possible deadlock in sctp_addr_wq_timeout_handler

4 views
Skip to first unread message

syzbot

unread,
Apr 28, 2021, 8:08:19 AM4/28/21
to syzkaller...@googlegroups.com
Hello,

syzbot found the following issue on:

HEAD commit: 97a8651c Linux 4.19.189
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=17950db9d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=82311d18bf81a023
dashboard link: https://syzkaller.appspot.com/bug?extid=c735e1c426c273b10493

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+c735e1...@syzkaller.appspotmail.com

IPv6: ADDRCONF(NETDEV_CHANGE): wlan0: link becomes ready
wlan1: Created IBSS using preconfigured BSSID 50:50:50:50:50:50
wlan1: Creating new IBSS network, BSSID 50:50:50:50:50:50
IPv6: ADDRCONF(NETDEV_CHANGE): wlan1: link becomes ready
======================================================
WARNING: possible circular locking dependency detected
4.19.189-syzkaller #0 Not tainted
------------------------------------------------------
swapper/0/0 is trying to acquire lock:
0000000003e0fbc5 (slock-AF_INET6){+.-.}, at: spin_lock include/linux/spinlock.h:329 [inline]
0000000003e0fbc5 (slock-AF_INET6){+.-.}, at: sctp_addr_wq_timeout_handler+0x1a1/0x550 net/sctp/protocol.c:680

but task is already holding lock:
000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: spin_lock_bh include/linux/spinlock.h:334 [inline]
000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: sctp_addr_wq_timeout_handler+0x38/0x550 net/sctp/protocol.c:640

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}:
spin_lock_bh include/linux/spinlock.h:334 [inline]
sctp_destroy_sock+0x234/0x480 net/sctp/socket.c:4811
sctp_v6_destroy_sock+0x11/0x20 net/sctp/socket.c:8973
sk_common_release+0x64/0x2d0 net/core/sock.c:3093
sctp_close+0x46d/0x800 net/sctp/socket.c:1580
inet_release+0xd7/0x1e0 net/ipv4/af_inet.c:427
inet6_release+0x4c/0x70 net/ipv6/af_inet6.c:472
__sock_release+0xcd/0x2a0 net/socket.c:579
sock_close+0x15/0x20 net/socket.c:1140
__fput+0x2ce/0x890 fs/file_table.c:278
task_work_run+0x148/0x1c0 kernel/task_work.c:113
tracehook_notify_resume include/linux/tracehook.h:193 [inline]
exit_to_usermode_loop+0x251/0x2a0 arch/x86/entry/common.c:167
prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline]
syscall_return_slowpath arch/x86/entry/common.c:271 [inline]
do_syscall_64+0x538/0x620 arch/x86/entry/common.c:296
entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (slock-AF_INET6){+.-.}:
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
sctp_addr_wq_timeout_handler+0x1a1/0x550 net/sctp/protocol.c:680
call_timer_fn+0x177/0x700 kernel/time/timer.c:1338
expire_timers+0x243/0x4e0 kernel/time/timer.c:1375
__run_timers kernel/time/timer.c:1696 [inline]
run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709
__do_softirq+0x265/0x980 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:372 [inline]
irq_exit+0x215/0x260 kernel/softirq.c:412
exiting_irq arch/x86/include/asm/apic.h:535 [inline]
smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60
arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
default_idle+0x49/0x310 arch/x86/kernel/process.c:557
cpuidle_idle_call kernel/sched/idle.c:153 [inline]
do_idle+0x2ec/0x4b0 kernel/sched/idle.c:263
cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369
start_kernel+0x8d6/0x911 init/main.c:736
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

other info that might help us debug this:

Possible unsafe locking scenario:

CPU0 CPU1
---- ----
lock(&(&net->sctp.addr_wq_lock)->rlock);
lock(slock-AF_INET6);
lock(&(&net->sctp.addr_wq_lock)->rlock);
lock(slock-AF_INET6);

*** DEADLOCK ***

2 locks held by swapper/0/0:
#0: 000000009aa23dc6 ((&net->sctp.addr_wq_timer)){+.-.}, at: lockdep_copy_map include/linux/lockdep.h:168 [inline]
#0: 000000009aa23dc6 ((&net->sctp.addr_wq_timer)){+.-.}, at: call_timer_fn+0xc9/0x700 kernel/time/timer.c:1328
#1: 000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: spin_lock_bh include/linux/spinlock.h:334 [inline]
#1: 000000001e83ae24 (&(&net->sctp.addr_wq_lock)->rlock){+.-.}, at: sctp_addr_wq_timeout_handler+0x38/0x550 net/sctp/protocol.c:640

stack backtrace:
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.19.189-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
check_prev_add kernel/locking/lockdep.c:1866 [inline]
check_prevs_add kernel/locking/lockdep.c:1979 [inline]
validate_chain kernel/locking/lockdep.c:2420 [inline]
__lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
__raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
_raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:144
spin_lock include/linux/spinlock.h:329 [inline]
sctp_addr_wq_timeout_handler+0x1a1/0x550 net/sctp/protocol.c:680
call_timer_fn+0x177/0x700 kernel/time/timer.c:1338
expire_timers+0x243/0x4e0 kernel/time/timer.c:1375
__run_timers kernel/time/timer.c:1696 [inline]
run_timer_softirq+0x21c/0x670 kernel/time/timer.c:1709
__do_softirq+0x265/0x980 kernel/softirq.c:292
invoke_softirq kernel/softirq.c:372 [inline]
irq_exit+0x215/0x260 kernel/softirq.c:412
exiting_irq arch/x86/include/asm/apic.h:535 [inline]
smp_apic_timer_interrupt+0x136/0x550 arch/x86/kernel/apic/apic.c:1098
apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:894
</IRQ>
RIP: 0010:native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:61
Code: 48 89 df e8 a4 36 80 f9 e9 2e ff ff ff 48 89 df e8 97 36 80 f9 eb 82 90 90 90 90 90 e9 07 00 00 00 0f 00 2d b4 9a 4f 00 fb f4 <c3> 90 e9 07 00 00 00 0f 00 2d a4 9a 4f 00 f4 c3 90 90 41 56 41 55
RSP: 0018:ffffffff89e07d40 EFLAGS: 00000282 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff13e304c RBX: dffffc0000000000 RCX: 0000000000000000
RDX: dffffc0000000000 RSI: 0000000000000001 RDI: ffffffff89e78904
RBP: 0000000000000000 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff89f18250
R13: 1ffffffff13c0fb2 R14: 0000000000000000 R15: 0000000000000000
arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline]
default_idle+0x49/0x310 arch/x86/kernel/process.c:557
cpuidle_idle_call kernel/sched/idle.c:153 [inline]
do_idle+0x2ec/0x4b0 kernel/sched/idle.c:263
cpu_startup_entry+0xc5/0xe0 kernel/sched/idle.c:369
start_kernel+0x8d6/0x911 init/main.c:736
secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
devpts: called with bogus options
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
devpts: called with bogus options
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
IPv6: ADDRCONF(NETDEV_UP): veth3: link is not ready
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
devpts: called with bogus options
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
IPv6: ADDRCONF(NETDEV_UP): veth3: link is not ready
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.4'.
IPv6: ADDRCONF(NETDEV_UP): veth5: link is not ready
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.5'.
IPv6: ADDRCONF(NETDEV_UP): veth5: link is not ready
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
IPv6: ADDRCONF(NETDEV_UP): veth7: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth7: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth9: link is not ready
IPv6: ADDRCONF(NETDEV_UP): veth11: link is not ready


---
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:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

syzbot

unread,
Aug 26, 2021, 8:08:13 AM8/26/21
to syzkaller...@googlegroups.com
Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.
Reply all
Reply to author
Forward
0 new messages