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 --- drivers/of/module.c | 81 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 81 insertions(+) create mode 100644 drivers/of/module.c (limited to 'drivers/of/module.c') diff --git a/drivers/of/module.c b/drivers/of/module.c new file mode 100644 index 000000000..1e735fc13 --- /dev/null +++ b/drivers/of/module.c @@ -0,0 +1,81 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Linux kernel module helpers. + */ + +#include +#include +#include +#include + +ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len) +{ + const char *compat; + char *c; + struct property *p; + ssize_t csize; + ssize_t tsize; + + /* + * Prevent a kernel oops in vsnprintf() -- it only allows passing a + * NULL ptr when the length is also 0. Also filter out the negative + * lengths... + */ + if ((len > 0 && !str) || len < 0) + return -EINVAL; + + /* Name & Type */ + /* %p eats all alphanum characters, so %c must be used here */ + csize = snprintf(str, len, "of:N%pOFn%c%s", np, 'T', + of_node_get_device_type(np)); + tsize = csize; + if (csize >= len) + csize = len > 0 ? len - 1 : 0; + len -= csize; + str += csize; + + of_property_for_each_string(np, "compatible", p, compat) { + csize = snprintf(str, len, "C%s", compat); + tsize += csize; + if (csize >= len) + continue; + for (c = str; c; ) { + c = strchr(c, ' '); + if (c) + *c++ = '_'; + } + len -= csize; + str += csize; + } + + return tsize; +} + +int of_request_module(const struct device_node *np) +{ + char *str; + ssize_t size; + int ret; + + if (!np) + return -ENODEV; + + size = of_modalias(np, NULL, 0); + if (size < 0) + return size; + + /* Reserve an additional byte for the trailing '\0' */ + size++; + + str = kmalloc(size, GFP_KERNEL); + if (!str) + return -ENOMEM; + + of_modalias(np, str, size); + str[size - 1] = '\0'; + ret = request_module(str); + kfree(str); + + return ret; +} +EXPORT_SYMBOL_GPL(of_request_module); -- cgit v1.3.1