linux-kernel - Re: [PATCH v1] PM: sleep: core: Synchronize runtime PM status of parents and children

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Message-ID: <Z6YPpbRF_U0TxAbf@hovoldconsulting.com>
Date: Fri, 7 Feb 2025 14:50:29 +0100
From: Johan Hovold <johan@...nel.org>
To: Jon Hunter <jonathanh@...dia.com>,
	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc: Linux PM <linux-pm@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Alan Stern <stern@...land.harvard.edu>,
	Bjorn Helgaas <helgaas@...nel.org>,
	Linux PCI <linux-pci@...r.kernel.org>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>,
	Kevin Xie <kevin.xie@...rfivetech.com>,
	"linux-tegra@...r.kernel.org" <linux-tegra@...r.kernel.org>
Subject: Re: [PATCH v1] PM: sleep: core: Synchronize runtime PM status of
 parents and children

On Fri, Feb 07, 2025 at 01:38:58PM +0000, Jon Hunter wrote:
> On 28/01/2025 19:24, Rafael J. Wysocki wrote:
> > From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> > 
> > Commit 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the
> > resume phase") overlooked the case in which the parent of a device with
> > DPM_FLAG_SMART_SUSPEND set did not use that flag and could be runtime-
> > suspended before a transition into a system-wide sleep state.  In that
> > case, if the child is resumed during the subsequent transition from
> > that state into the working state, its runtime PM status will be set to
> > RPM_ACTIVE, but the runtime PM status of the parent will not be updated
> > accordingly, even though the parent will be resumed too, because of the
> > dev_pm_skip_suspend() check in device_resume_noirq().
> > 
> > Address this problem by tracking the need to set the runtime PM status
> > to RPM_ACTIVE during system-wide resume transitions for devices with
> > DPM_FLAG_SMART_SUSPEND set and all of the devices depended on by them.
> > 
> > Fixes: 6e176bf8d461 ("PM: sleep: core: Do not skip callbacks in the resume phase")
> > Closes: https://lore.kernel.org/linux-pm/Z30p2Etwf3F2AUvD@hovoldconsulting.com/
> > Reported-by: Johan Hovold <johan@...nel.org>
> > Tested-by: Manivannan Sadhasivam <manivannan.sadhasivam@...aro.org>
> > Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>

> I am seeing the following crash during suspend on a couple of our boards (with mainline/next) and bisect is pointing to this commit ...
> 
> [  216.311009] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000

> [  216.468986] Call trace:
> [  216.471179]  simple_pm_bus_runtime_suspend+0x14/0x48 (P)
> [  216.476775]  pm_generic_runtime_suspend+0x2c/0x44
> [  216.481499]  pm_runtime_force_suspend+0x54/0x14c
> [  216.486049]  device_suspend_noirq+0x6c/0x278
> [  216.490253]  dpm_suspend_noirq+0xc0/0x198
> [  216.494278]  suspend_devices_and_enter+0x210/0x4c0
> [  216.499348]  pm_suspend+0x164/0x1c8
> [  216.503023]  state_store+0x8c/0xfc
> [  216.506260]  kobj_attr_store+0x18/0x2c
> [  216.509940]  sysfs_kf_write+0x44/0x54
> [  216.513699]  kernfs_fop_write_iter+0x118/0x1a8
> [  216.518163]  vfs_write+0x2b0/0x35c
> [  216.521399]  ksys_write+0x68/0xfc
> [  216.524810]  __arm64_sys_write+0x1c/0x28
> [  216.528574]  invoke_syscall+0x48/0x110
> [  216.532253]  el0_svc_common.constprop.0+0x40/0xe8
> [  216.536628]  do_el0_svc+0x20/0x2c
> [  216.540299]  el0_svc+0x30/0xd0
> [  216.543016]  el0t_64_sync_handler+0x144/0x168
> [  216.547736]  el0t_64_sync+0x198/0x19c
> [  216.551327] Code: a9be7bfd 910003fd a90153f3 f9403c00 (f9400014)
> [  216.557197] ---[ end trace 0000000000000000 ]---
> 
> I have not looked any further, but if you have any thoughts, let me know.

Yeah, I hit something like this yesterday as well and did confirm that
reverting this commit makes the problem go away. Haven't had time to dig
much further.

[  110.522368] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
[  110.531751] Mem abort info:
[  110.534785]   ESR = 0x0000000096000004
[  110.538799]   EC = 0x25: DABT (current EL), IL = 32 bits
[  110.544421]   SET = 0, FnV = 0
[  110.547716]   EA = 0, S1PTW = 0
[  110.551097]   FSC = 0x04: level 0 translation fault
[  110.556274] Data abort info:
[  110.559385]   ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
[  110.565188]   CM = 0, WnR = 0, TnD = 0, TagAccess = 0
[  110.570536]   GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[  110.576157] user pgtable: 4k pages, 48-bit VAs, pgdp=0000000892256000
[  110.582946] [0000000000000000] pgd=0000000000000000, p4d=0000000000000000
[  110.590348] Internal error: Oops: 0000000096000004 [#1] PREEMPT SMP
...
[  110.742358] CPU: 2 UID: 0 PID: 420 Comm: suspend-test.sh Not tainted 6.13.0 #118
[  110.750067] Hardware name: Qualcomm CRD, BIOS 6.0.231221.BOOT.MXF.2.4-00348.1-HAMOA-1 12/21/2023
[  110.759198] pstate: 81400005 (Nzcv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
[  110.766462] pc : simple_pm_bus_runtime_suspend+0x14/0x48
[  110.772048] lr : pm_generic_runtime_suspend+0x2c/0x44
[  110.777352] sp : ffff8000839d3a20
[  110.780866] x29: ffff8000839d3a20 x28: ffff0edf80fff810 x27: ffffa2dc2d1f1d30
[  110.788303] x26: ffffa2dc2dd82000 x25: 0000000000000002 x24: ffffa2dc2cc7aca0
[  110.795741] x23: ffffa2dc2dd1e000 x22: 0000000000000000 x21: ffffa2dc2d090e50
[  110.803177] x20: ffffa2dc2c612498 x19: ffff0edf80fff810 x18: 0000000000000030
[  110.810615] x17: 0005002c00000000 x16: ffffa2dc2c614ce4 x15: ffffffffffffffff
[  110.818052] x14: 0000000000000000 x13: ffff0edf80fff980 x12: 705f64706e65675f
[  110.825490] x11: ffffa2dc2d9c5890 x10: 0000000000000000 x9 : 0000000000000000
[  110.832927] x8 : ffffa2dc2d2af000 x7 : ffff8000839d3a10 x6 : ffff8000839d39b0
[  110.840364] x5 : ffff8000839d4000 x4 : 0000000000000004 x3 : ffff0edf953e0000
[  110.847801] x2 : ffffa2dc2c4e5784 x1 : 0000000000000000 x0 : 0000000000000000
[  110.855238] Call trace:
[  110.857861]  simple_pm_bus_runtime_suspend+0x14/0x48 (P)
[  110.863425]  pm_generic_runtime_suspend+0x2c/0x44
[  110.868362]  pm_runtime_force_suspend+0x54/0x100
[  110.873217]  dpm_run_callback+0xb4/0x228
[  110.877347]  device_suspend_noirq+0x70/0x2a8
[  110.881844]  dpm_noirq_suspend_devices+0xe0/0x230
[  110.886778]  dpm_suspend_noirq+0x24/0x98
[  110.890904]  suspend_devices_and_enter+0x368/0x678
[  110.895941]  pm_suspend+0x1b4/0x348
[  110.899627]  state_store+0x8c/0xfc
[  110.903228]  kobj_attr_store+0x18/0x2c
[  110.907195]  sysfs_kf_write+0x4c/0x78
[  110.911074]  kernfs_fop_write_iter+0x120/0x1b4
[  110.915735]  vfs_write+0x2ac/0x358
[  110.919352]  ksys_write+0x68/0xfc
[  110.922873]  __arm64_sys_write+0x1c/0x28
[  110.927002]  invoke_syscall+0x48/0x110
[  110.930969]  el0_svc_common.constprop.0+0x40/0xe0
[  110.935907]  do_el0_svc+0x1c/0x28
[  110.939427]  el0_svc+0x48/0x114
[  110.942769]  el0t_64_sync_handler+0xc8/0xcc
[  110.947180]  el0t_64_sync+0x198/0x19c
[  110.951059] Code: a9be7bfd 910003fd a90153f3 f9403c00 (f9400014)
[  110.957428] ---[ end trace 0000000000000000 ]---

Johan