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 --- include/kunit/static_stub.h | 113 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 113 insertions(+) create mode 100644 include/kunit/static_stub.h (limited to 'include/kunit/static_stub.h') diff --git a/include/kunit/static_stub.h b/include/kunit/static_stub.h new file mode 100644 index 000000000..bf940322d --- /dev/null +++ b/include/kunit/static_stub.h @@ -0,0 +1,113 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +/* + * KUnit function redirection (static stubbing) API. + * + * Copyright (C) 2022, Google LLC. + * Author: David Gow + */ +#ifndef _KUNIT_STATIC_STUB_H +#define _KUNIT_STATIC_STUB_H + +#if !IS_ENABLED(CONFIG_KUNIT) + +/* If CONFIG_KUNIT is not enabled, these stubs quietly disappear. */ +#define KUNIT_STATIC_STUB_REDIRECT(real_fn_name, args...) do {} while (0) + +#else + +#include +#include + +#include /* for {un,}likely() */ +#include /* for task_struct */ + + +/** + * KUNIT_STATIC_STUB_REDIRECT() - call a replacement 'static stub' if one exists + * @real_fn_name: The name of this function (as an identifier, not a string) + * @args: All of the arguments passed to this function + * + * This is a function prologue which is used to allow calls to the current + * function to be redirected by a KUnit test. KUnit tests can call + * kunit_activate_static_stub() to pass a replacement function in. The + * replacement function will be called by KUNIT_STATIC_STUB_REDIRECT(), which + * will then return from the function. If the caller is not in a KUnit context, + * the function will continue execution as normal. + * + * Example: + * + * .. code-block:: c + * + * int real_func(int n) + * { + * KUNIT_STATIC_STUB_REDIRECT(real_func, n); + * return 0; + * } + * + * int replacement_func(int n) + * { + * return 42; + * } + * + * void example_test(struct kunit *test) + * { + * kunit_activate_static_stub(test, real_func, replacement_func); + * KUNIT_EXPECT_EQ(test, real_func(1), 42); + * } + * + */ +#define KUNIT_STATIC_STUB_REDIRECT(real_fn_name, args...) \ +do { \ + typeof(&real_fn_name) replacement; \ + struct kunit *current_test = kunit_get_current_test(); \ + \ + if (likely(!current_test)) \ + break; \ + \ + replacement = kunit_hooks.get_static_stub_address(current_test, \ + &real_fn_name); \ + \ + if (unlikely(replacement)) \ + return replacement(args); \ +} while (0) + +/* Helper function for kunit_activate_static_stub(). The macro does + * typechecking, so use it instead. + */ +void __kunit_activate_static_stub(struct kunit *test, + void *real_fn_addr, + void *replacement_addr); + +/** + * kunit_activate_static_stub() - replace a function using static stubs. + * @test: A pointer to the 'struct kunit' test context for the current test. + * @real_fn_addr: The address of the function to replace. + * @replacement_addr: The address of the function to replace it with. + * + * When activated, calls to real_fn_addr from within this test (even if called + * indirectly) will instead call replacement_addr. The function pointed to by + * real_fn_addr must begin with the static stub prologue in + * KUNIT_STATIC_STUB_REDIRECT() for this to work. real_fn_addr and + * replacement_addr must have the same type. + * + * The redirection can be disabled again with kunit_deactivate_static_stub(). + */ +#define kunit_activate_static_stub(test, real_fn_addr, replacement_addr) do { \ + typecheck_fn(typeof(&replacement_addr), real_fn_addr); \ + __kunit_activate_static_stub(test, real_fn_addr, replacement_addr); \ +} while (0) + + +/** + * kunit_deactivate_static_stub() - disable a function redirection + * @test: A pointer to the 'struct kunit' test context for the current test. + * @real_fn_addr: The address of the function to no-longer redirect + * + * Deactivates a redirection configured with kunit_activate_static_stub(). After + * this function returns, calls to real_fn_addr() will execute the original + * real_fn, not any previously-configured replacement. + */ +void kunit_deactivate_static_stub(struct kunit *test, void *real_fn_addr); + +#endif +#endif -- cgit v1.3.1