Hello,
syzbot found the following crash on:
HEAD commit: 78d697fc Linux 4.14.172
git tree: linux-4.14.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=16a35fd9e00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=31ad682bcda9b93f
dashboard link:
https://syzkaller.appspot.com/bug?extid=ea5c21ae1f10dd6e4d5f
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by:
syzbot+ea5c21...@syzkaller.appspotmail.com
ip_tables: iptables: counters copy to user failed while replacing table
ptrace attach of "/root/syz-executor.1"[26732] was attempted by "/root/syz-executor.1"[26736]
======================================================
WARNING: possible circular locking dependency detected
4.14.172-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor.4/26726 is trying to acquire lock:
(&table[i].mutex){+.+.}, at: [<ffffffff85306aeb>] ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730
but task is already holding lock:
(&xt[i].mutex){+.+.}, at: [<ffffffff852bdb45>] xt_find_table_lock+0x35/0x3d0 net/netfilter/x_tables.c:1092
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&xt[i].mutex){+.+.}:
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
xt_find_revision+0x89/0x200 net/netfilter/x_tables.c:373
nfnl_compat_get+0x1f7/0x8a0 net/netfilter/nft_compat.c:678
nfnetlink_rcv_msg+0xa08/0xc00 net/netfilter/nfnetlink.c:214
netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2432
nfnetlink_rcv+0x1ab/0x1650 net/netfilter/nfnetlink.c:515
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xc5/0x100 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
-> #0 (&table[i].mutex){+.+.}:
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730
set_target_v1_destroy+0xd7/0x150 net/netfilter/xt_set.c:392
cleanup_entry+0x169/0x220 net/ipv4/netfilter/ip_tables.c:666
__do_replace+0x38d/0x570 net/ipv4/netfilter/ip_tables.c:1086
do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline]
do_ipt_set_ctl+0x255/0x39d net/ipv4/netfilter/ip_tables.c:1674
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline]
ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240
raw_setsockopt+0xac/0xd0 net/ipv4/raw.c:855
SYSC_setsockopt net/socket.c:1865 [inline]
SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0 CPU1
---- ----
lock(&xt[i].mutex);
lock(&table[i].mutex);
lock(&xt[i].mutex);
lock(&table[i].mutex);
*** DEADLOCK ***
1 lock held by syz-executor.4/26726:
#0: (&xt[i].mutex){+.+.}, at: [<ffffffff852bdb45>] xt_find_table_lock+0x35/0x3d0 net/netfilter/x_tables.c:1092
stack backtrace:
CPU: 0 PID: 26726 Comm: syz-executor.4 Not tainted 4.14.172-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:17 [inline]
dump_stack+0x13e/0x194 lib/dump_stack.c:58
print_circular_bug.isra.0.cold+0x1c4/0x282 kernel/locking/lockdep.c:1258
check_prev_add kernel/locking/lockdep.c:1901 [inline]
check_prevs_add kernel/locking/lockdep.c:2018 [inline]
validate_chain kernel/locking/lockdep.c:2460 [inline]
__lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487
lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3994
__mutex_lock_common kernel/locking/mutex.c:756 [inline]
__mutex_lock+0xe8/0x1470 kernel/locking/mutex.c:893
ip_set_nfnl_put+0x11b/0x310 net/netfilter/ipset/ip_set_core.c:730
set_target_v1_destroy+0xd7/0x150 net/netfilter/xt_set.c:392
cleanup_entry+0x169/0x220 net/ipv4/netfilter/ip_tables.c:666
__do_replace+0x38d/0x570 net/ipv4/netfilter/ip_tables.c:1086
do_replace net/ipv4/netfilter/ip_tables.c:1142 [inline]
do_ipt_set_ctl+0x255/0x39d net/ipv4/netfilter/ip_tables.c:1674
nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
nf_setsockopt+0x5f/0xb0 net/netfilter/nf_sockopt.c:115
ip_setsockopt net/ipv4/ip_sockglue.c:1255 [inline]
ip_setsockopt+0x94/0xb0 net/ipv4/ip_sockglue.c:1240
raw_setsockopt+0xac/0xd0 net/ipv4/raw.c:855
SYSC_setsockopt net/socket.c:1865 [inline]
SyS_setsockopt+0x110/0x1e0 net/socket.c:1844
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c479
RSP: 002b:00007f6adb4d2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 00007f6adb4d36d4 RCX: 000000000045c479
RDX: 0000000000000040 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 000000000076bf20 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020000240 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000a34 R14: 00000000004cc9d4 R15: 000000000076bf2c
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.1'.
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
ip_tables: iptables: counters copy to user failed while replacing table
---
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