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/tracex1.bpf.c | 47 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) create mode 100644 samples/bpf/tracex1.bpf.c (limited to 'samples/bpf/tracex1.bpf.c') diff --git a/samples/bpf/tracex1.bpf.c b/samples/bpf/tracex1.bpf.c new file mode 100644 index 000000000..ceedf0b1d --- /dev/null +++ b/samples/bpf/tracex1.bpf.c @@ -0,0 +1,47 @@ +/* Copyright (c) 2013-2015 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 "net_shared.h" +#include +#include +#include +#include + +/* kprobe is NOT a stable ABI + * kernel functions can be removed, renamed or completely change semantics. + * Number of arguments and their positions can change, etc. + * In such case this bpf+kprobe example will no longer be meaningful + */ +SEC("kprobe.multi/__netif_receive_skb_core*") +int bpf_prog1(struct pt_regs *ctx) +{ + /* attaches to kprobe __netif_receive_skb_core, + * looks for packets on loopback device and prints them + * (wildcard is used for avoiding symbol mismatch due to optimization) + */ + char devname[IFNAMSIZ]; + struct net_device *dev; + struct sk_buff *skb; + int len; + + bpf_core_read(&skb, sizeof(skb), (void *)PT_REGS_PARM1(ctx)); + dev = BPF_CORE_READ(skb, dev); + len = BPF_CORE_READ(skb, len); + + BPF_CORE_READ_STR_INTO(&devname, dev, name); + + if (devname[0] == 'l' && devname[1] == 'o') { + char fmt[] = "skb %p len %d\n"; + /* using bpf_trace_printk() for DEBUG ONLY */ + bpf_trace_printk(fmt, sizeof(fmt), skb, len); + } + + return 0; +} + +char _license[] SEC("license") = "GPL"; +u32 _version SEC("version") = LINUX_VERSION_CODE; -- cgit v1.3.1