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 --- fs/proc/nommu.c | 116 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 fs/proc/nommu.c (limited to 'fs/proc/nommu.c') diff --git a/fs/proc/nommu.c b/fs/proc/nommu.c new file mode 100644 index 000000000..c6e7ebc63 --- /dev/null +++ b/fs/proc/nommu.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* nommu.c: mmu-less memory info files + * + * Copyright (C) 2004 Red Hat, Inc. All Rights Reserved. + * Written by David Howells (dhowells@redhat.com) + */ + +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include "internal.h" + +/* + * display a single region to a sequenced file + */ +static int nommu_region_show(struct seq_file *m, struct vm_region *region) +{ + unsigned long ino = 0; + struct file *file; + dev_t dev = 0; + int flags; + + flags = region->vm_flags; + file = region->vm_file; + + if (file) { + struct inode *inode = file_inode(region->vm_file); + dev = inode->i_sb->s_dev; + ino = inode->i_ino; + } + + seq_setwidth(m, 25 + sizeof(void *) * 6 - 1); + seq_printf(m, + "%08lx-%08lx %c%c%c%c %08llx %02x:%02x %lu ", + region->vm_start, + region->vm_end, + flags & VM_READ ? 'r' : '-', + flags & VM_WRITE ? 'w' : '-', + flags & VM_EXEC ? 'x' : '-', + flags & VM_MAYSHARE ? flags & VM_SHARED ? 'S' : 's' : 'p', + ((loff_t)region->vm_pgoff) << PAGE_SHIFT, + MAJOR(dev), MINOR(dev), ino); + + if (file) { + seq_pad(m, ' '); + seq_path(m, file_user_path(file), ""); + } + + seq_putc(m, '\n'); + return 0; +} + +/* + * display a list of all the REGIONs the kernel knows about + * - nommu kernels have a single flat list + */ +static int nommu_region_list_show(struct seq_file *m, void *_p) +{ + struct rb_node *p = _p; + + return nommu_region_show(m, rb_entry(p, struct vm_region, vm_rb)); +} + +static void *nommu_region_list_start(struct seq_file *m, loff_t *_pos) +{ + struct rb_node *p; + loff_t pos = *_pos; + + down_read(&nommu_region_sem); + + for (p = rb_first(&nommu_region_tree); p; p = rb_next(p)) + if (pos-- == 0) + return p; + return NULL; +} + +static void nommu_region_list_stop(struct seq_file *m, void *v) +{ + up_read(&nommu_region_sem); +} + +static void *nommu_region_list_next(struct seq_file *m, void *v, loff_t *pos) +{ + (*pos)++; + return rb_next((struct rb_node *) v); +} + +static const struct seq_operations proc_nommu_region_list_seqop = { + .start = nommu_region_list_start, + .next = nommu_region_list_next, + .stop = nommu_region_list_stop, + .show = nommu_region_list_show +}; + +static int __init proc_nommu_init(void) +{ + proc_create_seq("maps", S_IRUGO, NULL, &proc_nommu_region_list_seqop); + return 0; +} + +fs_initcall(proc_nommu_init); -- cgit v1.3.1