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605b52497b
rlb_clear_slave intentionally keeps RLB hash-table entries on
the rx_hashtbl_used_head list with slave set to NULL when no
replacement slave is available. However, bond_debug_rlb_hash_show
visites client_info->slave without checking if it's NULL.
Other used-list iterators in bond_alb.c already handle this NULL-slave
state safely:
- rlb_update_client returns early on !client_info->slave
- rlb_req_update_slave_clients, rlb_clear_slave, and rlb_rebalance
compare slave values before visiting
- lb_req_update_subnet_clients continues if slave is NULL
The following NULL deref crash can be trigger in
bond_debug_rlb_hash_show:
[ 1.289791] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1.292058] RIP: 0010:bond_debug_rlb_hash_show (drivers/net/bonding/bond_debugfs.c:41)
[ 1.293101] RSP: 0018:ffffc900004a7d00 EFLAGS: 00010286
[ 1.293333] RAX: 0000000000000000 RBX: ffff888102b48200 RCX: ffff888102b48204
[ 1.293631] RDX: ffff888102b48200 RSI: ffffffff839daad5 RDI: ffff888102815078
[ 1.293924] RBP: ffff888102815078 R08: ffff888102b4820e R09: 0000000000000000
[ 1.294267] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888100f929c0
[ 1.294564] R13: ffff888100f92a00 R14: 0000000000000001 R15: ffffc900004a7ed8
[ 1.294864] FS: 0000000001395380(0000) GS:ffff888196e75000(0000) knlGS:0000000000000000
[ 1.295239] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.295480] CR2: 0000000000000000 CR3: 0000000102adc004 CR4: 0000000000772ef0
[ 1.295897] Call Trace:
[ 1.296134] seq_read_iter (fs/seq_file.c:231)
[ 1.296341] seq_read (fs/seq_file.c:164)
[ 1.296493] full_proxy_read (fs/debugfs/file.c:378 (discriminator 1))
[ 1.296658] vfs_read (fs/read_write.c:572)
[ 1.296981] ksys_read (fs/read_write.c:717)
[ 1.297132] do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
[ 1.297325] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Add a NULL check and print "(none)" for entries with no assigned slave.
Fixes: caafa84251 ("bonding: add the debugfs interface to see RLB hash table")
Reported-by: Weiming Shi <bestswngs@gmail.com>
Signed-off-by: Xiang Mei <xmei5@asu.edu>
Link: https://patch.msgid.link/20260317005034.1888794-1-xmei5@asu.edu
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
117 lines
2.5 KiB
C
117 lines
2.5 KiB
C
// SPDX-License-Identifier: GPL-2.0
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/device.h>
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#include <linux/netdevice.h>
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#include <net/bonding.h>
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#include <net/bond_alb.h>
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#if defined(CONFIG_DEBUG_FS) && !defined(CONFIG_NET_NS)
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#include <linux/debugfs.h>
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#include <linux/seq_file.h>
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static struct dentry *bonding_debug_root;
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/* Show RLB hash table */
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static int bond_debug_rlb_hash_show(struct seq_file *m, void *v)
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{
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struct bonding *bond = m->private;
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struct alb_bond_info *bond_info = &(BOND_ALB_INFO(bond));
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struct rlb_client_info *client_info;
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u32 hash_index;
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if (BOND_MODE(bond) != BOND_MODE_ALB)
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return 0;
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seq_printf(m, "SourceIP DestinationIP "
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"Destination MAC DEV\n");
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spin_lock_bh(&bond->mode_lock);
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hash_index = bond_info->rx_hashtbl_used_head;
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for (; hash_index != RLB_NULL_INDEX;
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hash_index = client_info->used_next) {
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client_info = &(bond_info->rx_hashtbl[hash_index]);
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if (client_info->slave)
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seq_printf(m, "%-15pI4 %-15pI4 %-17pM %s\n",
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&client_info->ip_src,
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&client_info->ip_dst,
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&client_info->mac_dst,
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client_info->slave->dev->name);
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else
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seq_printf(m, "%-15pI4 %-15pI4 %-17pM (none)\n",
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&client_info->ip_src,
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&client_info->ip_dst,
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&client_info->mac_dst);
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}
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spin_unlock_bh(&bond->mode_lock);
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return 0;
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}
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DEFINE_SHOW_ATTRIBUTE(bond_debug_rlb_hash);
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void bond_debug_register(struct bonding *bond)
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{
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bond->debug_dir =
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debugfs_create_dir(bond->dev->name, bonding_debug_root);
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debugfs_create_file("rlb_hash_table", 0400, bond->debug_dir,
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bond, &bond_debug_rlb_hash_fops);
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}
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void bond_debug_unregister(struct bonding *bond)
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{
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debugfs_remove_recursive(bond->debug_dir);
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}
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void bond_debug_reregister(struct bonding *bond)
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{
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int err = debugfs_change_name(bond->debug_dir, "%s", bond->dev->name);
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if (err) {
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netdev_warn(bond->dev, "failed to reregister, so just unregister old one\n");
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bond_debug_unregister(bond);
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}
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}
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void __init bond_create_debugfs(void)
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{
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bonding_debug_root = debugfs_create_dir("bonding", NULL);
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if (IS_ERR(bonding_debug_root))
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pr_warn("Warning: Cannot create bonding directory in debugfs\n");
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}
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void bond_destroy_debugfs(void)
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{
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debugfs_remove_recursive(bonding_debug_root);
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bonding_debug_root = NULL;
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}
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#else /* !CONFIG_DEBUG_FS */
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void bond_debug_register(struct bonding *bond)
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{
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}
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void bond_debug_unregister(struct bonding *bond)
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{
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}
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void bond_debug_reregister(struct bonding *bond)
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{
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}
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void __init bond_create_debugfs(void)
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{
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}
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void bond_destroy_debugfs(void)
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{
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}
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#endif /* CONFIG_DEBUG_FS */
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