From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-oi1-f207.google.com (mail-oi1-f207.google.com [209.85.167.207]) (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 13AB923BD1B for ; Fri, 26 Jun 2026 05:10:44 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.167.207 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782450646; cv=none; b=PlxMiTtqG8YyLLTlHynbA0l6sxhMpH0ETSXTlzewjok0VCLmsH1vs7X32uuV9Yis0vs+NyBGDMzzanfoAaaIeflQdi64VJiJuSQm7AjxgPg9DE6E7XJMzS2KIly5WMaF2k3PFUD4QuiY7sl498wWRVXQOg1Jj2LKCuKZTAQyJpw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782450646; c=relaxed/simple; bh=E1AnKSkvy/SR7910eEeXX6LnKezjUXwr4DVkJG9Xr6U=; h=MIME-Version:Date:Message-ID:Subject:From:To:Content-Type; b=WEffjvpHfkYvdimV3qRBXqTmpy0MDclTPFy6k14SfpfMKrIOba++3sEbkfrsdFJlhJjs1s5hXsj4Tx7RGzaNU7qz4Y3ACxOLikRUccedtPR3+PKlJDE4gUbXlRnIfUm4S0hoCD399j9Uu+d3VBtIsgcdgV4EnrIi3a/GxuqRTN0= 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=209.85.167.207 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-oi1-f207.google.com with SMTP id 5614622812f47-48656ba24fdso813071b6e.2 for ; Thu, 25 Jun 2026 22:10:44 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782450644; x=1783055444; h=to:from:subject:message-id:date:mime-version:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=WqVuhnGlA98jHg+WNh0FbxGqsq0xgE7hvDd90gJez9Q=; b=naB9h+GpiaCA9WFmDhuvqHUM12yWaNa16+Z95R0HtBhKMOn1JnCp4ZagpktpgXmXpo kkM7DokUtg1qNbb3iYijQnOb0EfbltJc05BlGVKe0OvurD2/YQzOLW0rAUMM5zJW4kPP gS/H2v/Ah5PxH0Kwwl0llJIHNIPw8O1+053lp2DH0RLgf1UJLhCYSRa5qQkXmysHVaob FceYCfvxbsNvJw6oeOPQRmyOhWRvD6yEoca+6fpXxo795EFBZO8Yj/ZgNuBR3nseawHX kAby74BmdKgoqzsWW1V8/Id1aPKowsHdpw8i/l6EloF3YZNhZP1KGUHNTfE490U0tq7c 26GQ== X-Gm-Message-State: AOJu0YwosNbLX5vmwqGJaRnT8otxyBcuwI61rZP9fcMVE0FVCJymSN9t MkuEFqV1c5b/CuWL7nlGe1uv9OvaFBt3CF/IS1K06altKMrj++oEw+ucymFHaLPoi/55WleriGN HcZfHefNgdwRw+sKWNVtOWD5duzICc75eZmc8LDKAld95uYZnGPLXlr/f5VPG1g== Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Received: by 2002:a05:6808:1a15:b0:48a:9afa:e632 with SMTP id 5614622812f47-49217721971mr4241241b6e.27.1782450644117; Thu, 25 Jun 2026 22:10:44 -0700 (PDT) Date: Thu, 25 Jun 2026 22:10:44 -0700 X-Google-Appengine-App-Id: s~syzkaller X-Google-Appengine-App-Id-Alias: syzkaller Message-ID: <6a3e09d4.ac7367b4.6675.0003.GAE@google.com> Subject: [syzbot] [cgroups?] INFO: task hung in cgroup1_get_tree From: syzbot To: cgroups@vger.kernel.org, hannes@cmpxchg.org, linux-kernel@vger.kernel.org, mkoutny@suse.com, syzkaller-bugs@googlegroups.com, tj@kernel.org Content-Type: text/plain; charset="UTF-8" Hello, syzbot found the following issue on: HEAD commit: ab9de95c9cf9 Merge tag 'rust-7.2-2' of git://git.kernel.or.. git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=13976591580000 kernel config: https://syzkaller.appspot.com/x/.config?x=77808e35144e725c dashboard link: https://syzkaller.appspot.com/bug?extid=4e415f7013e8d1af362b compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/ea216d6c635b/disk-ab9de95c.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/a4726046a068/vmlinux-ab9de95c.xz kernel image: https://storage.googleapis.com/syzbot-assets/1ee56b4f63b2/bzImage-ab9de95c.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+4e415f7013e8d1af362b@syzkaller.appspotmail.com INFO: task syz.3.5067:25142 blocked for more than 143 seconds. Tainted: G L syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.5067 state:D stack:27688 pid:25142 tgid:25139 ppid:24491 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5504 [inline] __schedule+0x125c/0x6730 kernel/sched/core.c:7228 __schedule_loop kernel/sched/core.c:7307 [inline] schedule+0xdd/0x390 kernel/sched/core.c:7322 cgroup_lock_and_drain_offline+0x383/0x800 kernel/cgroup/cgroup.c:3275 cgroup1_get_tree+0xc2/0x1620 kernel/cgroup/cgroup-v1.c:1265 vfs_get_tree+0x92/0x320 fs/super.c:1694 fc_mount fs/namespace.c:1198 [inline] do_new_mount_fc fs/namespace.c:3765 [inline] do_new_mount fs/namespace.c:3841 [inline] path_mount+0x7d0/0x23d0 fs/namespace.c:4161 do_mount fs/namespace.c:4174 [inline] __do_sys_mount fs/namespace.c:4390 [inline] __se_sys_mount fs/namespace.c:4367 [inline] __x64_sys_mount+0x293/0x310 fs/namespace.c:4367 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x115/0x870 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fe24299ce59 RSP: 002b:00007fe243858028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fe242c16090 RCX: 00007fe24299ce59 RDX: 0000200000000080 RSI: 0000200000001180 RDI: 0000000000000000 RBP: 00007fe242a32e6f R08: 0000200000000000 R09: 0000000000000000 R10: 0000000000004000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fe242c16128 R14: 00007fe242c16090 R15: 00007ffc1d1628c8 Showing all locks held in the system: 1 lock held by khungtaskd/31: #0: ffffffff8e7e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline] #0: ffffffff8e7e60c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:840 [inline] #0: ffffffff8e7e60c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775 6 locks held by kworker/1:6/5718: #0: ffff8880202ea940 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work+0x12b1/0x1940 kernel/workqueue.c:3297 #1: ffffc900040d7d08 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work+0x988/0x1940 kernel/workqueue.c:3298 #2: ffff88802ac581d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1102 [inline] #2: ffff88802ac581d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x1bd/0x4af0 drivers/usb/core/hub.c:5899 #3: ffff88802ad59568 (&port_dev->status_lock){+.+.}-{4:4}, at: usb_lock_port drivers/usb/core/hub.c:3252 [inline] #3: ffff88802ad59568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5464 [inline] #3: ffff88802ad59568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #3: ffff88802ad59568 (&port_dev->status_lock){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #3: ffff88802ad59568 (&port_dev->status_lock){+.+.}-{4:4}, at: hub_event+0x2bd2/0x4af0 drivers/usb/core/hub.c:5953 #4: ffff88802ac76760 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect drivers/usb/core/hub.c:5465 [inline] #4: ffff88802ac76760 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_port_connect_change drivers/usb/core/hub.c:5707 [inline] #4: ffff88802ac76760 (hcd->address0_mutex){+.+.}-{4:4}, at: port_event drivers/usb/core/hub.c:5871 [inline] #4: ffff88802ac76760 (hcd->address0_mutex){+.+.}-{4:4}, at: hub_event+0x2bfb/0x4af0 drivers/usb/core/hub.c:5953 #5: ffffffff8fbf2c48 (ehci_cf_port_reset_rwsem){.+.+}-{4:4}, at: hub_port_reset+0x1a5/0x1c60 drivers/usb/core/hub.c:3067 2 locks held by getty/13406: #0: ffff8880383d10a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243 #1: ffffc9000202e2e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x419/0x14e0 drivers/tty/n_tty.c:2211 1 lock held by syz.2.5163/25788: #0: ffff88807d22e0d8 (&type->s_umount_key#64){++++}-{4:4}, at: do_remount fs/namespace.c:3404 [inline] #0: ffff88807d22e0d8 (&type->s_umount_key#64){++++}-{4:4}, at: path_mount+0x1757/0x23d0 fs/namespace.c:4153 1 lock held by syz.0.5462/27160: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 Call Trace: __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:122 nmi_trigger_cpumask_backtrace+0x21c/0x2a0 lib/nmi_backtrace.c:65 trigger_all_cpu_backtrace include/linux/nmi.h:162 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x141/0x190 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:353 [inline] watchdog+0xcb1/0x1030 kernel/hung_task.c:561 kthread+0x370/0x450 kernel/kthread.c:436 ret_from_fork+0x72b/0xd50 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Tainted: G L syzkaller #0 PREEMPT(full) Tainted: [L]=SOFTLOCKUP Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/09/2026 RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:64 Code: d6 85 02 c3 cc cc cc cc 0f 1f 00 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 23 28 10 00 fb f4 fc 48 03 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90 RSP: 0018:ffffffff8e407e10 EFLAGS: 00000246 RAX: 00000000088c3e3f RBX: ffffffff8e491480 RCX: ffffffff8b9b72d5 RDX: 0000000000000000 RSI: ffffffff8df596ca RDI: ffffffff8c1e7180 RBP: fffffbfff1c92290 R08: 0000000000000001 R09: ffffed101708678d R10: ffff8880b8433c6b R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 1ffffffff1c80fc6 R15: dffffc0000000000 FS: 0000000000000000(0000) GS:ffff8881242e7000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fa09d875d58 CR3: 000000004c22a000 CR4: 00000000003526f0 DR0: 0000000000000008 DR1: 0000000000000007 DR2: 0000000000000004 DR3: 0000000000000008 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: arch_safe_halt arch/x86/include/asm/paravirt.h:62 [inline] default_idle+0x9/0x10 arch/x86/kernel/process.c:768 default_idle_call+0x6c/0xb0 kernel/sched/idle.c:122 cpuidle_idle_call kernel/sched/idle.c:199 [inline] do_idle+0x3a7/0x5b0 kernel/sched/idle.c:355 cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:454 rest_init+0x251/0x260 init/main.c:717 start_kernel+0x48e/0x490 init/main.c:1175 x86_64_start_reservations+0x24/0x30 arch/x86/kernel/head64.c:310 x86_64_start_kernel+0x12b/0x130 arch/x86/kernel/head64.c:291 common_startup_64+0x13e/0x158 --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@googlegroups.com. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup