![nixiaoming](/assets/img/avatar_default.png)
[ Upstream commitc79dde629d
] After rmmod 8250.ko tty_kref_put starts kwork (release_one_tty) to release proc interface oops when accessing driver->driver_name in proc_tty_unregister_driver Use jprobe, found driver->driver_name point to 8250.ko static static struct uart_driver serial8250_reg .driver_name= serial, Use name in proc_dir_entry instead of driver->driver_name to fix oops test on linux 4.1.12: BUG: unable to handle kernel paging request at ffffffffa01979de IP: [<ffffffff81310f40>] strchr+0x0/0x30 PGD1a0d067
PUD 1a0e063 PMD 851c1f067 PTE 0 Oops: 0000 [#1] PREEMPT SMP Modules linked in: ... ... [last unloaded: 8250] CPU: 7 PID: 116 Comm: kworker/7:1 Tainted: G O 4.1.12 #1 Hardware name: Insyde RiverForest/Type2 - Board Product Name1, BIOS NE5KV904 12/21/2015 Workqueue: events release_one_tty task: ffff88085b684960 ti: ffff880852884000 task.ti: ffff880852884000 RIP: 0010:[<ffffffff81310f40>] [<ffffffff81310f40>] strchr+0x0/0x30 RSP: 0018:ffff880852887c90 EFLAGS: 00010282 RAX: ffffffff81a5eca0 RBX: ffffffffa01979de RCX: 0000000000000004 RDX: ffff880852887d10 RSI: 000000000000002f RDI: ffffffffa01979de RBP: ffff880852887cd8 R08: 0000000000000000 R09: ffff88085f5d94d0 R10: 0000000000000195 R11: 0000000000000000 R12: ffffffffa01979de R13: ffff880852887d00 R14: ffffffffa01979de R15: ffff88085f02e840 FS: 0000000000000000(0000) GS:ffff88085f5c0000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffa01979de CR3: 0000000001a0c000 CR4: 00000000001406e0 Stack: ffffffff812349b1 ffff880852887cb8 ffff880852887d10 ffff88085f5cd6c2 ffff880852800a80 ffffffffa01979de ffff880852800a84 0000000000000010 ffff88085bb28bd8 ffff880852887d38 ffffffff812354f0 ffff880852887d08 Call Trace: [<ffffffff812349b1>] ? __xlate_proc_name+0x71/0xd0 [<ffffffff812354f0>] remove_proc_entry+0x40/0x180 [<ffffffff815f6811>] ? _raw_spin_lock_irqsave+0x41/0x60 [<ffffffff813be520>] ? destruct_tty_driver+0x60/0xe0 [<ffffffff81237c68>] proc_tty_unregister_driver+0x28/0x40 [<ffffffff813be548>] destruct_tty_driver+0x88/0xe0 [<ffffffff813be5bd>] tty_driver_kref_put+0x1d/0x20 [<ffffffff813becca>] release_one_tty+0x5a/0xd0 [<ffffffff81074159>] process_one_work+0x139/0x420 [<ffffffff810745a1>] worker_thread+0x121/0x450 [<ffffffff81074480>] ? process_scheduled_works+0x40/0x40 [<ffffffff8107a16c>] kthread+0xec/0x110 [<ffffffff81080000>] ? tg_rt_schedulable+0x210/0x220 [<ffffffff8107a080>] ? kthread_freezable_should_stop+0x80/0x80 [<ffffffff815f7292>] ret_from_fork+0x42/0x70 [<ffffffff8107a080>] ? kthread_freezable_should_stop+0x80/0x80 Signed-off-by: nixiaoming <nixiaoming@huawei.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Sasha Levin <alexander.levin@verizon.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
192 lines
4.7 KiB
C
192 lines
4.7 KiB
C
// SPDX-License-Identifier: GPL-2.0
|
|
/*
|
|
* proc_tty.c -- handles /proc/tty
|
|
*
|
|
* Copyright 1997, Theodore Ts'o
|
|
*/
|
|
|
|
#include <linux/uaccess.h>
|
|
#include <linux/module.h>
|
|
#include <linux/init.h>
|
|
#include <linux/errno.h>
|
|
#include <linux/time.h>
|
|
#include <linux/proc_fs.h>
|
|
#include <linux/stat.h>
|
|
#include <linux/tty.h>
|
|
#include <linux/seq_file.h>
|
|
#include <linux/bitops.h>
|
|
#include "internal.h"
|
|
|
|
/*
|
|
* The /proc/tty directory inodes...
|
|
*/
|
|
static struct proc_dir_entry *proc_tty_driver;
|
|
|
|
/*
|
|
* This is the handler for /proc/tty/drivers
|
|
*/
|
|
static void show_tty_range(struct seq_file *m, struct tty_driver *p,
|
|
dev_t from, int num)
|
|
{
|
|
seq_printf(m, "%-20s ", p->driver_name ? p->driver_name : "unknown");
|
|
seq_printf(m, "/dev/%-8s ", p->name);
|
|
if (p->num > 1) {
|
|
seq_printf(m, "%3d %d-%d ", MAJOR(from), MINOR(from),
|
|
MINOR(from) + num - 1);
|
|
} else {
|
|
seq_printf(m, "%3d %7d ", MAJOR(from), MINOR(from));
|
|
}
|
|
switch (p->type) {
|
|
case TTY_DRIVER_TYPE_SYSTEM:
|
|
seq_puts(m, "system");
|
|
if (p->subtype == SYSTEM_TYPE_TTY)
|
|
seq_puts(m, ":/dev/tty");
|
|
else if (p->subtype == SYSTEM_TYPE_SYSCONS)
|
|
seq_puts(m, ":console");
|
|
else if (p->subtype == SYSTEM_TYPE_CONSOLE)
|
|
seq_puts(m, ":vtmaster");
|
|
break;
|
|
case TTY_DRIVER_TYPE_CONSOLE:
|
|
seq_puts(m, "console");
|
|
break;
|
|
case TTY_DRIVER_TYPE_SERIAL:
|
|
seq_puts(m, "serial");
|
|
break;
|
|
case TTY_DRIVER_TYPE_PTY:
|
|
if (p->subtype == PTY_TYPE_MASTER)
|
|
seq_puts(m, "pty:master");
|
|
else if (p->subtype == PTY_TYPE_SLAVE)
|
|
seq_puts(m, "pty:slave");
|
|
else
|
|
seq_puts(m, "pty");
|
|
break;
|
|
default:
|
|
seq_printf(m, "type:%d.%d", p->type, p->subtype);
|
|
}
|
|
seq_putc(m, '\n');
|
|
}
|
|
|
|
static int show_tty_driver(struct seq_file *m, void *v)
|
|
{
|
|
struct tty_driver *p = list_entry(v, struct tty_driver, tty_drivers);
|
|
dev_t from = MKDEV(p->major, p->minor_start);
|
|
dev_t to = from + p->num;
|
|
|
|
if (&p->tty_drivers == tty_drivers.next) {
|
|
/* pseudo-drivers first */
|
|
seq_printf(m, "%-20s /dev/%-8s ", "/dev/tty", "tty");
|
|
seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 0);
|
|
seq_puts(m, "system:/dev/tty\n");
|
|
seq_printf(m, "%-20s /dev/%-8s ", "/dev/console", "console");
|
|
seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 1);
|
|
seq_puts(m, "system:console\n");
|
|
#ifdef CONFIG_UNIX98_PTYS
|
|
seq_printf(m, "%-20s /dev/%-8s ", "/dev/ptmx", "ptmx");
|
|
seq_printf(m, "%3d %7d ", TTYAUX_MAJOR, 2);
|
|
seq_puts(m, "system\n");
|
|
#endif
|
|
#ifdef CONFIG_VT
|
|
seq_printf(m, "%-20s /dev/%-8s ", "/dev/vc/0", "vc/0");
|
|
seq_printf(m, "%3d %7d ", TTY_MAJOR, 0);
|
|
seq_puts(m, "system:vtmaster\n");
|
|
#endif
|
|
}
|
|
|
|
while (MAJOR(from) < MAJOR(to)) {
|
|
dev_t next = MKDEV(MAJOR(from)+1, 0);
|
|
show_tty_range(m, p, from, next - from);
|
|
from = next;
|
|
}
|
|
if (from != to)
|
|
show_tty_range(m, p, from, to - from);
|
|
return 0;
|
|
}
|
|
|
|
/* iterator */
|
|
static void *t_start(struct seq_file *m, loff_t *pos)
|
|
{
|
|
mutex_lock(&tty_mutex);
|
|
return seq_list_start(&tty_drivers, *pos);
|
|
}
|
|
|
|
static void *t_next(struct seq_file *m, void *v, loff_t *pos)
|
|
{
|
|
return seq_list_next(v, &tty_drivers, pos);
|
|
}
|
|
|
|
static void t_stop(struct seq_file *m, void *v)
|
|
{
|
|
mutex_unlock(&tty_mutex);
|
|
}
|
|
|
|
static const struct seq_operations tty_drivers_op = {
|
|
.start = t_start,
|
|
.next = t_next,
|
|
.stop = t_stop,
|
|
.show = show_tty_driver
|
|
};
|
|
|
|
static int tty_drivers_open(struct inode *inode, struct file *file)
|
|
{
|
|
return seq_open(file, &tty_drivers_op);
|
|
}
|
|
|
|
static const struct file_operations proc_tty_drivers_operations = {
|
|
.open = tty_drivers_open,
|
|
.read = seq_read,
|
|
.llseek = seq_lseek,
|
|
.release = seq_release,
|
|
};
|
|
|
|
/*
|
|
* This function is called by tty_register_driver() to handle
|
|
* registering the driver's /proc handler into /proc/tty/driver/<foo>
|
|
*/
|
|
void proc_tty_register_driver(struct tty_driver *driver)
|
|
{
|
|
struct proc_dir_entry *ent;
|
|
|
|
if (!driver->driver_name || driver->proc_entry ||
|
|
!driver->ops->proc_fops)
|
|
return;
|
|
|
|
ent = proc_create_data(driver->driver_name, 0, proc_tty_driver,
|
|
driver->ops->proc_fops, driver);
|
|
driver->proc_entry = ent;
|
|
}
|
|
|
|
/*
|
|
* This function is called by tty_unregister_driver()
|
|
*/
|
|
void proc_tty_unregister_driver(struct tty_driver *driver)
|
|
{
|
|
struct proc_dir_entry *ent;
|
|
|
|
ent = driver->proc_entry;
|
|
if (!ent)
|
|
return;
|
|
|
|
remove_proc_entry(ent->name, proc_tty_driver);
|
|
|
|
driver->proc_entry = NULL;
|
|
}
|
|
|
|
/*
|
|
* Called by proc_root_init() to initialize the /proc/tty subtree
|
|
*/
|
|
void __init proc_tty_init(void)
|
|
{
|
|
if (!proc_mkdir("tty", NULL))
|
|
return;
|
|
proc_mkdir("tty/ldisc", NULL); /* Preserved: it's userspace visible */
|
|
/*
|
|
* /proc/tty/driver/serial reveals the exact character counts for
|
|
* serial links which is just too easy to abuse for inferring
|
|
* password lengths and inter-keystroke timings during password
|
|
* entry.
|
|
*/
|
|
proc_tty_driver = proc_mkdir_mode("tty/driver", S_IRUSR|S_IXUSR, NULL);
|
|
proc_create("tty/ldiscs", 0, NULL, &tty_ldiscs_proc_fops);
|
|
proc_create("tty/drivers", 0, NULL, &proc_tty_drivers_operations);
|
|
}
|