Jordan Rife says:
====================
This patch series migrates test cases out of test_sock.c to
prog_tests-style tests. It moves all BPF_CGROUP_INET4_POST_BIND and
BPF_CGROUP_INET6_POST_BIND test cases into a new prog_test,
sock_post_bind.c, while reimplementing all LOAD_REJECT test cases as
verifier tests in progs/verifier_sock.c. Finally, it moves remaining
BPF_CGROUP_INET_SOCK_CREATE test coverage into prog_tests/sock_create.c
before retiring test_sock.c completely.
Changes
=======
v1->v2:
- Remove superfluous verbose bool from the top of sock_post_bind.c.
- Use ASSERT_OK_FD instead of ASSERT_GE to test cgroup_fd validity.
- Run sock_post_bind tests in their own namespace, "sock_post_bind".
====================
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
Implement bpf_send_signal_task kfunc that is similar to
bpf_send_signal_thread and bpf_send_signal helpers but can be used to
send signals to other threads and processes. It also supports sending a
cookie with the signal similar to sigqueue().
If the receiving process establishes a handler for the signal using the
SA_SIGINFO flag to sigaction(), then it can obtain this cookie via the
si_value field of the siginfo_t structure passed as the second argument
to the handler.
Signed-off-by: Puranjay Mohan <puranjay@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241016084136.10305-2-puranjay@kernel.org
Leon Hwang says:
====================
bpf: Fix tailcall infinite loop caused by freplace
Previously, I addressed a tailcall infinite loop issue related to
trampolines[0].
In this patchset, I resolve a similar issue where a tailcall infinite loop
can occur due to the combination of tailcalls and freplace programs. The
fix prevents adding extended programs to the prog_array map and blocks the
extension of a tail callee program with freplace.
Key changes:
1. If a program or its subprogram has been extended by an freplace program,
it can no longer be updated to a prog_array map.
2. If a program has been added to a prog_array map, neither it nor its
subprograms can be extended by an freplace program.
Additionally, an extension program should not be tailcalled. As a result,
return -EINVAL if the program has a type of BPF_PROG_TYPE_EXT when adding
it to a prog_array map.
Changes:
v7 -> v8:
* Address comment from Alexei:
* guard(mutex) should not hold range all the way through
bpf_arch_text_poke().
* Address suggestion from Xu Kuohai:
* Extension prog should not be tailcalled independently.
v6 -> v7:
* Address comments from Alexei:
* Rewrite commit message more imperative and consice with AI.
* Extend bpf_trampoline_link_prog() and bpf_trampoline_unlink_prog()
to link and unlink target prog for freplace prog.
* Use guard(mutex)(&tgt_prog->aux->ext_mutex) instead of
mutex_lock()&mutex_unlock() pair.
* Address comment from Eduard:
* Remove misplaced "Reported-by" and "Closes" tags.
v5 -> v6:
* Fix a build warning reported by kernel test robot.
v4 -> v5:
* Move code of linking/unlinking target prog of freplace to trampoline.c.
* Address comments from Alexei:
* Change type of prog_array_member_cnt to u64.
* Combine two patches to one.
v3 -> v4:
* Address comments from Eduard:
* Rename 'tail_callee_cnt' to 'prog_array_member_cnt'.
* Add comment to 'prog_array_member_cnt'.
* Use a mutex to protect 'is_extended' and 'prog_array_member_cnt'.
v2 -> v3:
* Address comments from Alexei:
* Stop hacking JIT.
* Prevent the specific use case at attach/update time.
v1 -> v2:
* Address comment from Eduard:
* Explain why nop5 and xor/nop3 are swapped at prologue.
* Address comment from Alexei:
* Disallow attaching tail_call_reachable freplace prog to
not-tail_call_reachable target in verifier.
* Update "bpf, arm64: Fix tailcall infinite loop caused by freplace" with
latest arm64 JIT code.
Links:
[0] https://lore.kernel.org/bpf/20230912150442.2009-1-hffilwlqm@gmail.com/
====================
Link: https://lore.kernel.org/r/20241015150207.70264-1-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch adds test cases for bpf_task_from_vpid() kfunc.
task_kfunc_from_vpid_no_null_check is used to test the case where
the return value is not checked for NULL pointer.
test_task_from_vpid_current is used to test obtaining the
struct task_struct of the process in the pid namespace based on vpid.
test_task_from_vpid_invalid is used to test the case of invalid vpid.
test_task_from_vpid_current and test_task_from_vpid_invalid will run
in the new namespace.
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Link: https://lore.kernel.org/r/AM6PR03MB5848F13435CD650AC4B7BD7099442@AM6PR03MB5848.eurprd03.prod.outlook.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Add a test case to ensure that attaching a tail callee program with an
freplace program fails, and that updating an extended program to a
prog_array map is also prohibited.
This test is designed to prevent the potential infinite loop issue caused
by the combination of tail calls and freplace, ensuring the correct
behavior and stability of the system.
Additionally, fix the broken tailcalls/tailcall_freplace selftest
because an extension prog should not be tailcalled.
cd tools/testing/selftests/bpf; ./test_progs -t tailcalls
337/25 tailcalls/tailcall_freplace:OK
337/26 tailcalls/tailcall_bpf2bpf_freplace:OK
337 tailcalls:OK
Summary: 1/26 PASSED, 0 SKIPPED, 0 FAILED
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20241015150207.70264-3-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
bpf_task_from_pid() that currently exists looks up the
struct task_struct corresponding to the pid in the root pid
namespace (init_pid_ns).
This patch adds bpf_task_from_vpid() which looks up the
struct task_struct corresponding to vpid in the pid namespace
of the current process.
This is useful for getting information about other processes
in the same pid namespace.
Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Link: https://lore.kernel.org/r/AM6PR03MB5848E50DA58F79CDE65433C399442@AM6PR03MB5848.eurprd03.prod.outlook.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
There is a potential infinite loop issue that can occur when using a
combination of tail calls and freplace.
In an upcoming selftest, the attach target for entry_freplace of
tailcall_freplace.c is subprog_tc of tc_bpf2bpf.c, while the tail call in
entry_freplace leads to entry_tc. This results in an infinite loop:
entry_tc -> subprog_tc -> entry_freplace --tailcall-> entry_tc.
The problem arises because the tail_call_cnt in entry_freplace resets to
zero each time entry_freplace is executed, causing the tail call mechanism
to never terminate, eventually leading to a kernel panic.
To fix this issue, the solution is twofold:
1. Prevent updating a program extended by an freplace program to a
prog_array map.
2. Prevent extending a program that is already part of a prog_array map
with an freplace program.
This ensures that:
* If a program or its subprogram has been extended by an freplace program,
it can no longer be updated to a prog_array map.
* If a program has been added to a prog_array map, neither it nor its
subprograms can be extended by an freplace program.
Moreover, an extension program should not be tailcalled. As such, return
-EINVAL if the program has a type of BPF_PROG_TYPE_EXT when adding it to a
prog_array map.
Additionally, fix a minor code style issue by replacing eight spaces with a
tab for proper formatting.
Reviewed-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Leon Hwang <leon.hwang@linux.dev>
Link: https://lore.kernel.org/r/20241015150207.70264-2-leon.hwang@linux.dev
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Namhyung Kim says:
====================
bpf: Add kmem_cache iterator and kfunc
Hello,
I'm proposing a new iterator and a kfunc for the slab memory allocator
to get information of each kmem_cache like in /proc/slabinfo or
/sys/kernel/slab in more flexible way.
v5 changes
* set PTR_UNTRUSTED for return value of bpf_get_kmem_cache() (Alexei)
* add KF_RCU_PROTECTED to bpf_get_kmem_cache(). See below. (Song)
* add WARN_ON_ONCE and comment in kmem_cache_iter_seq_next() (Song)
* change kmem_cache_iter_seq functions not to call BPF on intermediate stop
* add a subtest to compare the kmem cache info with /proc/slabinfo (Alexei)
v4: https://lore.kernel.org/lkml/20241002180956.1781008-1-namhyung@kernel.org
* skip kmem_cache_destroy() in kmem_cache_iter_seq_stop() if possible (Vlastimil)
* fix a bug in the kmem_cache_iter_seq_start() for the last entry
v3: https://lore.kernel.org/lkml/20241002065456.1580143-1-namhyung@kernel.org/
* rework kmem_cache_iter not to hold slab_mutex when running BPF (Alexei)
* add virt_addr_valid() check (Alexei)
* fix random test failure by running test with the current task (Hyeonggon)
v2: https://lore.kernel.org/lkml/20240927184133.968283-1-namhyung@kernel.org/
* rename it to "kmem_cache_iter"
* fix a build issue
* add Acked-by's from Roman and Vlastimil (Thanks!)
* add error codes in the test for debugging
v1: https://lore.kernel.org/lkml/20240925223023.735947-1-namhyung@kernel.org/
My use case is `perf lock contention` tool which shows contended locks
but many of them are not global locks and don't have symbols. If it
can tranlate the address of the lock in a slab object to the name of
the slab, it'd be much more useful.
I'm not aware of type information in slab yet, but I was told there's
a work to associate BTF ID with it. It'd be definitely helpful to my
use case. Probably we need another kfunc to get the start address of
the object or the offset in the object from an address if the type
info is available. But I want to start with a simple thing first.
The kmem_cache_iter iterates kmem_cache objects under slab_mutex and
will be useful for userspace to prepare some work for specific slabs
like setting up filters in advance. And the bpf_get_kmem_cache()
kfunc will return a pointer to a slab from the address of a lock.
And the test code is to read from the iterator and make sure it finds
a slab cache of the task_struct for the current task.
The code is available at 'bpf/slab-iter-v5' branch in
https://git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git
Thanks,
Namhyung
====================
Link: https://lore.kernel.org/r/20241010232505.1339892-1-namhyung@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The test traverses all slab caches using the kmem_cache_iter and save
the data into slab_result array map. And check if current task's
pointer is from "task_struct" slab cache using bpf_get_kmem_cache().
Also compare the result array with /proc/slabinfo if available (when
CONFIG_SLUB_DEBUG is on). Note that many of the fields in the slabinfo
are transient, so it only compares the name and objsize fields.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20241010232505.1339892-4-namhyung@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The bpf_get_kmem_cache() is to get a slab cache information from a
virtual address like virt_to_cache(). If the address is a pointer
to a slab object, it'd return a valid kmem_cache pointer, otherwise
NULL is returned.
It doesn't grab a reference count of the kmem_cache so the caller is
responsible to manage the access. The returned point is marked as
PTR_UNTRUSTED.
The intended use case for now is to symbolize locks in slab objects
from the lock contention tracepoints.
Suggested-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Roman Gushchin <roman.gushchin@linux.dev> (mm/*)
Acked-by: Vlastimil Babka <vbabka@suse.cz> #mm/slab
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20241010232505.1339892-3-namhyung@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The new "kmem_cache" iterator will traverse the list of slab caches
and call attached BPF programs for each entry. It should check the
argument (ctx.s) if it's NULL before using it.
Now the iteration grabs the slab_mutex only if it traverse the list and
releases the mutex when it runs the BPF program. The kmem_cache entry
is protected by a refcount during the execution.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz> #slab
Link: https://lore.kernel.org/r/20241010232505.1339892-2-namhyung@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The hashmap__for_each_entry[_safe] is accessing 'map' as a pointer.
But it does without parentheses so passing a static hash map with an
ampersand (like '&slab_hash') will cause compiler warnings due
to unmatched types as '->' operator has a higher precedence.
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20241011170021.1490836-1-namhyung@kernel.org
Add a subprogram to BPF object file that otherwise has no entry BPF
programs to validate that libbpf can still load this correctly.
Until this was fixed, user could expect this very confusing error message:
libbpf: prog 'dangling_subprog': missing BPF prog type, check ELF section name '.text'
libbpf: prog 'dangling_subprog': failed to load: -22
libbpf: failed to load object 'struct_ops_detach'
libbpf: failed to load BPF skeleton 'struct_ops_detach': -22
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241010211731.4121837-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Libbpf pre-1.0 had a legacy logic of allowing singular non-annotated
(i.e., not having explicit SEC() annotation) function to be treated as
sole entry BPF program (unless there were other explicit entry
programs).
This behavior was dropped during libbpf 1.0 transition period (unless
LIBBPF_STRICT_SEC_NAME flag was unset in libbpf_mode). When 1.0 was
released and all the legacy behavior was removed, the bug slipped
through leaving this legacy behavior around.
Fix this for good, as it actually causes very confusing behavior if BPF
object file only has subprograms, but no entry programs.
Fixes: bd054102a8 ("libbpf: enforce strict libbpf 1.0 behaviors")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241010211731.4121837-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Daniel T. Lee says:
====================
selftests/bpf: migrate and remove cgroup/tracing related tests
The BPF testing framework has evolved significantly over time. However,
some legacy tests in the samples/bpf directory have not kept up with
these changes. These outdated tests can cause confusion and increase
maintenance efforts.
This patchset focuses on migrating outdated cgroup and tracing-related
tests from samples/bpf to selftests/bpf, ensuring the BPF test suite
remains current and efficient. Tests that are already covered by
selftests/bpf are removed, while those not yet covered are migrated.
This includes cgroup sock create tests for setting socket attributes
and blocking socket creation, as well as the removal of redundant
cgroup and tracing tests that have been replaced by newer tests.
This patchset covers the following cgroup/tracing tests:
- test_overhead: tests the overhead of BPF programs with task_rename,
now covered by selftests and benchmark tests (rename-*). [1]
- test_override_return: tests the return override functionality, now
handled by kprobe_multi_override in selftests.
- test_probe_write_user: tests the probe_write_user functionality,
now replaced by the probe_user test in selftests.
- test_cgrp2_sock: tests cgroup BPF's ability to set sk_bound_dev_if,
mark, and priority during socket creation. Migrated to selftests as
'sock_create' since no existing tests fully cover this.
- test_cgrp2_sock2: tests blocking socket creation for specific types
(AF_INET{6}, SOCK_DGRAM, IPPROTO_ICMP{V6}). Migrated to selftests
in 'sock_create' test for coverage.
- test_current_task_under_cgroup: tests bpf_current_task_under_cgroup()
to check if a task belongs to a cgroup. Already covered by
task_under_cgroup at selftest and other cgroup ID tests.
- test_cgrp2_tc: tests bpf_skb_under_cgroup() to filter packets based
on cgroup. This behavior is now validated by cgroup_skb_sk_lookup,
which uses bpf_skb_cgroup_id, making this test redundant.
[1]: https://patchwork.kernel.org/cover/13759916
---
Changes in v2:
- commit message fix
Changes in v3:
- Makefile fix
====================
Link: https://lore.kernel.org/r/20241011044847.51584-1-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The samples/bpf has become outdated and often does not follow up with
the latest. This commit removes obsolete tracing-related tests.
Specifically, 'test_overhead' is duplicate with selftests (and bench),
and 'test_override_return', 'test_probe_write_user' tests are obsolete
since they have been replaced by kprobe_multi_override and probe_user
from selftests respectively.
The following files are removed:
- test_overhead: tests the overhead of BPF programs with task_rename,
now covered by selftests and benchmark tests (rename-*). [1]
- test_override_return: tests the return override functionality, now
handled by kprobe_multi_override in selftests.
- test_probe_write_user: tests the probe_write_user functionality,
now replaced by the probe_user test in selftests.
This cleanup will help to streamline the testing framework by removing
redundant tests.
[1]: https://patchwork.kernel.org/cover/13759916
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20241011044847.51584-5-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch removes the obsolete cgroup related tests. These tests are
now redundant because their functionality is already covered by more
modern and comprehensive tests under selftests/bpf.
The following files are removed:
- test_current_task_under_cgroup: tests bpf_current_task_under_cgroup()
to check if a task belongs to a cgroup. Already covered by
task_under_cgroup at selftest and other cgroup ID tests.
- test_cgrp2_tc: tests bpf_skb_under_cgroup() to filter packets based
on cgroup. This behavior is now validated by cgroup_skb_sk_lookup,
which uses bpf_skb_cgroup_id, making this test redundant.
By removing these outdated tests, this patch helps streamline and
modernize the test suite, avoiding duplication of test coverage.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20241011044847.51584-4-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch continues the migration and removal process for cgroup
sock_create tests to selftests.
The test being migrated verifies the ability of cgroup BPF to block the
creation of specific types of sockets using a verdict. Specifically, the
test denies socket creation when the socket is of type AF_INET{6},
SOCK_DGRAM, and IPPROTO_ICMP{V6}. If the requested socket type matches
these attributes, the cgroup BPF verdict blocks the socket creation.
As with the previous commit, this test currently lacks coverage in
selftests, so this patch migrates the functionality into the sock_create
tests under selftests. This migration ensures that the socket creation
blocking behavior with cgroup bpf program is properly tested within the
selftest framework.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20241011044847.51584-3-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This patch migrates the old test for cgroup BPF that sets
sk_bound_dev_if, mark, and priority when AF_INET{6} sockets are created.
The most closely related tests under selftests are 'test_sock' and
'sockopt'. However, these existing tests serve different purposes.
'test_sock' focuses mainly on verifying the socket binding process,
while 'sockopt' concentrates on testing the behavior of getsockopt and
setsockopt operations for various socket options.
Neither of these existing tests directly covers the ability of cgroup
BPF to set socket attributes such as sk_bound_dev_if, mark, and priority
during socket creation. To address this gap, this patch introduces a
migration of the old cgroup socket attribute test, now included as the
'sock_create' test in selftests/bpf. This ensures that the ability to
configure these attributes during socket creation is properly tested.
Signed-off-by: Daniel T. Lee <danieltimlee@gmail.com>
Link: https://lore.kernel.org/r/20241011044847.51584-2-danieltimlee@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
The documentation says CONFIG_FUNCTION_ERROR_INJECTION is supported only
on x86. This was presumably true at the time of writing, but it's now
supported on many other architectures too. Drop this statement, since
it's not correct anymore and it fits better in other documentation
anyway.
Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com>
Link: https://lore.kernel.org/r/20241010193301.995909-1-martin.kelly@crowdstrike.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
sym_is_subprog() is incorrectly rejecting relocations against *weak*
global subprogs. Fix that by realizing that STB_WEAK is also a global
function.
While it seems like verifier doesn't support taking an address of
non-static subprog right now, it's still best to fix support for it on
libbpf side, otherwise users will get a very confusing error during BPF
skeleton generation or static linking due to misinterpreted relocation:
libbpf: prog 'handle_tp': bad map relo against 'foo' in section '.text'
Error: failed to open BPF object file: Relocation failed
It's clearly not a map relocation, but is treated and reported as such
without this fix.
Fixes: 53eddb5e04 ("libbpf: Support subprog address relocation")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20241009011554.880168-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
test_progs uses glibc specific functions backtrace() and
backtrace_symbols_fd() to print backtrace in case of SIGSEGV.
Recent commit (see fixes) updated test_progs.c to define stub versions
of the same functions with attriubte "weak" in order to allow linking
test_progs against musl libc. Unfortunately this broke the backtrace
handling for glibc builds.
As it turns out, glibc defines backtrace() and backtrace_symbols_fd()
as weak:
$ llvm-readelf --symbols /lib64/libc.so.6 \
| grep -P '( backtrace_symbols_fd| backtrace)$'
4910: 0000000000126b40 161 FUNC WEAK DEFAULT 16 backtrace
6843: 0000000000126f90 852 FUNC WEAK DEFAULT 16 backtrace_symbols_fd
So does test_progs:
$ llvm-readelf --symbols test_progs \
| grep -P '( backtrace_symbols_fd| backtrace)$'
2891: 00000000006ad190 15 FUNC WEAK DEFAULT 13 backtrace
11215: 00000000006ad1a0 41 FUNC WEAK DEFAULT 13 backtrace_symbols_fd
In such situation dynamic linker is not obliged to favour glibc
implementation over the one defined in test_progs.
Compiling with the following simple modification to test_progs.c
demonstrates the issue:
$ git diff
...
\--- a/tools/testing/selftests/bpf/test_progs.c
\+++ b/tools/testing/selftests/bpf/test_progs.c
\@@ -1817,6 +1817,7 @@ int main(int argc, char **argv)
if (err)
return err;
+ *(int *)0xdeadbeef = 42;
err = cd_flavor_subdir(argv[0]);
if (err)
return err;
$ ./test_progs
[0]: Caught signal #11!
Stack trace:
<backtrace not supported>
Segmentation fault (core dumped)
Resolve this by hiding stub definitions behind __GLIBC__ macro check
instead of using "weak" attribute.
Fixes: c9a83e76b5 ("selftests/bpf: Fix compile if backtrace support missing in libc")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Tested-by: Tony Ambardar <tony.ambardar@gmail.com>
Reviewed-by: Tony Ambardar <tony.ambardar@gmail.com>
Acked-by: Daniel Xu <dxu@dxuuu.xyz>
Link: https://lore.kernel.org/bpf/20241003210307.3847907-1-eddyz87@gmail.com
During the xdp_adjust_tail test, probabilistic failure occurs and SKB package
is discarded by the kernel. After checking the issues by tracking SKB package,
it is identified that they were caused by checksum errors. Refer to checksum
of the arch/arm64/include/asm/checksum.h for fixing.
v2: Based on Alexei Starovoitov's suggestions, it is necessary to keep the code
implementation consistent.
Fixes: c6ffd1ff78 (bpf: add bpf_xdp_adjust_tail sample prog)
Signed-off-by: Yuan Chen <chenyuan@kylinos.cn>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240930024115.52841-1-chenyuan_fl@163.com
The prog_tests programs do not include the per-arch tools include
path, e.g. tools/arch/riscv/include. Some architectures depend those
files to build properly.
Include tools/arch/$(SUBARCH)/include in the selftests bpf build.
Fixes: 6d74d178fe ("tools: Add riscv barrier implementation")
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240927131355.350918-2-bjorn@kernel.org
Production BPF programs are increasing in number of instructions and states
to the point, where optimising verification process for them is necessary
to avoid running into instruction limit. Authors of those BPF programs
need to analyze verifier output, for example, collecting the most
frequent source code lines to understand which part of the program has
the biggest verification cost.
This patch introduces `--top-src-lines` flag in veristat.
`--top-src-lines=N` makes veristat output N the most popular sorce code
lines, parsed from verification log.
An example of output:
```
sudo ./veristat --top-src-lines=2 bpf_flow.bpf.o
Processing 'bpf_flow.bpf.o'...
Top source lines (_dissect):
4: (bpf_helpers.h:161) asm volatile("r1 = %[ctx]\n\t"
4: (bpf_flow.c:155) if (iph && iph->ihl == 5 &&
...
```
Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240930231522.58650-1-mykyta.yatsenko5@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Eduard Zingerman says:
====================
'bpf_fastcall' attribute in vmlinux.h and bpf_helper_defs.h
The goal of this patch-set is to reflect attribute bpf_fastcall
for supported helpers and kfuncs in generated header files.
For helpers this requires a tweak for scripts/bpf_doc.py and an update
to uapi/linux/bpf.h doc-comment.
For kfuncs this requires:
- introduction of a new KF_FASTCALL flag;
- modification to pahole to read kfunc flags and generate
DECL_TAG "bpf_fastcall" for marked kfuncs;
- modification to bpftool to scan for DECL_TAG "bpf_fastcall"
presence.
In both cases the following helper macro is defined in the generated
header:
#ifndef __bpf_fastcall
#if __has_attribute(bpf_fastcall)
#define __bpf_fastcall __attribute__((bpf_fastcall))
#else
#define __bpf_fastcall
#endif
#endif
And is used to mark appropriate function prototypes. More information
about bpf_fastcall attribute could be found in [1] and [2].
Modifications to pahole are submitted separately.
[1] LLVM source tree commit:
64e464349bfc ("[BPF] introduce __attribute__((bpf_fastcall))")
[2] Linux kernel tree commit (note: feature was renamed from
no_caller_saved_registers to bpf_fastcall after this commit):
52839f31ce ("Merge branch 'no_caller_saved_registers-attribute-for-helper-calls'")
====================
Link: https://lore.kernel.org/r/20240916091712.2929279-1-eddyz87@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Since [1] kernel supports __bpf_fastcall attribute for helper function
bpf_get_smp_processor_id(). Update uapi definition for this helper in
order to have this attribute in the generated bpf_helper_defs.h
[1] commit 91b7fbf393 ("bpf, x86, riscv, arm: no_caller_saved_registers for bpf_get_smp_processor_id()")
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240916091712.2929279-3-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Allow a new optional 'Attributes' section to be specified for helper
functions description, e.g.:
* u32 bpf_get_smp_processor_id(void)
* ...
* Return
* ...
* Attributes
* __bpf_fastcall
*
Generated header for the example above:
#ifndef __bpf_fastcall
#if __has_attribute(__bpf_fastcall)
#define __bpf_fastcall __attribute__((bpf_fastcall))
#else
#define __bpf_fastcall
#endif
#endif
...
__bpf_fastcall
static __u32 (* const bpf_get_smp_processor_id)(void) = (void *) 8;
The following rules apply:
- when present, section must follow 'Return' section;
- attribute names are specified on the line following 'Attribute'
keyword;
- attribute names are separated by spaces;
- section ends with an "empty" line (" *\n").
Valid attribute names are recorded in the ATTRS map.
ATTRS maps shortcut attribute name to correct C syntax.
Signed-off-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20240916091712.2929279-2-eddyz87@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Tony Ambardar says:
====================
libbpf, selftests/bpf: Support cross-endian usage
Hello all,
This patch series targets a long-standing BPF usability issue - the lack
of general cross-compilation support - by enabling cross-endian usage of
libbpf and bpftool, as well as supporting cross-endian build targets for
selftests/bpf.
Benefits include improved BPF development and testing for embedded systems
based on e.g. big-endian MIPS, more build options e.g for s390x systems,
and better accessibility to the very latest test tools e.g. 'test_progs'.
The series touches many functional areas: BTF.ext handling; object access,
introspection, and linking; generation of normal and "light" skeletons.
Initial development and testing used mips64, since this arch makes
switching the build byte-order trivial and is thus very handy for A/B
testing. However, it lacks some key features (bpf2bpf call, kfuncs, etc)
making for poor selftests/bpf coverage.
Final testing takes the kernel and selftests/bpf cross-built from x86_64
to s390x, and runs the result under QEMU/s390x. That same configuration
could also be used on kernel-patches/bpf CI for regression testing endian
support or perhaps load-sharing s390x builds across x86_64 systems.
This thread includes some background regarding testing on QEMU/s390x and
the generally favourable results:
https://lore.kernel.org/bpf/ZsEcsaa3juxxQBUf@kodidev-ubuntu/
Earlier versions and related discussion of the series are here:
v1: https://lore.kernel.org/bpf/cover.1724216108.git.tony.ambardar@gmail.com/
v2: https://lore.kernel.org/bpf/cover.1724313164.git.tony.ambardar@gmail.com/
v3: https://lore.kernel.org/bpf/cover.1724843049.git.tony.ambardar@gmail.com/
v4: https://lore.kernel.org/bpf/cover.1724976539.git.tony.ambardar@gmail.com/
v5: https://lore.kernel.org/bpf/cover.1725347944.git.tony.ambardar@gmail.com/
Feedback and suggestions are welcome!
Best regards,
Tony
Changelog:
---------
v5 -> v6: (comments from Andrii, Alexei, Eduard)
- clarify info_blob_bswap() by making it explicitly conditional on
non-native target endianness, and merge a pair of related debug
statements
- reformat debug statement in bpf_object_bswap_progs() on single line
- update existing info setup functions to validate and parse info
section metadata prior to any byte-swapping, and drop earlier added
validation checks
- rework cross-endian BTF.ext handling by using callback functions to
byte-swap different types of info records, but after initial parsing
- fix a bug always outputting BTF.ext raw data in native endianness
- include v5 "Acked-by:" from Alexei, Yonghong
v4 -> v5: (feedback from Andrii and Eduard)
- add separate functions to byte-swap info metadata and records, and
ensure ordering so record bswaps occur when metadata is native endian
- use new and existing macros to iterate through info sections/records,
and check embedded record sizes match that of info structs used
- drop use of <cough> evil callbacks
- move setting swapped_endian flag to after byte-swapping functions are
called during initialization, allowing funcs to infer endianness and
drop a 'bool native' call parameter
- simplify byte-swapping macro used to generate light skeleton, and use
internal lib funcs to swap info records instead of assuming all __u32
- change info bswap library funcs to void return
- rework/consolidate new debug statements to reduce their number
- remove some unneeded handling of impossible errors, and drop a safety
check already handled elsewhere
- add and clarify some comments
v3 -> v4:
- fix a use-after-free ELF data-handling error causing rare CI failures
- move bswap functions for func/line/core-relo records to internal header
- use bswap functions also for info blobs in light skeleton
v2 -> v3: (feedback from Andrii)
- improve some log and commit message formatting
- restructure BTF.ext endianness safety checks and byte-swapping
- use BTF.ext info record definitions for swapping, require BTF v1
- follow BTF API implementation more closely for BTF.ext
- explicitly reject loading non-native endianness program into kernel
- simplify linker output byte-order setting
- drop redundant safety checks during linking
- simplify endianness macro and improve blob setup code for light skel
- no unexpected test failures after cross-compiling x86_64 -> s390x
v1 -> v2:
- fixed a light skeleton bug causing test_progs 'map_ptr' failure
- simplified some BTF.ext related endianness logic
- remove an 'inline' usage related to CI checkpatch failure
- improve some formatting noted by checkpatch warnings
- unexpected 'test_progs' failures drop 3 -> 2 (x86_64 to s390x cross)
====================
Link: https://lore.kernel.org/r/cover.1726475448.git.tony.ambardar@gmail.com
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
When building selftests, the following was seen:
uprobe_multi.c: In function ‘trigger_uprobe’:
uprobe_multi.c:108:40: error: ‘MADV_PAGEOUT’ undeclared (first use in this function)
108 | madvise(addr, page_sz, MADV_PAGEOUT);
| ^~~~~~~~~~~~
uprobe_multi.c:108:40: note: each undeclared identifier is reported only once for each function it appears in
make: *** [Makefile:850: bpf-next/tools/testing/selftests/bpf/uprobe_multi] Error 1
...even with updated UAPI headers. It seems the above value is
defined in UAPI <linux/mman.h> but including that file triggers
other redefinition errors. Simplest solution is to add a
guarded definition, as was done for MADV_POPULATE_READ.
Fixes: 3c217a1820 ("selftests/bpf: add build ID tests")
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20240926144948.172090-1-alan.maguire@oracle.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Track target endianness in 'struct bpf_gen' and process in-memory data in
native byte-order, but on finalization convert the embedded loader BPF
insns to target endianness.
The light skeleton also includes a target-accessed data blob which is
heterogeneous and thus difficult to convert to target byte-order on
finalization. Add support functions to convert data to target endianness
as it is added to the blob.
Also add additional debug logging for data blob structure details and
skeleton loading.
Signed-off-by: Tony Ambardar <tony.ambardar@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/569562e1d5bf1cce80a1f1a3882461ee2da1ffd5.1726475448.git.tony.ambardar@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
