[syzbot] [net?] [s390?] KASAN: slab-use-after-free Read in netdev_walk_all_lower_dev

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 896d8946da97 Merge tag 'net-6.13-rc2' of git://git.kernel...
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=176a18df980000
kernel config: https://syzkaller.appspot.com/x/.config?x=1362a5aee630ff34
dashboard link: https://syzkaller.appspot.com/bug?extid=2eab87cf3100f45423ec
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10de5330580000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/d9f3eeec9a50/disk-896d8946.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4d3aee65183c/vmlinux-896d8946.xz
kernel image: https://storage.googleapis.com/syzbot-assets/b0806603e601/bzImage-896d8946.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2eab87...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in netdev_next_lower_dev net/core/dev.c:7522 [inline]
BUG: KASAN: slab-use-after-free in netdev_walk_all_lower_dev+0x131/0x390 net/core/dev.c:7570
Read of size 8 at addr ffff88805f8b81b8 by task syz.0.15/6035

CPU: 0 UID: 0 PID: 6035 Comm: syz.0.15 Not tainted 6.13.0-rc1-syzkaller-00170-g896d8946da97 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602
netdev_next_lower_dev net/core/dev.c:7522 [inline]
netdev_walk_all_lower_dev+0x131/0x390 net/core/dev.c:7570
smc_vlan_by_tcpsk+0x3ab/0x4e0 net/smc/smc_core.c:1899
__smc_connect+0x292/0x1850 net/smc/af_smc.c:1517
smc_connect+0x868/0xde0 net/smc/af_smc.c:1693
__sys_connect_file net/socket.c:2055 [inline]
__sys_connect+0x288/0x2d0 net/socket.c:2074
__do_sys_connect net/socket.c:2080 [inline]
__se_sys_connect net/socket.c:2077 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2077
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7f29d7ff19
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f7f2ab9b058 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f7f29f46240 RCX: 00007f7f29d7ff19
RDX: 000000000000001c RSI: 0000000020000080 RDI: 000000000000000c
RBP: 00007f7f29df3986 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f7f29f46240 R15: 00007ffe913e1c98
</TASK>

Allocated by task 5919:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:260 [inline]
__do_kmalloc_node mm/slub.c:4283 [inline]
__kmalloc_node_noprof+0x290/0x4d0 mm/slub.c:4289
__kvmalloc_node_noprof+0x72/0x190 mm/util.c:650
alloc_netdev_mqs+0xa4/0x1080 net/core/dev.c:11209
rtnl_create_link+0x2f9/0xc20 net/core/rtnetlink.c:3595
rtnl_newlink_create+0x210/0xa40 net/core/rtnetlink.c:3771
__rtnl_newlink net/core/rtnetlink.c:3896 [inline]
rtnl_newlink+0x1b40/0x20e0 net/core/rtnetlink.c:4009
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542
netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:726
__sys_sendto+0x363/0x4c0 net/socket.c:2197
__do_sys_sendto net/socket.c:2204 [inline]
__se_sys_sendto net/socket.c:2200 [inline]
__x64_sys_sendto+0xde/0x100 net/socket.c:2200
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 6033:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:582
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:233 [inline]
slab_free_hook mm/slub.c:2338 [inline]
slab_free mm/slub.c:4598 [inline]
kfree+0x196/0x430 mm/slub.c:4746
device_release+0x99/0x1c0
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x22f/0x480 lib/kobject.c:737
netdev_run_todo+0xe79/0x1000 net/core/dev.c:10924
rtnl_unlock net/core/rtnetlink.c:152 [inline]
rtnl_net_unlock include/linux/rtnetlink.h:133 [inline]
rtnl_dellink+0x760/0x8d0 net/core/rtnetlink.c:3526
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542
netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:726
sock_write_iter+0x2d7/0x3f0 net/socket.c:1147
new_sync_write fs/read_write.c:586 [inline]
vfs_write+0xaeb/0xd30 fs/read_write.c:679
ksys_write+0x18f/0x2b0 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
insert_work+0x3e/0x330 kernel/workqueue.c:2183
__queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
queue_work include/linux/workqueue.h:662 [inline]
schedule_work include/linux/workqueue.h:723 [inline]
__rhashtable_remove_fast_one include/linux/rhashtable.h:1069 [inline]
__rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]
rhashtable_remove_fast+0xd63/0xe20 include/linux/rhashtable.h:1122
br_multicast_del_mdb_entry net/bridge/br_multicast.c:642 [inline]
br_multicast_dev_del+0x157/0x5e0 net/bridge/br_multicast.c:4366
br_dev_uninit+0x1c/0x40 net/bridge/br_device.c:155
unregister_netdevice_many_notify+0x1735/0x1da0 net/core/dev.c:11548
rtnl_delete_link net/core/rtnetlink.c:3476 [inline]
rtnl_dellink+0x52b/0x8d0 net/core/rtnetlink.c:3518
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542
netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:726
sock_write_iter+0x2d7/0x3f0 net/socket.c:1147
new_sync_write fs/read_write.c:586 [inline]
vfs_write+0xaeb/0xd30 fs/read_write.c:679
ksys_write+0x18f/0x2b0 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Second to last potentially related work creation:
kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
__kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
insert_work+0x3e/0x330 kernel/workqueue.c:2183
__queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
queue_work_on+0x1c2/0x380 kernel/workqueue.c:2390
queue_work include/linux/workqueue.h:662 [inline]
br_multicast_del_mdb_entry net/bridge/br_multicast.c:646 [inline]
br_multicast_dev_del+0x342/0x5e0 net/bridge/br_multicast.c:4366
br_dev_uninit+0x1c/0x40 net/bridge/br_device.c:155
unregister_netdevice_many_notify+0x1735/0x1da0 net/core/dev.c:11548
rtnl_delete_link net/core/rtnetlink.c:3476 [inline]
rtnl_dellink+0x52b/0x8d0 net/core/rtnetlink.c:3518
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542
netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:726
sock_write_iter+0x2d7/0x3f0 net/socket.c:1147
new_sync_write fs/read_write.c:586 [inline]
vfs_write+0xaeb/0xd30 fs/read_write.c:679
ksys_write+0x18f/0x2b0 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88805f8b8000
which belongs to the cache kmalloc-cg-8k of size 8192
The buggy address is located 440 bytes inside of
freed 8192-byte region [ffff88805f8b8000, ffff88805f8ba000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5f8b8
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888030fab001
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801ac4f640 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000020002 00000001f5000000 ffff888030fab001
head: 00fff00000000040 ffff88801ac4f640 dead000000000122 0000000000000000
head: 0000000000000000 0000000000020002 00000001f5000000 ffff888030fab001
head: 00fff00000000003 ffffea00017e2e01 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5919, tgid 5919 (syz-executor), ts 71968276413, free_ts 71704730558
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3474
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x140 mm/slub.c:2408
allocate_slab+0x5a/0x2f0 mm/slub.c:2574
new_slab mm/slub.c:2627 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815
__slab_alloc+0x58/0xa0 mm/slub.c:3905
__slab_alloc_node mm/slub.c:3980 [inline]
slab_alloc_node mm/slub.c:4141 [inline]
__do_kmalloc_node mm/slub.c:4282 [inline]
__kmalloc_node_noprof+0x2ee/0x4d0 mm/slub.c:4289
__kvmalloc_node_noprof+0x72/0x190 mm/util.c:650
alloc_netdev_mqs+0xa4/0x1080 net/core/dev.c:11209
rtnl_create_link+0x2f9/0xc20 net/core/rtnetlink.c:3595
rtnl_newlink_create+0x210/0xa40 net/core/rtnetlink.c:3771
__rtnl_newlink net/core/rtnetlink.c:3896 [inline]
rtnl_newlink+0x1b40/0x20e0 net/core/rtnetlink.c:4009
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542
page last free pid 5866 tgid 5866 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1127 [inline]
free_unref_page+0xdef/0x1130 mm/page_alloc.c:2657
vfree+0x186/0x2e0 mm/vmalloc.c:3382
kcov_put kernel/kcov.c:439 [inline]
kcov_close+0x28/0x50 kernel/kcov.c:535
__fput+0x23c/0xa50 fs/file_table.c:450
task_work_run+0x24f/0x310 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa2f/0x28e0 kernel/exit.c:938
do_group_exit+0x207/0x2c0 kernel/exit.c:1087
get_signal+0x16b2/0x1750 kernel/signal.c:3017
arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:337
exit_to_user_mode_loop kernel/entry/common.c:111 [inline]
exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
__syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
syscall_exit_to_user_mode+0xce/0x340 kernel/entry/common.c:218
do_syscall_64+0x100/0x230 arch/x86/entry/common.c:89
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff88805f8b8080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88805f8b8100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88805f8b8180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88805f8b8200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88805f8b8280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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If the report is already addressed, let syzbot know by replying with:
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If you want syzbot to run the reproducer, reply with:
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If you attach or paste a git patch, syzbot will apply it before testing.

If you want to overwrite report's subsystems, reply with:
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If you want to undo deduplication, reply with:
#syz undup

[Hillf Danton]

On Fri, 06 Dec 2024 07:59:25 -0800

> syzbot found the following issue on:
>
> HEAD commit: 896d8946da97 Merge tag 'net-6.13-rc2' of git://git.kernel...
> git tree: net

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10de5330580000

#syz test

--- x/net/smc/smc_core.c
+++ y/net/smc/smc_core.c
@@ -1896,7 +1896,7 @@ int smc_vlan_by_tcpsk(struct socket *clc

priv.data = (void *)&ini->vlan_id;
rtnl_lock();
- netdev_walk_all_lower_dev(ndev, smc_vlan_by_tcpsk_walk, &priv);
+ netdev_walk_all_lower_dev_rcu(ndev, smc_vlan_by_tcpsk_walk, &priv);
rtnl_unlock();

out_rel:
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in netdev_walk_all_lower_dev_rcu

==================================================================
BUG: KASAN: slab-use-after-free in netdev_next_lower_dev_rcu net/core/dev.c:7650 [inline]
BUG: KASAN: slab-use-after-free in netdev_walk_all_lower_dev_rcu+0x131/0x390 net/core/dev.c:7755
Read of size 8 at addr ffff8880281a41b8 by task syz.0.15/6768

CPU: 0 UID: 0 PID: 6768 Comm: syz.0.15 Not tainted 6.13.0-rc1-syzkaller-00172-g11776cff0b56-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602

netdev_next_lower_dev_rcu net/core/dev.c:7650 [inline]
netdev_walk_all_lower_dev_rcu+0x131/0x390 net/core/dev.c:7755

smc_vlan_by_tcpsk+0x3ab/0x4e0 net/smc/smc_core.c:1899
__smc_connect+0x292/0x1850 net/smc/af_smc.c:1517
smc_connect+0x868/0xde0 net/smc/af_smc.c:1693
__sys_connect_file net/socket.c:2055 [inline]
__sys_connect+0x288/0x2d0 net/socket.c:2074
__do_sys_connect net/socket.c:2080 [inline]
__se_sys_connect net/socket.c:2077 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2077
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7fce44d7ff19

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007fce45b0d058 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007fce44f46080 RCX: 00007fce44d7ff19
RDX: 000000000000001c RSI: 0000000020000080 RDI: 000000000000000a
RBP: 00007fce44df3986 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 0000000000000000 R14: 00007fce44f46080 R15: 00007ffee596f8c8
</TASK>

Allocated by task 6551:

Freed by task 6759:

schedule_work include/linux/workqueue.h:723 [inline]
__rhashtable_remove_fast_one include/linux/rhashtable.h:1069 [inline]
__rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]

rhashtable_remove_fast include/linux/rhashtable.h:1122 [inline]
fdb_delete+0x100c/0x1210 net/bridge/br_fdb.c:320
br_fdb_delete_by_port+0x1ec/0x310 net/bridge/br_fdb.c:780
del_nbp+0x665/0xb40 net/bridge/br_if.c:357
br_dev_delete+0x6e/0x100 net/bridge/br_if.c:386
rtnl_delete_link net/core/rtnetlink.c:3475 [inline]
rtnl_dellink+0x518/0x8d0 net/core/rtnetlink.c:3518

rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542
netlink_unicast_kernel net/netlink/af_netlink.c:1321 [inline]
netlink_unicast+0x7f6/0x990 net/netlink/af_netlink.c:1347
netlink_sendmsg+0x8e4/0xcb0 net/netlink/af_netlink.c:1891
sock_sendmsg_nosec net/socket.c:711 [inline]
__sock_sendmsg+0x221/0x270 net/socket.c:726
sock_write_iter+0x2d7/0x3f0 net/socket.c:1147
new_sync_write fs/read_write.c:586 [inline]
vfs_write+0xaeb/0xd30 fs/read_write.c:679
ksys_write+0x18f/0x2b0 fs/read_write.c:731
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff8880281a4000

which belongs to the cache kmalloc-cg-8k of size 8192
The buggy address is located 440 bytes inside of

freed 8192-byte region [ffff8880281a4000, ffff8880281a6000)

The buggy address belongs to the physical page:

page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x281a0

head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0

memcg:ffff888061d19001

flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)

raw: 00fff00000000040 ffff88801ac4f640 dead000000000100 dead000000000122
raw: 0000000000000000 0000000000020002 00000001f5000000 ffff888061d19001
head: 00fff00000000040 ffff88801ac4f640 dead000000000100 dead000000000122
head: 0000000000000000 0000000000020002 00000001f5000000 ffff888061d19001
head: 00fff00000000003 ffffea0000a06801 ffffffffffffffff 0000000000000000

head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated

page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5920, tgid 5920 (syz-executor), ts 70312920153, free_ts 70066156251

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3474
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x140 mm/slub.c:2408
allocate_slab+0x5a/0x2f0 mm/slub.c:2574
new_slab mm/slub.c:2627 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815
__slab_alloc+0x58/0xa0 mm/slub.c:3905
__slab_alloc_node mm/slub.c:3980 [inline]
slab_alloc_node mm/slub.c:4141 [inline]
__do_kmalloc_node mm/slub.c:4282 [inline]
__kmalloc_node_noprof+0x2ee/0x4d0 mm/slub.c:4289
__kvmalloc_node_noprof+0x72/0x190 mm/util.c:650
alloc_netdev_mqs+0xa4/0x1080 net/core/dev.c:11209
rtnl_create_link+0x2f9/0xc20 net/core/rtnetlink.c:3595
rtnl_newlink_create+0x210/0xa40 net/core/rtnetlink.c:3771
__rtnl_newlink net/core/rtnetlink.c:3896 [inline]
rtnl_newlink+0x1b40/0x20e0 net/core/rtnetlink.c:4009
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542

page last free pid 5840 tgid 5840 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1127 [inline]
free_unref_page+0xdef/0x1130 mm/page_alloc.c:2657

discard_slab mm/slub.c:2673 [inline]
__put_partials+0xeb/0x130 mm/slub.c:3142
put_cpu_partial+0x17c/0x250 mm/slub.c:3217
__slab_free+0x2ea/0x3d0 mm/slub.c:4468
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4104 [inline]
slab_alloc_node mm/slub.c:4153 [inline]
__kmalloc_cache_noprof+0x1d9/0x390 mm/slub.c:4309
kmalloc_noprof include/linux/slab.h:901 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]
kernfs_fop_open+0x3e0/0xd10 fs/kernfs/file.c:623
do_dentry_open+0xbe1/0x1b70 fs/open.c:945
vfs_open+0x3e/0x330 fs/open.c:1075
do_open fs/namei.c:3828 [inline]
path_openat+0x2c84/0x3590 fs/namei.c:3987
do_filp_open+0x27f/0x4e0 fs/namei.c:4014
do_sys_openat2+0x13e/0x1d0 fs/open.c:1402
do_sys_open fs/open.c:1417 [inline]
__do_sys_openat fs/open.c:1433 [inline]
__se_sys_openat fs/open.c:1428 [inline]
__x64_sys_openat+0x247/0x2a0 fs/open.c:1428

do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83

Memory state around the buggy address:

ffff8880281a4080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880281a4100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8880281a4180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880281a4200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880281a4280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: 11776cff net/mlx5: DR, prevent potential error pointer..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=17383330580000

kernel config: https://syzkaller.appspot.com/x/.config?x=1362a5aee630ff34
dashboard link: https://syzkaller.appspot.com/bug?extid=2eab87cf3100f45423ec
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=11f6a020580000

[Hillf Danton]

On Fri, 06 Dec 2024 07:59:25 -0800

> syzbot found the following issue on:
>
> HEAD commit: 896d8946da97 Merge tag 'net-6.13-rc2' of git://git.kernel...
> git tree: net

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10de5330580000

#syz test

--- x/net/smc/smc_core.c
+++ y/net/smc/smc_core.c

@@ -1896,7 +1896,9 @@ int smc_vlan_by_tcpsk(struct socket *clc

priv.data = (void *)&ini->vlan_id;
rtnl_lock();

+ rcu_read_lock();
netdev_walk_all_lower_dev(ndev, smc_vlan_by_tcpsk_walk, &priv);
+ rcu_read_unlock();
rtnl_unlock();

out_rel:
--

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
KASAN: slab-use-after-free Read in netdev_walk_all_lower_dev

==================================================================
BUG: KASAN: slab-use-after-free in netdev_next_lower_dev net/core/dev.c:7522 [inline]
BUG: KASAN: slab-use-after-free in netdev_walk_all_lower_dev+0x131/0x390 net/core/dev.c:7570
Read of size 8 at addr ffff88807edc01b8 by task syz.4.19/6654

CPU: 1 UID: 0 PID: 6654 Comm: syz.4.19 Not tainted 6.13.0-rc1-syzkaller-00180-gff9b30531510-dirty #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0x169/0x550 mm/kasan/report.c:489
kasan_report+0x143/0x180 mm/kasan/report.c:602

netdev_next_lower_dev net/core/dev.c:7522 [inline]
netdev_walk_all_lower_dev+0x131/0x390 net/core/dev.c:7570

smc_vlan_by_tcpsk+0x4ce/0x620 net/smc/smc_core.c:1900

__smc_connect+0x292/0x1850 net/smc/af_smc.c:1517
smc_connect+0x868/0xde0 net/smc/af_smc.c:1693
__sys_connect_file net/socket.c:2055 [inline]
__sys_connect+0x288/0x2d0 net/socket.c:2074
__do_sys_connect net/socket.c:2080 [inline]
__se_sys_connect net/socket.c:2077 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2077
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

RIP: 0033:0x7f703397ff19

Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48

RSP: 002b:00007f70347c6058 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f7033b45fa0 RCX: 00007f703397ff19

RDX: 000000000000001c RSI: 0000000020000080 RDI: 000000000000000a

RBP: 00007f70339f3986 R08: 0000000000000000 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000

R13: 0000000000000000 R14: 00007f7033b45fa0 R15: 00007ffc1bd14ae8
</TASK>

Allocated by task 6387:

Freed by task 6655:

schedule_work include/linux/workqueue.h:723 [inline]
__rhashtable_remove_fast_one include/linux/rhashtable.h:1069 [inline]
__rhashtable_remove_fast include/linux/rhashtable.h:1093 [inline]

rhashtable_remove_fast+0xd63/0xe20 include/linux/rhashtable.h:1122
br_multicast_del_mdb_entry net/bridge/br_multicast.c:642 [inline]

br_multicast_dev_del+0x157/0x5e0 net/bridge/br_multicast.c:4366

The buggy address belongs to the object at ffff88807edc0000

which belongs to the cache kmalloc-cg-8k of size 8192
The buggy address is located 440 bytes inside of

freed 8192-byte region [ffff88807edc0000, ffff88807edc2000)

The buggy address belongs to the physical page:

page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x7edc0

head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0

memcg:ffff8880335ffae1
anon flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801ac4f640 ffffea000183b400 0000000000000005
raw: 0000000000000000 0000000000020002 00000001f5000000 ffff8880335ffae1
head: 00fff00000000040 ffff88801ac4f640 ffffea000183b400 0000000000000005
head: 0000000000000000 0000000000020002 00000001f5000000 ffff8880335ffae1
head: 00fff00000000003 ffffea0001fb7001 ffffffffffffffff 0000000000000000

head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated

page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd60c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_RETRY_MAYFAIL|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5925, tgid 5925 (syz-executor), ts 73502170533, free_ts 73488682794

set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
prep_new_page mm/page_alloc.c:1564 [inline]
get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3474
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x140 mm/slub.c:2408
allocate_slab+0x5a/0x2f0 mm/slub.c:2574
new_slab mm/slub.c:2627 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3815
__slab_alloc+0x58/0xa0 mm/slub.c:3905
__slab_alloc_node mm/slub.c:3980 [inline]
slab_alloc_node mm/slub.c:4141 [inline]
__do_kmalloc_node mm/slub.c:4282 [inline]
__kmalloc_node_noprof+0x2ee/0x4d0 mm/slub.c:4289
__kvmalloc_node_noprof+0x72/0x190 mm/util.c:650
alloc_netdev_mqs+0xa4/0x1080 net/core/dev.c:11209
rtnl_create_link+0x2f9/0xc20 net/core/rtnetlink.c:3595
rtnl_newlink_create+0x210/0xa40 net/core/rtnetlink.c:3771
__rtnl_newlink net/core/rtnetlink.c:3896 [inline]
rtnl_newlink+0x1b40/0x20e0 net/core/rtnetlink.c:4009
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919
netlink_rcv_skb+0x1e3/0x430 net/netlink/af_netlink.c:2542

page last free pid 5925 tgid 5925 stack trace:

reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1127 [inline]
free_unref_page+0xdef/0x1130 mm/page_alloc.c:2657
discard_slab mm/slub.c:2673 [inline]
__put_partials+0xeb/0x130 mm/slub.c:3142
put_cpu_partial+0x17c/0x250 mm/slub.c:3217
__slab_free+0x2ea/0x3d0 mm/slub.c:4468
qlink_free mm/kasan/quarantine.c:163 [inline]
qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
__kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
kasan_slab_alloc include/linux/kasan.h:250 [inline]
slab_post_alloc_hook mm/slub.c:4104 [inline]
slab_alloc_node mm/slub.c:4153 [inline]
__kmalloc_cache_noprof+0x1d9/0x390 mm/slub.c:4309
kmalloc_noprof include/linux/slab.h:901 [inline]
kzalloc_noprof include/linux/slab.h:1037 [inline]

ref_tracker_alloc+0x14b/0x490 lib/ref_tracker.c:203
__netdev_tracker_alloc include/linux/netdevice.h:4136 [inline]
netdev_hold include/linux/netdevice.h:4165 [inline]
netdev_queue_add_kobject net/core/net-sysfs.c:1786 [inline]
netdev_queue_update_kobjects+0x181/0x550 net/core/net-sysfs.c:1841
register_queue_kobjects net/core/net-sysfs.c:1903 [inline]
netdev_register_kobject+0x234/0x2e0 net/core/net-sysfs.c:2143
register_netdevice+0x12c5/0x1b00 net/core/dev.c:10599
br_dev_newlink+0x27/0x100 net/bridge/br_netlink.c:1563
rtnl_newlink_create+0x2ee/0xa40 net/core/rtnetlink.c:3786

__rtnl_newlink net/core/rtnetlink.c:3896 [inline]
rtnl_newlink+0x1b40/0x20e0 net/core/rtnetlink.c:4009
rtnetlink_rcv_msg+0x791/0xcf0 net/core/rtnetlink.c:6919

Memory state around the buggy address:

ffff88807edc0080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807edc0100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88807edc0180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88807edc0200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88807edc0280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: ff9b3053 Merge branch 'bnxt_en-bug-fixes'
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1475a020580000

kernel config: https://syzkaller.appspot.com/x/.config?x=1362a5aee630ff34
dashboard link: https://syzkaller.appspot.com/bug?extid=2eab87cf3100f45423ec
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=17dc3330580000

[Hillf Danton]

On Fri, 06 Dec 2024 07:59:25 -0800

> syzbot found the following issue on:
>
> HEAD commit: 896d8946da97 Merge tag 'net-6.13-rc2' of git://git.kernel...
> git tree: net

> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10de5330580000

#syz test

--- x/net/smc/smc_core.c
+++ y/net/smc/smc_core.c

@@ -1893,10 +1893,22 @@ int smc_vlan_by_tcpsk(struct socket *clc
ini->vlan_id = vlan_dev_vlan_id(ndev);
goto out_rel;
}
+ rcu_read_lock();
+ if (ndev->reg_state == NETREG_UNREGISTERING || ndev->reg_state == NETREG_UNREGISTERED) {
+ rcu_read_unlock();
+ rc = -ENODEV;
+ goto out_rel;
+ }
+ rcu_read_unlock();

priv.data = (void *)&ini->vlan_id;
rtnl_lock();

- netdev_walk_all_lower_dev(ndev, smc_vlan_by_tcpsk_walk, &priv);
+ rcu_read_lock();
+ if (ndev->reg_state == NETREG_UNREGISTERING || ndev->reg_state == NETREG_UNREGISTERED)
+ rc = -ENODEV;
+ else
+ netdev_walk_all_lower_dev(ndev, smc_vlan_by_tcpsk_walk, &priv);

[syzbot]

Hello,

syzbot has tested the proposed patch and the reproducer did not trigger any issue:

Reported-by: syzbot+2eab87...@syzkaller.appspotmail.com
Tested-by: syzbot+2eab87...@syzkaller.appspotmail.com

Tested on:

commit: 0f6ede9f net: defer final 'struct net' free in netns d..
git tree: net
console output: https://syzkaller.appspot.com/x/log.txt?x=1273a020580000

kernel config: https://syzkaller.appspot.com/x/.config?x=1362a5aee630ff34
dashboard link: https://syzkaller.appspot.com/bug?extid=2eab87cf3100f45423ec
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

patch: https://syzkaller.appspot.com/x/patch.diff?x=13c3a020580000

Note: testing is done by a robot and is best-effort only.

[syzbot]

Auto-closing this bug as obsolete.
No recent activity, existing reproducers are no longer triggering the issue.