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INFO: task hung in htable_put

Status: fixed on 2020/11/16 12:12
Reported-by: syzbot+84936245a918e2cddb32@syzkaller.appspotmail.com
Fix commit: 99b79c3900d4 netfilter: xt_hashlimit: unregister proc file before releasing mutex
First crash: 1583d, last: 1528d
Cause bisection: introduced by (bisect log) :
commit b8c8a338f75e052d9fa2fed851259320af412e3f
Author: Johannes Weiner <hannes@cmpxchg.org>
Date: Fri Oct 13 22:58:05 2017 +0000

  Revert "vmalloc: back off when the current task is killed"

Crash: INFO: task hung in hashlimit_mt_check_common (log)
Repro: C syz .config
  
Fix bisection: fixed by (bisect log) :
commit 99b79c3900d4627672c85d9f344b5b0f06bc2a4d
Author: Cong Wang <xiyou.wangcong@gmail.com>
Date: Thu Feb 13 06:53:52 2020 +0000

  netfilter: xt_hashlimit: unregister proc file before releasing mutex

  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
INFO: task hung in htable_put 1 (3) 2020/11/11 13:29
▶ ▼ Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in htable_put C done 8 1522d 1568d 1/1 fixed on 2020/03/24 16:08
linux-4.19 INFO: task hung in htable_put (2) 1 1148d 1148d 0/1 auto-closed as invalid on 2021/07/01 18:58

Sample crash report:
INFO: task syz-executor334:11027 blocked for more than 143 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor334 D28040 11027  11013 0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1871
 do_wait_for_common kernel/sched/completion.c:83 [inline]
 __wait_for_common kernel/sched/completion.c:104 [inline]
 wait_for_common kernel/sched/completion.c:115 [inline]
 wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136
 __flush_work+0x4fe/0xa50 kernel/workqueue.c:3041
 __cancel_work_timer+0x3d9/0x540 kernel/workqueue.c:3128
 cancel_delayed_work_sync+0x1b/0x20 kernel/workqueue.c:3260
 htable_destroy net/netfilter/xt_hashlimit.c:406 [inline]
 htable_put+0x15f/0x220 net/netfilter/xt_hashlimit.c:435
 hashlimit_mt_destroy+0x56/0x70 net/netfilter/xt_hashlimit.c:971
 cleanup_match+0xde/0x170 net/ipv6/netfilter/ip6_tables.c:478
 find_check_entry.isra.0+0x454/0x920 net/ipv4/netfilter/ip_tables.c:564
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 udp_setsockopt+0x68/0xb0 net/ipv4/udp.c:2640
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441c69
Code: 64 0a 00 00 00 00 00 00 00 72 73 79 73 6c 6f 67 64 3a 20 76 65 72 73 69 6f 6e 20 25 73 2c 20 63 6f 6e 66 69 67 20 76 61 6c 69 <64> 61 74 69 6f 6e 20 72 75 6e 20 28 6c 65 76 65 6c 20 25 64 29 2c
RSP: 002b:00007fffb3323b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441c69
RDX: 0000000000000040 RSI: ffffff0f00000000 RDI: 0000000000000003
RBP: 0000000000054472 R08: 0000000000000418 R09: 00000000004002c8
R10: 0000000020000380 R11: 0000000000000246 R12: 00000000004029e0
R13: 0000000000402a70 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor334:11030 blocked for more than 143 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor334 D28072 11030  11011 0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
 hashlimit_mt_check+0xa4/0xd0 net/netfilter/xt_hashlimit.c:949
 xt_check_match+0x280/0x690 net/netfilter/x_tables.c:501
 check_match net/ipv4/netfilter/ip_tables.c:472 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:488 [inline]
 find_check_entry.isra.0+0x32f/0x920 net/ipv4/netfilter/ip_tables.c:538
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 udp_setsockopt+0x68/0xb0 net/ipv4/udp.c:2640
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441c69
Code: 64 0a 00 00 00 00 00 00 00 72 73 79 73 6c 6f 67 64 3a 20 76 65 72 73 69 6f 6e 20 25 73 2c 20 63 6f 6e 66 69 67 20 76 61 6c 69 <64> 61 74 69 6f 6e 20 72 75 6e 20 28 6c 65 76 65 6c 20 25 64 29 2c
RSP: 002b:00007fffb3323b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441c69
RDX: 0000000000000040 RSI: ffffff0f00000000 RDI: 0000000000000003
RBP: 000000000005558f R08: 0000000000000418 R09: 00000000004002c8
R10: 0000000020000380 R11: 0000000000000246 R12: 00000000004029e0
R13: 0000000000402a70 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor334:11031 blocked for more than 144 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor334 D28072 11031  11014 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
 hashlimit_mt_check+0xa4/0xd0 net/netfilter/xt_hashlimit.c:949
 xt_check_match+0x280/0x690 net/netfilter/x_tables.c:501
 check_match net/ipv4/netfilter/ip_tables.c:472 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:488 [inline]
 find_check_entry.isra.0+0x32f/0x920 net/ipv4/netfilter/ip_tables.c:538
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 udp_setsockopt+0x68/0xb0 net/ipv4/udp.c:2640
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441c69
Code: 64 0a 00 00 00 00 00 00 00 72 73 79 73 6c 6f 67 64 3a 20 76 65 72 73 69 6f 6e 20 25 73 2c 20 63 6f 6e 66 69 67 20 76 61 6c 69 <64> 61 74 69 6f 6e 20 72 75 6e 20 28 6c 65 76 65 6c 20 25 64 29 2c
RSP: 002b:00007fffb3323b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441c69
RDX: 0000000000000040 RSI: ffffff0f00000000 RDI: 0000000000000003
RBP: 0000000000055590 R08: 0000000000000418 R09: 00000000004002c8
R10: 0000000020000380 R11: 0000000000000246 R12: 00000000004029e0
R13: 0000000000402a70 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor334:11032 blocked for more than 144 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor334 D27928 11032  11015 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
 hashlimit_mt_check+0xa4/0xd0 net/netfilter/xt_hashlimit.c:949
 xt_check_match+0x280/0x690 net/netfilter/x_tables.c:501
 check_match net/ipv4/netfilter/ip_tables.c:472 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:488 [inline]
 find_check_entry.isra.0+0x32f/0x920 net/ipv4/netfilter/ip_tables.c:538
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 udp_setsockopt+0x68/0xb0 net/ipv4/udp.c:2640
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441c69
Code: 64 0a 00 00 00 00 00 00 00 72 73 79 73 6c 6f 67 64 3a 20 76 65 72 73 69 6f 6e 20 25 73 2c 20 63 6f 6e 66 69 67 20 76 61 6c 69 <64> 61 74 69 6f 6e 20 72 75 6e 20 28 6c 65 76 65 6c 20 25 64 29 2c
RSP: 002b:00007fffb3323b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441c69
RDX: 0000000000000040 RSI: ffffff0f00000000 RDI: 0000000000000003
RBP: 0000000000055594 R08: 0000000000000418 R09: 00000000004002c8
R10: 0000000020000380 R11: 0000000000000246 R12: 00000000004029e0
R13: 0000000000402a70 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor334:11033 blocked for more than 144 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor334 D28072 11033  11016 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
 hashlimit_mt_check+0xa4/0xd0 net/netfilter/xt_hashlimit.c:949
 xt_check_match+0x280/0x690 net/netfilter/x_tables.c:501
 check_match net/ipv4/netfilter/ip_tables.c:472 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:488 [inline]
 find_check_entry.isra.0+0x32f/0x920 net/ipv4/netfilter/ip_tables.c:538
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 udp_setsockopt+0x68/0xb0 net/ipv4/udp.c:2640
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441c69
Code: 64 0a 00 00 00 00 00 00 00 72 73 79 73 6c 6f 67 64 3a 20 76 65 72 73 69 6f 6e 20 25 73 2c 20 63 6f 6e 66 69 67 20 76 61 6c 69 <64> 61 74 69 6f 6e 20 72 75 6e 20 28 6c 65 76 65 6c 20 25 64 29 2c
RSP: 002b:00007fffb3323b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441c69
RDX: 0000000000000040 RSI: ffffff0f00000000 RDI: 0000000000000003
RBP: 00000000000555bf R08: 0000000000000418 R09: 00000000004002c8
R10: 0000000020000380 R11: 0000000000000246 R12: 00000000004029e0
R13: 0000000000402a70 R14: 0000000000000000 R15: 0000000000000000
INFO: task syz-executor334:11034 blocked for more than 145 seconds.
      Not tainted 5.6.0-rc1-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor334 D27968 11034  11012 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3386 [inline]
 __schedule+0x934/0x1f90 kernel/sched/core.c:4082
 schedule+0xdc/0x2b0 kernel/sched/core.c:4156
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:4215
 __mutex_lock_common kernel/locking/mutex.c:1033 [inline]
 __mutex_lock+0x7ab/0x13c0 kernel/locking/mutex.c:1103
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1118
 hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
 hashlimit_mt_check+0xa4/0xd0 net/netfilter/xt_hashlimit.c:949
 xt_check_match+0x280/0x690 net/netfilter/x_tables.c:501
 check_match net/ipv4/netfilter/ip_tables.c:472 [inline]
 find_check_match net/ipv4/netfilter/ip_tables.c:488 [inline]
 find_check_entry.isra.0+0x32f/0x920 net/ipv4/netfilter/ip_tables.c:538
 translate_table+0xcb4/0x17d0 net/ipv4/netfilter/ip_tables.c:717
 do_replace net/ipv4/netfilter/ip_tables.c:1136 [inline]
 do_ipt_set_ctl+0x2fe/0x4c2 net/ipv4/netfilter/ip_tables.c:1672
 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline]
 nf_setsockopt+0x77/0xd0 net/netfilter/nf_sockopt.c:115
 ip_setsockopt net/ipv4/ip_sockglue.c:1260 [inline]
 ip_setsockopt+0xdf/0x100 net/ipv4/ip_sockglue.c:1240
 udp_setsockopt+0x68/0xb0 net/ipv4/udp.c:2640
 sock_common_setsockopt+0x94/0xd0 net/core/sock.c:3149
 __sys_setsockopt+0x261/0x4c0 net/socket.c:2130
 __do_sys_setsockopt net/socket.c:2146 [inline]
 __se_sys_setsockopt net/socket.c:2143 [inline]
 __x64_sys_setsockopt+0xbe/0x150 net/socket.c:2143
 do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x441c69
Code: 64 0a 00 00 00 00 00 00 00 72 73 79 73 6c 6f 67 64 3a 20 76 65 72 73 69 6f 6e 20 25 73 2c 20 63 6f 6e 66 69 67 20 76 61 6c 69 <64> 61 74 69 6f 6e 20 72 75 6e 20 28 6c 65 76 65 6c 20 25 64 29 2c
RSP: 002b:00007fffb3323b38 EFLAGS: 00000246 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000441c69
RDX: 0000000000000040 RSI: ffffff0f00000000 RDI: 0000000000000003
RBP: 00000000000555c4 R08: 0000000000000418 R09: 00000000004002c8
R10: 0000000020000380 R11: 0000000000000246 R12: 00000000004029e0
R13: 0000000000402a70 R14: 0000000000000000 R15: 0000000000000000

Showing all locks held in the system:
1 lock held by khungtaskd/1106:
 #0: ffffffff89bac240 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x279 kernel/locking/lockdep.c:5333
2 locks held by kworker/1:48/2896:
1 lock held by rsyslogd/10858:
 #0: ffff8880a4c986a0 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:821
2 locks held by getty/10980:
 #0: ffff88808e4c0090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001aeb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/10981:
 #0: ffff8880a9019090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001b3b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/10982:
 #0: ffff8880a7554090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001b2b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/10983:
 #0: ffff8880a8ba2090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001b4b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/10984:
 #0: ffff88808f781090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001abb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/10985:
 #0: ffff888094d93090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001afb2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
2 locks held by getty/10986:
 #0: ffff888091606090 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:340
 #1: ffffc90001a8b2e0 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x220/0x1bf0 drivers/tty/n_tty.c:2156
1 lock held by syz-executor334/11027:
 #0: ffffffff8a7d2620 (hashlimit_mutex){+.+.}, at: htable_put+0x21/0x220 net/netfilter/xt_hashlimit.c:432
1 lock held by syz-executor334/11030:
 #0: ffffffff8a7d2620 (hashlimit_mutex){+.+.}, at: hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
1 lock held by syz-executor334/11031:
 #0: ffffffff8a7d2620 (hashlimit_mutex){+.+.}, at: hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
1 lock held by syz-executor334/11032:
 #0: ffffffff8a7d2620 (hashlimit_mutex){+.+.}, at: hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
1 lock held by syz-executor334/11033:
 #0: ffffffff8a7d2620 (hashlimit_mutex){+.+.}, at: hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889
1 lock held by syz-executor334/11034:
 #0: ffffffff8a7d2620 (hashlimit_mutex){+.+.}, at: hashlimit_mt_check_common.isra.0+0x341/0x1500 net/netfilter/xt_hashlimit.c:889

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

NMI backtrace for cpu 0
CPU: 0 PID: 1106 Comm: khungtaskd Not tainted 5.6.0-rc1-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+0x197/0x210 lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x23b/0x28b lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline]
 watchdog+0xb11/0x10c0 kernel/hung_task.c:289
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 2896 Comm: kworker/1:48 Not tainted 5.6.0-rc1-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: events_power_efficient htable_gc
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:163 [inline]
RIP: 0010:mark_lock+0xa9/0x1220 kernel/locking/lockdep.c:3642
Code: b8 00 00 00 00 00 fc ff df 48 c1 ea 03 0f b6 04 02 84 c0 74 08 3c 03 0f 8e 8d 0e 00 00 41 0f b7 5d 20 66 81 e3 ff 1f 0f b7 db <be> 08 00 00 00 48 89 d8 48 c1 f8 06 48 8d 3c c5 60 9b 51 8b e8 1e
RSP: 0018:ffffc900088dfb68 EFLAGS: 00000002
RAX: 0000000000000000 RBX: 00000000000005b6 RCX: 0000000000000006
RDX: 1ffff11013dd6974 RSI: ffff88809eeb4b80 RDI: ffff88809eeb42c0
RBP: ffffc900088dfbb8 R08: 1ffffffff16a3373 R09: fffffbfff16a3374
R10: fffffbfff16a3373 R11: ffffffff8b519b9f R12: 0000000000000006
R13: ffff88809eeb4b80 R14: dffffc0000000000 R15: ffff88809eeb4b58
FS:  0000000000000000(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000004c0308 CR3: 00000000a4735000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mark_held_locks+0xa4/0xf0 kernel/locking/lockdep.c:3359
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3388 [inline]
 lockdep_hardirqs_on+0x421/0x5e0 kernel/locking/lockdep.c:3433
 trace_hardirqs_on+0x67/0x240 kernel/trace/trace_preemptirq.c:31
 __local_bh_enable_ip+0x15a/0x270 kernel/softirq.c:194
 __raw_spin_unlock_bh include/linux/spinlock_api_smp.h:176 [inline]
 _raw_spin_unlock_bh+0x2c/0x30 kernel/locking/spinlock.c:207
 spin_unlock_bh include/linux/spinlock.h:383 [inline]
 htable_selective_cleanup+0x232/0x340 net/netfilter/xt_hashlimit.c:373
 htable_gc+0x21/0xb0 net/netfilter/xt_hashlimit.c:384
 process_one_work+0xa05/0x17a0 kernel/workqueue.c:2264
 worker_thread+0x98/0xe40 kernel/workqueue.c:2410
 kthread+0x361/0x430 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Crashes (29):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/02/12 22:57 upstream f2850dd5ee01 84f4fc8a .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/02/11 11:24 upstream 0a679e13ea30 084454ae .config console log report syz C ci-upstream-kasan-gce-root
2020/02/08 08:09 upstream 41dcd67e8868 06150bf1 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/02/04 10:50 upstream 322bf2d3446a 93e5e335 .config console log report syz C ci-upstream-kasan-gce
2020/02/01 19:21 upstream 26dca6dbd62d 0eb59c27 .config console log report syz C ci-upstream-kasan-gce-root
2020/01/28 00:24 upstream d5226fa6dbae 56cd6c9b .config console log report syz C ci-upstream-kasan-gce
2020/01/20 18:10 upstream def9d2780727 d2557fb5 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/01/12 10:11 upstream ac61145a725a 4c04afaa .config console log report syz C ci-upstream-kasan-gce-root
2019/12/27 00:53 upstream 46cf053efec6 be5c2c81 .config console log report syz C ci-upstream-kasan-gce
2019/12/25 06:01 upstream 46cf053efec6 be5c2c81 .config console log report syz C ci-upstream-kasan-gce-selinux-root
2020/02/09 15:28 net-next-old fdfa3a6778b1 6ece2ea5 .config console log report syz C ci-upstream-net-kasan-gce
2020/01/31 18:02 net-next-old 9f68e3655aae 5ed23f9a .config console log report syz C ci-upstream-net-kasan-gce
2020/01/12 08:48 net-next-old 5c9166f03825 4c04afaa .config console log report syz C ci-upstream-net-kasan-gce
2020/02/18 03:19 upstream 11a48a5a18c6 1ce142dc .config console log report ci-upstream-kasan-gce-root
2020/02/04 03:42 upstream 754beeec1d90 93e5e335 .config console log report ci-upstream-kasan-gce-root
2020/01/20 04:39 upstream 8f8972a3127f 0342f8c7 .config console log report ci-upstream-kasan-gce-root
2020/01/19 04:58 upstream 244dc2689085 bc8bc756 .config console log report ci-upstream-kasan-gce
2020/01/17 05:05 upstream f5ae2ea6347a 3de7aabb .config console log report ci-upstream-kasan-gce
2020/01/17 00:20 upstream f5ae2ea6347a 3de7aabb .config console log report ci-upstream-kasan-gce
2020/01/13 20:17 upstream b3a987b0264d 99565c1a .config console log report ci-upstream-kasan-gce-root
2020/01/12 16:17 upstream 6327edceb62b 31290a45 .config console log report ci-upstream-kasan-gce
2020/01/05 20:57 upstream 36487907f341 d646e21f .config console log report ci-upstream-kasan-gce-root
2020/01/09 17:05 upstream b07f636fca1c ddc3e859 .config console log report ci-upstream-kasan-gce-386
2020/01/18 05:02 net-old 5a9ef19454cd 3de7aabb .config console log report ci-upstream-net-this-kasan-gce
2020/01/09 03:58 net-old 2f806c2a16b3 ddc3e859 .config console log report ci-upstream-net-this-kasan-gce
2020/02/17 12:28 net-next-old ce7805513d90 2b411596 .config console log report ci-upstream-net-kasan-gce
2020/01/24 23:53 net-next-old 23f4eacdd24a 2e95ab33 .config console log report ci-upstream-net-kasan-gce
2020/01/23 17:03 net-next-old fd786fb1d2ca 3334d684 .config console log report ci-upstream-net-kasan-gce
2020/01/22 14:53 net-next-old 4f2c17e0f332 8eda0b95 .config console log report ci-upstream-net-kasan-gce
* Struck through repros no longer work on HEAD.