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.bpf.c | 93 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 93 insertions(+) create mode 100644 samples/bpf/tracex5.bpf.c (limited to 'samples/bpf/tracex5.bpf.c') diff --git a/samples/bpf/tracex5.bpf.c b/samples/bpf/tracex5.bpf.c new file mode 100644 index 000000000..4d3d6c9b2 --- /dev/null +++ b/samples/bpf/tracex5.bpf.c @@ -0,0 +1,93 @@ +/* Copyright (c) 2015 PLUMgrid, http://plumgrid.com + * + * 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 "syscall_nrs.h" +#include +#include +#include +#include +#include + +#define __stringify(x) #x +#define PROG(F) SEC("kprobe/"__stringify(F)) int bpf_func_##F + +struct { + __uint(type, BPF_MAP_TYPE_PROG_ARRAY); + __uint(key_size, sizeof(u32)); + __uint(value_size, sizeof(u32)); +#ifdef __mips__ + __uint(max_entries, 6000); /* MIPS n64 syscalls start at 5000 */ +#else + __uint(max_entries, 1024); +#endif +} progs SEC(".maps"); + +SEC("kprobe/__seccomp_filter") +int bpf_prog1(struct pt_regs *ctx) +{ + int sc_nr = (int)PT_REGS_PARM1(ctx); + + /* dispatch into next BPF program depending on syscall number */ + bpf_tail_call(ctx, &progs, sc_nr); + + /* fall through -> unknown syscall */ + if (sc_nr >= __NR_getuid && sc_nr <= __NR_getsid) { + char fmt[] = "syscall=%d (one of get/set uid/pid/gid)\n"; + bpf_trace_printk(fmt, sizeof(fmt), sc_nr); + } + return 0; +} + +/* we jump here when syscall number == __NR_write */ +PROG(SYS__NR_write)(struct pt_regs *ctx) +{ + struct seccomp_data sd; + + bpf_core_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); + if (sd.args[2] == 512) { + char fmt[] = "write(fd=%d, buf=%p, size=%d)\n"; + bpf_trace_printk(fmt, sizeof(fmt), + sd.args[0], sd.args[1], sd.args[2]); + } + return 0; +} + +PROG(SYS__NR_read)(struct pt_regs *ctx) +{ + struct seccomp_data sd; + + bpf_core_read(&sd, sizeof(sd), (void *)PT_REGS_PARM2(ctx)); + if (sd.args[2] > 128 && sd.args[2] <= 1024) { + char fmt[] = "read(fd=%d, buf=%p, size=%d)\n"; + bpf_trace_printk(fmt, sizeof(fmt), + sd.args[0], sd.args[1], sd.args[2]); + } + return 0; +} + +#ifdef __NR_mmap2 +PROG(SYS__NR_mmap2)(struct pt_regs *ctx) +{ + char fmt[] = "mmap2\n"; + + bpf_trace_printk(fmt, sizeof(fmt)); + return 0; +} +#endif + +#ifdef __NR_mmap +PROG(SYS__NR_mmap)(struct pt_regs *ctx) +{ + char fmt[] = "mmap\n"; + + bpf_trace_printk(fmt, sizeof(fmt)); + return 0; +} +#endif + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; -- cgit v1.3.1