix BTF dedup to support recursive typedef definitions
Handle recursive typedefs in BTF deduplication

Pahole fails to encode BTF for some Go projects (e.g. Kubernetes and
Podman) due to recursive type definitions that create reference loops
not representable in C. These recursive typedefs trigger a failure in
the BTF deduplication algorithm.

This patch extends btf_dedup_ref_type() to properly handle potential
recursion for BTF_KIND_TYPEDEF, similar to how recursion is already
handled for BTF_KIND_STRUCT. This allows pahole to successfully
generate BTF for Go binaries using recursive types without impacting
existing C-based workflows.

Suggested-by: Tristan d'Audibert <tristan.daudibert@gmail.com>
Co-developed-by: Martin Horth <martin.horth@telecom-sudparis.eu>
Co-developed-by: Ouail Derghal <ouail.derghal@imt-atlantique.fr>
Co-developed-by: Guilhem Jazeron <guilhem.jazeron@inria.fr>
Co-developed-by: Ludovic Paillat <ludovic.paillat@inria.fr>
Co-developed-by: Robin Theveniaut <robin.theveniaut@irit.fr>
Signed-off-by: Martin Horth <martin.horth@telecom-sudparis.eu>
Signed-off-by: Ouail Derghal <ouail.derghal@imt-atlantique.fr>
Signed-off-by: Guilhem Jazeron <guilhem.jazeron@inria.fr>
Signed-off-by: Ludovic Paillat <ludovic.paillat@inria.fr>
Signed-off-by: Robin Theveniaut <robin.theveniaut@irit.fr>
Signed-off-by: Paul Houssel <paul.houssel@orange.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/bf00857b1e06f282aac12f6834de7396a7547ba6.1763037045.git.paul.houssel@orange.com
2025-12-16 09:52:07 -08:00
James Clark
8cc0f2c095 perf: Add perf_event_attr::config4
Arm FEAT_SPE_FDS adds the ability to filter on the data source of a
packet using another 64-bits of event filtering control. As the existing
perf_event_attr::configN fields are all used up for SPE PMU, an
additional field is needed. Add a new 'config4' field.

Reviewed-by: Leo Yan <leo.yan@arm.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Ian Rogers <irogers@google.com>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: James Clark <james.clark@linaro.org>
Signed-off-by: Will Deacon <will@kernel.org>
2025-12-16 09:52:07 -08:00
Heiko Carstens
9905b35d8a tools: Remove s390 compat support
Remove s390 compat support from everything within tools, since s390 compat
support will be removed from the kernel.

Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Thomas Weißschuh <linux@weissschuh.net> # tools/nolibc selftests/nolibc
Reviewed-by: Thomas Weißschuh <linux@weissschuh.net> # selftests/vDSO
Acked-by: Alexei Starovoitov <ast@kernel.org> # bpf bits
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
2025-12-16 09:52:07 -08:00
Peter Zijlstra
8d178bd7b6 perf: Support deferred user unwind
Add support for deferred userspace unwind to perf.

Where perf currently relies on in-place stack unwinding; from NMI
context and all that. This moves the userspace part of the unwind to
right before the return-to-userspace.

This has two distinct benefits, the biggest is that it moves the
unwind to a faultable context. It becomes possible to fault in debug
info (.eh_frame, SFrame etc.) that might not otherwise be readily
available. And secondly, it de-duplicates the user callchain where
multiple samples happen during the same kernel entry.

To facilitate this the perf interface is extended with a new record
type:

  PERF_RECORD_CALLCHAIN_DEFERRED

and two new attribute flags:

  perf_event_attr::defer_callchain - to request the user unwind be deferred
  perf_event_attr::defer_output    - to request PERF_RECORD_CALLCHAIN_DEFERRED records

The existing PERF_RECORD_SAMPLE callchain section gets a new
context type:

  PERF_CONTEXT_USER_DEFERRED

After which will come a single entry, denoting the 'cookie' of the
deferred callchain that should be attached here, matching the 'cookie'
field of the above mentioned PERF_RECORD_CALLCHAIN_DEFERRED.

The 'defer_callchain' flag is expected on all events with
PERF_SAMPLE_CALLCHAIN. The 'defer_output' flag is expect on the event
responsible for collecting side-band events (like mmap, comm etc.).
Setting 'defer_output' on multiple events will get you duplicated
PERF_RECORD_CALLCHAIN_DEFERRED records.

Based on earlier patches by Josh and Steven.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://patch.msgid.link/20251023150002.GR4067720@noisy.programming.kicks-ass.net
2025-12-16 09:52:07 -08:00
Jeff Layton
530f40421a vfs: add needed headers for new struct delegation definition
The definition of struct delegation uses stdint.h integer types. Add the
necessary headers to ensure that always works.

Fixes: 1602bad16d7d ("vfs: expose delegation support to userland")
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-12-16 09:52:07 -08:00
Jeff Layton
4f10610ae5 vfs: expose delegation support to userland
Now that support for recallable directory delegations is available,
expose this functionality to userland with new F_SETDELEG and F_GETDELEG
commands for fcntl().

Note that this also allows userland to request a FL_DELEG type lease on
files too. Userland applications that do will get signalled when there
are metadata changes in addition to just data changes (which is a
limitation of FL_LEASE leases).

These commands accept a new "struct delegation" argument that contains a
flags field for future expansion.

Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20251111-dir-deleg-ro-v6-17-52f3feebb2f2@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-12-16 09:52:07 -08:00
Andrii Nakryiko
d65dbb412d sync: latest libbpf changes from kernel
Syncing latest libbpf commits from kernel repository.
Baseline bpf-next commit:   de7342228b7343774d6a9981c2ddbfb5e201044b
Checkpoint bpf-next commit: f8c67d8550ee69ce684c7015b2c8c63cda24bbfb
Baseline bpf commit:        4d920ed684392ae064af62957d6f5a90312dfaf6
Checkpoint bpf commit:      e427054ae7bc8b1268cf1989381a43885795616f

Alan Maguire (1):
  libbpf: Fix parsing of multi-split BTF

Andrii Nakryiko (1):
  libbpf: Fix powerpc's stack register definition in bpf_tracing.h

Anton Protopopov (4):
  libbpf: fix formatting of bpf_object__append_subprog_code
  bpf, x86: add new map type: instructions array
  libbpf: Recognize insn_array map type
  libbpf: support llvm-generated indirect jumps

Donald Hunter (1):
  docs/bpf: Add missing BPF k/uprobe program types to docs

Jianyun Gao (4):
  libbpf: Optimize the redundant code in the
    bpf_object__init_user_btf_maps() function.
  libbpf: Fix the incorrect reference to the memlock_rlim variable in
    the comment.
  libbpf: Complete the missing @param and @return tags in btf.h
  libbpf: Update the comment to remove the reference to the deprecated
    interface bpf_program__load().

Mykyta Yatsenko (2):
  bpf: widen dynptr size/offset to 64 bit
  bpf: add _impl suffix for bpf_stream_vprintk() kfunc

Xu Kuohai (1):
  bpf: Add overwrite mode for BPF ring buffer

 docs/program_types.rst   |  18 +++
 include/uapi/linux/bpf.h |  33 ++++-
 src/bpf.c                |   2 +-
 src/bpf_helpers.h        |  28 ++--
 src/bpf_tracing.h        |   2 +-
 src/btf.c                |   4 +-
 src/btf.h                |   8 ++
 src/libbpf.c             | 296 +++++++++++++++++++++++++++++++++++----
 src/libbpf_internal.h    |   2 +
 src/libbpf_probes.c      |   4 +
 src/linker.c             |   3 +
 11 files changed, 353 insertions(+), 47 deletions(-)

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2025-11-07 14:00:07 -08:00
Andrii Nakryiko
befbf010d7 sync: auto-generate latest BPF helpers
Latest changes to BPF helper definitions.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
2025-11-07 14:00:07 -08:00
Mykyta Yatsenko
a00b10df8c bpf: add _impl suffix for bpf_stream_vprintk() kfunc
Rename bpf_stream_vprintk() to bpf_stream_vprintk_impl().

This makes bpf_stream_vprintk() follow the already established "_impl"
suffix-based naming convention for kfuncs with the bpf_prog_aux
argument provided by the verifier implicitly. This convention will be
taken advantage of with the upcoming KF_IMPLICIT_ARGS feature to
preserve backwards compatibility to BPF programs.

Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Link: https://lore.kernel.org/r/20251104-implv2-v3-2-4772b9ae0e06@meta.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Ihor Solodrai <ihor.solodrai@linux.dev>
2025-11-07 14:00:07 -08:00
Anton Protopopov
24a89cb35d libbpf: support llvm-generated indirect jumps
For v4 instruction set LLVM is allowed to generate indirect jumps for
switch statements and for 'goto *rX' assembly. Every such a jump will
be accompanied by necessary metadata, e.g. (`llvm-objdump -Sr ...`):

       0:       r2 = 0x0 ll
                0000000000000030:  R_BPF_64_64  BPF.JT.0.0

Here BPF.JT.1.0 is a symbol residing in the .jumptables section:

    Symbol table:
       4: 0000000000000000   240 OBJECT  GLOBAL DEFAULT     4 BPF.JT.0.0

The -bpf-min-jump-table-entries llvm option may be used to control the
minimal size of a switch which will be converted to an indirect jumps.

Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-11-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-07 14:00:07 -08:00
Anton Protopopov
349b78117b libbpf: Recognize insn_array map type
Teach libbpf about the existence of the new instruction array map.

Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-4-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-07 14:00:07 -08:00
Anton Protopopov
9d159773c5 bpf, x86: add new map type: instructions array
On bpf(BPF_PROG_LOAD) syscall user-supplied BPF programs are
translated by the verifier into "xlated" BPF programs. During this
process the original instructions offsets might be adjusted and/or
individual instructions might be replaced by new sets of instructions,
or deleted.

Add a new BPF map type which is aimed to keep track of how, for a
given program, the original instructions were relocated during the
verification. Also, besides keeping track of the original -> xlated
mapping, make x86 JIT to build the xlated -> jitted mapping for every
instruction listed in an instruction array. This is required for every
future application of instruction arrays: static keys, indirect jumps
and indirect calls.

A map of the BPF_MAP_TYPE_INSN_ARRAY type must be created with a u32
keys and value of size 8. The values have different semantics for
userspace and for BPF space. For userspace a value consists of two
u32 values – xlated and jitted offsets. For BPF side the value is
a real pointer to a jitted instruction.

On map creation/initialization, before loading the program, each
element of the map should be initialized to point to an instruction
offset within the program. Before the program load such maps should
be made frozen. After the program verification xlated and jitted
offsets can be read via the bpf(2) syscall.

If a tracked instruction is removed by the verifier, then the xlated
offset is set to (u32)-1 which is considered to be too big for a valid
BPF program offset.

One such a map can, obviously, be used to track one and only one BPF
program.  If the verification process was unsuccessful, then the same
map can be re-used to verify the program with a different log level.
However, if the program was loaded fine, then such a map, being
frozen in any case, can't be reused by other programs even after the
program release.

Example. Consider the following original and xlated programs:

    Original prog:                      Xlated prog:

     0:  r1 = 0x0                        0: r1 = 0
     1:  *(u32 *)(r10 - 0x4) = r1        1: *(u32 *)(r10 -4) = r1
     2:  r2 = r10                        2: r2 = r10
     3:  r2 += -0x4                      3: r2 += -4
     4:  r1 = 0x0 ll                     4: r1 = map[id:88]
     6:  call 0x1                        6: r1 += 272
                                         7: r0 = *(u32 *)(r2 +0)
                                         8: if r0 >= 0x1 goto pc+3
                                         9: r0 <<= 3
                                        10: r0 += r1
                                        11: goto pc+1
                                        12: r0 = 0
     7:  r6 = r0                        13: r6 = r0
     8:  if r6 == 0x0 goto +0x2         14: if r6 == 0x0 goto pc+4
     9:  call 0x76                      15: r0 = 0xffffffff8d2079c0
                                        17: r0 = *(u64 *)(r0 +0)
    10:  *(u64 *)(r6 + 0x0) = r0        18: *(u64 *)(r6 +0) = r0
    11:  r0 = 0x0                       19: r0 = 0x0
    12:  exit                           20: exit

An instruction array map, containing, e.g., instructions [0,4,7,12]
will be translated by the verifier to [0,4,13,20]. A map with
index 5 (the middle of 16-byte instruction) or indexes greater than 12
(outside the program boundaries) would be rejected.

The functionality provided by this patch will be extended in consequent
patches to implement BPF Static Keys, indirect jumps, and indirect calls.

Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251105090410.1250500-2-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-07 14:00:07 -08:00
Alan Maguire
0e14a12a1d libbpf: Fix parsing of multi-split BTF
When creating multi-split BTF we correctly set the start string offset
to be the size of the base string section plus the base BTF start
string offset; the latter is needed for multi-split BTF since the
offset is non-zero there.

Unfortunately the BTF parsing case needed that logic and it was
missed.

Fixes: 4e29128a9ace ("libbpf/btf: Fix string handling to support multi-split BTF")
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251104203309.318429-2-alan.maguire@oracle.com
2025-11-07 14:00:07 -08:00
Donald Hunter
813fbe13ab docs/bpf: Add missing BPF k/uprobe program types to docs
Update the table of program types in the libbpf docs with the missing
k/uprobe multi and session program types.

Signed-off-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251029180932.98038-1-donald.hunter@gmail.com
2025-11-07 14:00:07 -08:00
Jianyun Gao
fd00fd999f libbpf: Update the comment to remove the reference to the deprecated interface bpf_program__load().
Commit be2f2d1680df ("libbpf: Deprecate bpf_program__load() API") marked
bpf_program__load() as deprecated starting with libbpf v0.6. And later
in commit 146bf811f5ac ("libbpf: remove most other deprecated high-level
APIs") actually removed the bpf_program__load() implementation and
related old high-level APIs.

This patch update the comment in bpf_program__set_attach_target() to
remove the reference to the deprecated interface bpf_program__load().

Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251103120727.145965-1-jianyungao89@gmail.com
2025-11-07 14:00:07 -08:00
Jianyun Gao
f4b32db745 libbpf: Complete the missing @param and @return tags in btf.h
Complete the missing @param and @return tags in the Doxygen comments of
the btf.h file.

Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251103115836.144339-1-jianyungao89@gmail.com
2025-11-07 14:00:07 -08:00
Andrii Nakryiko
99bf90957a libbpf: Fix powerpc's stack register definition in bpf_tracing.h
retsnoop's build on powerpc (ppc64le) architecture ([0]) failed due to
wrong definition of PT_REGS_SP() macro. Looking at powerpc's
implementation of stack unwinding in perf_callchain_user_64() clearly
shows that stack pointer register is gpr[1].

Fix libbpf's definition of __PT_SP_REG for powerpc to fix all this.

  [0] https://kojipkgs.fedoraproject.org/work/tasks/1544/137921544/build.log

Fixes: 138d6153a139 ("samples/bpf: Enable powerpc support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Naveen N Rao (AMD) <naveen@kernel.org>
Link: https://lore.kernel.org/r/20251020203643.989467-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-07 14:00:07 -08:00
Jianyun Gao
98b6e51fc6 libbpf: Fix the incorrect reference to the memlock_rlim variable in the comment.
The variable "memlock_rlim_max" referenced in the comment does not exist.
I think that the author probably meant the variable "memlock_rlim". So,
correct it.

Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251027032008.738944-1-jianyungao89@gmail.com
2025-11-07 14:00:07 -08:00
Jianyun Gao
bc3b400e06 libbpf: Optimize the redundant code in the bpf_object__init_user_btf_maps() function.
In the elf_sec_data() function, the input parameter 'scn' will be
evaluated. If it is NULL, then it will directly return NULL. Therefore,
the return value of the elf_sec_data() function already takes into
account the case where the input parameter scn is NULL. Therefore,
subsequently, the code only needs to check whether the return value of
the elf_sec_data() function is NULL.

Signed-off-by: Jianyun Gao <jianyungao89@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/bpf/20251024080802.642189-1-jianyungao89@gmail.com
2025-11-07 14:00:07 -08:00
Xu Kuohai
665ad8c7f7 bpf: Add overwrite mode for BPF ring buffer
When the BPF ring buffer is full, a new event cannot be recorded until one
or more old events are consumed to make enough space for it. In cases such
as fault diagnostics, where recent events are more useful than older ones,
this mechanism may lead to critical events being lost.

So add overwrite mode for BPF ring buffer to address it. In this mode, the
new event overwrites the oldest event when the buffer is full.

The basic idea is as follows:

1. producer_pos tracks the next position to record new event. When there
   is enough free space, producer_pos is simply advanced by producer to
   make space for the new event.

2. To avoid waiting for consumer when the buffer is full, a new variable,
   overwrite_pos, is introduced for producer. It points to the oldest event
   committed in the buffer. It is advanced by producer to discard one or more
   oldest events to make space for the new event when the buffer is full.

3. pending_pos tracks the oldest event to be committed. pending_pos is never
   passed by producer_pos, so multiple producers never write to the same
   position at the same time.

The following example diagrams show how it works in a 4096-byte ring buffer.

1. At first, {producer,overwrite,pending,consumer}_pos are all set to 0.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |                                                                       |
   |                                                                       |
   |                                                                       |
   +-----------------------------------------------------------------------+
   ^
   |
   |
producer_pos = 0
overwrite_pos = 0
pending_pos = 0
consumer_pos = 0

2. Now reserve a 512-byte event A.

   There is enough free space, so A is allocated at offset 0. And producer_pos
   is advanced to 512, the end of A. Since A is not submitted, the BUSY bit is
   set.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |        |                                                              |
   |   A    |                                                              |
   | [BUSY] |                                                              |
   +-----------------------------------------------------------------------+
   ^        ^
   |        |
   |        |
   |    producer_pos = 512
   |
overwrite_pos = 0
pending_pos = 0
consumer_pos = 0

3. Reserve event B, size 1024.

   B is allocated at offset 512 with BUSY bit set, and producer_pos is advanced
   to the end of B.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |        |                 |                                            |
   |   A    |        B        |                                            |
   | [BUSY] |      [BUSY]     |                                            |
   +-----------------------------------------------------------------------+
   ^                          ^
   |                          |
   |                          |
   |                   producer_pos = 1536
   |
overwrite_pos = 0
pending_pos = 0
consumer_pos = 0

4. Reserve event C, size 2048.

   C is allocated at offset 1536, and producer_pos is advanced to 3584.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |        |                 |                                   |        |
   |    A   |        B        |                 C                 |        |
   | [BUSY] |      [BUSY]     |               [BUSY]              |        |
   +-----------------------------------------------------------------------+
   ^                                                              ^
   |                                                              |
   |                                                              |
   |                                                    producer_pos = 3584
   |
overwrite_pos = 0
pending_pos = 0
consumer_pos = 0

5. Submit event A.

   The BUSY bit of A is cleared. B becomes the oldest event to be committed, so
   pending_pos is advanced to 512, the start of B.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |        |                 |                                   |        |
   |    A   |        B        |                 C                 |        |
   |        |      [BUSY]     |               [BUSY]              |        |
   +-----------------------------------------------------------------------+
   ^        ^                                                     ^
   |        |                                                     |
   |        |                                                     |
   |   pending_pos = 512                                  producer_pos = 3584
   |
overwrite_pos = 0
consumer_pos = 0

6. Submit event B.

   The BUSY bit of B is cleared, and pending_pos is advanced to the start of C,
   which is now the oldest event to be committed.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |        |                 |                                   |        |
   |    A   |        B        |                 C                 |        |
   |        |                 |               [BUSY]              |        |
   +-----------------------------------------------------------------------+
   ^                          ^                                   ^
   |                          |                                   |
   |                          |                                   |
   |                     pending_pos = 1536               producer_pos = 3584
   |
overwrite_pos = 0
consumer_pos = 0

7. Reserve event D, size 1536 (3 * 512).

   There are 2048 bytes not being written between producer_pos (currently 3584)
   and pending_pos, so D is allocated at offset 3584, and producer_pos is advanced
   by 1536 (from 3584 to 5120).

   Since event D will overwrite all bytes of event A and the first 512 bytes of
   event B, overwrite_pos is advanced to the start of event C, the oldest event
   that is not overwritten.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |                 |        |                                   |        |
   |      D End      |        |                 C                 | D Begin|
   |      [BUSY]     |        |               [BUSY]              | [BUSY] |
   +-----------------------------------------------------------------------+
   ^                 ^        ^
   |                 |        |
   |                 |   pending_pos = 1536
   |                 |   overwrite_pos = 1536
   |                 |
   |             producer_pos=5120
   |
consumer_pos = 0

8. Reserve event E, size 1024.

   Although there are 512 bytes not being written between producer_pos and
   pending_pos, E cannot be reserved, as it would overwrite the first 512
   bytes of event C, which is still being written.

9. Submit event C and D.

   pending_pos is advanced to the end of D.

   0       512      1024    1536     2048     2560     3072     3584       4096
   +-----------------------------------------------------------------------+
   |                 |        |                                   |        |
   |      D End      |        |                 C                 | D Begin|
   |                 |        |                                   |        |
   +-----------------------------------------------------------------------+
   ^                 ^        ^
   |                 |        |
   |                 |   overwrite_pos = 1536
   |                 |
   |             producer_pos=5120
   |             pending_pos=5120
   |
consumer_pos = 0

The performance data for overwrite mode will be provided in a follow-up
patch that adds overwrite-mode benchmarks.

A sample of performance data for non-overwrite mode, collected on an x86_64
CPU and an arm64 CPU, before and after this patch, is shown below. As we can
see, no obvious performance regression occurs.

- x86_64 (AMD EPYC 9654)

Before:

Ringbuf, multi-producer contention
==================================
rb-libbpf nr_prod 1  11.623 ± 0.027M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 2  15.812 ± 0.014M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 3  7.871 ± 0.003M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 4  6.703 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 8  2.896 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 12 2.054 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 16 1.864 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 20 1.580 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 24 1.484 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 28 1.369 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 32 1.316 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 36 1.272 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 40 1.239 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 44 1.226 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 48 1.213 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 52 1.193 ± 0.001M/s (drops 0.000 ± 0.000M/s)

After:

Ringbuf, multi-producer contention
==================================
rb-libbpf nr_prod 1  11.845 ± 0.036M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 2  15.889 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 3  8.155 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 4  6.708 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 8  2.918 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 12 2.065 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 16 1.870 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 20 1.582 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 24 1.482 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 28 1.372 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 32 1.323 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 36 1.264 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 40 1.236 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 44 1.209 ± 0.002M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 48 1.189 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 52 1.165 ± 0.002M/s (drops 0.000 ± 0.000M/s)

- arm64 (HiSilicon Kunpeng 920)

Before:

Ringbuf, multi-producer contention
==================================
rb-libbpf nr_prod 1  11.310 ± 0.623M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 2  9.947 ± 0.004M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 3  6.634 ± 0.011M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 4  4.502 ± 0.003M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 8  3.888 ± 0.003M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 12 3.372 ± 0.005M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 16 3.189 ± 0.010M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 20 2.998 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 24 3.086 ± 0.018M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 28 2.845 ± 0.004M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 32 2.815 ± 0.008M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 36 2.771 ± 0.009M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 40 2.814 ± 0.011M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 44 2.752 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 48 2.695 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 52 2.710 ± 0.006M/s (drops 0.000 ± 0.000M/s)

After:

Ringbuf, multi-producer contention
==================================
rb-libbpf nr_prod 1  11.283 ± 0.550M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 2  9.993 ± 0.003M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 3  6.898 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 4  5.257 ± 0.001M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 8  3.830 ± 0.005M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 12 3.528 ± 0.013M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 16 3.265 ± 0.018M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 20 2.990 ± 0.007M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 24 2.929 ± 0.014M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 28 2.898 ± 0.010M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 32 2.818 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 36 2.789 ± 0.012M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 40 2.770 ± 0.006M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 44 2.651 ± 0.007M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 48 2.669 ± 0.005M/s (drops 0.000 ± 0.000M/s)
rb-libbpf nr_prod 52 2.695 ± 0.009M/s (drops 0.000 ± 0.000M/s)

Signed-off-by: Xu Kuohai <xukuohai@huawei.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20251018035738.4039621-2-xukuohai@huaweicloud.com
2025-11-07 14:00:07 -08:00
Mykyta Yatsenko
42995c95b9 bpf: widen dynptr size/offset to 64 bit
Dynptr currently caps size and offset at 24 bits, which isn’t sufficient
for file-backed use cases; even 32 bits can be limiting. Refactor dynptr
helpers/kfuncs to use 64-bit size and offset, ensuring consistency
across the APIs.

This change does not affect internals of xdp, skb or other dynptrs,
which continue to behave as before. Also it does not break binary
compatibility.

The widening enables large-file access support via dynptr, implemented
in the next patches.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20251026203853.135105-3-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-07 14:00:07 -08:00
Anton Protopopov
49c5e0eef4 libbpf: fix formatting of bpf_object__append_subprog_code
The commit 6c918709bd30 ("libbpf: Refactor bpf_object__reloc_code")
added the bpf_object__append_subprog_code() with incorrect indentations.
Use tabs instead. (This also makes a consequent commit better readable.)

Signed-off-by: Anton Protopopov <a.s.protopopov@gmail.com>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20251019202145.3944697-14-a.s.protopopov@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
2025-11-07 14:00:07 -08:00
Alain Knaff
30599e72bf include: add __poll_t typedef in include/linux/types.h for Android/Termux
On Android/Termux, linux/types.h is included (indirectly) by sys/epoll.h which
depends on this definition to be present.

Signed-off-by: Alain Knaff <github@misc.lka.org.lu>
2025-11-07 12:35:07 -08:00