From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ot1-f71.google.com (mail-ot1-f71.google.com [209.85.210.71]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D3AC94DDCD7 for ; Thu, 8 Jan 2026 13:14:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.210.71 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767878049; cv=none; b=TYHmeBH8+QAuTUvsNZws3zoWHwFEw4hvFaU+yFZUeWRUpDVaGtz8zFj8IB3kJ8YoSgjKcDN+hssf9HJQSCfsxOb8w+/bg1v+HUhLPvayBco744OccOeDasbD/1B8s3rMGcOs5b6hpPxfFJXQVkrUyN+JOsd+nyEOEL+GzRq6K5M= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767878049; c=relaxed/simple; bh=6CL1nX2SK0LLib5Sp5qICbQfj3R0NIHb/FDeZNf083k=; h=MIME-Version:Date:In-Reply-To:Message-ID:Subject:From:To: Content-Type; b=HLq7FseVojgj3JsICuAT+NVLngLBxK8vMH+VWLIPXtsDDEJI5b2iam2hUN0J6LRtezHZcjHcfo0apW2AStlebCdlR+v4oP81PE1vAgv44lyTdT5M0YQ1MeD+xe/gdem2LZZZ2HWMYNA5vDrvLzUdKFP4UakrBYd5hOXGzft27Ds= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com; arc=none smtp.client-ip=209.85.210.71 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=syzkaller.appspotmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=M3KW2WVRGUFZ5GODRSRYTGD7.apphosting.bounces.google.com Received: by mail-ot1-f71.google.com with SMTP id 46e09a7af769-7c701a712ecso5548323a34.0 for ; Thu, 08 Jan 2026 05:14:04 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1767878043; x=1768482843; h=to:from:subject:message-id:in-reply-to:date:mime-version :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8d5OaK/25zmghw8YzpkBaXY6lm7HLQo+nwMRe2apEqM=; b=DkVlIX/6puo6FrLTvXxeHdf2e0Wd/gaiXIFrarp2eBNzf1wbm9mWCLWyZ0xbqORqg1 VaQowguNguWtboOYJW/6ITHSj4mqvGDxZlxRNkvvgCHpqMlVU89qgILtNSbssyOlisYk tN1wDUA9HJLrjjhEz8+9JIgvfkVUkng/zMdDkIaeFfRrDmk5lOqWYKvgHN+ob1wPmQD4 vvJc/JC3eYQ0gPfp8zMGK1EC4hoKyIT4YHObsrZQhBmOF7F9e6y37GBRICYzyfN0+Ghr qgixLTg6/3Wbk/sn3gMf7usNL5d8/QwV2Dzuuq1Gp06L7Cvfknk6QQAhCNMHhkmtNXTZ 5FJg== X-Gm-Message-State: AOJu0YyEBOKZlE876w4RBsUukR5LTvqK9ErTPPAiRNDOS6RXuFnuZksz dK9dz6zJk1Zck3WXcb1vRYPC1KitvDqAA0Fgwn06WjUGbfy39ZkYWkgoDmM7GxHbpnoOm8pnarb rNQNz9AX0KkNoJ7B/KfqqzncJ8umSschyM35Og2RJUjXT5Md6QrZjnPcRaik= X-Google-Smtp-Source: AGHT+IFESgHVMd+zSHpJIZNXC8v/XGrlD9dNtkEyO9UtBuOLW7WRu/FsBNsaUSGcDUrj8XnN6KbnH4fiuuBFiHjYHPt9YH2O9nc+ Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6820:2e8d:b0:659:a130:dfdf with SMTP id 006d021491bc7-65f481b9b2fmr3896026eaf.8.1767878043741; Thu, 08 Jan 2026 05:14:03 -0800 (PST) Date: Thu, 08 Jan 2026 05:14:03 -0800 In-Reply-To: X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <695fad9b.050a0220.1c677c.039e.GAE@google.com> Subject: Re: [syzbot] [mm?] INFO: task hung in __rmap_walk_file From: syzbot To: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com, wangjinchao600@gmail.com Content-Type: text/plain; charset="UTF-8" Hello, syzbot has tested the proposed patch but the reproducer is still triggering an issue: INFO: task hung in __rmap_walk_file INFO: task syz.1.55:6564 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.55 state:D stack:25592 pid:6564 tgid:6562 ppid:6268 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_read_slowpath+0x5fd/0x8f0 kernel/locking/rwsem.c:1086 __down_read_common kernel/locking/rwsem.c:1261 [inline] __down_read kernel/locking/rwsem.c:1274 [inline] down_read+0x99/0x2e0 kernel/locking/rwsem.c:1539 i_mmap_lock_read include/linux/fs.h:532 [inline] __rmap_walk_file+0x227/0x620 mm/rmap.c:2914 remove_migration_ptes mm/migrate.c:472 [inline] unmap_and_move_huge_page mm/migrate.c:1528 [inline] migrate_hugetlbs mm/migrate.c:1649 [inline] migrate_pages+0xc88/0x28e0 mm/migrate.c:2088 do_mbind mm/mempolicy.c:1609 [inline] kernel_mbind mm/mempolicy.c:1752 [inline] __do_sys_mbind mm/mempolicy.c:1826 [inline] __se_sys_mbind+0xa47/0xc40 mm/mempolicy.c:1822 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe1ae78efc9 RSP: 002b:00007fe1af5f4038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed RAX: ffffffffffffffda RBX: 00007fe1ae9e5fa0 RCX: 00007fe1ae78efc9 RDX: 0000000000000000 RSI: 0000000000800000 RDI: 0000200000001000 RBP: 00007fe1ae811f91 R08: 0000000000000000 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe1ae9e6038 R14: 00007fe1ae9e5fa0 R15: 00007ffd318d3218 INFO: task syz.1.55:6569 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.55 state:D stack:26712 pid:6569 tgid:6562 ppid:6268 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 io_schedule+0x80/0xd0 kernel/sched/core.c:7789 folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1323 __folio_lock mm/filemap.c:1699 [inline] folio_lock include/linux/pagemap.h:1159 [inline] __filemap_get_folio_mpol+0x13e/0xb00 mm/filemap.c:1954 __filemap_get_folio include/linux/pagemap.h:763 [inline] filemap_lock_folio include/linux/pagemap.h:825 [inline] filemap_lock_hugetlb_folio include/linux/hugetlb.h:817 [inline] hugetlbfs_zero_partial_page+0xb1/0x620 fs/hugetlbfs/inode.c:664 hugetlbfs_punch_hole fs/hugetlbfs/inode.c:718 [inline] hugetlbfs_fallocate+0xb94/0x10e0 fs/hugetlbfs/inode.c:751 vfs_fallocate+0x669/0x7e0 fs/open.c:339 madvise_remove mm/madvise.c:1046 [inline] madvise_vma_behavior+0x28bd/0x4170 mm/madvise.c:1360 madvise_walk_vmas+0x575/0xaf0 mm/madvise.c:1721 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1937 do_madvise+0x1bc/0x270 mm/madvise.c:2030 __do_sys_madvise mm/madvise.c:2039 [inline] __se_sys_madvise mm/madvise.c:2037 [inline] __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:2037 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe1ae78efc9 RSP: 002b:00007fe1af5a0038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007fe1ae9e6090 RCX: 00007fe1ae78efc9 RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000 RBP: 00007fe1ae811f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe1ae9e6128 R14: 00007fe1ae9e6090 R15: 00007ffd318d3218 INFO: task syz.3.236:7005 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.236 state:D stack:25240 pid:7005 tgid:7004 ppid:6269 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7017 rwsem_down_read_slowpath+0x5fd/0x8f0 kernel/locking/rwsem.c:1086 __down_read_common kernel/locking/rwsem.c:1261 [inline] __down_read kernel/locking/rwsem.c:1274 [inline] down_read+0x99/0x2e0 kernel/locking/rwsem.c:1539 i_mmap_lock_read include/linux/fs.h:532 [inline] __rmap_walk_file+0x227/0x620 mm/rmap.c:2914 remove_migration_ptes mm/migrate.c:472 [inline] unmap_and_move_huge_page mm/migrate.c:1528 [inline] migrate_hugetlbs mm/migrate.c:1649 [inline] migrate_pages+0xc88/0x28e0 mm/migrate.c:2088 do_mbind mm/mempolicy.c:1609 [inline] kernel_mbind mm/mempolicy.c:1752 [inline] __do_sys_mbind mm/mempolicy.c:1826 [inline] __se_sys_mbind+0xa47/0xc40 mm/mempolicy.c:1822 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6f9cb8efc9 RSP: 002b:00007f6f9da0d038 EFLAGS: 00000246 ORIG_RAX: 00000000000000ed RAX: ffffffffffffffda RBX: 00007f6f9cde5fa0 RCX: 00007f6f9cb8efc9 RDX: 0000000000000000 RSI: 0000000000800000 RDI: 0000200000001000 RBP: 00007f6f9cc11f91 R08: 0000000000000000 R09: 0000000000000002 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6f9cde6038 R14: 00007f6f9cde5fa0 R15: 00007ffed1ac48e8 INFO: task syz.3.236:7013 blocked for more than 144 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.236 state:D stack:26704 pid:7013 tgid:7004 ppid:6269 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x149b/0x4fd0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] schedule+0x165/0x360 kernel/sched/core.c:6960 io_schedule+0x80/0xd0 kernel/sched/core.c:7789 folio_wait_bit_common+0x6b0/0xb80 mm/filemap.c:1323 __folio_lock mm/filemap.c:1699 [inline] folio_lock include/linux/pagemap.h:1159 [inline] __filemap_get_folio_mpol+0x13e/0xb00 mm/filemap.c:1954 __filemap_get_folio include/linux/pagemap.h:763 [inline] filemap_lock_folio include/linux/pagemap.h:825 [inline] filemap_lock_hugetlb_folio include/linux/hugetlb.h:817 [inline] hugetlbfs_zero_partial_page+0xb1/0x620 fs/hugetlbfs/inode.c:664 hugetlbfs_punch_hole fs/hugetlbfs/inode.c:718 [inline] hugetlbfs_fallocate+0xb94/0x10e0 fs/hugetlbfs/inode.c:751 vfs_fallocate+0x669/0x7e0 fs/open.c:339 madvise_remove mm/madvise.c:1046 [inline] madvise_vma_behavior+0x28bd/0x4170 mm/madvise.c:1360 madvise_walk_vmas+0x575/0xaf0 mm/madvise.c:1721 madvise_do_behavior+0x38e/0x550 mm/madvise.c:1937 do_madvise+0x1bc/0x270 mm/madvise.c:2030 __do_sys_madvise mm/madvise.c:2039 [inline] __se_sys_madvise mm/madvise.c:2037 [inline] __x64_sys_madvise+0xa7/0xc0 mm/madvise.c:2037 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f6f9cb8efc9 RSP: 002b:00007f6f9d9b9038 EFLAGS: 00000246 ORIG_RAX: 000000000000001c RAX: ffffffffffffffda RBX: 00007f6f9cde6090 RCX: 00007f6f9cb8efc9 RDX: 0000000000000009 RSI: 0000000000600002 RDI: 0000200000000000 RBP: 00007f6f9cc11f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f6f9cde6128 R14: 00007f6f9cde6090 R15: 00007ffed1ac48e8 Showing all locks held in the system: 1 lock held by rcu_exp_gp_kthr/18: 1 lock held by khungtaskd/31: #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8df41aa0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 7 locks held by kworker/u8:2/36: 3 locks held by kworker/u8:5/81: #0: ffff88813ff29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88813ff29948 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc900023bfbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc900023bfbc0 ((linkwatch_work).work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8f311e08 (rtnl_mutex){+.+.}-{4:4}, at: linkwatch_event+0xe/0x60 net/core/link_watch.c:303 5 locks held by kworker/u8:7/1000: #0: ffff88801aa9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88801aa9f148 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90003ee7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90003ee7bc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8f304d50 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7a0 net/core/net_namespace.c:670 #3: ffffffff8f311e08 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch+0xdc/0x9e0 net/core/dev.c:13024 #4: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline] #4: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2b1/0x6e0 kernel/rcu/tree_exp.h:956 2 locks held by dhcpcd/5498: #0: ffffffff8f379a70 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218 #1: ffffffff8f311e08 (rtnl_mutex){+.+.}-{4:4}, at: nl80211_pre_doit+0x5f/0x930 net/wireless/nl80211.c:17932 2 locks held by getty/5593: #0: ffff88814d60c0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x449/0x1460 drivers/tty/n_tty.c:2211 1 lock held by syz.1.55/6564: #0: ffff88801f6d2718 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: i_mmap_lock_read include/linux/fs.h:532 [inline] #0: ffff88801f6d2718 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: __rmap_walk_file+0x227/0x620 mm/rmap.c:2914 3 locks held by syz.1.55/6569: #0: ffff8880212ce420 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #0: ffff8880212ce420 (sb_writers#12){.+.+}-{0:0}, at: vfs_fallocate+0x5f0/0x7e0 fs/open.c:338 #1: ffff88801f6d2448 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88801f6d2448 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: hugetlbfs_punch_hole fs/hugetlbfs/inode.c:693 [inline] #1: ffff88801f6d2448 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: hugetlbfs_fallocate+0x3cc/0x10e0 fs/hugetlbfs/inode.c:751 #2: ffff88801f6d2718 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: i_mmap_lock_write include/linux/fs.h:512 [inline] #2: ffff88801f6d2718 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: hugetlbfs_punch_hole fs/hugetlbfs/inode.c:701 [inline] #2: ffff88801f6d2718 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: hugetlbfs_fallocate+0x4b5/0x10e0 fs/hugetlbfs/inode.c:751 1 lock held by syz.3.236/7005: #0: ffff88803441fb18 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: i_mmap_lock_read include/linux/fs.h:532 [inline] #0: ffff88803441fb18 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: __rmap_walk_file+0x227/0x620 mm/rmap.c:2914 3 locks held by syz.3.236/7013: #0: ffff8880212ce420 (sb_writers#12){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #0: ffff8880212ce420 (sb_writers#12){.+.+}-{0:0}, at: vfs_fallocate+0x5f0/0x7e0 fs/open.c:338 #1: ffff88803441f848 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88803441f848 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: hugetlbfs_punch_hole fs/hugetlbfs/inode.c:693 [inline] #1: ffff88803441f848 (&sb->s_type->i_mutex_key#24){+.+.}-{4:4}, at: hugetlbfs_fallocate+0x3cc/0x10e0 fs/hugetlbfs/inode.c:751 #2: ffff88803441fb18 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: i_mmap_lock_write include/linux/fs.h:512 [inline] #2: ffff88803441fb18 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: hugetlbfs_punch_hole fs/hugetlbfs/inode.c:701 [inline] #2: ffff88803441fb18 (&hugetlbfs_i_mmap_rwsem_key){++++}-{4:4}, at: hugetlbfs_fallocate+0x4b5/0x10e0 fs/hugetlbfs/inode.c:751 2 locks held by syz-executor/24198: #0: ffffffff8ea958a8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8ea958a8 (&ops->srcu#2){.+.+}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8ea958a8 (&ops->srcu#2){.+.+}-{0:0}, at: rtnl_link_ops_get+0x23/0x250 net/core/rtnetlink.c:570 #1: ffffffff8f311e08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #1: ffffffff8f311e08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #1: ffffffff8f311e08 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8ec/0x1c90 net/core/rtnetlink.c:4071 1 lock held by syz.5.8656/24840: #0: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline] #0: ffffffff8df475f8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x36e/0x6e0 kernel/rcu/tree_exp.h:956 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 0 Comm: swapper/1 Not tainted syzkaller #0 PREEMPT(full) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:pv_native_safe_halt+0x13/0x20 arch/x86/kernel/paravirt.c:82 Code: cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 b1 0e 00 f3 0f 1e fa fb f4 08 e3 02 00 cc cc cc cc cc cc cc cc 90 90 90 90 90 90 90 90 90 RSP: 0018:ffffc90000197e20 EFLAGS: 000002c6 RAX: 000000000008dcb5 RBX: ffffffff819713ee RCX: 0000000080000001 RDX: 0000000000000001 RSI: ffffffff8d792135 RDI: ffffffff8bc08360 RBP: ffffc90000197f10 R08: ffff8880b87336db R09: 1ffff110170e66db R10: dffffc0000000000 R11: ffffed10170e66dc R12: ffffffff8f822370 R13: 1ffff11003950b70 R14: 0000000000000001 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff888125f1f000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f78b5a0cd58 CR3: 000000007bb18000 CR4: 00000000003526f0 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline] default_idle+0x13/0x20 arch/x86/kernel/process.c:767 default_idle_call+0x73/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:191 [inline] do_idle+0x1be/0x4d0 kernel/sched/idle.c:332 cpu_startup_entry+0x44/0x60 kernel/sched/idle.c:430 start_secondary+0x101/0x110 arch/x86/kernel/smpboot.c:312 common_startup_64+0x13e/0x147 Tested on: commit: f0b9d8eb Merge tag 'nfsd-6.19-3' of git://git.kernel.o.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16ab11fc580000 kernel config: https://syzkaller.appspot.com/x/.config?x=e5a01f6352682866 dashboard link: https://syzkaller.appspot.com/bug?extid=2d9c96466c978346b55f compiler: Debian clang version 20.1.8 (++20250708063551+0c9f909b7976-1~exp1~20250708183702.136), Debian LLD 20.1.8 Note: no patches were applied.