x86/amd_node: Fix PCI device reference counting in amd_smn_init()grafted

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 <sashiko-bot@kernel.org>
Assisted-by: LLM
Signed-off-by: Yazen Ghannam <yazen.ghannam@amd.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>
Cc: <stable@kernel.org>
Link: https://patch.msgid.link/20260903154325.74343-1-yazen.ghannam@amd.com

1 files changed, 62 insertions, 0 deletions

diff --git a/include/uapi/asm-generic/resource.h b/include/uapi/asm-generic/resource.h
new file mode 100644
index 000000000..f12db7a0d
--- /dev/null
+++ b/include/uapi/asm-generic/resource.h
@@ -0,0 +1,62 @@
+/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
+#ifndef _UAPI_ASM_GENERIC_RESOURCE_H
+#define _UAPI_ASM_GENERIC_RESOURCE_H
+
+/*
+ * Resource limit IDs
+ *
+ * ( Compatibility detail: there are architectures that have
+ *   a different rlimit ID order in the 5-9 range and want
+ *   to keep that order for binary compatibility. The reasons
+ *   are historic and all new rlimits are identical across all
+ *   arches. If an arch has such special order for some rlimits
+ *   then it defines them prior including asm-generic/resource.h. )
+ */
+
+#define RLIMIT_CPU		0	/* CPU time in sec */
+#define RLIMIT_FSIZE		1	/* Maximum filesize */
+#define RLIMIT_DATA		2	/* max data size */
+#define RLIMIT_STACK		3	/* max stack size */
+#define RLIMIT_CORE		4	/* max core file size */
+
+#ifndef RLIMIT_RSS
+# define RLIMIT_RSS		5	/* max resident set size */
+#endif
+
+#ifndef RLIMIT_NPROC
+# define RLIMIT_NPROC		6	/* max number of processes */
+#endif
+
+#ifndef RLIMIT_NOFILE
+# define RLIMIT_NOFILE		7	/* max number of open files */
+#endif
+
+#ifndef RLIMIT_MEMLOCK
+# define RLIMIT_MEMLOCK		8	/* max locked-in-memory address space */
+#endif
+
+#ifndef RLIMIT_AS
+# define RLIMIT_AS		9	/* address space limit */
+#endif
+
+#define RLIMIT_LOCKS		10	/* maximum file locks held */
+#define RLIMIT_SIGPENDING	11	/* max number of pending signals */
+#define RLIMIT_MSGQUEUE		12	/* maximum bytes in POSIX mqueues */
+#define RLIMIT_NICE		13	/* max nice prio allowed to raise to
+					   0-39 for nice level 19 .. -20 */
+#define RLIMIT_RTPRIO		14	/* maximum realtime priority */
+#define RLIMIT_RTTIME		15	/* timeout for RT tasks in us */
+#define RLIM_NLIMITS		16
+
+/*
+ * SuS says limits have to be unsigned.
+ * Which makes a ton more sense anyway.
+ *
+ * Some architectures override this (for compatibility reasons):
+ */
+#ifndef RLIM_INFINITY
+# define RLIM_INFINITY		(~0UL)
+#endif
+
+
+#endif /* _UAPI_ASM_GENERIC_RESOURCE_H */