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 --- arch/x86/lib/cpu.c | 51 +++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+) create mode 100644 arch/x86/lib/cpu.c (limited to 'arch/x86/lib/cpu.c') diff --git a/arch/x86/lib/cpu.c b/arch/x86/lib/cpu.c new file mode 100644 index 000000000..d39fba72f --- /dev/null +++ b/arch/x86/lib/cpu.c @@ -0,0 +1,51 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include + +#include +#include + +static unsigned int __x86_family(unsigned int base_fam, unsigned int ext_fam) +{ + if (base_fam == 0xf) + base_fam += ext_fam; + + return base_fam; +} + +static unsigned int __x86_model(unsigned int family, unsigned int base_model, + unsigned int ext_model) +{ + if (family >= 0x6) + base_model |= ext_model << 4; + + return base_model; +} + +unsigned int x86_family(unsigned int sig) +{ + return __x86_family((sig >> 8) & 0xf, (sig >> 20) & 0xff); +} +EXPORT_SYMBOL_GPL(x86_family); + +unsigned int x86_model(unsigned int sig) +{ + return __x86_model(x86_family(sig), (sig >> 4) & 0xf, (sig >> 16) & 0xf); +} +EXPORT_SYMBOL_GPL(x86_model); + +unsigned int x86_stepping(unsigned int sig) +{ + return sig & 0xf; +} +EXPORT_SYMBOL_GPL(x86_stepping); + +unsigned int cpuid_family(const struct leaf_0x1_0 *l) +{ + return __x86_family(l->base_family_id, l->ext_family); +} + +unsigned int cpuid_model(const struct leaf_0x1_0 *l) +{ + return __x86_model(cpuid_family(l), l->base_model, l->ext_model); +} -- cgit v1.3.1