KASAN: use-after-free Read in tcf_action_destroy

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 0f9ad4e7 Merge branch 's390-qeth-next'
git tree: net-next
console output: https://syzkaller.appspot.com/x/log.txt?x=15fc6755900000
kernel config: https://syzkaller.appspot.com/x/.config?x=d29a102d22f784ea
dashboard link: https://syzkaller.appspot.com/bug?extid=2287853d392e4b42374a
compiler: gcc (GCC) 10.1.0-syz 20200507
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133e6cc5900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=11c4158b900000

The issue was bisected to:

commit 4e8ddd7f1758ca4ddd0c1f7cf3e66fce736241d2
Author: Vlad Buslov <vla...@mellanox.com>
Date: Thu Jul 5 14:24:30 2018 +0000

net: sched: don't release reference on action overwrite

bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=13a50d01900000
final oops: https://syzkaller.appspot.com/x/report.txt?x=10650d01900000
console output: https://syzkaller.appspot.com/x/log.txt?x=17a50d01900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+228785...@syzkaller.appspotmail.com
Fixes: 4e8ddd7f1758 ("net: sched: don't release reference on action overwrite")

netlink: 32 bytes leftover after parsing attributes in process `syz-executor259'.
==================================================================
BUG: KASAN: use-after-free in tcf_action_destroy+0x188/0x1b0 net/sched/act_api.c:724
Read of size 8 at addr ffff8880a6998c00 by task syz-executor259/6880

CPU: 0 PID: 6880 Comm: syz-executor259 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
tcf_action_destroy+0x188/0x1b0 net/sched/act_api.c:724
tcf_action_init+0x285/0x380 net/sched/act_api.c:1059
tcf_action_add+0xd9/0x360 net/sched/act_api.c:1452
tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1505
rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x446c69
Code: e8 5c b3 02 00 48 83 c4 18 c3 0f 1f 80 00 00 00 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 0f 83 8b 07 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f16641f8d98 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000006dbc28 RCX: 0000000000446c69
RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003
RBP: 00000000006dbc20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006dbc2c
R13: 0001008400000000 R14: 0000000000000000 R15: 053b003000000098

Allocated by task 6880:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
__do_kmalloc mm/slab.c:3655 [inline]
__kmalloc+0x1b0/0x310 mm/slab.c:3664
kmalloc include/linux/slab.h:559 [inline]
kzalloc include/linux/slab.h:666 [inline]
tcf_idr_create+0x5b/0x7b0 net/sched/act_api.c:408
tcf_connmark_init+0x535/0x960 net/sched/act_connmark.c:126
tcf_action_init_1+0x6a5/0xac0 net/sched/act_api.c:984
tcf_action_init+0x249/0x380 net/sched/act_api.c:1044
tcf_action_add+0xd9/0x360 net/sched/act_api.c:1452
tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1505
rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 6882:
kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
__kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
__cache_free mm/slab.c:3418 [inline]
kfree+0x10e/0x2b0 mm/slab.c:3756
tcf_idr_release_unsafe net/sched/act_api.c:284 [inline]
tcf_del_walker net/sched/act_api.c:310 [inline]
tcf_generic_walker+0x959/0xb60 net/sched/act_api.c:339
tca_action_flush+0x42b/0x920 net/sched/act_api.c:1279
tca_action_gd+0x8ac/0xda0 net/sched/act_api.c:1386
tc_ctl_action+0x280/0x439 net/sched/act_api.c:1513
rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff8880a6998c00
which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of
512-byte region [ffff8880a6998c00, ffff8880a6998e00)
The buggy address belongs to the page:
page:00000000db318149 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff8880a6998400 pfn:0xa6998
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00029e0748 ffffea00029b4808 ffff8880aa040600
raw: ffff8880a6998400 ffff8880a6998000 0000000100000003 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8880a6998b00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff8880a6998b80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a6998c00: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff8880a6998c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8880a6998d00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
This report is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this issue. See:
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For information about bisection process see: https://goo.gl/tpsmEJ#bisection
syzbot can test patches for this issue, for details see:
https://goo.gl/tpsmEJ#testing-patches

[Hillf Danton]

On Sun, 20 Sep 2020 08:12:18 -0700

Fix uaf by holding an extra grab to action before adding it to idr.
Note other pathes than tcf_action_add() are not considered.

--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -136,6 +136,14 @@ static int tcf_connmark_init(struct net
ci->net = net;
ci->zone = parm->zone;

+ /* because action becomes publically visable after insert,
+ * hold extra grab to make it safe to derefer it at call site,
+ * leaving the caller responsible for dropping it at right time.
+ *
+ * TODO add tc_action_get/put(a) helpers in net/act_api.h
+ * rather than fiddle with tcfa_refcnt here and there.
+ */
+ refcount_inc(&(*a)->tcfa_refcnt);
tcf_idr_insert(tn, *a);
ret = ACT_P_CREATED;
} else if (ret > 0) {
--- a/net/sched/act_api.c
+++ b/net/sched/act_api.c
@@ -1056,7 +1056,7 @@ int tcf_action_init(struct net *net, str
return i - 1;

err:
- tcf_action_destroy(actions, bind);
+ tcf_action_put_many(actions);
return err;
}

@@ -1458,9 +1458,7 @@ static int tcf_action_add(struct net *ne
if (ret < 0)
return ret;
ret = tcf_add_notify(net, n, actions, portid, attr_size, extack);
- if (ovr)
- tcf_action_put_many(actions);
-
+ tcf_action_put_many(actions);
return ret;
}

[syzbot]

Hello,

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

==================================================================
BUG: KASAN: use-after-free in tcf_action_destroy+0x188/0x1b0 net/sched/act_api.c:713
Read of size 8 at addr ffff88808de4f000 by task syz-executor.3/8274

CPU: 0 PID: 8274 Comm: syz-executor.3 Not tainted 5.9.0-rc3-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118
print_address_description.constprop.0.cold+0xae/0x497 mm/kasan/report.c:383
__kasan_report mm/kasan/report.c:513 [inline]
kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530

tcf_action_destroy+0x188/0x1b0 net/sched/act_api.c:713
tcf_action_init+0x285/0x380 net/sched/act_api.c:1060
tcf_action_add+0xd9/0x360 net/sched/act_api.c:1453
tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1506

rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

RIP: 0033:0x45d5f9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5b32255c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 000000000002cf40 RCX: 000000000045d5f9

RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003

RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffdb0cb1bef R14: 00007f5b322569c0 R15: 000000000118cf4c

Allocated by task 8274:

kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track mm/kasan/common.c:56 [inline]
__kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:461
__do_kmalloc mm/slab.c:3655 [inline]
__kmalloc+0x1b0/0x310 mm/slab.c:3664
kmalloc include/linux/slab.h:559 [inline]
kzalloc include/linux/slab.h:666 [inline]
tcf_idr_create+0x5b/0x7b0 net/sched/act_api.c:408

tcf_connmark_init+0x535/0x910 net/sched/act_connmark.c:126
tcf_action_init_1+0x78e/0xc60 net/sched/act_api.c:983
tcf_action_init+0x249/0x380 net/sched/act_api.c:1045
tcf_action_add+0xd9/0x360 net/sched/act_api.c:1453
tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1506

rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

Freed by task 8277:

kasan_save_stack+0x1b/0x40 mm/kasan/common.c:48
kasan_set_track+0x1c/0x30 mm/kasan/common.c:56
kasan_set_free_info+0x1b/0x30 mm/kasan/generic.c:355
__kasan_slab_free+0xd8/0x120 mm/kasan/common.c:422
__cache_free mm/slab.c:3418 [inline]
kfree+0x10e/0x2b0 mm/slab.c:3756
tcf_idr_release_unsafe net/sched/act_api.c:284 [inline]
tcf_del_walker net/sched/act_api.c:310 [inline]
tcf_generic_walker+0x959/0xb60 net/sched/act_api.c:339

tca_action_flush+0x42b/0x920 net/sched/act_api.c:1280
tca_action_gd+0x8ac/0xda0 net/sched/act_api.c:1387
tc_ctl_action+0x280/0x439 net/sched/act_api.c:1514

rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9

The buggy address belongs to the object at ffff88808de4f000

which belongs to the cache kmalloc-512 of size 512
The buggy address is located 0 bytes inside of

512-byte region [ffff88808de4f000, ffff88808de4f200)

The buggy address belongs to the page:

page:000000006d998f28 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x8de4f
flags: 0xfffe0000000200(slab)
raw: 00fffe0000000200 ffffea00028435c8 ffffea000277b648 ffff8880aa040600
raw: 0000000000000000 ffff88808de4f000 0000000100000004 0000000000000000

page dumped because: kasan: bad access detected

Memory state around the buggy address:

ffff88808de4ef00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
ffff88808de4ef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88808de4f000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88808de4f080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808de4f100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


Tested on:

commit: fa181da2 net_sched: defer tcf_idr_insert() as late as poss..
git tree: https://github.com/congwang/linux.git net
console output: https://syzkaller.appspot.com/x/log.txt?x=172d119b900000
kernel config: https://syzkaller.appspot.com/x/.config?x=bd46548257448703

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

KASAN: null-ptr-deref Read in tcf_generic_walker

==================================================================
BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:56 [inline]
BUG: KASAN: null-ptr-deref in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
BUG: KASAN: null-ptr-deref in tcf_idr_release_unsafe net/sched/act_api.c:279 [inline]
BUG: KASAN: null-ptr-deref in tcf_del_walker net/sched/act_api.c:310 [inline]
BUG: KASAN: null-ptr-deref in tcf_generic_walker+0x730/0xb60 net/sched/act_api.c:339
Read of size 4 at addr 0000000000000010 by task syz-executor.3/8290

CPU: 1 PID: 8290 Comm: syz-executor.3 Not tainted 5.9.0-rc3-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118

__kasan_report mm/kasan/report.c:517 [inline]
kasan_report.cold+0x5/0x37 mm/kasan/report.c:530
check_memory_region_inline mm/kasan/generic.c:186 [inline]
check_memory_region+0x13d/0x180 mm/kasan/generic.c:192
instrument_atomic_read include/linux/instrumented.h:56 [inline]
atomic_read include/asm-generic/atomic-instrumented.h:27 [inline]
tcf_idr_release_unsafe net/sched/act_api.c:279 [inline]
tcf_del_walker net/sched/act_api.c:310 [inline]
tcf_generic_walker+0x730/0xb60 net/sched/act_api.c:339
tca_action_flush+0x42b/0x920 net/sched/act_api.c:1292
tca_action_gd+0x8ac/0xda0 net/sched/act_api.c:1399
tc_ctl_action+0x280/0x439 net/sched/act_api.c:1526

rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5f9
Code: 5d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00

RSP: 002b:00007f7720fe6c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e

RAX: ffffffffffffffda RBX: 000000000002cf40 RCX: 000000000045d5f9

RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000004
RBP: 000000000118d020 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cfec
R13: 00007ffeb835ee7f R14: 00007f7720fe79c0 R15: 000000000118cfec
==================================================================


Tested on:

commit: d77fa51b net_sched: group action insertions together

git tree: https://github.com/congwang/linux.git net

console output: https://syzkaller.appspot.com/x/log.txt?x=15b1b6c3900000

[syzbot]

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:

INFO: task hung in addrconf_dad_work

INFO: task kworker/1:1:23 blocked for more than 143 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/1:1 state:D stack:26600 pid: 23 ppid: 2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
addrconf_dad_work+0xa3/0x1280 net/ipv6/addrconf.c:4027
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
INFO: task kworker/0:2:2464 blocked for more than 143 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2 state:D stack:27432 pid: 2464 ppid: 2 flags:0x00004000
Workqueue: ipv6_addrconf addrconf_dad_work
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
addrconf_dad_work+0xa3/0x1280 net/ipv6/addrconf.c:4027
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
INFO: task syz-executor.0:6966 blocked for more than 144 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.0 state:D stack:24248 pid: 6966 ppid: 1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
rtnl_lock net/core/rtnetlink.c:72 [inline]
rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671

__sys_sendto+0x21c/0x320 net/socket.c:1992
__do_sys_sendto net/socket.c:2004 [inline]
__se_sys_sendto net/socket.c:2000 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4170c7
Code: Bad RIP value.
RSP: 002b:00007ffce1969710 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000016a3700 RCX: 00000000004170c7
RDX: 0000000000000040 RSI: 00000000016a3750 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffce1969720 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00000000016a3750 R15: 0000000000000003
INFO: task syz-executor.4:6968 blocked for more than 144 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4 state:D stack:24440 pid: 6968 ppid: 1 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
rtnl_lock net/core/rtnetlink.c:72 [inline]
rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671

__sys_sendto+0x21c/0x320 net/socket.c:1992
__do_sys_sendto net/socket.c:2004 [inline]
__se_sys_sendto net/socket.c:2000 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4170c7
Code: Bad RIP value.
RSP: 002b:00007fffc2c20530 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000016a3700 RCX: 00000000004170c7
RDX: 0000000000000028 RSI: 00000000016a3750 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007fffc2c20540 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00000000016a3750 R15: 0000000000000003
INFO: task syz-executor.3:6972 blocked for more than 145 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3 state:D stack:24248 pid: 6972 ppid: 1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
rtnl_lock net/core/rtnetlink.c:72 [inline]
rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671

__sys_sendto+0x21c/0x320 net/socket.c:1992
__do_sys_sendto net/socket.c:2004 [inline]
__se_sys_sendto net/socket.c:2000 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4170c7
Code: Bad RIP value.
RSP: 002b:00007ffc98e0f530 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000016a3700 RCX: 00000000004170c7
RDX: 0000000000000028 RSI: 00000000016a3750 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffc98e0f540 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00000000016a3750 R15: 0000000000000003
INFO: task syz-executor.1:6974 blocked for more than 145 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.1 state:D stack:24248 pid: 6974 ppid: 1 flags:0x00000004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
rtnl_lock net/core/rtnetlink.c:72 [inline]
rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671

__sys_sendto+0x21c/0x320 net/socket.c:1992
__do_sys_sendto net/socket.c:2004 [inline]
__se_sys_sendto net/socket.c:2000 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4170c7
Code: Bad RIP value.
RSP: 002b:00007ffca79aad90 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000016a3700 RCX: 00000000004170c7
RDX: 0000000000000028 RSI: 00000000016a3750 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffca79aada0 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00000000016a3750 R15: 0000000000000003
INFO: task syz-executor.5:6975 blocked for more than 146 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.5 state:D stack:23792 pid: 6975 ppid: 1 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
rtnl_lock net/core/rtnetlink.c:72 [inline]
rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671

__sys_sendto+0x21c/0x320 net/socket.c:1992
__do_sys_sendto net/socket.c:2004 [inline]
__se_sys_sendto net/socket.c:2000 [inline]
__x64_sys_sendto+0xdd/0x1b0 net/socket.c:2000
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4170c7
Code: Bad RIP value.
RSP: 002b:00007ffc657c5ac0 EFLAGS: 00000293 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00000000016a3700 RCX: 00000000004170c7
RDX: 0000000000000028 RSI: 00000000016a3750 RDI: 0000000000000003
RBP: 0000000000000000 R08: 00007ffc657c5ad0 R09: 000000000000000c
R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000
R13: 0000000000000000 R14: 00000000016a3750 R15: 0000000000000003
INFO: task kworker/0:4:8273 blocked for more than 146 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:4 state:D stack:27400 pid: 8273 ppid: 2 flags:0x00004000
Workqueue: events linkwatch_event
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
linkwatch_event+0xb/0x60 net/core/link_watch.c:254
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
INFO: task syz-executor.2:8281 blocked for more than 146 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2 state:D stack:25808 pid: 8281 ppid: 6973 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
tcf_action_init_1+0x85f/0xac0 net/sched/act_api.c:976
tcf_action_init+0x24e/0x460 net/sched/act_api.c:1057
tcf_action_add+0xd9/0x360 net/sched/act_api.c:1470
tc_ctl_action+0x33a/0x439 net/sched/act_api.c:1523

rtnetlink_rcv_msg+0x44e/0xad0 net/core/rtnetlink.c:5563
netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5f9

Code: Bad RIP value.
RSP: 002b:00007f473c491c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e

RAX: ffffffffffffffda RBX: 000000000002cf40 RCX: 000000000045d5f9

RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003
RBP: 000000000118cf80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffefde8df0f R14: 00007f473c4929c0 R15: 000000000118cf4c
INFO: task syz-executor.2:8286 blocked for more than 147 seconds.
Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.2 state:D stack:28088 pid: 8286 ppid: 6973 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:3778 [inline]
__schedule+0xea9/0x2230 kernel/sched/core.c:4527
schedule+0xd0/0x2a0 kernel/sched/core.c:4602
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:4661
__mutex_lock_common kernel/locking/mutex.c:1033 [inline]
__mutex_lock+0x3e2/0x10e0 kernel/locking/mutex.c:1103
rtnl_lock net/core/rtnetlink.c:72 [inline]
rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

netlink_rcv_skb+0x15a/0x430 net/netlink/af_netlink.c:2470
netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline]
netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330
netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919
sock_sendmsg_nosec net/socket.c:651 [inline]
sock_sendmsg+0xcf/0x120 net/socket.c:671
____sys_sendmsg+0x6e8/0x810 net/socket.c:2353
___sys_sendmsg+0xf3/0x170 net/socket.c:2407
__sys_sendmsg+0xe5/0x1b0 net/socket.c:2440
do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5f9

Code: Bad RIP value.
RSP: 002b:00007f473c44fc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e

RAX: ffffffffffffffda RBX: 000000000002cf40 RCX: 000000000045d5f9

RDX: 0000000000000000 RSI: 0000000020002980 RDI: 0000000000000003
RBP: 000000000118d0c0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118d08c
R13: 00007ffefde8df0f R14: 00007f473c4509c0 R15: 000000000118d08c

Showing all locks held in the system:
3 locks held by kworker/1:1/23:
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: ffffc90000df7da8 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
#2: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xa3/0x1280 net/ipv6/addrconf.c:4027
1 lock held by khungtaskd/1171:
#0: ffffffff89bd6a40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5829
3 locks held by kworker/0:2/2464:
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff888099e3dd38 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: ffffc9000868fda8 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
#2: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_dad_work+0xa3/0x1280 net/ipv6/addrconf.c:4027
1 lock held by in:imklog/6521:
#0: ffff8880a2398370 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930
1 lock held by syz-executor.0/6966:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560
1 lock held by syz-executor.4/6968:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560
1 lock held by syz-executor.3/6972:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560
1 lock held by syz-executor.1/6974:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560
1 lock held by syz-executor.5/6975:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560
3 locks held by kworker/1:4/8264:
#0: ffff8880aa070d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8880aa070d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff8880aa070d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff8880aa070d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff8880aa070d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff8880aa070d38 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: ffffc9000a10fda8 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
#2: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: reg_check_chans_work+0x71/0xe10 net/wireless/reg.c:2199
3 locks held by kworker/0:4/8273:
#0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
#0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
#0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
#0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
#0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
#0: ffff8880aa063d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
#1: ffffc9000a05fda8 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
#2: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xb/0x60 net/core/link_watch.c:254
1 lock held by syz-executor.2/8281:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: tcf_action_init_1+0x85f/0xac0 net/sched/act_api.c:976
2 locks held by syz-executor.2/8282:
1 lock held by syz-executor.2/8286:
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:72 [inline]
#0: ffffffff8a7ea488 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3f9/0xad0 net/core/rtnetlink.c:5560

=============================================

NMI backtrace for cpu 0
CPU: 0 PID: 1171 Comm: khungtaskd Not tainted 5.9.0-rc3-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x198/0x1fd lib/dump_stack.c:118

nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
watchdog+0xd7d/0x1000 kernel/hung_task.c:295
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 26 Comm: kworker/u4:2 Not tainted 5.9.0-rc3-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

Workqueue: bat_events batadv_nc_worker
RIP: 0010:lock_acquire+0x63/0xae0 kernel/locking/lockdep.c:4977
Code: 24 08 48 89 c6 48 b8 00 00 00 00 00 fc ff df 48 c7 44 24 20 64 7c 6a 89 48 01 f0 48 c7 44 24 28 f0 6d 5a 81 c7 00 f1 f1 f1 f1 <c7> 40 04 f1 f1 00 00 c7 40 08 00 00 00 f3 c7 40 0c f3 f3 f3 f3 65
RSP: 0018:ffffc90000e27b88 EFLAGS: 00000286
RAX: fffff520001c4f74 RBX: 0000000000000000 RCX: 0000000000000002
RDX: 0000000000000000 RSI: 1ffff920001c4f74 RDI: ffffffff89bd6a40
RBP: ffffffff89bd6a40 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000343 R11: 0000000000000000 R12: 0000000000000002
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000343
FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc579789000 CR3: 00000000a29e3000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
rcu_lock_acquire include/linux/rcupdate.h:241 [inline]
rcu_read_lock include/linux/rcupdate.h:634 [inline]
batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:407 [inline]
batadv_nc_worker+0x12d/0xe50 net/batman-adv/network-coding.c:718
process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
kthread+0x3b5/0x4a0 kernel/kthread.c:292
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294


Tested on:

commit: 2092bf06 net_sched: check error pointer in tcf_del_walker()

git tree: https://github.com/congwang/linux.git net

console output: https://syzkaller.appspot.com/x/log.txt?x=15c19c03900000

[syzbot]

Hello,

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

Reported-and-tested-by: syzbot+228785...@syzkaller.appspotmail.com

Tested on:

commit: 9745d927 net_sched: check error pointer in tcf_del_walker()

git tree: https://github.com/congwang/linux.git net

kernel config: https://syzkaller.appspot.com/x/.config?x=bd46548257448703
dashboard link: https://syzkaller.appspot.com/bug?extid=2287853d392e4b42374a
compiler: gcc (GCC) 10.1.0-syz 20200507

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