Subject: Re: [PATCH net-next v5 0/2] net: Split ndo_set_rx_mode into snapshot

From: Jakub Kicinski <[email-masked]>
Date: Thu, 20 Nov 2025 07:17:15 -0800

On Thu, 20 Nov 2025 19:43:52 +0530 I Viswanath wrote:
> Teardown path:
> 
> Relevant as they flush the work item. ens4 is the virtio-net interface.
> 
> virtnet_remove:
> ip maddr add 01:00:5e:00:03:02 dev ens4; echo 1 > /sys/bus/pci/devices/0000:00:04.0/remove
> 
> virtnet_freeze_down:
> ip maddr add 01:00:5e:00:03:02 dev ens4; echo mem > /sys/power/state

Running 

make -C tools/testing/selftests TARGETS="drivers/net/virtio_net" run_tests

[    1.967073] BUG: kernel NULL pointer dereference, address: 0000000000000018
[    1.967179] #PF: supervisor read access in kernel mode
[    1.967237] #PF: error_code(0x0000) - not-present page
[    1.967296] PGD 0 P4D 0 
[    1.967327] Oops: Oops: 0000 [#1] SMP
[    1.967372] CPU: 2 UID: 0 PID: 220 Comm: basic_features. Not tainted 6.18.0-rc5-virtme #1 PREEMPT(voluntary) 
[    1.967500] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[    1.967576] RIP: 0010:__flush_work+0x33/0x3a0
[    1.967651] Code: 41 55 41 54 55 53 48 83 ec 60 44 0f b6 25 0d ab 91 01 65 48 8b 05 2d ff 8d 01 48 89 44 24 58 31 c0 45 84 e4 0f 84 35 03 00 00 <48> 83 7f 18 00 48 89 fd 0f 84 30 03 00 00 41 89 f5 e8 07 24 07 00
[    1.967861] RSP: 0018:ffffab9bc0597cf0 EFLAGS: 00010202
[    1.967920] RAX: 0000000000000000 RBX: ffff9d08c2c549c0 RCX: ffffab9bc0597d28
[    1.968010] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[    1.968100] RBP: ffff9d08c1cd5000 R08: ffff9d08c1db7b70 R09: 0000000000000000
[    1.968189] R10: ffff9d08c1db7f80 R11: ffff9d08c152e480 R12: 0000000000000001
[    1.968281] R13: ffffffffbd9ffe00 R14: ffff9d08c193e140 R15: 0000000000000008
[    1.968371] FS:  00007fb66173b000(0000) GS:ffff9d0940ce9000(0000) knlGS:0000000000000000
[    1.968472] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.968546] CR2: 0000000000000018 CR3: 00000000045e5006 CR4: 0000000000772ef0
[    1.968640] PKRU: 55555554
[    1.968669] Call Trace:
[    1.968700]  <TASK>
[    1.968729]  ? kernfs_should_drain_open_files+0x2e/0x40
[    1.968796]  ? __rtnl_unlock+0x37/0x60
[    1.968849]  ? netdev_run_todo+0x63/0x550
[    1.968894]  ? kernfs_name_hash+0x12/0x80
[    1.968938]  virtnet_remove+0x65/0xb0
[    1.968984]  virtio_dev_remove+0x3c/0x80
[    1.969029]  device_release_driver_internal+0x193/0x200
[    1.969090]  unbind_store+0x9d/0xb0
[    1.969136]  kernfs_fop_write_iter+0x12b/0x1c0
[    1.969197]  vfs_write+0x33a/0x470
[    1.969242]  ksys_write+0x65/0xe0
[    1.969287]  do_syscall_64+0xa4/0xfd0
[    1.969333]  entry_SYSCALL_64_after_hwframe+0x4b/0x53
[    1.969393] RIP: 0033:0x7fb66183b257
[    1.969434] Code: 0f 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 51 c3 48 83 ec 28 48 89 54 24 18 48 89 74 24
[    1.969640] RSP: 002b:00007fffca552fe8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[    1.969729] RAX: ffffffffffffffda RBX: 00007fb661937780 RCX: 00007fb66183b257
[    1.969820] RDX: 0000000000000008 RSI: 0000558903e5a280 RDI: 0000000000000001
[    1.969911] RBP: 0000000000000008 R08: 0000000000000003 R09: 0000000000000077
[    1.970004] R10: 0000000000000063 R11: 0000000000000246 R12: 0000000000000008
[    1.970096] R13: 0000558903e5a280 R14: 0000000000000008 R15: 00007fb6619329c0
[    1.970189]  </TASK>
[    1.970218] Modules linked in:
[    1.970266] CR2: 0000000000000018
[    1.970311] ---[ end trace 0000000000000000 ]---
[    1.970372] RIP: 0010:__flush_work+0x33/0x3a0
[    1.970441] Code: 41 55 41 54 55 53 48 83 ec 60 44 0f b6 25 0d ab 91 01 65 48 8b 05 2d ff 8d 01 48 89 44 24 58 31 c0 45 84 e4 0f 84 35 03 00 00 <48> 83 7f 18 00 48 89 fd 0f 84 30 03 00 00 41 89 f5 e8 07 24 07 00
[    1.970656] RSP: 0018:ffffab9bc0597cf0 EFLAGS: 00010202
[    1.970717] RAX: 0000000000000000 RBX: ffff9d08c2c549c0 RCX: ffffab9bc0597d28
[    1.970806] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
[    1.970897] RBP: ffff9d08c1cd5000 R08: ffff9d08c1db7b70 R09: 0000000000000000
[    1.970988] R10: ffff9d08c1db7f80 R11: ffff9d08c152e480 R12: 0000000000000001
[    1.971081] R13: ffffffffbd9ffe00 R14: ffff9d08c193e140 R15: 0000000000000008
[    1.971174] FS:  00007fb66173b000(0000) GS:ffff9d0940ce9000(0000) knlGS:0000000000000000
[    1.971264] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    1.971337] CR2: 0000000000000018 CR3: 00000000045e5006 CR4: 0000000000772ef0
[    1.971431] PKRU: 55555554
[    1.971460] note: basic_features.[220] exited with irqs disabled
-- 
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