====================================================== WARNING: possible circular locking dependency detected syzkaller #0 Not tainted ------------------------------------------------------ syz.6.652/8163 is trying to acquire lock: ffff88806e69a358 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: touch_work_lockdep_map kernel/workqueue.c:3955 [inline] ffff88806e69a358 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: start_flush_work kernel/workqueue.c:4209 [inline] ffff88806e69a358 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}, at: __flush_work+0x4d0/0xcc0 kernel/workqueue.c:4241 but task is already holding lock: ffff88806e698ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x3a5/0x620 net/smc/af_smc.c:339 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (sk_lock-AF_SMC/1){+.+.}-{0:0}: lock_sock_nested+0x41/0xf0 net/core/sock.c:3780 smc_listen_out+0x202/0x4a0 net/smc/af_smc.c:1924 smc_listen_out_connected net/smc/af_smc.c:1944 [inline] smc_listen_work+0x5a3/0x50b0 net/smc/af_smc.c:2466 process_one_work+0x9ba/0x1b20 kernel/workqueue.c:3257 process_scheduled_works kernel/workqueue.c:3340 [inline] worker_thread+0x6c8/0xf10 kernel/workqueue.c:3421 kthread+0x3c5/0x780 kernel/kthread.c:463 ret_from_fork+0x983/0xb10 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 -> #0 ((work_completion)(&new_smc->smc_listen_work)){+.+.}-{0:0}: check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1669/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 touch_work_lockdep_map kernel/workqueue.c:3955 [inline] start_flush_work kernel/workqueue.c:4209 [inline] __flush_work+0x4e4/0xcc0 kernel/workqueue.c:4241 __cancel_work_sync kernel/workqueue.c:4397 [inline] cancel_work_sync+0xd1/0xf0 kernel/workqueue.c:4434 smc_clcsock_release+0x5f/0xe0 net/smc/smc_close.c:29 __smc_release+0x5c2/0x880 net/smc/af_smc.c:304 smc_close_non_accepted+0xda/0x200 net/smc/af_smc.c:1855 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline] smc_close_active+0xc3c/0x1070 net/smc/smc_close.c:225 __smc_release+0x634/0x880 net/smc/af_smc.c:280 smc_release+0x1fc/0x620 net/smc/af_smc.c:347 __sock_release+0xb3/0x270 net/socket.c:662 sock_close+0x1c/0x30 net/socket.c:1455 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xfb/0x540 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] __do_fast_syscall_32+0x4a4/0x680 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sk_lock-AF_SMC/1); lock((work_completion)(&new_smc->smc_listen_work)); lock(sk_lock-AF_SMC/1); lock((work_completion)(&new_smc->smc_listen_work)); *** DEADLOCK *** 3 locks held by syz.6.652/8163: #0: ffff8880123ed288 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #0: ffff8880123ed288 (&sb->s_type->i_mutex_key#13){+.+.}-{4:4}, at: __sock_release+0x86/0x270 net/socket.c:661 #1: ffff88806e698ee0 (sk_lock-AF_SMC/1){+.+.}-{0:0}, at: smc_release+0x3a5/0x620 net/smc/af_smc.c:339 #2: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #2: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #2: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: start_flush_work kernel/workqueue.c:4183 [inline] #2: ffffffff8e3c94a0 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xfb/0xcc0 kernel/workqueue.c:4241 stack backtrace: CPU: 0 UID: 0 PID: 8163 Comm: syz.6.652 Not tainted syzkaller #0 PREEMPT(full) Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120 print_circular_bug+0x275/0x340 kernel/locking/lockdep.c:2043 check_noncircular+0x146/0x160 kernel/locking/lockdep.c:2175 check_prev_add kernel/locking/lockdep.c:3165 [inline] check_prevs_add kernel/locking/lockdep.c:3284 [inline] validate_chain kernel/locking/lockdep.c:3908 [inline] __lock_acquire+0x1669/0x2890 kernel/locking/lockdep.c:5237 lock_acquire kernel/locking/lockdep.c:5868 [inline] lock_acquire+0x179/0x330 kernel/locking/lockdep.c:5825 touch_work_lockdep_map kernel/workqueue.c:3955 [inline] start_flush_work kernel/workqueue.c:4209 [inline] __flush_work+0x4e4/0xcc0 kernel/workqueue.c:4241 __cancel_work_sync kernel/workqueue.c:4397 [inline] cancel_work_sync+0xd1/0xf0 kernel/workqueue.c:4434 smc_clcsock_release+0x5f/0xe0 net/smc/smc_close.c:29 __smc_release+0x5c2/0x880 net/smc/af_smc.c:304 smc_close_non_accepted+0xda/0x200 net/smc/af_smc.c:1855 smc_close_cleanup_listen net/smc/smc_close.c:45 [inline] smc_close_active+0xc3c/0x1070 net/smc/smc_close.c:225 __smc_release+0x634/0x880 net/smc/af_smc.c:280 smc_release+0x1fc/0x620 net/smc/af_smc.c:347 __sock_release+0xb3/0x270 net/socket.c:662 sock_close+0x1c/0x30 net/socket.c:1455 __fput+0x402/0xb70 fs/file_table.c:468 task_work_run+0x150/0x240 kernel/task_work.c:233 resume_user_mode_work include/linux/resume_user_mode.h:50 [inline] __exit_to_user_mode_loop kernel/entry/common.c:44 [inline] exit_to_user_mode_loop+0xfb/0x540 kernel/entry/common.c:75 __exit_to_user_mode_prepare include/linux/irq-entry-common.h:226 [inline] syscall_exit_to_user_mode_prepare include/linux/irq-entry-common.h:256 [inline] syscall_exit_to_user_mode_work include/linux/entry-common.h:159 [inline] syscall_exit_to_user_mode include/linux/entry-common.h:194 [inline] __do_fast_syscall_32+0x4a4/0x680 arch/x86/entry/syscall_32.c:310 do_fast_syscall_32+0x32/0x80 arch/x86/entry/syscall_32.c:332 entry_SYSENTER_compat_after_hwframe+0x84/0x8e RIP: 0023:0xf702d579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f541d55c EFLAGS: 00000296 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 0000000000000003 RCX: 00000000ffffffff RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ---------------- Code disassembly (best guess), 2 bytes skipped: 0: 10 06 adc %al,(%rsi) 2: 03 74 b4 01 add 0x1(%rsp,%rsi,4),%esi 6: 10 07 adc %al,(%rdi) 8: 03 74 b0 01 add 0x1(%rax,%rsi,4),%esi c: 10 08 adc %cl,(%rax) e: 03 74 d8 01 add 0x1(%rax,%rbx,8),%esi 1e: 00 51 52 add %dl,0x52(%rcx) 21: 55 push %rbp 22: 89 e5 mov %esp,%ebp 24: 0f 34 sysenter 26: cd 80 int $0x80 * 28: 5d pop %rbp <-- trapping instruction 29: 5a pop %rdx 2a: 59 pop %rcx 2b: c3 ret 2c: 90 nop 2d: 90 nop 2e: 90 nop 2f: 90 nop 30: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi 37: 8d b4 26 00 00 00 00 lea 0x0(%rsi,%riz,1),%esi