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)
Tony Ambardar (8):
libbpf: Improve log message formatting
libbpf: Fix header comment typos for BTF.ext
libbpf: Fix output .symtab byte-order during linking
libbpf: Support BTF.ext loading and output in either endianness
libbpf: Support opening bpf objects of either endianness
libbpf: Support linking bpf objects of either endianness
libbpf: Support creating light skeleton of either endianness
selftests/bpf: Support cross-endian building
tools/lib/bpf/bpf_gen_internal.h | 1 +
tools/lib/bpf/btf.c | 284 +++++++++++++++++++++------
tools/lib/bpf/btf.h | 3 +
tools/lib/bpf/btf_dump.c | 2 +-
tools/lib/bpf/btf_relocate.c | 2 +-
tools/lib/bpf/gen_loader.c | 187 +++++++++++++-----
tools/lib/bpf/libbpf.c | 56 ++++--
tools/lib/bpf/libbpf.map | 2 +
tools/lib/bpf/libbpf_internal.h | 45 ++++-
tools/lib/bpf/linker.c | 80 ++++++--
tools/lib/bpf/relo_core.c | 2 +-
tools/lib/bpf/skel_internal.h | 3 +-
tools/testing/selftests/bpf/Makefile | 7 +-
13 files changed, 527 insertions(+), 147 deletions(-)
--
2.34.1
Hello,
kernel test robot noticed "kernel-selftests.vDSO.vdso_standalone_test_x86.fail" on:
commit: ecb8bd70d51ccf9009219a6097cef293deada65b ("selftests: vDSO: build tests with O2 optimization")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master
in testcase: kernel-selftests
version: kernel-selftests-x86_64-977d51cf-1_20240508
with following parameters:
group: group-03
compiler: gcc-12
test machine: 36 threads 1 sockets Intel(R) Core(TM) i9-10980XE CPU @ 3.00GHz (Cascade Lake) with 32G memory
(please refer to attached dmesg/kmsg for entire log/backtrace)
If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <oliver.sang(a)intel.com>
| Closes: https://lore.kernel.org/oe-lkp/202409241558.98e13f6f-oliver.sang@intel.com
# timeout set to 300
# selftests: vDSO: vdso_standalone_test_x86
# Segmentation fault
not ok 5 selftests: vDSO: vdso_standalone_test_x86 # exit=139
The kernel config and materials to reproduce are available at:
https://download.01.org/0day-ci/archive/20240924/202409241558.98e13f6f-oliv…
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
The hmm2 double_map test was failing due to an incorrect
buffer->mirror size. The buffer->mirror size was 6, while buffer->ptr
size was 6 * PAGE_SIZE. The test failed because the kernel's
copy_to_user function was attempting to copy a 6 * PAGE_SIZE buffer
to buffer->mirror. Since the size of buffer->mirror was incorrect,
copy_to_user failed.
This patch corrects the buffer->mirror size to 6 * PAGE_SIZE.
Test Result without this patch
==============================
# RUN hmm2.hmm2_device_private.double_map ...
# hmm-tests.c:1680:double_map:Expected ret (-14) == 0 (0)
# double_map: Test terminated by assertion
# FAIL hmm2.hmm2_device_private.double_map
not ok 53 hmm2.hmm2_device_private.double_map
Test Result with this patch
===========================
# RUN hmm2.hmm2_device_private.double_map ...
# OK hmm2.hmm2_device_private.double_map
ok 53 hmm2.hmm2_device_private.double_map
Signed-off-by: Donet Tom <donettom(a)linux.ibm.com>
---
tools/testing/selftests/mm/hmm-tests.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/mm/hmm-tests.c b/tools/testing/selftests/mm/hmm-tests.c
index d2cfc9b494a0..141bf63cbe05 100644
--- a/tools/testing/selftests/mm/hmm-tests.c
+++ b/tools/testing/selftests/mm/hmm-tests.c
@@ -1657,7 +1657,7 @@ TEST_F(hmm2, double_map)
buffer->fd = -1;
buffer->size = size;
- buffer->mirror = malloc(npages);
+ buffer->mirror = malloc(size);
ASSERT_NE(buffer->mirror, NULL);
/* Reserve a range of addresses. */
--
2.43.5
Fix typo.
Currently, the second bridge command overwrites the first one.
Fix this by adding this VID to the interface behind $swp2.
Fixes: 476a4f05d9b8 ("selftests: forwarding: add a no_forwarding.sh test")
Signed-off-by: Kacper Ludwinski <kacper(a)ludwinski.dev>
---
tools/testing/selftests/net/forwarding/no_forwarding.sh | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/net/forwarding/no_forwarding.sh b/tools/testing/selftests/net/forwarding/no_forwarding.sh
index 9e677aa64a06..694ece9ba3a7 100755
--- a/tools/testing/selftests/net/forwarding/no_forwarding.sh
+++ b/tools/testing/selftests/net/forwarding/no_forwarding.sh
@@ -202,7 +202,7 @@ one_bridge_two_pvids()
ip link set $swp2 master br0
bridge vlan add dev $swp1 vid 1 pvid untagged
- bridge vlan add dev $swp1 vid 2 pvid untagged
+ bridge vlan add dev $swp2 vid 2 pvid untagged
run_test "Switch ports in VLAN-aware bridge with different PVIDs"
--
2.43.0