lkml.org 
[lkml]   [2022]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
From
Date
Subjectpossible deadlock in sch_direct_xmit
Hello,

When using modified Syzkaller to fuzz the Linux kernel-5.19, the
following crash was triggered.
We would appreciate a CVE ID if this is a security issue.

HEAD commit: 3d7cb6b04c3f Linux-5.19
git tree: upstream

console output:
https://drive.google.com/file/d/1ba6S6vbR1GdjkocR9Z14H5fAvrnXnc9T/view?usp=sharing
kernel config: https://drive.google.com/file/d/1wgIUDwP5ho29AM-K7HhysSTfWFpfXYkG/view?usp=sharing
syz repro: https://drive.google.com/file/d/1bz7Wga1bdlnlUrqfLi26IRGMoAqy6NAf/view?usp=sharing
C reproducer: https://drive.google.com/file/d/1Qz_ChFTK3zJEssQ_CfgPGNTdgGHxVFOY/view?usp=sharing

Description:
When sending socket to device, HARD_TX_LOCK() in sch_direct_xmit() is
called to ensure only one CPU can execute it. However,
sch_direct_xmit() could be re-entrant through ops->ndo_start_xmit in
__netdev_start_xmit().
Such call stack is:

ip_send_skb();
HARD_TX_LOCK();
sch_direct_xmit();
__netdev_start_xmit();
ip_tunnel_xmit();
HARD_TX_LOCK();
sch_direct_xmit();

Environment:
Ubuntu 20.04 on Linux 5.4.0
QEMU 4.2.1:
qemu-system-x86_64 \
-m 2G \
-smp 2 \
-kernel /home/workdir/bzImage \
-append "console=ttyS0 root=/dev/sda earlyprintk=serial net.ifnames=0" \
-drive file=/home/workdir/stretch.img,format=raw \
-net user,host=10.0.2.10,hostfwd=tcp:127.0.0.1:10021-:22 \
-net nic,model=e1000 \
-enable-kvm \
-nographic \
-pidfile vm.pid \
2>&1 | tee vm.log

If you fix this issue, please add the following tag to the commit:
Reported-by Jiacheng Xu<578001344xu@gmail.com>

============================================
WARNING: possible recursive locking detected
5.19.0 #2 Not tainted
--------------------------------------------
syz-executor/7687 is trying to acquire lock:
ffff88810b142458 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock
include/linux/spinlock.h:349 [inline]
ffff88810b142458 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock
include/linux/netdevice.h:4256 [inline]
ffff88810b142458 (_xmit_ETHER#2){+.-.}-{2:2}, at:
sch_direct_xmit+0x318/0xc70 net/sched/sch_generic.c:340

but task is already holding lock:
ffff88801dba0cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock
include/linux/spinlock.h:349 [inline]
ffff88801dba0cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock
include/linux/netdevice.h:4256 [inline]
ffff88801dba0cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at:
sch_direct_xmit+0x318/0xc70 net/sched/sch_generic.c:340

other info that might help us debug this:
Possible unsafe locking scenario:

CPU0
----
lock(_xmit_ETHER#2);
lock(_xmit_ETHER#2);

*** DEADLOCK ***

May be due to missing lock nesting notation

7 locks held by syz-executor/7687:
#0: ffffffff8bd86e00 (rcu_read_lock_bh){....}-{1:2}, at:
lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline]
#0: ffffffff8bd86e00 (rcu_read_lock_bh){....}-{1:2}, at:
ip_finish_output2+0x29b/0x2200 net/ipv4/ip_output.c:214
#1: ffffffff8bd86e00 (rcu_read_lock_bh){....}-{1:2}, at:
__dev_queue_xmit+0x20a/0x3ad0 net/core/dev.c:4172
#2: ffff88801abac258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock
include/linux/spinlock.h:359 [inline]
#2: ffff88801abac258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin
include/net/sch_generic.h:187 [inline]
#2: ffff88801abac258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin
include/net/sch_generic.h:184 [inline]
#2: ffff88801abac258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb
net/core/dev.c:3804 [inline]
#2: ffff88801abac258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1384/0x3ad0
net/core/dev.c:4221
#3: ffff88801dba0cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: spin_lock
include/linux/spinlock.h:349 [inline]
#3: ffff88801dba0cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at: __netif_tx_lock
include/linux/netdevice.h:4256 [inline]
#3: ffff88801dba0cd8 (_xmit_ETHER#2){+.-.}-{2:2}, at:
sch_direct_xmit+0x318/0xc70 net/sched/sch_generic.c:340
#4: ffffffff8bd86e00 (rcu_read_lock_bh){....}-{1:2}, at:
lwtunnel_xmit_redirect include/net/lwtunnel.h:95 [inline]
#4: ffffffff8bd86e00 (rcu_read_lock_bh){....}-{1:2}, at:
ip_finish_output2+0x29b/0x2200 net/ipv4/ip_output.c:214
#5: ffffffff8bd86e00 (rcu_read_lock_bh){....}-{1:2}, at:
__dev_queue_xmit+0x20a/0x3ad0 net/core/dev.c:4172
#6: ffff88810b772258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: spin_trylock
include/linux/spinlock.h:359 [inline]
#6: ffff88810b772258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin
include/net/sch_generic.h:187 [inline]
#6: ffff88810b772258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: qdisc_run_begin
include/net/sch_generic.h:184 [inline]
#6: ffff88810b772258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: __dev_xmit_skb
net/core/dev.c:3804 [inline]
#6: ffff88810b772258 (dev->qdisc_tx_busylock ?:
&qdisc_tx_busylock){+...}-{2:2}, at: __dev_queue_xmit+0x1384/0x3ad0
net/core/dev.c:4221

stack backtrace:
CPU: 0 PID: 7687 Comm: syz-executor Not tainted 5.19.0 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.13.0-1ubuntu1.1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:88 [inline]
dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
print_deadlock_bug kernel/locking/lockdep.c:2988 [inline]
check_deadlock kernel/locking/lockdep.c:3031 [inline]
validate_chain kernel/locking/lockdep.c:3816 [inline]
__lock_acquire.cold+0x152/0x3ca kernel/locking/lockdep.c:5053
lock_acquire kernel/locking/lockdep.c:5665 [inline]
lock_acquire+0x1ab/0x580 kernel/locking/lockdep.c:5630
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:349 [inline]
__netif_tx_lock include/linux/netdevice.h:4256 [inline]
sch_direct_xmit+0x318/0xc70 net/sched/sch_generic.c:340
__dev_xmit_skb net/core/dev.c:3817 [inline]
__dev_queue_xmit+0x15c6/0x3ad0 net/core/dev.c:4221
dev_queue_xmit include/linux/netdevice.h:2994 [inline]
neigh_resolve_output net/core/neighbour.c:1528 [inline]
neigh_resolve_output+0x53d/0x870 net/core/neighbour.c:1508
neigh_output include/net/neighbour.h:549 [inline]
ip_finish_output2+0x7ab/0x2200 net/ipv4/ip_output.c:228
__ip_finish_output net/ipv4/ip_output.c:306 [inline]
__ip_finish_output+0x85c/0x1450 net/ipv4/ip_output.c:288
ip_finish_output+0x32/0x280 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:296 [inline]
ip_output+0x20a/0x620 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:451 [inline]
ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:126
iptunnel_xmit+0x693/0xa80 net/ipv4/ip_tunnel_core.c:82
ip_tunnel_xmit+0xff9/0x2c40 net/ipv4/ip_tunnel.c:811
erspan_xmit+0x521/0x2b00 net/ipv4/ip_gre.c:715
__netdev_start_xmit include/linux/netdevice.h:4805 [inline]
netdev_start_xmit include/linux/netdevice.h:4819 [inline]
xmit_one net/core/dev.c:3590 [inline]
dev_hard_start_xmit+0x19d/0x8b0 net/core/dev.c:3606
sch_direct_xmit+0x19f/0xc70 net/sched/sch_generic.c:342
__dev_xmit_skb net/core/dev.c:3817 [inline]
__dev_queue_xmit+0x15c6/0x3ad0 net/core/dev.c:4221
dev_queue_xmit include/linux/netdevice.h:2994 [inline]
neigh_resolve_output net/core/neighbour.c:1528 [inline]
neigh_resolve_output+0x53d/0x870 net/core/neighbour.c:1508
neigh_output include/net/neighbour.h:549 [inline]
ip_finish_output2+0x7ab/0x2200 net/ipv4/ip_output.c:228
__ip_finish_output net/ipv4/ip_output.c:306 [inline]
__ip_finish_output+0x85c/0x1450 net/ipv4/ip_output.c:288
ip_finish_output+0x32/0x280 net/ipv4/ip_output.c:316
NF_HOOK_COND include/linux/netfilter.h:296 [inline]
ip_output+0x20a/0x620 net/ipv4/ip_output.c:430
dst_output include/net/dst.h:451 [inline]
ip_local_out+0xaf/0x1a0 net/ipv4/ip_output.c:126
ip_send_skb+0x3e/0xe0 net/ipv4/ip_output.c:1571
udp_send_skb.isra.0+0x731/0x1460 net/ipv4/udp.c:967
udp_sendmsg+0x1dc3/0x2830 net/ipv4/udp.c:1254
udpv6_sendmsg+0x1762/0x2bd0 net/ipv6/udp.c:1365
inet6_sendmsg+0x99/0xe0 net/ipv6/af_inet6.c:652
sock_sendmsg_nosec net/socket.c:714 [inline]
sock_sendmsg net/socket.c:734 [inline]
sock_sendmsg+0xc3/0x120 net/socket.c:729
____sys_sendmsg+0x334/0x810 net/socket.c:2488
___sys_sendmsg+0x100/0x170 net/socket.c:2542
__sys_sendmmsg+0x195/0x470 net/socket.c:2628
__do_sys_sendmmsg net/socket.c:2657 [inline]
__se_sys_sendmmsg net/socket.c:2654 [inline]
__x64_sys_sendmmsg+0x99/0x100 net/socket.c:2654
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f545b495dfd
Code: 02 b8 ff ff ff ff c3 66 0f 1f 44 00 00 f3 0f 1e fa 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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f545c6afc58 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 00007f545b5bc0a0 RCX: 00007f545b495dfd
RDX: 0000000000000001 RSI: 0000000020000140 RDI: 0000000000000004
RBP: 00007f545b4ff4c1 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000004000000 R11: 0000000000000246 R12: 00007f545b5bc0a0
R13: 00007fffca7bf54f R14: 00007fffca7bf6f0 R15: 00007f545c6afdc0
</TASK>

\
 
 \ /
  Last update: 2022-08-29 08:56    [W:2.357 / U:0.076 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site