[PATCH] wifi: mt76: mt7921: fix null pointer access in mt792x_mac_link_bss_remove

Thu Aug 1 05:38:56 PDT 2024

I also saw the following after I restarted my router on two machines -
they both have this fix applied already:

Aug 01 08:59:33 quark kernel: BUG: kernel NULL pointer dereference,
address: 0000000000000008
Aug 01 08:59:33 quark kernel: #PF: supervisor read access in kernel mode
Aug 01 08:59:33 quark kernel: #PF: error_code(0x0000) - not-present page
Aug 01 08:59:33 quark kernel: PGD 0 P4D 0
Aug 01 08:59:33 quark kernel: Oops: Oops: 0000 [#1] PREEMPT SMP
Aug 01 08:59:33 quark kernel: CPU: 13 UID: 0 PID: 468 Comm:
NetworkManager Not tainted 6.11.0-rc1-tip+ #3200
9c927d6f3c59d826d15d8e39c195392d1d16b8a8
Aug 01 08:59:33 quark kernel: Hardware name: Micro Computer (HK) Tech
Limited EliteMini Series/HPBSD, BIOS 1.02 03/28/2024
Aug 01 08:59:33 quark kernel: RIP: 0010:mt7921_ipv6_addr_change
Aug 01 08:59:33 quark kernel: Code: 41 57 41 56 41 54 53 48 83 e4 f0
48 83 ec 50 48 8b 86 70 09 00 00 0f b6 8e 90 04 00 00 4c 8d ba 68 02
00 00 49 89 d6 4c 89 ff <48> 8b 58 08 88 4c 24 04 66 c7 44 24 05 00 00
c6 44 24 07 00 66 c7
Aug 01 08:59:33 quark kernel: RSP: 0018:ffffc900069373b0 EFLAGS: 00010282
Aug 01 08:59:33 quark kernel: RAX: 0000000000000000 RBX:
ffff888106740920 RCX: 0000000000000000
Aug 01 08:59:33 quark kernel: RDX: ffff888106854800 RSI:
ffff88810bb35ca0 RDI: ffff888106854a68
Aug 01 08:59:33 quark kernel: RBP: ffffc90006937420 R08:
0000000000000000 R09: ffff888104c98200
Aug 01 08:59:33 quark kernel: R10: ffffffff7fff0000 R11:
0000000000000020 R12: 0000000000000002
Aug 01 08:59:33 quark kernel: R13: 0000000000000000 R14:
ffff888106854800 R15: ffff888106854a68
Aug 01 08:59:33 quark kernel: FS:  00007f4265049400(0000)
GS:ffff888c2df40000(0000) knlGS:0000000000000000
Aug 01 08:59:33 quark kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Aug 01 08:59:33 quark kernel: CR2: 0000000000000008 CR3:
0000000117250000 CR4: 0000000000350ef0
Aug 01 08:59:33 quark kernel: Call Trace:
Aug 01 08:59:33 quark kernel:  <TASK>
Aug 01 08:59:33 quark kernel:  ? __die_body+0x66/0xb0
Aug 01 08:59:33 quark kernel:  ? page_fault_oops+0x39a/0x410
Aug 01 08:59:33 quark kernel:  ? exc_page_fault+0x59/0xa0
Aug 01 08:59:33 quark kernel:  ? asm_exc_page_fault+0x22/0x30
Aug 01 08:59:33 quark kernel:  ? mt7921_ipv6_addr_change
Aug 01 08:59:33 quark kernel:  ? __try_to_del_timer_sync
Aug 01 08:59:33 quark kernel:  ieee80211_ifa6_changed+0x68/0x120
Aug 01 08:59:33 quark kernel:  atomic_notifier_call_chain+0x45/0xc0
Aug 01 08:59:33 quark kernel:  addrconf_ifdown+0x521/0x7d0
Aug 01 08:59:33 quark kernel:  addrconf_notify+0x1ed/0x4a0
Aug 01 08:59:33 quark kernel:  raw_notifier_call_chain+0x45/0xb0
Aug 01 08:59:33 quark kernel:  __dev_notify_flags+0xf4/0x200
Aug 01 08:59:33 quark kernel:  dev_change_flags+0x49/0x50
Aug 01 08:59:33 quark kernel:  do_setlink+0x49b/0x1300
Aug 01 08:59:33 quark kernel:  ? terminate_walk+0x6b/0x100
Aug 01 08:59:33 quark kernel:  ? __nla_validate_parse
Aug 01 08:59:33 quark kernel:  ? filename_lookup+0xc7/0x1b0
Aug 01 08:59:33 quark kernel:  rtnl_newlink+0xb6a/0xde0
Aug 01 08:59:33 quark kernel:  ? __wake_up_sync_key+0x51/0x80
Aug 01 08:59:33 quark kernel:  ? scm_destroy+0xc/0x30
Aug 01 08:59:33 quark kernel:  ? security_capable+0x38/0x50
Aug 01 08:59:33 quark kernel:  rtnetlink_rcv_msg+0x2dd/0x330
Aug 01 08:59:33 quark kernel:  ? select_task_rq_fair
Aug 01 08:59:33 quark kernel:  ? rtnetlink_bind+0x30/0x30
Aug 01 08:59:33 quark kernel:  netlink_rcv_skb+0xb5/0xf0
Aug 01 08:59:33 quark kernel:  netlink_unicast+0x230/0x330
Aug 01 08:59:33 quark kernel:  netlink_sendmsg+0x3b1/0x460
Aug 01 08:59:33 quark kernel:  ____sys_sendmsg
Aug 01 08:59:33 quark kernel:  ? chacha_block_generic+0x6a/0x130
Aug 01 08:59:33 quark kernel:  ___sys_sendmsg+0x282/0x2a0
Aug 01 08:59:33 quark kernel:  ? __fget_files+0x95/0xb0
Aug 01 08:59:33 quark kernel:  __se_sys_sendmsg+0xf4/0x120
Aug 01 08:59:33 quark kernel:  do_syscall_64+0x7e/0x130
Aug 01 08:59:33 quark kernel:  ? pollwake+0x52/0x60
Aug 01 08:59:33 quark kernel:  ? do_task_dead+0x50/0x50
Aug 01 08:59:33 quark kernel:  ? __wake_up_locked_key+0x48/0x70
Aug 01 08:59:33 quark kernel:  ? eventfd_write+0x193/0x1b0
Aug 01 08:59:33 quark kernel:  ? syscall_exit_to_user_mode+0x93/0xc0
Aug 01 08:59:33 quark kernel:  ? vfs_write+0xfa/0x3d0
Aug 01 08:59:33 quark kernel:  ? __fget_files+0x95/0xb0
Aug 01 08:59:33 quark kernel:  ? __fget_files+0x95/0xb0
Aug 01 08:59:33 quark kernel:  ? ksys_write+0x8f/0xb0
Aug 01 08:59:33 quark kernel:  ? arch_exit_to_user_mode_prepare+0x11/0x50
Aug 01 08:59:33 quark kernel:  ? syscall_exit_to_user_mode+0x93/0xc0
Aug 01 08:59:33 quark kernel:  ? do_syscall_64+0x8a/0x130
Aug 01 08:59:33 quark kernel:  ? syscall_exit_to_user_mode+0x93/0xc0
Aug 01 08:59:33 quark kernel:  ? do_syscall_64+0x8a/0x130
Aug 01 08:59:33 quark kernel:  ? do_syscall_64+0x8a/0x130
Aug 01 08:59:33 quark kernel:  ? do_syscall_64+0x8a/0x130
Aug 01 08:59:33 quark kernel:  ? arch_exit_to_user_mode_prepare+0x11/0x50
Aug 01 08:59:33 quark kernel:  entry_SYSCALL_64_after_hwframe+0x4b/0x53
Aug 01 08:59:33 quark kernel: RIP: 0033:0x7f4264d31fae
Aug 01 08:59:33 quark kernel: Code: 20 89 54 24 1c 48 89 74 24 10 89
7c 24 08 e8 a9 75 f7 ff 41 89 c0 8b 54 24 1c 48 8b 74 24 10 b8 2e 00
00 00 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 3a 44 89 c7 48 89 44 24
08 e8 fd 75 f7 ff 48
Aug 01 08:59:33 quark kernel: RSP: 002b:00007ffff4b1afa0 EFLAGS:
00000293 ORIG_RAX: 000000000000002e
Aug 01 08:59:33 quark kernel: RAX: ffffffffffffffda RBX:
000055c35260c570 RCX: 00007f4264d31fae
Aug 01 08:59:33 quark kernel: RDX: 0000000000000000 RSI:
00007ffff4b1afe0 RDI: 000000000000000d
Aug 01 08:59:33 quark kernel: RBP: 00007ffff4b1b050 R08:
0000000000000000 R09: 0000000000000000
Aug 01 08:59:33 quark kernel: R10: 000000000000009d R11:
0000000000000293 R12: 0000000000000004
Aug 01 08:59:33 quark kernel: R13: 0000000000000000 R14:
0000000000000000 R15: 0000000000000000
Aug 01 08:59:33 quark kernel:  </TASK>
Aug 01 08:59:33 quark kernel: Modules linked in:
Aug 01 08:59:33 quark kernel: CR2: 0000000000000008
Aug 01 08:59:33 quark kernel: ---[ end trace 0000000000000000 ]---
Aug 01 08:59:33 quark kernel: RIP: 0010:mt7921_ipv6_addr_change
Aug 01 08:59:33 quark kernel: Code: 41 57 41 56 41 54 53 48 83 e4 f0
48 83 ec 50 48 8b 86 70 09 00 00 0f b6 8e 90 04 00 00 4c 8d ba 68 02
00 00 49 89 d6 4c 89 ff <48> 8b 58 08 88 4c 24 04 66 c7 44 24 05 00 00
c6 44 24 07 00 66 c7
Aug 01 08:59:33 quark kernel: RSP: 0018:ffffc900069373b0 EFLAGS: 00010282
Aug 01 08:59:33 quark kernel: RAX: 0000000000000000 RBX:
ffff888106740920 RCX: 0000000000000000
Aug 01 08:59:33 quark kernel: RDX: ffff888106854800 RSI:
ffff88810bb35ca0 RDI: ffff888106854a68
Aug 01 08:59:33 quark kernel: RBP: ffffc90006937420 R08:
0000000000000000 R09: ffff888104c98200
Aug 01 08:59:33 quark kernel: R10: ffffffff7fff0000 R11:
0000000000000020 R12: 0000000000000002
Aug 01 08:59:33 quark kernel: R13: 0000000000000000 R14:
ffff888106854800 R15: ffff888106854a68
Aug 01 08:59:33 quark kernel: FS:  00007f4265049400(0000)
GS:ffff888c2df40000(0000) knlGS:0000000000000000
Aug 01 08:59:33 quark kernel: CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
Aug 01 08:59:33 quark kernel: CR2: 0000000000000008 CR3:
0000000117250000 CR4: 0000000000350ef0

On Wed, 24 Jul 2024 at 10:36, Linux regression tracking (Thorsten
Leemhuis) <regressions at leemhuis.info> wrote:
>
>
>
> On 19.07.24 01:46, sean.wang at kernel.org wrote:
> > From: Sean Wang <sean.wang at mediatek.com>
> >
> > Fix null pointer access in mt792x_mac_link_bss_remove.
> >
> > To prevent null pointer access, we should assign the vif to bss_conf in
> > mt7921_add_interface. This ensures that subsequent operations on the BSS
> > can properly reference the correct vif.
> >
> > [...]
> >> Fixes: 1541d63c5fe2 ("wifi: mt76: mt7925: add
> mt7925_mac_link_bss_remove to remove per-link BSS")
> > Reported-by: Bert Karwatzki <spasswolf at web.de>
> > Closes: https://lore.kernel.org/linux-wireless/2fee61f8c903d02a900ca3188c3742c7effd102e.camel@web.de/#b
> > Signed-off-by: Sean Wang <sean.wang at mediatek.com>
>
> TWIMC, Mike (now CCed) ran into the problem and on bugzilla confirmed
> that this fixes the problem:
>
> https://bugzilla.kernel.org/show_bug.cgi?id=219084
> https://lore.kernel.org/all/CAHbf0-HOS-jdRGvJOBmEgaaox3PDbDSTgnnZkZF9pz37Bmh2iw@mail.gmail.com/
>
> Ciao, Thorsten (wearing his 'the Linux kernel's regression tracker' hat)
> --
> Everything you wanna know about Linux kernel regression tracking:
> https://linux-regtracking.leemhuis.info/about/#tldr
> If I did something stupid, please tell me, as explained on that page.