linux-stable.git/tools/testing/selftests/bpf/prog_tests/snprintf.c, branch linux-rolling-stable

bpf: allow UTF-8 literals in bpf_bprintf_prepare()

2026-05-23T11:09:07+00:00

[ Upstream commit b960430ea8862ef37ce53c8bf74a8dc79d3f2404 ]

bpf_bprintf_prepare() only needs ASCII parsing for conversion
specifiers. Plain text can safely carry bytes >= 0x80, so allow
UTF-8 literals outside '%' sequences while keeping ASCII control
bytes rejected and format specifiers ASCII-only.

This keeps existing parsing rules for format directives unchanged,
while allowing helpers such as bpf_trace_printk() to emit UTF-8
literal text.

Update test_snprintf_negative() in the same commit so selftests keep
matching the new plain-text vs format-specifier split during bisection.

Fixes: 48cac3f4a96d ("bpf: Implement formatted output helpers with bstr_printf")
Signed-off-by: Yihan Ding 
Acked-by: Paul Chaignon 
Link: https://lore.kernel.org/r/20260416120142.1420646-2-dingyihan@uniontech.com
Signed-off-by: Alexei Starovoitov 
Signed-off-by: Sasha Levin

selftests/bpf: Add negative test cases for snprintf

2025-07-01T22:22:46+00:00

This patch adds a couple negative test cases with a trailing % at the
end of the format string. The %p% case was fixed by the previous commit,
whereas the %s% case was already successfully rejected before.

Acked-by: Yonghong Song 
Signed-off-by: Paul Chaignon 
Link: https://lore.kernel.org/r/0669bf6eb4f9e5bb10e949d60311c06e2d942447.1751395489.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov

selftests/bpf: Drop duplicate max/min definitions

2022-04-11T15:18:09+00:00

Drop duplicate macros min() and MAX() definitions in prog_tests and use
MIN() or MAX() in sys/param.h instead.

Signed-off-by: Geliang Tang 
Signed-off-by: Daniel Borkmann 
Acked-by: Song Liu 
Link: https://lore.kernel.org/bpf/1ae276da9925c2de59b5bdc93b693b4c243e692e.1649462033.git.geliang.tang@suse.com

selftests/bpf: Normalize selftest entry points

2021-10-25T21:45:45+00:00

Ensure that all test entry points are global void functions with no
input arguments. Mark few subtest entry points as static.

Signed-off-by: Andrii Nakryiko 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20211022223228.99920-2-andrii@kernel.org

selftest/bpf: Extend the bpf_snprintf() test for "%c".

2021-08-15T07:19:10+00:00

This patch adds various "positive" patterns for "%c" and two "negative"
patterns for wide character.

Signed-off-by: Kuniyuki Iwashima 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210814015718.42704-5-kuniyu@amazon.co.jp

selftests/bpf: Fix the snprintf test

2021-04-30T17:36:59+00:00

The BPF program for the snprintf selftest runs on all syscall entries.
On busy multicore systems this can cause concurrency issues.

For example it was observed that sometimes the userspace part of the
test reads "    4 0000" instead of "    4 000" (extra '0' at the end)
which seems to happen just before snprintf on another core sets
end[-1] = '\0'.

This patch adds a pid filter to the test to ensure that no
bpf_snprintf() will write over the test's output buffers while the
userspace reads the values.

Fixes: c2e39c6bdc7e ("selftests/bpf: Add a series of tests for bpf_snprintf")
Reported-by: Andrii Nakryiko 
Signed-off-by: Florent Revest 
Signed-off-by: Andrii Nakryiko 
Link: https://lore.kernel.org/bpf/20210428152501.1024509-1-revest@chromium.org

selftests/bpf: Add a series of tests for bpf_snprintf

2021-04-19T22:27:37+00:00

The "positive" part tests all format specifiers when things go well.

The "negative" part makes sure that incorrect format strings fail at
load time.

Signed-off-by: Florent Revest 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210419155243.1632274-7-revest@chromium.org