Subject: [syzbot] INFO: task hung in cangw_pernet_exit (3)

From: syzbot <[email-masked]>
Date: Sun, 12 Sep 2021 12:22:24 -0700

Hello,

syzbot found the following issue on:

HEAD commit:    999569d59a0a Add linux-next specific files for 20210908
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=17c68851300000
kernel config:  https://syzkaller.appspot.com/x/.config?x=7ad035460e67a9c3
dashboard link: https://syzkaller.appspot.com/bug?extid=c46e2a20b7d78a4e5c6a
compiler:       gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.1
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=1653aab5300000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: [email-masked]

INFO: task syz-executor.1:8622 can't die for more than 143 seconds.
task:syz-executor.1  state:D stack:25536 pid: 8622 ppid:  6556 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4955 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6302
 schedule+0xd3/0x270 kernel/sched/core.c:6381
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6440
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1244
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:168
 setup_net+0x639/0xa30 net/core/net_namespace.c:349
 copy_net_ns+0x319/0x760 net/core/net_namespace.c:470
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3127
 __do_sys_unshare kernel/fork.c:3201 [inline]
 __se_sys_unshare kernel/fork.c:3199 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3199
 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+0x44/0xae
RIP: 0033:0x4665f9
RSP: 002b:00007fdd1cebc188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe22423e0f R14: 00007fdd1cebc300 R15: 0000000000022000
INFO: task syz-executor.2:8795 can't die for more than 146 seconds.
task:syz-executor.2  state:D stack:25208 pid: 8795 ppid:  6559 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4955 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6302
 schedule+0xd3/0x270 kernel/sched/core.c:6381
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6440
 __mutex_lock_common kernel/locking/mutex.c:669 [inline]
 __mutex_lock+0xa34/0x12f0 kernel/locking/mutex.c:729
 cangw_pernet_exit+0xe/0x20 net/can/gw.c:1244
 ops_exit_list+0xb0/0x160 net/core/net_namespace.c:168
 setup_net+0x639/0xa30 net/core/net_namespace.c:349
 copy_net_ns+0x319/0x760 net/core/net_namespace.c:470
 create_new_namespaces+0x3f6/0xb20 kernel/nsproxy.c:110
 unshare_nsproxy_namespaces+0xc1/0x1f0 kernel/nsproxy.c:226
 ksys_unshare+0x445/0x920 kernel/fork.c:3127
 __do_sys_unshare kernel/fork.c:3201 [inline]
 __se_sys_unshare kernel/fork.c:3199 [inline]
 __x64_sys_unshare+0x2d/0x40 kernel/fork.c:3199
 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+0x44/0xae
RIP: 0033:0x4665f9
RSP: 002b:00007f42a74e7188 EFLAGS: 00000246 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665f9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000
RBP: 00000000004bfcc4 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffe2b27af6f R14: 00007f42a74e7300 R15: 0000000000022000
INFO: task syz-executor.5:8889 can't die for more than 148 seconds.
task:syz-executor.5  state:R  running task     stack:25288 pid: 8889 ppid:  6557 flags:0x00004006
Call Trace:
INFO: task syz-executor.3:8988 can't die for more than 151 seconds.
task:syz-executor.3  state:R  running task     stack:25760 pid: 8988 ppid:  6554 flags:0x00004006
Call Trace:
 context_switch kernel/sched/core.c:4955 [inline]
 __schedule+0x940/0x26f0 kernel/sched/core.c:6302
 preempt_schedule_irq+0x4e/0x90 kernel/sched/core.c:6702
 irqentry_exit+0x31/0x80 kernel/entry/common.c:427
 asm_sysvec_apic_timer_interrupt+0x12/0x20 arch/x86/include/asm/idtentry.h:638
RIP: 0000:0x0
Code: Unable to access opcode bytes at RIP 0xffffffffffffffd6.
RSP: d5a7ae8:0000000000000000 EFLAGS: 00000046 ORIG_RAX: 0000000000000001
RAX: dffffc0000000000 RBX: 1ffff92001ab4f58 RCX: f4d672f5b9097ca7
RDX: ffffffff8d6e3a57 RSI: 0000000000000000 RDI: 0000000000000001
RBP: ffffed1003aa4390 R08: 0000000000000001 R09: ffffffff8fcfa92f
R10: dffffc0000000000 R11: 0000000000000002 R12: ffff88801d521c80
R13: 64a21813a00bdf00 R14: ffffed1017386541 R15: 0000000000000000

---
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