On Fri, 2024-12-13 at 12:31 +0100, Thomas Gleixner wrote: > On Fri, Dec 13 2024 at 19:09, Ming Lei wrote: > > On Fri, Dec 13, 2024 at 11:42:59AM +0100, Thomas Gleixner wrote: > > > That's the control thread on CPU0. The hotplug thread on CPU1 is stuck > > > here: > > > > > > task:cpuhp/1 state:D stack:0 pid:24 tgid:24 ppid:2 flags:0x00004000 > > > Call Trace: > > > <TASK> > > > __schedule+0x51f/0x1a80 > > > schedule+0x3a/0x140 > > > schedule_timeout+0x90/0x110 > > > msleep+0x2b/0x40 > > > blk_mq_hctx_notify_offline+0x160/0x3a0 > > > cpuhp_invoke_callback+0x2a8/0x6c0 > > > cpuhp_thread_fun+0x1ed/0x270 > > > smpboot_thread_fn+0xda/0x1d0 > > > > > > So something with those blk_mq fixes went sideways. > > > > The cpuhp callback is just waiting for inflight IOs to be completed when > > the irq is still live. > > > > It looks same with the following report: > > > > https://lore.kernel.org/linux-scsi/F991D40F7D096653+20241203211857.0291ab1b@john-PC/ > > > > Still triggered in case of kexec & qemu, which should be one qemu > > problem. > > I'd rather say, that's a kexec problem. On the same instance a loop test > of suspend to ram with pm_test=core just works fine. That's equivalent > to the kexec scenario. It goes down to syscore_suspend() and skips the > actual suspend low level magic. It then resumes with syscore_resume() > and brings the machine back up. > > That runs for 2 hours now, while the kexec muck dies within 2 > minutes.... > > And if you look at the difference of these implementations, you might > notice that kexec just implemented some rudimentary version of the > actual suspend logic. Based on let's hope it works that way. > > This is just insane and should be rewritten to actually reuse the suspend > mechanism, which is way better tested than this kexec jump muck. Not sure it helps for the above linux-scsi issue since that's an *actual* kexec, not 'kexec jump muck'. But for the kjump this dirty proof of concept seems to work: --- a/kernel/power/suspend.c +++ b/kernel/power/suspend.c @@ -19,6 +19,7 @@ #include <linux/gfp.h> #include <linux/io.h> #include <linux/kernel.h> +#include <linux/kexec.h> #include <linux/list.h> #include <linux/mm.h> #include <linux/slab.h> @@ -446,6 +447,9 @@ static int suspend_enter(suspend_state_t state, bool *wakeup) error = syscore_suspend(); if (!error) { *wakeup = pm_wakeup_pending(); + if (kexec_image && kexec_image->preserve_context) { + machine_kexec(kexec_image); + } else if (!(suspend_test(TEST_CORE) || *wakeup)) { trace_suspend_resume(TPS("machine_suspend"), state, true); [root@localhost ~]# echo mem > /sys/power/state [ 61.854085] PM: suspend entry (deep) [ 61.868380] Filesystems sync: 0.013 seconds [ 61.873692] Freezing user space processes [ 61.876739] Freezing user space processes completed (elapsed 0.002 seconds) [ 61.878175] OOM killer disabled. [ 61.878861] Freezing remaining freezable tasks [ 61.880818] Freezing remaining freezable tasks completed (elapsed 0.001 seconds) [ 61.889138] ata2.00: Check power mode failed (err_mask=0x1) [ 61.893351] PM: suspend devices took 0.011 seconds [ 61.899373] ACPI: PM: Preparing to enter system sleep state S3 [ 61.900802] ACPI: PM: Saving platform NVS memory [ 61.901861] Disabling non-boot CPUs ... [ 61.906841] smpboot: CPU 1 is now offline Exc:0000000000000003 Err:0000000000000000 rip:0000228e60970000 rax:0000000000000018 rbx:0000000000000000 rcx:0000000000000001 rdx:0000000000000000 rsi:00000000228e6540 rdi:00000000228e4002 r8 :0000000000000000 r9 :0000000022927000 r10:0000000000000000 r11:0000000000000001 r12:0000000000170e70 r13:0000000000170ef0 r14:ffff888006064110 r15:ffff888006f61e20 cr2:00007f408f990098 B[ 61.925154] Enabling non-boot CPUs ... [ 61.925987] smpboot: Booting Node 0 Processor 1 APIC 0x1 [ 61.929886] CPU1 is up [ 61.930514] ACPI: PM: Waking up from system sleep state S3 [ 61.950391] virtio_blk virtio1: 2/0/0 default/read/poll queues [ 61.954844] PM: resume devices took 0.020 seconds [ 61.955968] OOM killer enabled. [ 61.956500] Restarting tasks ... done. [ 61.958890] random: crng reseeded on system resumption [ 61.962280] PM: suspend exit
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