Hi I've hit the following lockdep warning when I trigger hibernate on arm64 platform (Juno-r2) echo suspend > /sys/power/disk echo disk > /sys/power/state I only had a usb flash drive attached to it. Let me know if you need more info. # echo suspend > disk # echo disk > state [ 325.775152] PM: hibernation: hibernation entry [ 325.780708] Filesystems sync: 0.000 seconds [ 325.784976] Freezing user space processes ... (elapsed 0.001 seconds) done. [ 325.793322] OOM killer disabled. [ 325.797934] PM: hibernation: Preallocating image memory [ 326.852851] PM: hibernation: Allocated 96124 pages for snapshot [ 326.858826] PM: hibernation: Allocated 384496 kbytes in 1.04 seconds (369.70 MB/s) [ 326.866447] Freezing remaining freezable tasks ... (elapsed 0.001 seconds) done. [ 326.876429] printk: Suspending console(s) (use no_console_suspend to debug) [ 326.947751] Disabling non-boot CPUs ... [ 326.948909] CPU1: shutdown [ 326.948918] psci: CPU1 killed (polled 0 ms) [ 326.951082] CPU2: shutdown [ 326.952130] psci: CPU2 killed (polled 0 ms) [ 326.954600] CPU3: shutdown [ 326.954613] psci: CPU3 killed (polled 0 ms) [ 326.957217] CPU4: shutdown [ 326.957229] psci: CPU4 killed (polled 0 ms) [ 326.958924] CPU5: shutdown [ 326.958936] psci: CPU5 killed (polled 0 ms) [ 326.959878] PM: hibernation: Creating image: [ 326.959878] PM: hibernation: Need to copy 94789 pages [ 326.959878] PM: hibernation: Image created (94789 pages copied) [ 326.959994] Enabling non-boot CPUs ... [ 326.973678] Detected PIPT I-cache on CPU1 [ 326.973728] CPU1: Booted secondary processor 0x0000000000 [0x410fd080] [ 326.975172] CPU1 is up [ 326.993051] Detected PIPT I-cache on CPU2 [ 326.993081] CPU2: Booted secondary processor 0x0000000001 [0x410fd080] [ 326.993839] CPU2 is up [ 327.007492] Detected VIPT I-cache on CPU3 [ 327.007557] CPU3: Booted secondary processor 0x0000000101 [0x410fd033] [ 327.009075] CPU3 is up [ 327.022636] Detected VIPT I-cache on CPU4 [ 327.022682] CPU4: Booted secondary processor 0x0000000102 [0x410fd033] [ 327.024296] CPU4 is up [ 327.038227] Detected VIPT I-cache on CPU5 [ 327.038272] CPU5: Booted secondary processor 0x0000000103 [0x410fd033] [ 327.039921] CPU5 is up [ 327.154849] usb usb2: runtime PM trying to activate child device usb2 but parent (7ffb0000.ohci) is not active [ 327.290355] PM: Cannot find swap device, try swapon -a [ 327.295533] PM: Cannot get swap writer [ 327.480758] OOM killer enabled. [ 327.483939] Restarting tasks ... [ 327.484229] ------------[ cut here ]------------ [ 327.484664] done. [ 327.487743] URB 000000000c121c1c submitted while active [ 327.499622] WARNING: CPU: 1 PID: 296 at drivers/usb/core/urb.c:363 usb_submit_urb+0x3f0/0x520 [ 327.508191] Modules linked in: [ 327.511262] CPU: 1 PID: 296 Comm: kworker/1:2 Not tainted 5.6.0-rc6 #533 [ 327.517993] Hardware name: ARM Juno development board (r2) (DT) [ 327.523944] Workqueue: usb_hub_wq hub_event [ 327.528148] pstate: 40000005 (nZcv daif -PAN -UAO) [ 327.532959] pc : usb_submit_urb+0x3f0/0x520 [ 327.537160] lr : usb_submit_urb+0x3f0/0x520 [ 327.541360] sp : ffff80001891b8c0 [ 327.544687] x29: ffff80001891b8c0 x28: ffff000973f7a000 [ 327.550024] x27: ffff00097049f320 x26: 0000000000000003 [ 327.555361] x25: ffff8000101704e8 x24: ffff80001891bb48 [ 327.560697] x23: ffff80001323d000 x22: 0000000000000c00 [ 327.566033] x21: 0000000000000004 x20: 00000000fffffff0 [ 327.571369] x19: ffff0009703f0300 x18: 0000000000000000 [ 327.576705] x17: 0000000000000000 x16: 0000000000000000 [ 327.582041] x15: 0000000000000000 x14: 0000000000000000 [ 327.587376] x13: 0000000000000000 x12: 0000000000000000 [ 327.592712] x11: 0000000000000000 x10: 0000000000000000 [ 327.598048] x9 : ffff80001323da88 x8 : ffff00097ef0a798 [ 327.603384] x7 : ffff800010148c08 x6 : ffff00097eef7450 [ 327.608720] x5 : ffff00097eef7450 x4 : 0000000000000000 [ 327.614055] x3 : ffff00097ef06df0 x2 : 0000000000000001 [ 327.619391] x1 : 1798c844b4d7c300 x0 : 0000000000000000 [ 327.624727] Call trace: [ 327.627183] usb_submit_urb+0x3f0/0x520 [ 327.631035] hub_activate+0x108/0x788 [ 327.634713] hub_resume+0x40/0x108 [ 327.638129] usb_resume_interface.isra.9+0x60/0x108 [ 327.643028] usb_resume_both+0xe4/0x140 [ 327.646881] usb_runtime_resume+0x24/0x30 [ 327.650910] __rpm_callback+0xdc/0x138 [ 327.654675] rpm_callback+0x34/0x98 [ 327.658178] rpm_resume+0x4a8/0x720 [ 327.661681] rpm_resume+0x50c/0x720 [ 327.665183] __pm_runtime_resume+0x4c/0xb8 [ 327.669297] usb_autopm_get_interface+0x28/0x60 [ 327.673848] hub_event+0x80/0x1368 [ 327.677266] process_one_work+0x2a4/0x748 [ 327.681292] worker_thread+0x48/0x498 [ 327.684970] kthread+0x13c/0x140 [ 327.688211] ret_from_fork+0x10/0x18 [ 327.691801] irq event stamp: 17114 [ 327.695219] hardirqs last enabled at (17113): [<ffff80001191b29c>] _raw_spin_unlock_irq+0x34/0x68 [ 327.704224] hardirqs last disabled at (17114): [<ffff8000119132d8>] __schedule+0xd0/0x7e8 [ 327.712442] softirqs last enabled at (16742): [<ffff8000100818a4>] __do_softirq+0x4bc/0x568 [ 327.720922] softirqs last disabled at (16731): [<ffff800010114064>] irq_exit+0x144/0x150 [ 327.729051] ---[ end trace 7d41436f96488c51 ]--- [ 327.733762] PM: hibernation: hibernation exit sh: write error: No such device # [ 327.739972] hub 2-0:1.0: activate --> -16 Thanks -- Qais Yousef