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 --- samples/bpf/tracex5_user.c | 98 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 98 insertions(+) create mode 100644 samples/bpf/tracex5_user.c (limited to 'samples/bpf/tracex5_user.c') diff --git a/samples/bpf/tracex5_user.c b/samples/bpf/tracex5_user.c new file mode 100644 index 000000000..7e2d8397f --- /dev/null +++ b/samples/bpf/tracex5_user.c @@ -0,0 +1,98 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include +#include +#include +#include +#include "trace_helpers.h" +#include "bpf_util.h" + +#ifdef __mips__ +#define MAX_ENTRIES 6000 /* MIPS n64 syscalls start at 5000 */ +#else +#define MAX_ENTRIES 1024 +#endif + +/* install fake seccomp program to enable seccomp code path inside the kernel, + * so that our kprobe attached to seccomp_phase1() can be triggered + */ +static void install_accept_all_seccomp(void) +{ + struct sock_filter filter[] = { + BPF_STMT(BPF_RET+BPF_K, SECCOMP_RET_ALLOW), + }; + struct sock_fprog prog = { + .len = (unsigned short)ARRAY_SIZE(filter), + .filter = filter, + }; + if (prctl(PR_SET_SECCOMP, 2, &prog)) + perror("prctl"); +} + +int main(int ac, char **argv) +{ + struct bpf_link *link = NULL; + struct bpf_program *prog; + struct bpf_object *obj; + int key, fd, progs_fd; + const char *section; + char filename[256]; + FILE *f; + + snprintf(filename, sizeof(filename), "%s.bpf.o", argv[0]); + obj = bpf_object__open_file(filename, NULL); + if (libbpf_get_error(obj)) { + fprintf(stderr, "ERROR: opening BPF object file failed\n"); + return 0; + } + + prog = bpf_object__find_program_by_name(obj, "bpf_prog1"); + if (!prog) { + printf("finding a prog in obj file failed\n"); + goto cleanup; + } + + /* load BPF program */ + if (bpf_object__load(obj)) { + fprintf(stderr, "ERROR: loading BPF object file failed\n"); + goto cleanup; + } + + link = bpf_program__attach(prog); + if (libbpf_get_error(link)) { + fprintf(stderr, "ERROR: bpf_program__attach failed\n"); + link = NULL; + goto cleanup; + } + + progs_fd = bpf_object__find_map_fd_by_name(obj, "progs"); + if (progs_fd < 0) { + fprintf(stderr, "ERROR: finding a map in obj file failed\n"); + goto cleanup; + } + + bpf_object__for_each_program(prog, obj) { + section = bpf_program__section_name(prog); + /* register only syscalls to PROG_ARRAY */ + if (sscanf(section, "kprobe/%d", &key) != 1) + continue; + + fd = bpf_program__fd(prog); + bpf_map_update_elem(progs_fd, &key, &fd, BPF_ANY); + } + + install_accept_all_seccomp(); + + f = popen("dd if=/dev/zero of=/dev/null count=5", "r"); + (void) f; + + read_trace_pipe(); + +cleanup: + bpf_link__destroy(link); + bpf_object__close(obj); + return 0; +} -- cgit v1.3.1