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/consoles.c | 116 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 116 insertions(+) create mode 100644 fs/proc/consoles.c (limited to 'fs/proc/consoles.c') diff --git a/fs/proc/consoles.c b/fs/proc/consoles.c new file mode 100644 index 000000000..b7cab1ad9 --- /dev/null +++ b/fs/proc/consoles.c @@ -0,0 +1,116 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Copyright (c) 2010 Werner Fink, Jiri Slaby + */ + +#include +#include +#include +#include +#include + +/* + * This is handler for /proc/consoles + */ +static int show_console_dev(struct seq_file *m, void *v) +{ + static const struct { + short flag; + char name; + } con_flags[] = { + { CON_ENABLED, 'E' }, + { CON_CONSDEV, 'C' }, + { CON_BOOT, 'B' }, + { CON_NBCON, 'N' }, + { CON_PRINTBUFFER, 'p' }, + { CON_BRL, 'b' }, + { CON_ANYTIME, 'a' }, + }; + char flags[ARRAY_SIZE(con_flags) + 1]; + struct console *con = v; + unsigned int a; + dev_t dev = 0; + + if (con->device) { + const struct tty_driver *driver; + int index; + + /* + * Take console_lock to serialize device() callback with + * other console operations. For example, fg_console is + * modified under console_lock when switching vt. + */ + console_lock(); + driver = con->device(con, &index); + console_unlock(); + + if (driver) { + dev = MKDEV(driver->major, driver->minor_start); + dev += index; + } + } + + for (a = 0; a < ARRAY_SIZE(con_flags); a++) + flags[a] = (con->flags & con_flags[a].flag) ? + con_flags[a].name : ' '; + flags[a] = 0; + + seq_setwidth(m, 21 - 1); + seq_printf(m, "%s%d", con->name, con->index); + seq_pad(m, ' '); + seq_printf(m, "%c%c%c (%s)", con->read ? 'R' : '-', + ((con->flags & CON_NBCON) || con->write) ? 'W' : '-', + con->unblank ? 'U' : '-', flags); + if (dev) + seq_printf(m, " %4d:%d", MAJOR(dev), MINOR(dev)); + + seq_putc(m, '\n'); + return 0; +} + +static void *c_start(struct seq_file *m, loff_t *pos) + __acquires(&console_mutex) +{ + struct console *con; + loff_t off = 0; + + /* + * Hold the console_list_lock to guarantee safe traversal of the + * console list. SRCU cannot be used because there is no + * place to store the SRCU cookie. + */ + console_list_lock(); + for_each_console(con) + if (off++ == *pos) + break; + + return con; +} + +static void *c_next(struct seq_file *m, void *v, loff_t *pos) +{ + struct console *con = v; + + ++*pos; + return hlist_entry_safe(con->node.next, struct console, node); +} + +static void c_stop(struct seq_file *m, void *v) + __releases(&console_mutex) +{ + console_list_unlock(); +} + +static const struct seq_operations consoles_op = { + .start = c_start, + .next = c_next, + .stop = c_stop, + .show = show_console_dev +}; + +static int __init proc_consoles_init(void) +{ + proc_create_seq("consoles", 0, NULL, &consoles_op); + return 0; +} +fs_initcall(proc_consoles_init); -- cgit v1.3.1