syzbot


possible deadlock in smc_shutdown (2)

Status: upstream: reported on 2025/01/26 13:59
Subsystems: net s390
[Documentation on labels]
Reported-by: syzbot+3667d719a932ebc28119@syzkaller.appspotmail.com
First crash: 7d18h, last: 1d10h
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [net?] [s390?] possible deadlock in smc_shutdown (2) 0 (1) 2025/01/26 13:59
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream possible deadlock in smc_shutdown s390 net 3 189d 207d 0/28 auto-obsoleted due to no activity on 2024/11/01 22:25

Sample crash report:
======================================================
WARNING: possible circular locking dependency detected
6.13.0-syzkaller-08291-g805ba04cb7cc #0 Not tainted
------------------------------------------------------
syz.8.21414/19194 is trying to acquire lock:
ffff88806a455e58 (sk_lock-AF_SMC){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1624 [inline]
ffff88806a455e58 (sk_lock-AF_SMC){+.+.}-{0:0}, at: smc_shutdown+0x65/0x7f0 net/smc/af_smc.c:2930

but task is already holding lock:
ffff888026b96270 (&nsock->tx_lock){+.+.}-{4:4}, at: sock_shutdown+0x16f/0x280 drivers/block/nbd.c:410

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #6 (&nsock->tx_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       sock_shutdown+0x16f/0x280 drivers/block/nbd.c:410
       nbd_clear_sock drivers/block/nbd.c:1415 [inline]
       nbd_clear_sock_ioctl drivers/block/nbd.c:1553 [inline]
       __nbd_ioctl drivers/block/nbd.c:1581 [inline]
       nbd_ioctl+0x49b/0xd60 drivers/block/nbd.c:1641
       compat_blkdev_ioctl+0x2f7/0x750 block/ioctl.c:749
       __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004
       do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
       __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
       do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

-> #5 (&nbd->config_lock){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       refcount_dec_and_mutex_lock+0x51/0xc0 lib/refcount.c:118
       nbd_config_put+0x31/0x750 drivers/block/nbd.c:1422
       nbd_release+0xb7/0x190 drivers/block/nbd.c:1734
       blkdev_put_whole+0xad/0xf0 block/bdev.c:679
       bdev_release+0x47e/0x6d0 block/bdev.c:1102
       blkdev_release+0x15/0x20 block/fops.c:660
       __fput+0x3ff/0xb70 fs/file_table.c:450
       __fput_sync+0xa1/0xc0 fs/file_table.c:536
       __do_sys_close fs/open.c:1579 [inline]
       __se_sys_close fs/open.c:1564 [inline]
       __x64_sys_close+0x86/0x100 fs/open.c:1564
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (&disk->open_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       bdev_open+0x41a/0xe20 block/bdev.c:903
       bdev_file_open_by_dev block/bdev.c:1017 [inline]
       bdev_file_open_by_dev+0x17d/0x210 block/bdev.c:992
       disk_scan_partitions+0x1ed/0x320 block/genhd.c:374
       add_disk_fwnode+0x1006/0x1320 block/genhd.c:526
       pmem_attach_disk+0x9a1/0x13e0 drivers/nvdimm/pmem.c:576
       nd_pmem_probe+0x1a9/0x1f0 drivers/nvdimm/pmem.c:649
       nvdimm_bus_probe+0x169/0x5d0 drivers/nvdimm/bus.c:94
       call_driver_probe drivers/base/dd.c:579 [inline]
       really_probe+0x23e/0xa90 drivers/base/dd.c:658
       __driver_probe_device+0x1de/0x440 drivers/base/dd.c:800
       driver_probe_device+0x4c/0x1b0 drivers/base/dd.c:830
       __driver_attach+0x283/0x580 drivers/base/dd.c:1216
       bus_for_each_dev+0x13c/0x1d0 drivers/base/bus.c:370
       bus_add_driver+0x2e9/0x690 drivers/base/bus.c:675
       driver_register+0x15c/0x4b0 drivers/base/driver.c:246
       __nd_driver_register+0x103/0x1a0 drivers/nvdimm/bus.c:622
       do_one_initcall+0x128/0x630 init/main.c:1257
       do_initcall_level init/main.c:1319 [inline]
       do_initcalls init/main.c:1335 [inline]
       do_basic_setup init/main.c:1354 [inline]
       kernel_init_freeable+0x58f/0x8b0 init/main.c:1568
       kernel_init+0x1c/0x2b0 init/main.c:1457
       ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:148
       ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

-> #3 (&nvdimm_namespace_key){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       device_lock include/linux/device.h:1014 [inline]
       uevent_show+0x188/0x3b0 drivers/base/core.c:2729
       dev_attr_show+0x53/0xe0 drivers/base/core.c:2423
       sysfs_kf_seq_show+0x223/0x3e0 fs/sysfs/file.c:59
       seq_read_iter+0x4f4/0x12b0 fs/seq_file.c:230
       kernfs_fop_read_iter+0x414/0x580 fs/kernfs/file.c:279
       new_sync_read fs/read_write.c:484 [inline]
       vfs_read+0x886/0xbf0 fs/read_write.c:565
       ksys_read+0x12b/0x250 fs/read_write.c:708
       do_syscall_x64 arch/x86/entry/common.c:52 [inline]
       do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (kn->active#5){++++}-{0:0}:
       kernfs_drain+0x48f/0x590 fs/kernfs/dir.c:500
       __kernfs_remove+0x281/0x670 fs/kernfs/dir.c:1486
       kernfs_remove_by_name_ns+0xb2/0x130 fs/kernfs/dir.c:1694
       sysfs_remove_file include/linux/sysfs.h:794 [inline]
       device_remove_file drivers/base/core.c:3047 [inline]
       device_remove_file drivers/base/core.c:3043 [inline]
       device_del+0x381/0x9f0 drivers/base/core.c:3852
       unregister_netdevice_many_notify+0x148d/0x21a0 net/core/dev.c:11845
       unregister_netdevice_many net/core/dev.c:11875 [inline]
       unregister_netdevice_queue+0x307/0x3f0 net/core/dev.c:11741
       unregister_netdevice include/linux/netdevice.h:3329 [inline]
       unregister_netdev+0x21/0x30 net/core/dev.c:11895
       mkiss_close+0x1e7/0x340 drivers/net/hamradio/mkiss.c:797
       tty_ldisc_close+0x111/0x1a0 drivers/tty/tty_ldisc.c:455
       tty_ldisc_kill+0x8e/0x150 drivers/tty/tty_ldisc.c:613
       tty_ldisc_release+0x17b/0x2a0 drivers/tty/tty_ldisc.c:781
       tty_release_struct+0x23/0xe0 drivers/tty/tty_io.c:1690
       tty_release+0xe25/0x1410 drivers/tty/tty_io.c:1861
       __fput+0x3ff/0xb70 fs/file_table.c:450
       task_work_run+0x14e/0x250 kernel/task_work.c:227
       resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
       exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
       exit_to_user_mode_prepare include/linux/entry-common.h:329 [inline]
       __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
       syscall_exit_to_user_mode+0x27b/0x2a0 kernel/entry/common.c:218
       __do_fast_syscall_32+0x80/0x120 arch/x86/entry/common.c:389
       do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

-> #1 (rtnl_mutex){+.+.}-{4:4}:
       __mutex_lock_common kernel/locking/mutex.c:585 [inline]
       __mutex_lock+0x19b/0xb10 kernel/locking/mutex.c:730
       smc_vlan_by_tcpsk+0x251/0x620 net/smc/smc_core.c:1908
       __smc_connect+0x466/0x4920 net/smc/af_smc.c:1520
       smc_connect+0x2fc/0x760 net/smc/af_smc.c:1696
       __sys_connect_file+0x13e/0x1a0 net/socket.c:2040
       __sys_connect+0x14f/0x170 net/socket.c:2059
       __do_sys_connect net/socket.c:2065 [inline]
       __se_sys_connect net/socket.c:2062 [inline]
       __ia32_sys_connect+0x71/0xb0 net/socket.c:2062
       do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
       __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
       do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

-> #0 (sk_lock-AF_SMC){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3163 [inline]
       check_prevs_add kernel/locking/lockdep.c:3282 [inline]
       validate_chain kernel/locking/lockdep.c:3906 [inline]
       __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
       lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
       lock_sock_nested+0x3a/0xf0 net/core/sock.c:3645
       lock_sock include/net/sock.h:1624 [inline]
       smc_shutdown+0x65/0x7f0 net/smc/af_smc.c:2930
       nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:318
       sock_shutdown+0x17c/0x280 drivers/block/nbd.c:411
       nbd_clear_sock drivers/block/nbd.c:1415 [inline]
       nbd_clear_sock_ioctl drivers/block/nbd.c:1553 [inline]
       __nbd_ioctl drivers/block/nbd.c:1581 [inline]
       nbd_ioctl+0x49b/0xd60 drivers/block/nbd.c:1641
       compat_blkdev_ioctl+0x2f7/0x750 block/ioctl.c:749
       __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004
       do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
       __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
       do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
       entry_SYSENTER_compat_after_hwframe+0x84/0x8e

other info that might help us debug this:

Chain exists of:
  sk_lock-AF_SMC --> &nbd->config_lock --> &nsock->tx_lock

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&nsock->tx_lock);
                               lock(&nbd->config_lock);
                               lock(&nsock->tx_lock);
  lock(sk_lock-AF_SMC);

 *** DEADLOCK ***

2 locks held by syz.8.21414/19194:
 #0: ffff88802012e998 (&nbd->config_lock){+.+.}-{4:4}, at: nbd_ioctl+0x151/0xd60 drivers/block/nbd.c:1634
 #1: ffff888026b96270 (&nsock->tx_lock){+.+.}-{4:4}, at: sock_shutdown+0x16f/0x280 drivers/block/nbd.c:410

stack backtrace:
CPU: 0 UID: 0 PID: 19194 Comm: syz.8.21414 Not tainted 6.13.0-syzkaller-08291-g805ba04cb7cc #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
 print_circular_bug+0x490/0x760 kernel/locking/lockdep.c:2076
 check_noncircular+0x31a/0x400 kernel/locking/lockdep.c:2208
 check_prev_add kernel/locking/lockdep.c:3163 [inline]
 check_prevs_add kernel/locking/lockdep.c:3282 [inline]
 validate_chain kernel/locking/lockdep.c:3906 [inline]
 __lock_acquire+0x249e/0x3c40 kernel/locking/lockdep.c:5228
 lock_acquire.part.0+0x11b/0x380 kernel/locking/lockdep.c:5851
 lock_sock_nested+0x3a/0xf0 net/core/sock.c:3645
 lock_sock include/net/sock.h:1624 [inline]
 smc_shutdown+0x65/0x7f0 net/smc/af_smc.c:2930
 nbd_mark_nsock_dead+0xae/0x5d0 drivers/block/nbd.c:318
 sock_shutdown+0x17c/0x280 drivers/block/nbd.c:411
 nbd_clear_sock drivers/block/nbd.c:1415 [inline]
 nbd_clear_sock_ioctl drivers/block/nbd.c:1553 [inline]
 __nbd_ioctl drivers/block/nbd.c:1581 [inline]
 nbd_ioctl+0x49b/0xd60 drivers/block/nbd.c:1641
 compat_blkdev_ioctl+0x2f7/0x750 block/ioctl.c:749
 __do_compat_sys_ioctl+0x1cb/0x2c0 fs/ioctl.c:1004
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0x73/0x120 arch/x86/entry/common.c:386
 do_fast_syscall_32+0x32/0x80 arch/x86/entry/common.c:411
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e
RIP: 0023:0xf7fb4579
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:00000000f50d655c EFLAGS: 00000296 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000000ab04
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>
block nbd8: shutting down sockets
----------------
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

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/28 21:45 upstream 805ba04cb7cc 865ef71e .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in smc_shutdown
2025/01/22 13:48 upstream c4b9570cfb63 25e17fd3 .config console log report info [disk image (non-bootable)] [vmlinux] [kernel image] ci-qemu-upstream-386 possible deadlock in smc_shutdown
* Struck through repros no longer work on HEAD.