net: mana: cleanup mana struct after debugfs_remove()
CVE: CVE-2025-21953
Component: kernel
CWE: CWE-476
Severity: Low
CVSS v3: 4.4/AV:L/AC:H/PR:L/UI:R/S:U/C:N/I:N/A:H
Release date: 2025-04-01T00:00:00+00:00

In the Linux kernel, the following vulnerability has been resolved:

net: mana: cleanup mana struct after debugfs_remove()

When on a MANA VM hibernation is triggered, as part of hibernate_snapshot(),
mana_gd_suspend() and mana_gd_resume() are called. If during this
mana_gd_resume(), a failure occurs with HWC creation, mana_port_debugfs
pointer does not get reinitialized and ends up pointing to older,
cleaned-up dentry.
Further in the hibernation path, as part of power_down(), mana_gd_shutdown()
is triggered. This call, unaware of the failures in resume, tries to cleanup
the already cleaned up  mana_port_debugfs value and hits the following bug:

[  191.359296] mana 7870:00:00.0: Shutdown was called
[  191.359918] BUG: kernel NULL pointer dereference, address: 0000000000000098
[  191.360584] #PF: supervisor write access in kernel mode
[  191.361125] #PF: error_code(0x0002) - not-present page
[  191.361727] PGD 1080ea067 P4D 0
[  191.362172] Oops: Oops: 0002 [#1] SMP NOPTI
[  191.362606] CPU: 11 UID: 0 PID: 1674 Comm: bash Not tainted 6.14.0-rc5+ #2
[  191.363292] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 11/21/2024
[  191.364124] RIP: 0010:down_write+0x19/0x50
[  191.364537] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 55 48 89 e5 53 48 89 fb e8 de cd ff ff 31 c0 ba 01 00 00 00 <f0> 48 0f b1 13 75 16 65 48 8b 05 88 24 4c 6a 48 89 43 08 48 8b 5d
[  191.365867] RSP: 0000:ff45fbe0c1c037b8 EFLAGS: 00010246
[  191.366350] RAX: 0000000000000000 RBX: 0000000000000098 RCX: ffffff8100000000
[  191.366951] RDX: 0000000000000001 RSI: 0000000000000064 RDI: 0000000000000098
[  191.367600] RBP: ff45fbe0c1c037c0 R08: 0000000000000000 R09: 0000000000000001
[  191.368225] R10: ff45fbe0d2b01000 R11: 0000000000000008 R12: 0000000000000000
[  191.368874] R13: 000000000000000b R14: ff43dc27509d67c0 R15: 0000000000000020
[  191.369549] FS:  00007dbc5001e740(0000) GS:ff43dc663f380000(0000) knlGS:0000000000000000
[  191.370213] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  191.370830] CR2: 0000000000000098 CR3: 0000000168e8e002 CR4: 0000000000b73ef0
[  191.371557] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  191.372192] DR3: 0000000000000000 DR6: 00000000fffe07f0 DR7: 0000000000000400
[  191.372906] Call Trace:
[  191.373262]  <TASK>
[  191.373621]  ? show_regs+0x64/0x70
[  191.374040]  ? __die+0x24/0x70
[  191.374468]  ? page_fault_oops+0x290/0x5b0
[  191.374875]  ? do_user_addr_fault+0x448/0x800
[  191.375357]  ? exc_page_fault+0x7a/0x160
[  191.375971]  ? asm_exc_page_fault+0x27/0x30
[  191.376416]  ? down_write+0x19/0x50
[  191.376832]  ? down_write+0x12/0x50
[  191.377232]  simple_recursive_removal+0x4a/0x2a0
[  191.377679]  ? __pfx_remove_one+0x10/0x10
[  191.378088]  debugfs_remove+0x44/0x70
[  191.378530]  mana_detach+0x17c/0x4f0
[  191.378950]  ? __flush_work+0x1e2/0x3b0
[  191.379362]  ? __cond_resched+0x1a/0x50
[  191.379787]  mana_remove+0xf2/0x1a0
[  191.380193]  mana_gd_shutdown+0x3b/0x70
[  191.380642]  pci_device_shutdown+0x3a/0x80
[  191.381063]  device_shutdown+0x13e/0x230
[  191.381480]  kernel_power_off+0x35/0x80
[  191.381890]  hibernate+0x3c6/0x470
[  191.382312]  state_store+0xcb/0xd0
[  191.382734]  kobj_attr_store+0x12/0x30
[  191.383211]  sysfs_kf_write+0x3e/0x50
[  191.383640]  kernfs_fop_write_iter+0x140/0x1d0
[  191.384106]  vfs_write+0x271/0x440
[  191.384521]  ksys_write+0x72/0xf0
[  191.384924]  __x64_sys_write+0x19/0x20
[  191.385313]  x64_sys_call+0x2b0/0x20b0
[  191.385736]  do_syscall_64+0x79/0x150
[  191.386146]  ? __mod_memcg_lruvec_state+0xe7/0x240
[  191.386676]  ? __lruvec_stat_mod_folio+0x79/0xb0
[  191.387124]  ? __pfx_lru_add+0x10/0x10
[  191.387515]  ? queued_spin_unlock+0x9/0x10
[  191.387937]  ? do_anonymous_page+0x33c/0xa00
[  191.388374]  ? __handle_mm_fault+0xcf3/0x1210
[  191.388805]  ? __count_memcg_events+0xbe/0x180
[  191.389235]  ? handle_mm_fault+0xae/0x300
[  19
---truncated---


Remediation: