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When hsr module is being removed, debugfs_remove() is called to remove
both debugfs directory and file.
When module is being removed, module state is changed to
MODULE_STATE_GOING then exit() is called.
At this moment, module couldn't be held so try_module_get()
will be failed.
debugfs's open() callback tries to hold the module if .owner is existing.
If it fails, warning message is printed.
CPU0 CPU1
delete_module()
try_stop_module()
hsr_exit() open() <-- WARNING
debugfs_remove()
In order to avoid the warning message, this patch makes hsr module does
not set .owner. Unsetting .owner is safe because these are protected by
inode_lock().
Test commands:
#SHELL1
ip link add dummy0 type dummy
ip link add dummy1 type dummy
while :
do
ip link add hsr0 type hsr slave1 dummy0 slave2 dummy1
modprobe -rv hsr
done
#SHELL2
while :
do
cat /sys/kernel/debug/hsr0/node_table
done
Splat looks like:
[ 101.223783][ T1271] ------------[ cut here ]------------
[ 101.230309][ T1271] debugfs file owner did not clean up at exit: node_table
[ 101.230380][ T1271] WARNING: CPU: 3 PID: 1271 at fs/debugfs/file.c:309 full_proxy_open+0x10f/0x650
[ 101.233153][ T1271] Modules linked in: hsr(-) dummy veth openvswitch nsh nf_conncount nf_nat nf_conntrack nf_d]
[ 101.237112][ T1271] CPU: 3 PID: 1271 Comm: cat Tainted: G W 5.5.0-rc1+ #204
[ 101.238270][ T1271] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006
[ 101.240379][ T1271] RIP: 0010:full_proxy_open+0x10f/0x650
[ 101.241166][ T1271] Code: 48 c1 ea 03 80 3c 02 00 0f 85 c1 04 00 00 49 8b 3c 24 e8 04 86 7e ff 84 c0 75 2d 4c 8
[ 101.251985][ T1271] RSP: 0018:ffff8880ca22fa38 EFLAGS: 00010286
[ 101.273355][ T1271] RAX: dffffc0000000008 RBX: ffff8880cc6e6200 RCX: 0000000000000000
[ 101.274466][ T1271] RDX: 0000000000000000 RSI: 0000000000000006 RDI: ffff8880c4dd5c14
[ 101.275581][ T1271] RBP: 0000000000000000 R08: fffffbfff2922f5d R09: 0000000000000000
[ 101.276733][ T1271] R10: 0000000000000001 R11: 0000000000000000 R12: ffffffffc0551bc0
[ 101.277853][ T1271] R13: ffff8880c4059a48 R14: ffff8880be50a5e0 R15: ffffffff941adaa0
[ 101.278956][ T1271] FS: 00007f8871cda540(0000) GS:ffff8880da800000(0000) knlGS:0000000000000000
[ 101.280216][ T1271] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 101.282832][ T1271] CR2: 00007f88717cfd10 CR3: 00000000b9440005 CR4: 00000000000606e0
[ 101.283974][ T1271] Call Trace:
[ 101.285328][ T1271] do_dentry_open+0x63c/0xf50
[ 101.286077][ T1271] ? open_proxy_open+0x270/0x270
[ 101.288271][ T1271] ? __x64_sys_fchdir+0x180/0x180
[ 101.288987][ T1271] ? inode_permission+0x65/0x390
[ 101.289682][ T1271] path_openat+0x701/0x2810
[ 101.290294][ T1271] ? path_lookupat+0x880/0x880
[ 101.290957][ T1271] ? check_chain_key+0x236/0x5d0
[ 101.291676][ T1271] ? __lock_acquire+0xdfe/0x3de0
[ 101.292358][ T1271] ? sched_clock+0x5/0x10
[ 101.292962][ T1271] ? sched_clock_cpu+0x18/0x170
[ 101.293644][ T1271] ? find_held_lock+0x39/0x1d0
[ 101.305616][ T1271] do_filp_open+0x17a/0x270
[ 101.306061][ T1271] ? may_open_dev+0xc0/0xc0
[ ... ]
Fixes: fc4ecaeebd
("net: hsr: add debugfs support for display node list")
Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
119 lines
3.2 KiB
C
119 lines
3.2 KiB
C
/*
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* hsr_debugfs code
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* Copyright (C) 2019 Texas Instruments Incorporated
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*
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* Author(s):
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* Murali Karicheri <m-karicheri2@ti.com>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation version 2.
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*
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* This program is distributed "as is" WITHOUT ANY WARRANTY of any
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* kind, whether express or implied; without even the implied warranty
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* of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/debugfs.h>
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#include "hsr_main.h"
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#include "hsr_framereg.h"
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static void print_mac_address(struct seq_file *sfp, unsigned char *mac)
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{
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seq_printf(sfp, "%02x:%02x:%02x:%02x:%02x:%02x:",
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mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]);
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}
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/* hsr_node_table_show - Formats and prints node_table entries */
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static int
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hsr_node_table_show(struct seq_file *sfp, void *data)
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{
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struct hsr_priv *priv = (struct hsr_priv *)sfp->private;
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struct hsr_node *node;
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seq_puts(sfp, "Node Table entries\n");
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seq_puts(sfp, "MAC-Address-A, MAC-Address-B, time_in[A], ");
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seq_puts(sfp, "time_in[B], Address-B port\n");
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rcu_read_lock();
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list_for_each_entry_rcu(node, &priv->node_db, mac_list) {
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/* skip self node */
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if (hsr_addr_is_self(priv, node->macaddress_A))
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continue;
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print_mac_address(sfp, &node->macaddress_A[0]);
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seq_puts(sfp, " ");
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print_mac_address(sfp, &node->macaddress_B[0]);
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seq_printf(sfp, "0x%lx, ", node->time_in[HSR_PT_SLAVE_A]);
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seq_printf(sfp, "0x%lx ", node->time_in[HSR_PT_SLAVE_B]);
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seq_printf(sfp, "0x%x\n", node->addr_B_port);
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}
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rcu_read_unlock();
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return 0;
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}
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/* hsr_node_table_open - Open the node_table file
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*
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* Description:
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* This routine opens a debugfs file node_table of specific hsr device
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*/
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static int
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hsr_node_table_open(struct inode *inode, struct file *filp)
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{
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return single_open(filp, hsr_node_table_show, inode->i_private);
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}
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static const struct file_operations hsr_fops = {
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.open = hsr_node_table_open,
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.read = seq_read,
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.llseek = seq_lseek,
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.release = single_release,
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};
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/* hsr_debugfs_init - create hsr node_table file for dumping
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* the node table
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*
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* Description:
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* When debugfs is configured this routine sets up the node_table file per
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* hsr device for dumping the node_table entries
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*/
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int hsr_debugfs_init(struct hsr_priv *priv, struct net_device *hsr_dev)
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{
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int rc = -1;
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struct dentry *de = NULL;
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de = debugfs_create_dir(hsr_dev->name, NULL);
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if (!de) {
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pr_err("Cannot create hsr debugfs root\n");
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return rc;
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}
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priv->node_tbl_root = de;
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de = debugfs_create_file("node_table", S_IFREG | 0444,
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priv->node_tbl_root, priv,
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&hsr_fops);
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if (!de) {
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pr_err("Cannot create hsr node_table directory\n");
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return rc;
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}
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priv->node_tbl_file = de;
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return 0;
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}
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/* hsr_debugfs_term - Tear down debugfs intrastructure
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*
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* Description:
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* When Debufs is configured this routine removes debugfs file system
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* elements that are specific to hsr
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*/
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void
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hsr_debugfs_term(struct hsr_priv *priv)
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{
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debugfs_remove(priv->node_tbl_file);
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priv->node_tbl_file = NULL;
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debugfs_remove(priv->node_tbl_root);
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priv->node_tbl_root = NULL;
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}
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