From 27600805e62f800bacf990354632eae4e487d34c Mon Sep 17 00:00:00 2001 From: Yazen Ghannam Date: Thu, 3 Sep 2026 10:43:25 -0500 Subject: x86/amd_node: Fix PCI device reference counting in amd_smn_init() The local "root" pointer is a temporary variable used during the device search. Therefore, refcount related to the search iterators should be cleaned up after the search is complete. Use the __free() cleanup macro to ensure the refcount is decremented when the temporary pointer goes out of scope. Additionally, increment the refcount when caching a root pointer. This ensures the in-use refcount is separate from the temporary search refcounting. Finally, drop the redundant "root = NULL" before the second search loop. The pci_get_class() iterator always decrements the refcount of its "from" argument, so the first loop can only fall through with "root" already NULL. Fixes: 0a4b61d9c2e4 ("x86/amd_node: Fix AMD root device caching") Closes: https://sashiko.dev/#/patchset/20260806160159.230453-1-jason.andryuk%40amd.com Reported-by: Sashiko Assisted-by: LLM Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Mario Limonciello (AMD) Cc: Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com --- tools/perf/util/bpf-utils.h | 86 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 tools/perf/util/bpf-utils.h (limited to 'tools/perf/util/bpf-utils.h') diff --git a/tools/perf/util/bpf-utils.h b/tools/perf/util/bpf-utils.h new file mode 100644 index 000000000..a8bc1a232 --- /dev/null +++ b/tools/perf/util/bpf-utils.h @@ -0,0 +1,86 @@ +/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */ + +#ifndef __PERF_BPF_UTILS_H +#define __PERF_BPF_UTILS_H + +#define ptr_to_u64(ptr) ((__u64)(unsigned long)(ptr)) + +#ifdef HAVE_LIBBPF_SUPPORT + +#include +#include + +#define LIBBPF_CURRENT_VERSION_GEQ(major, minor) \ + (LIBBPF_MAJOR_VERSION > (major) || \ + (LIBBPF_MAJOR_VERSION == (major) && LIBBPF_MINOR_VERSION >= (minor))) + +#if LIBBPF_CURRENT_VERSION_GEQ(1, 7) +// libbpf 1.7+ support the btf_dump_type_data_opts.emit_strings option. +#define HAVE_LIBBPF_STRINGS_SUPPORT 1 +#endif + +/* + * Get bpf_prog_info in continuous memory + * + * struct bpf_prog_info has multiple arrays. The user has option to choose + * arrays to fetch from kernel. The following APIs provide an uniform way to + * fetch these data. All arrays in bpf_prog_info are stored in a single + * continuous memory region. This makes it easy to store the info in a + * file. + * + * Before writing perf_bpil to files, it is necessary to + * translate pointers in bpf_prog_info to offsets. Helper functions + * bpil_addr_to_offs() and bpil_offs_to_addr() + * are introduced to switch between pointers and offsets. + * + * Examples: + * # To fetch map_ids and prog_tags: + * __u64 arrays = (1UL << PERF_BPIL_MAP_IDS) | + * (1UL << PERF_BPIL_PROG_TAGS); + * struct perf_bpil *info_linear = + * get_bpf_prog_info_linear(fd, arrays); + * + * # To save data in file + * bpil_addr_to_offs(info_linear); + * write(f, info_linear, sizeof(*info_linear) + info_linear->data_len); + * + * # To read data from file + * read(f, info_linear, ); + * bpil_offs_to_addr(info_linear); + */ +enum perf_bpil_array_types { + PERF_BPIL_FIRST_ARRAY = 0, + PERF_BPIL_JITED_INSNS = 0, + PERF_BPIL_XLATED_INSNS, + PERF_BPIL_MAP_IDS, + PERF_BPIL_JITED_KSYMS, + PERF_BPIL_JITED_FUNC_LENS, + PERF_BPIL_FUNC_INFO, + PERF_BPIL_LINE_INFO, + PERF_BPIL_JITED_LINE_INFO, + PERF_BPIL_PROG_TAGS, + PERF_BPIL_LAST_ARRAY, +}; + +struct perf_bpil { + /* size of struct bpf_prog_info, when the tool is compiled */ + __u32 info_len; + /* total bytes allocated for data, round up to 8 bytes */ + __u32 data_len; + /* which arrays are included in data */ + __u64 arrays; + struct bpf_prog_info info; + __u8 data[]; +}; + +struct perf_bpil * +get_bpf_prog_info_linear(int fd, __u64 arrays); + +void +bpil_addr_to_offs(struct perf_bpil *info_linear); + +void +bpil_offs_to_addr(struct perf_bpil *info_linear); + +#endif /* HAVE_LIBBPF_SUPPORT */ +#endif /* __PERF_BPF_UTILS_H */ -- cgit v1.3.1