sorry for not containing report plain text in last email. the report
is as follows:

INFO: task syz-executor.4:42949 blocked for more than 143 seconds.
      Not tainted 7.0.6 #1
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.4  state:D stack:26456 pid:42949 tgid:42937
ppid:9759   task_flags:0x400140 flags:0x00080002
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5298 [inline]
 __schedule+0x1006/0x5f00 kernel/sched/core.c:6911
 __schedule_loop kernel/sched/core.c:6993 [inline]
 schedule+0xe7/0x3a0 kernel/sched/core.c:7008
 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7065
 __mutex_lock_common kernel/locking/mutex.c:692 [inline]
 __mutex_lock+0xd9e/0x1df0 kernel/locking/mutex.c:776
 xt_find_table+0x59/0x1a0 net/netfilter/x_tables.c:1245
 ip6t_unregister_table_exit+0x22/0x50 net/ipv6/netfilter/ip6_tables.c:1808
 ops_exit_list net/core/net_namespace.c:199 [inline]
 ops_undo_list+0x2dd/0xa50 net/core/net_namespace.c:252
 setup_net+0x1f3/0x3a0 net/core/net_namespace.c:462
 copy_net_ns+0x351/0x7c0 net/core/net_namespace.c:579
 create_new_namespaces+0x3f6/0xac0 kernel/nsproxy.c:130
 copy_namespaces+0x45c/0x580 kernel/nsproxy.c:195
 copy_process+0x30cc/0x76d0 kernel/fork.c:2227
 kernel_clone+0xea/0x8f0 kernel/fork.c:2655
 __do_sys_clone+0xce/0x120 kernel/fork.c:2796
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x11b/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x471ecd
RSP: 002b:00007f51f163e008 EFLAGS: 00000202 ORIG_RAX: 0000000000000038
RAX: ffffffffffffffda RBX: 000000000059bf80 RCX: 0000000000471ecd
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040080020
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 000000000059bf8c
R13: 000000000000000b R14: 000000000059bf80 R15: 00007f51f161e000
 </TASK>

Showing all locks held in the system:
2 locks held by kthreadd/2:
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
1 lock held by khungtaskd/25:
 #0: ffffffff8e5e6ce0 (rcu_read_lock){....}-{1:3}, at:
rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
 #0: ffffffff8e5e6ce0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock
include/linux/rcupdate.h:850 [inline]
 #0: ffffffff8e5e6ce0 (rcu_read_lock){....}-{1:3}, at:
debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6775
4 locks held by kworker/u4:4/53:
 #0: ffff88801c73c948
((wq_completion)ext4-rsv-conversion){+.+.}-{0:0}, at:
process_one_work+0x139e/0x1c60 kernel/workqueue.c:3263
 #1: ffffc9000100fd08
((work_completion)(&ei->i_rsv_conversion_work)){+.+.}-{0:0}, at:
process_one_work+0x938/0x1c60 kernel/workqueue.c:3264
 #2: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
7 locks held by kworker/u4:5/74:
 #0: ffff88801c723148 ((wq_completion)writeback){+.+.}-{0:0}, at:
process_one_work+0x139e/0x1c60 kernel/workqueue.c:3263
 #1: ffffc9000125fd08
((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at:
process_one_work+0x938/0x1c60 kernel/workqueue.c:3264
 #2: ffff888025a820e0 (&type->s_umount_key#56){++++}-{4:4}, at:
super_trylock_shared+0x21/0x100 fs/super.c:565
 #3: ffff888025a80c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at:
do_writepages+0x242/0x5b0 mm/page-writeback.c:2575
 #4: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #5: ffff88802b266260 (&ei->i_data_sem){++++}-{4:4}, at:
ext4_map_blocks+0x54c/0xcc0 fs/ext4/inode.c:818
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
2 locks held by kswapd1/79:
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
balance_pgdat+0xc0b/0x1b60 mm/vmscan.c:7083
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
5 locks held by kworker/u4:6/340:
4 locks held by kworker/u4:7/3543:
 #0: ffff88801b894948 ((wq_completion)events_unbound#2){+.+.}-{0:0},
at: process_one_work+0x139e/0x1c60 kernel/workqueue.c:3263
 #1: ffffc9000b77fd08
((work_completion)(&sub_info->work)){+.+.}-{0:0}, at:
process_one_work+0x938/0x1c60 kernel/workqueue.c:3264
 #2: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #2: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #2: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #2: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
1 lock held by jbd2/sda-8/5138:
 #0: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #0: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #0: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #0: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
4 locks held by systemd-journal/5165:
 #0: ffff88804ebcbd08 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffff888025a82518 (sb_pagefaults){.+.+}-{0:0}, at:
do_page_mkwrite+0x17a/0x390 mm/memory.c:3602
 #2: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #3: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
2 locks held by systemd-udevd/5178:
2 locks held by cron/9006:
 #0: ffffffff8f04c678 (tomoyo_ss){.+.+}-{0:0}, at: srcu_lock_acquire
include/linux/srcu.h:187 [inline]
 #0: ffffffff8f04c678 (tomoyo_ss){.+.+}-{0:0}, at: srcu_read_lock
include/linux/srcu.h:294 [inline]
 #0: ffffffff8f04c678 (tomoyo_ss){.+.+}-{0:0}, at: tomoyo_read_lock
security/tomoyo/common.h:1112 [inline]
 #0: ffffffff8f04c678 (tomoyo_ss){.+.+}-{0:0}, at:
tomoyo_path_perm+0x223/0x420 security/tomoyo/file.c:826
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
1 lock held by in:imklog/9071:
5 locks held by rs:main Q:Reg/9072:
 #0: ffff888050036d38 (&f->f_pos_lock){+.+.}-{4:4}, at:
fdget_pos+0x2a0/0x370 fs/file.c:1261
 #1: ffff888025a82420 (sb_writers#4){.+.+}-{0:0}, at:
ksys_write+0x121/0x240 fs/read_write.c:740
 #2: ffff88802b2663d0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at:
inode_lock include/linux/fs.h:1028 [inline]
 #2: ffff88802b2663d0 (&sb->s_type->i_mutex_key#10){++++}-{4:4}, at:
ext4_buffered_write_iter+0xab/0x430 fs/ext4/file.c:295
 #3: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-fuzzer/9743:
 #0: ffff88804ea40bc8 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
5 locks held by syz-executor.2/9744:
 #0: ffff888025a412b8 (&f->f_pos_lock){+.+.}-{4:4}, at:
fdget_pos+0x2a0/0x370 fs/file.c:1261
 #1: ffff88804cd26d68 (&type->i_mutex_dir_key#3){++++}-{4:4}, at:
iterate_dir+0x197/0xb00 fs/readdir.c:101
 #2: ffff888025a82420 (sb_writers#4){.+.+}-{0:0}, at: file_accessed
include/linux/fs.h:2261 [inline]
 #2: ffff888025a82420 (sb_writers#4){.+.+}-{0:0}, at:
iterate_dir+0x869/0xb00 fs/readdir.c:111
 #3: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-executor.0/9745:
3 locks held by syz-executor.4/9759:
 #0: ffff8880469e2d08 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-executor.6/9760:
 #0: ffff8880501b4bc8 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
5 locks held by syz-executor.3/9761:
 #0: ffff888020c5ed38 (&f->f_pos_lock){+.+.}-{4:4}, at:
fdget_pos+0x2a0/0x370 fs/file.c:1261
 #1: ffff88804745e3d0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at:
iterate_dir+0x197/0xb00 fs/readdir.c:101
 #2: ffff888025a82420 (sb_writers#4){.+.+}-{0:0}, at: file_accessed
include/linux/fs.h:2261 [inline]
 #2: ffff888025a82420 (sb_writers#4){.+.+}-{0:0}, at:
iterate_dir+0x869/0xb00 fs/readdir.c:111
 #3: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-executor.1/9765:
 #0: ffff888022db2d88 (&xt[i].mutex){+.+.}-{4:4}, at:
xt_find_table_lock+0x5f/0x540 net/netfilter/x_tables.c:1266
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-executor.7/9772:
 #0: ffff88804d15cd08 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
5 locks held by syz-executor.5/9790:
 #0: ffffffff8e71f1d0 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm
kernel/fork.c:1531 [inline]
 #0: ffffffff8e71f1d0 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm
kernel/fork.c:1584 [inline]
 #0: ffffffff8e71f1d0 (dup_mmap_sem){.+.+}-{0:0}, at:
copy_process+0x6535/0x76d0 kernel/fork.c:2224
 #1: ffff888012e54cc0 (&mm->mmap_lock){++++}-{4:4}, at:
mmap_write_lock_killable include/linux/mmap_lock.h:554 [inline]
 #1: ffff888012e54cc0 (&mm->mmap_lock){++++}-{4:4}, at:
dup_mmap+0x124/0x2330 mm/mmap.c:1740
 #2: ffff88805c1cccc0 (&mm->mmap_lock/1){+.+.}-{4:4}, at:
mmap_write_lock_nested include/linux/mmap_lock.h:544 [inline]
 #2: ffff88805c1cccc0 (&mm->mmap_lock/1){+.+.}-{4:4}, at:
dup_mmap+0x1c6/0x2330 mm/mmap.c:1747
 #3: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #3: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #3: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #3: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #4: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
2 locks held by kworker/0:8/11473:
7 locks held by kworker/u4:8/12707:
 #0: ffff88801c723148 ((wq_completion)writeback){+.+.}-{0:0}, at:
process_one_work+0x139e/0x1c60 kernel/workqueue.c:3263
 #1: ffffc9000bfdfd08
((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at:
process_one_work+0x938/0x1c60 kernel/workqueue.c:3264
 #2: ffff888025a820e0 (&type->s_umount_key#56){++++}-{4:4}, at:
super_trylock_shared+0x21/0x100 fs/super.c:565
 #3: ffff888025a80c18 (&sbi->s_writepages_rwsem){++++}-{0:0}, at:
do_writepages+0x242/0x5b0 mm/page-writeback.c:2575
 #4: ffff888025a86950 (jbd2_handle){++++}-{0:0}, at:
start_this_handle+0xe33/0x12d0 fs/jbd2/transaction.c:444
 #5: ffff8880475115a0 (&ei->i_data_sem){++++}-{4:4}, at:
ext4_map_blocks+0x54c/0xcc0 fs/ext4/inode.c:818
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #6: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
2 locks held by kworker/u4:9/15616:
 #0: ffff88801b894948 ((wq_completion)events_unbound#2){+.+.}-{0:0},
at: process_one_work+0x139e/0x1c60 kernel/workqueue.c:3263
 #1: ffffc9001a077d08
((work_completion)(&sub_info->work)){+.+.}-{0:0}, at:
process_one_work+0x938/0x1c60 kernel/workqueue.c:3264
6 locks held by kworker/0:6/31120:
2 locks held by syz-executor.0/42951:
 #0: ffffffff903e44b0 (pernet_ops_rwsem){++++}-{4:4}, at:
copy_net_ns+0x335/0x7c0 net/core/net_namespace.c:575
 #1: ffff888022db2d88 (&xt[i].mutex){+.+.}-{4:4}, at:
xt_find_table+0x59/0x1a0 net/netfilter/x_tables.c:1245
2 locks held by syz-executor.4/42949:
 #0: ffffffff903e44b0 (pernet_ops_rwsem){++++}-{4:4}, at:
copy_net_ns+0x335/0x7c0 net/core/net_namespace.c:575
 #1: ffff888022db2d88 (&xt[i].mutex){+.+.}-{4:4}, at:
xt_find_table+0x59/0x1a0 net/netfilter/x_tables.c:1245
3 locks held by modprobe/43044:
 #0: ffff8880501b41c8 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-executor.7/43046:
 #0: ffff888049241808 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
2 locks held by syz-executor.7/43047:
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #0: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #1: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533
3 locks held by syz-executor.6/43050:
 #0: ffff88804d7b8a88 (vm_lock){++++}-{0:0}, at:
lock_vma_under_rcu+0x118/0x5a0 mm/mmap_lock.c:310
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at: __perform_reclaim
mm/page_alloc.c:4429 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_direct_reclaim mm/page_alloc.c:4454 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_pages_slowpath mm/page_alloc.c:4854 [inline]
 #1: ffffffff8e7a78a0 (fs_reclaim){+.+.}-{0:0}, at:
__alloc_frozen_pages_noprof+0x860/0x27e0 mm/page_alloc.c:5271
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: acomp_ctx_get_cpu_lock mm/zswap.c:834
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_compress mm/zswap.c:865 [inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store_page mm/zswap.c:1422
[inline]
 #2: ffffe8ffffc27170 (&per_cpu_ptr(pool->acomp_ctx,
cpu)->mutex){+.+.}-{4:4}, at: zswap_store+0x875/0x2710 mm/zswap.c:1533

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

NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 25 Comm: khungtaskd Not tainted 7.0.6 #1 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x116/0x1b0 lib/dump_stack.c:120
 nmi_cpu_backtrace+0x2a0/0x350 lib/nmi_backtrace.c:113
 nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
 __sys_info lib/sys_info.c:157 [inline]
 sys_info+0x133/0x180 lib/sys_info.c:165
 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
 watchdog+0xeac/0x11e0 kernel/hung_task.c:515
 kthread+0x38d/0x4a0 kernel/kthread.c:436
 ret_from_fork+0x942/0xe50 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Pablo Neira Ayuso [off-list ref] 于2026年6月10日周三 04:44写道：

Hi,

On Tue, Jun 09, 2026 at 07:55:34PM +0800, Longxing Li wrote:

quoted

Dear Linux kernel developers and maintainers,

We would like to report a new kernel bug found by our tool. INFO: task
hung in xt_find_table. Details are as follows.

Kernel commit: v7.0.6
Kernel config: see attachment
report: see attachment

We are currently analyzing the root cause and  working on a
reproducible PoC. We will provide further updates in this thread as
soon as we have more information.

No links to external web, please, inline in plain text to this email
the description of what you found.

Thanks.