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/spintest.bpf.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 60 insertions(+) create mode 100644 samples/bpf/spintest.bpf.c (limited to 'samples/bpf/spintest.bpf.c') diff --git a/samples/bpf/spintest.bpf.c b/samples/bpf/spintest.bpf.c new file mode 100644 index 000000000..cba5a9d50 --- /dev/null +++ b/samples/bpf/spintest.bpf.c @@ -0,0 +1,60 @@ +/* Copyright (c) 2016, Facebook + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of version 2 of the GNU General Public + * License as published by the Free Software Foundation. + */ +#include "vmlinux.h" +#include +#include +#include + +#ifndef PERF_MAX_STACK_DEPTH +#define PERF_MAX_STACK_DEPTH 127 +#endif + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, long); + __type(value, long); + __uint(max_entries, 1024); +} my_map SEC(".maps"); +struct { + __uint(type, BPF_MAP_TYPE_PERCPU_HASH); + __uint(key_size, sizeof(long)); + __uint(value_size, sizeof(long)); + __uint(max_entries, 1024); +} my_map2 SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_STACK_TRACE); + __uint(key_size, sizeof(u32)); + __uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64)); + __uint(max_entries, 10000); +} stackmap SEC(".maps"); + +#define PROG(foo) \ +int foo(struct pt_regs *ctx) \ +{ \ + long v = PT_REGS_IP(ctx), *val; \ +\ + val = bpf_map_lookup_elem(&my_map, &v); \ + bpf_map_update_elem(&my_map, &v, &v, BPF_ANY); \ + bpf_map_update_elem(&my_map2, &v, &v, BPF_ANY); \ + bpf_map_delete_elem(&my_map2, &v); \ + bpf_get_stackid(ctx, &stackmap, BPF_F_REUSE_STACKID); \ + return 0; \ +} + +/* add kprobes to all possible *spin* functions */ +SEC("kprobe.multi/spin_*lock*")PROG(spin_lock) +SEC("kprobe.multi/*_spin_on_owner")PROG(spin_on_owner) +SEC("kprobe.multi/_raw_spin_*lock*")PROG(raw_spin_lock) + +/* and to inner bpf helpers */ +SEC("kprobe/htab_map_update_elem")PROG(p15) +SEC("kprobe/__htab_percpu_map_update_elem")PROG(p16) +SEC("kprobe/htab_map_alloc")PROG(p17) + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; -- cgit v1.3.1