This is a note to let you know that I've just added the patch titled
gtp: Suppress list corruption splat in gtp_net_exit_batch_rtnl().
to the 6.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
gtp-suppress-list-corruption-splat-in-gtp_net_exit_b.patch
and it can be found in the queue-6.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit c49269d9e83d25865d45a2abd75754f73443b2df
Author: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Date: Mon Feb 17 12:37:04 2025 -0800
gtp: Suppress list corruption splat in gtp_net_exit_batch_rtnl().
[ Upstream commit 4ccacf86491d33d2486b62d4d44864d7101b299d ]
Brad Spengler reported the list_del() corruption splat in
gtp_net_exit_batch_rtnl(). [0]
Commit eb28fd76c0a0 ("gtp: Destroy device along with udp socket's netns
dismantle.") added the for_each_netdev() loop in gtp_net_exit_batch_rtnl()
to destroy devices in each netns as done in geneve and ip tunnels.
However, this could trigger ->dellink() twice for the same device during
->exit_batch_rtnl().
Say we have two netns A & B and gtp device B that resides in netns B but
whose UDP socket is in netns A.
1. cleanup_net() processes netns A and then B.
2. gtp_net_exit_batch_rtnl() finds the device B while iterating
netns A's gn->gtp_dev_list and calls ->dellink().
[ device B is not yet unlinked from netns B
as unregister_netdevice_many() has not been called. ]
3. gtp_net_exit_batch_rtnl() finds the device B while iterating
netns B's for_each_netdev() and calls ->dellink().
gtp_dellink() cleans up the device's hash table, unlinks the dev from
gn->gtp_dev_list, and calls unregister_netdevice_queue().
Basically, calling gtp_dellink() multiple times is fine unless
CONFIG_DEBUG_LIST is enabled.
Let's remove for_each_netdev() in gtp_net_exit_batch_rtnl() and
delegate the destruction to default_device_exit_batch() as done
in bareudp.
[0]:
list_del corruption, ffff8880aaa62c00->next (autoslab_size_M_dev_P_net_core_dev_11127_8_1328_8_S_4096_A_64_n_139+0xc00/0x1000 [slab object]) is LIST_POISON1 (ffffffffffffff02) (prev is 0xffffffffffffff04)
kernel BUG at lib/list_debug.c:58!
Oops: invalid opcode: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 UID: 0 PID: 1804 Comm: kworker/u8:7 Tainted: G T 6.12.13-grsec-full-20250211091339 #1
Tainted: [T]=RANDSTRUCT
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Workqueue: netns cleanup_net
RIP: 0010:[<ffffffff84947381>] __list_del_entry_valid_or_report+0x141/0x200 lib/list_debug.c:58
Code: c2 76 91 31 c0 e8 9f b1 f7 fc 0f 0b 4d 89 f0 48 c7 c1 02 ff ff ff 48 89 ea 48 89 ee 48 c7 c7 e0 c2 76 91 31 c0 e8 7f b1 f7 fc <0f> 0b 4d 89 e8 48 c7 c1 04 ff ff ff 48 89 ea 48 89 ee 48 c7 c7 60
RSP: 0018:fffffe8040b4fbd0 EFLAGS: 00010283
RAX: 00000000000000cc RBX: dffffc0000000000 RCX: ffffffff818c4054
RDX: ffffffff84947381 RSI: ffffffff818d1512 RDI: 0000000000000000
RBP: ffff8880aaa62c00 R08: 0000000000000001 R09: fffffbd008169f32
R10: fffffe8040b4f997 R11: 0000000000000001 R12: a1988d84f24943e4
R13: ffffffffffffff02 R14: ffffffffffffff04 R15: ffff8880aaa62c08
RBX: kasan shadow of 0x0
RCX: __wake_up_klogd.part.0+0x74/0xe0 kernel/printk/printk.c:4554
RDX: __list_del_entry_valid_or_report+0x141/0x200 lib/list_debug.c:58
RSI: vprintk+0x72/0x100 kernel/printk/printk_safe.c:71
RBP: autoslab_size_M_dev_P_net_core_dev_11127_8_1328_8_S_4096_A_64_n_139+0xc00/0x1000 [slab object]
RSP: process kstack fffffe8040b4fbd0+0x7bd0/0x8000 [kworker/u8:7+netns 1804 ]
R09: kasan shadow of process kstack fffffe8040b4f990+0x7990/0x8000 [kworker/u8:7+netns 1804 ]
R10: process kstack fffffe8040b4f997+0x7997/0x8000 [kworker/u8:7+netns 1804 ]
R15: autoslab_size_M_dev_P_net_core_dev_11127_8_1328_8_S_4096_A_64_n_139+0xc08/0x1000 [slab object]
FS: 0000000000000000(0000) GS:ffff888116000000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000748f5372c000 CR3: 0000000015408000 CR4: 00000000003406f0 shadow CR4: 00000000003406f0
Stack:
0000000000000000 ffffffff8a0c35e7 ffffffff8a0c3603 ffff8880aaa62c00
ffff8880aaa62c00 0000000000000004 ffff88811145311c 0000000000000005
0000000000000001 ffff8880aaa62000 fffffe8040b4fd40 ffffffff8a0c360d
Call Trace:
<TASK>
[<ffffffff8a0c360d>] __list_del_entry_valid include/linux/list.h:131 [inline] fffffe8040b4fc28
[<ffffffff8a0c360d>] __list_del_entry include/linux/list.h:248 [inline] fffffe8040b4fc28
[<ffffffff8a0c360d>] list_del include/linux/list.h:262 [inline] fffffe8040b4fc28
[<ffffffff8a0c360d>] gtp_dellink+0x16d/0x360 drivers/net/gtp.c:1557 fffffe8040b4fc28
[<ffffffff8a0d0404>] gtp_net_exit_batch_rtnl+0x124/0x2c0 drivers/net/gtp.c:2495 fffffe8040b4fc88
[<ffffffff8e705b24>] cleanup_net+0x5a4/0xbe0 net/core/net_namespace.c:635 fffffe8040b4fcd0
[<ffffffff81754c97>] process_one_work+0xbd7/0x2160 kernel/workqueue.c:3326 fffffe8040b4fd88
[<ffffffff81757195>] process_scheduled_works kernel/workqueue.c:3407 [inline] fffffe8040b4fec0
[<ffffffff81757195>] worker_thread+0x6b5/0xfa0 kernel/workqueue.c:3488 fffffe8040b4fec0
[<ffffffff817782a0>] kthread+0x360/0x4c0 kernel/kthread.c:397 fffffe8040b4ff78
[<ffffffff814d8594>] ret_from_fork+0x74/0xe0 arch/x86/kernel/process.c:172 fffffe8040b4ffb8
[<ffffffff8110f509>] ret_from_fork_asm+0x29/0xc0 arch/x86/entry/entry_64.S:399 fffffe8040b4ffe8
</TASK>
Modules linked in:
Fixes: eb28fd76c0a0 ("gtp: Destroy device along with udp socket's netns dismantle.")
Reported-by: Brad Spengler <spender@xxxxxxxxxxxxxx>
Signed-off-by: Kuniyuki Iwashima <kuniyu@xxxxxxxxxx>
Link: https://patch.msgid.link/20250217203705.40342-2-kuniyu@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/gtp.c b/drivers/net/gtp.c
index fbabada7d3ba9..2cb13e092a856 100644
--- a/drivers/net/gtp.c
+++ b/drivers/net/gtp.c
@@ -2479,11 +2479,6 @@ static void __net_exit gtp_net_exit_batch_rtnl(struct list_head *net_list,
list_for_each_entry(net, net_list, exit_list) {
struct gtp_net *gn = net_generic(net, gtp_net_id);
struct gtp_dev *gtp, *gtp_next;
- struct net_device *dev;
-
- for_each_netdev(net, dev)
- if (dev->rtnl_link_ops == >p_link_ops)
- gtp_dellink(dev, dev_to_kill);
list_for_each_entry_safe(gtp, gtp_next, &gn->gtp_dev_list, list)
gtp_dellink(gtp->dev, dev_to_kill);
