Re: [PATCH] mm/page_alloc: Add a reason for reserved pages in has_unmovable_pages()

[Qian Cai]

On Fri, 2019-10-04 at 17:14 +0530, Anshuman Khandual wrote:
> 
> On 10/04/2019 04:28 PM, Michal Hocko wrote:
> > On Thu 03-10-19 13:40:57, Anshuman Khandual wrote:
> > > Having unmovable pages on a given pageblock should be reported correctly
> > > when required with REPORT_FAILURE flag. But there can be a scenario where a
> > > reserved page in the page block will get reported as a generic "unmovable"
> > > reason code. Instead this should be changed to a more appropriate reason
> > > code like "Reserved page".
> > 
> > Others have already pointed out this is just redundant but I will have a
> 
> Sure.
> 
> > more generic comment on the changelog. There is essentially no
> > information why the current state is bad/unhelpful and why the chnage is
> 
> The current state is not necessarily bad or unhelpful. I just though that it
> could be improved upon. Some how calling out explicitly only the CMA page
> failure case just felt adhoc, where as there are other reasons like HugeTLB
> immovability which might depend on other factors apart from just page flags
> (though I did not propose that originally).
> 
> > needed. All you claim is that something is a certain way and then assert
> > that it should be done differently. That is not how changelogs should
> > look like.
> > 
> 
> Okay, probably I should have explained more on why "unmovable" is less than
> adequate to capture the exact reason for specific failure cases and how
> "Reserved Page" instead would been better. But got the point, will improve.
> 

It might be a good time to rethink if it is really a good idea to dump_page()
at all inside has_unmovable_pages(). As it is right now, it is a a potential
deadlock between console vs memory offline. More details are in this thread,

https://lore.kernel.org/lkml/1568817579.5576.172.camel@xxxxxx/

01: [ÂÂ672.875392] WARNING: possible circular locking dependency detectedÂÂÂÂÂÂÂ
01: [ÂÂ672.875394] 5.4.0-rc1-next-20191004+ #64 Not taintedÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875396] ------------------------------------------------------ÂÂÂÂÂÂÂ
01: [ÂÂ672.875398] test.sh/1724 is trying to acquire lock:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875400] 0000000052059ec0 (console_owner){-...}, at: console_unlock+0x
01: 328/0xa30ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875406]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875408] but task is already holding lock:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875409] 000000006ffd89c8 (&(&zone->lock)->rlock){-.-.}, at: start_iso
01: late_page_range+0x216/0x538ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875415]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875417] which lock already depends on the new lock.ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875418]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875419]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875421] the existing dependency chain (in reverse order) is:ÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875423]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875424] -> #2 (&(&zone->lock)->rlock){-.-.}:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875430]ÂÂÂÂÂÂÂÂlock_acquire+0x21a/0x468ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875431]ÂÂÂÂÂÂÂÂ_raw_spin_lock+0x54/0x68ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875433]ÂÂÂÂÂÂÂÂget_page_from_freelist+0x8b6/0x2d28ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875435]ÂÂÂÂÂÂÂÂ__alloc_pages_nodemask+0x246/0x658ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875437]ÂÂÂÂÂÂÂÂ__get_free_pages+0x34/0x78ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875438]ÂÂÂÂÂÂÂÂsclp_init+0x106/0x690ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875440]ÂÂÂÂÂÂÂÂsclp_register+0x2e/0x248ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875442]ÂÂÂÂÂÂÂÂsclp_rw_init+0x4a/0x70ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875443]ÂÂÂÂÂÂÂÂsclp_console_init+0x4a/0x1b8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875445]ÂÂÂÂÂÂÂÂconsole_init+0x2c8/0x410ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875447]ÂÂÂÂÂÂÂÂstart_kernel+0x530/0x6a0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875448]ÂÂÂÂÂÂÂÂstartup_continue+0x70/0xd0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875449]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875450] -> #1 (sclp_lock){-.-.}:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875458]ÂÂÂÂÂÂÂÂlock_acquire+0x21a/0x468ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875460]ÂÂÂÂÂÂÂÂ_raw_spin_lock_irqsave+0xcc/0xe8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875462]ÂÂÂÂÂÂÂÂsclp_add_request+0x34/0x308ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875464]ÂÂÂÂÂÂÂÂsclp_conbuf_emit+0x100/0x138ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875465]ÂÂÂÂÂÂÂÂsclp_console_write+0x96/0x3b8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875467]ÂÂÂÂÂÂÂÂconsole_unlock+0x6dc/0xa30ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875469]ÂÂÂÂÂÂÂÂvprintk_emit+0x184/0x3c8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875470]ÂÂÂÂÂÂÂÂvprintk_default+0x44/0x50ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875472]ÂÂÂÂÂÂÂÂprintk+0xa8/0xc0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875473]ÂÂÂÂÂÂÂÂiommu_debugfs_setup+0xf2/0x108ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875475]ÂÂÂÂÂÂÂÂiommu_init+0x6c/0x78ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875477]ÂÂÂÂÂÂÂÂdo_one_initcall+0x162/0x680ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875478]ÂÂÂÂÂÂÂÂkernel_init_freeable+0x4e8/0x5a8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875480]ÂÂÂÂÂÂÂÂkernel_init+0x2a/0x188ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875484]ÂÂÂÂÂÂÂÂret_from_fork+0x30/0x34ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875486]ÂÂÂÂÂÂÂÂkernel_thread_starter+0x0/0xcÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875487]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875488] -> #0 (console_owner){-...}:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875495]ÂÂÂÂÂÂÂÂcheck_noncircular+0x338/0x3e0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875496]ÂÂÂÂÂÂÂÂ__lock_acquire+0x1e66/0x2d88ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875498]ÂÂÂÂÂÂÂÂlock_acquire+0x21a/0x468ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875499]ÂÂÂÂÂÂÂÂconsole_unlock+0x3a6/0xa30ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875501]ÂÂÂÂÂÂÂÂvprintk_emit+0x184/0x3c8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875503]ÂÂÂÂÂÂÂÂvprintk_default+0x44/0x50ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875504]ÂÂÂÂÂÂÂÂprintk+0xa8/0xc0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875506]ÂÂÂÂÂÂÂÂ__dump_page+0x1dc/0x710ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875507]ÂÂÂÂÂÂÂÂdump_page+0x2e/0x58ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875509]ÂÂÂÂÂÂÂÂhas_unmovable_pages+0x2e8/0x470ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875511]ÂÂÂÂÂÂÂÂstart_isolate_page_range+0x404/0x538ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875513]ÂÂÂÂÂÂÂÂ__offline_pages+0x22c/0x1338ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875514]ÂÂÂÂÂÂÂÂmemory_subsys_offline+0xa6/0xe8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875516]ÂÂÂÂÂÂÂÂdevice_offline+0xe6/0x118ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875517]ÂÂÂÂÂÂÂÂstate_store+0xf0/0x110ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875519]ÂÂÂÂÂÂÂÂkernfs_fop_write+0x1bc/0x270ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875521]ÂÂÂÂÂÂÂÂvfs_write+0xce/0x220ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875522]ÂÂÂÂÂÂÂÂksys_write+0xea/0x190ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875524]ÂÂÂÂÂÂÂÂsystem_call+0xd8/0x2b4ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875525]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875527] other info that might help us debug this:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875528]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875529] Chain exists of:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875530]ÂÂÂconsole_owner --> sclp_lock --> &(&zone->lock)->rlockÂÂÂÂÂÂ
01: [ÂÂ672.875538]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875540]ÂÂPossible unsafe locking scenario:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875541]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875543]ÂÂÂÂÂÂÂÂCPU0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂCPU1ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875544]ÂÂÂÂÂÂÂÂ----ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ----ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875545]ÂÂÂlock(&(&zone->lock)->rlock);ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875549]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock(sclp_lock);ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875553]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock(&(&zone->lock)->rlock);ÂÂ
01: [ÂÂ672.875557]ÂÂÂlock(console_owner);ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875560]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875562]ÂÂ*** DEADLOCK ***ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875563]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875564] 9 locks held by test.sh/1724:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875565]ÂÂ#0: 000000000e925408 (sb_writers#4){.+.+}, at: vfs_write+0x2
01: 06/0x220ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875574]ÂÂ#1: 0000000050aa4280 (&of->mutex){+.+.}, at: kernfs_fop_writ
01: e+0x154/0x270ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875581]ÂÂ#2: 0000000062e5c628 (kn->count#198){.+.+}, at: kernfs_fop_w
01: rite+0x16a/0x270ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875590]ÂÂ#3: 00000000523236a0 (device_hotplug_lock){+.+.}, at: lock_d
01: evice_hotplug_sysfs+0x30/0x80ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875598]ÂÂ#4: 0000000062e70990 (&dev->mutex){....}, at: device_offline
01: +0x78/0x118ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875605]ÂÂ#5: 0000000051fd36b0 (cpu_hotplug_lock.rw_sem){++++}, at: __
01: offline_pages+0xec/0x1338ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875613]ÂÂ#6: 00000000521ca470 (mem_hotplug_lock.rw_sem){++++}, at: pe
01: rcpu_down_write+0x38/0x210ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875620]ÂÂ#7: 000000006ffd89c8 (&(&zone->lock)->rlock){-.-.}, at: star
01: t_isolate_page_range+0x216/0x538ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875628]ÂÂ#8: 000000005205a100 (console_lock){+.+.}, at: vprintk_emit+
01: 0x178/0x3c8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875635]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875636] stack backtrace:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875639] CPU: 1 PID: 1724 Comm: test.sh Not tainted 5.4.0-rc1-next-201
01: 91004+ #64ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875640] Hardware name: IBM 2964 N96 400 (z/VM 6.4.0)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875642] Call Trace:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875644] ([<00000000512ae218>] show_stack+0x110/0x1b0)ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875645]ÂÂ[<0000000051b6d506>] dump_stack+0x126/0x178ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875648]ÂÂ[<00000000513a4b08>] check_noncircular+0x338/0x3e0ÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875650]ÂÂ[<00000000513aaaf6>] __lock_acquire+0x1e66/0x2d88ÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875652]ÂÂ[<00000000513a7e12>] lock_acquire+0x21a/0x468ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875654]ÂÂ[<00000000513bb2fe>] console_unlock+0x3a6/0xa30ÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875655]ÂÂ[<00000000513bde2c>] vprintk_emit+0x184/0x3c8ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875657]ÂÂ[<00000000513be0b4>] vprintk_default+0x44/0x50ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875659]ÂÂ[<00000000513beb60>] printk+0xa8/0xc0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875661]ÂÂ[<000000005158c364>] __dump_page+0x1dc/0x710ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875663]ÂÂ[<000000005158c8c6>] dump_page+0x2e/0x58ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875665]ÂÂ[<00000000515d87c8>] has_unmovable_pages+0x2e8/0x470ÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875667]ÂÂ[<000000005167072c>] start_isolate_page_range+0x404/0x538ÂÂÂ
01: [ÂÂ672.875669]ÂÂ[<0000000051b96de4>] __offline_pages+0x22c/0x1338ÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875671]ÂÂ[<0000000051908586>] memory_subsys_offline+0xa6/0xe8ÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875673]ÂÂ[<00000000518e561e>] device_offline+0xe6/0x118ÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875675]ÂÂ[<0000000051908170>] state_store+0xf0/0x110ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875677]ÂÂ[<0000000051796384>] kernfs_fop_write+0x1bc/0x270ÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875679]ÂÂ[<000000005168972e>] vfs_write+0xce/0x220ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875681]ÂÂ[<0000000051689b9a>] ksys_write+0xea/0x190ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875685]ÂÂ[<0000000051ba9990>] system_call+0xd8/0x2b4ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ
01: [ÂÂ672.875687] INFO: lockdep is turned off.