github-mirror/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2026-08-04 22:38:46 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity Graph
d69bafe6ee
linux/tools/testing
History
Yonghong Song d69bafe6ee selftests/bpf: Fix usdt multispec failure with arm64/clang20 selftest build 
When building the selftest with arm64/clang20, the following test failed:
  ...
  ubtest_multispec_usdt:PASS:usdt_100_called 0 nsec
  subtest_multispec_usdt:PASS:usdt_100_sum 0 nsec
  subtest_multispec_usdt:FAIL:usdt_300_bad_attach unexpected pointer: 0xaaaad82a2a80
  #471/2   usdt/multispec:FAIL
  #471     usdt:FAIL

But arm64/gcc11 built kernel selftests succeeded. Further debug found arm64/clang
generated code has much less argument pattern after dedup, but gcc generated
code has a lot more.

Check usdt probes with usdt.test.o on arm64 platform:

with gcc11 build binary:
  stapsdt              0x0000002e       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x00000000000054f8, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[sp]
  stapsdt              0x00000031       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x0000000000005510, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[sp, 4]
  ...
  stapsdt              0x00000032       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x0000000000005660, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[sp, 60]
  ...
  stapsdt              0x00000034       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x00000000000070e8, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[sp, 1192]
  stapsdt              0x00000034       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x0000000000007100, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[sp, 1196]
  ...
  stapsdt              0x00000032       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x0000000000009ec4, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[sp, 60]

with clang20 build binary:
  stapsdt              0x0000002e       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x00000000000009a0, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[x9]
  stapsdt              0x0000002e       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x00000000000009b8, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[x9]
  ...
  stapsdt              0x0000002e       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x0000000000002590, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[x9]
  stapsdt              0x0000002e       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x00000000000025a8, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[x8]
  ...
  stapsdt              0x0000002f       NT_STAPSDT (SystemTap probe descriptors)
    Provider: test
    Name: usdt_300
    Location: 0x0000000000007fdc, Base: 0x0000000000000000, Semaphore: 0x0000000000000008
    Arguments: -4@[x10]

There are total 300 locations for usdt_300. For gcc11 built binary, there are
300 spec's. But for clang20 built binary, there are 3 spec's. The default
BPF_USDT_MAX_SPEC_CNT is 256, so bpf_program__attach_usdt() will fail for gcc
but it will succeed with clang.

To fix the problem, do not do bpf_program__attach_usdt() for usdt_300
with arm64/clang setup.

Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250624211802.2198821-1-yonghong.song@linux.dev
2025-06-25 12:52:54 -07:00
..
crypto/chacha20-s390 crypto: lib/chacha - strongly type the ChaCha state 2025-05-12 13:32:53 +08:00
cxl Merge branch 'for-6.16/cxl-features-ras' into cxl-for-next 2025-05-23 13:26:24 -07:00
fault-injection
ktest ktest: Fix Test Failures Due to Missing LOG_FILE Directories 2025-03-27 09:34:00 -04:00
kunit linux_kselftest-kunit-6.16-rc1 2025-05-26 14:29:44 -07:00
memblock memblock: add MEMBLOCK_RSRV_KERN flag 2025-05-12 23:50:38 -07:00
nvdimm
radix-tree maple_tree: add sufficient height 2025-05-11 17:48:29 -07:00
rbtree
scatterlist
selftests selftests/bpf: Fix usdt multispec failure with arm64/clang20 selftest build 2025-06-25 12:52:54 -07:00
shared test suite: use %zu to print size_t 2025-04-11 17:32:35 -07:00
vma tools/testing/vma: add missing function stub 2025-05-31 22:46:14 -07:00
vsock vsock/test: Add test for an unexpectedly lingering close() 2025-05-27 11:05:22 +02:00