From d22c3e0088e85be8131f7a9283f759cdbb20726d Mon Sep 17 00:00:00 2001 From: Sven Schnelle Date: Wed, 9 Sep 2026 11:29:53 +0200 Subject: selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc The current regex also matches symbols in modules, which makes the test fail on s390 where name_show is present only once in the kernel, but also multiple times in modules: 000001b1401cdc20 t name_show 000001b0c05e6c40 t name_show [mdev] 000001b0c0495f30 t name_show [i2c_core] Fix this by changing the regular expression to only match the function name. Link: https://lore.kernel.org/all/20260909092954.2200558-1-svens@linux.ibm.com/ Fixes: 03b80ff8023a ("selftests/ftrace: Add new test case which checks non unique symbol") Signed-off-by: Sven Schnelle Reviewed-by: Steven Rostedt Signed-off-by: Masami Hiramatsu (Google) --- lib/crc/crc4.c | 45 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 45 insertions(+) create mode 100644 lib/crc/crc4.c (limited to 'lib/crc/crc4.c') diff --git a/lib/crc/crc4.c b/lib/crc/crc4.c new file mode 100644 index 000000000..8e83fbe60 --- /dev/null +++ b/lib/crc/crc4.c @@ -0,0 +1,45 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * crc4.c - simple crc-4 calculations. + */ + +#include +#include +#include + +static const uint8_t crc4_tab[] = { + 0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2, + 0x1, 0x6, 0xf, 0x8, 0xa, 0xd, 0x4, 0x3, +}; + +/** + * crc4 - calculate the 4-bit crc of a value. + * @c: starting crc4 + * @x: value to checksum + * @bits: number of bits in @x to checksum + * + * Returns the crc4 value of @x, using polynomial 0b10111. + * + * The @x value is treated as left-aligned, and bits above @bits are ignored + * in the crc calculations. + */ +uint8_t crc4(uint8_t c, uint64_t x, int bits) +{ + int i; + + /* mask off anything above the top bit */ + x &= (1ull << bits) - 1; + + /* Align to 4-bits */ + bits = (bits + 3) & ~0x3; + + /* Calculate crc4 over four-bit nibbles, starting at the MSbit */ + for (i = bits - 4; i >= 0; i -= 4) + c = crc4_tab[c ^ ((x >> i) & 0xf)]; + + return c; +} +EXPORT_SYMBOL_GPL(crc4); + +MODULE_DESCRIPTION("CRC4 calculations"); +MODULE_LICENSE("GPL"); -- cgit v1.3.1