Re: Zram writeback feature unstable with heavy swap utilization - BUG: Bad page state in process...
From: Tino Lehnig
Date: Fri Jul 27 2018 - 07:00:07 EST
On 07/27/2018 11:14 AM, Minchan Kim wrote:
I tried to reproduce with KVM but was not successful and I don't have
real mahcine to reproduce it. I am asking one device for it.
Anyway, I want to try this patch.
Could you apply attached two patches?
Thanks, I applied the patches on 4.18-rc6, but unfortunately, they do
not solve the problem for me. Kernel message below.
I am confusing. You mean after 4.15-rc9, you are not seeing*hung* problem?
Correct.
So you mean you see page state bug with recent kernel right?
It seems there are two problems now.
1. Hung and 2. bad page
What bugs between them happens against what kernel version?
Could you clarify it?
* pre 0bcac06f27d75 (4.15-rc1): all good
* 4.15-rc1: hung task (I have not encountered bad page here yet...)
* 4.15-rc2 through 4.15-rc8: hung task + bad page (very rare)
* 4.15-rc9 and newer: bad page
--
[ 809.149272] BUG: Bad page state in process kvm pfn:1cb08a8
[ 809.149332] flags: 0x57ffffc0000008(uptodate)
[ 809.149350] raw: 0057ffffc0000008 dead000000000100 dead000000000200
0000000000000000
[ 809.149378] raw: 0000000000000001 0000000000000000 00000000ffffffff
0000000000000000
[ 809.149405] page dumped because: PAGE_FLAGS_CHECK_AT_PREP flag set
[ 809.149427] bad because of flags: 0x8(uptodate)
[ 809.149444] Modules linked in: lz4 lz4_compress zram
[ 809.149450] CPU: 14 PID: 3734 Comm: kvm Not tainted 4.18.0-rc6+ #1
[ 809.149450] Hardware name: Supermicro Super Server/X10DRL-i, BIOS
3.0a 02/09/2018
[ 809.149451] Call Trace:
[ 809.149458] dump_stack+0x63/0x85
[ 809.149463] bad_page+0xc1/0x120
[ 809.149465] check_new_page_bad+0x67/0x80
[ 809.149467] get_page_from_freelist+0xe25/0x12f0
[ 809.149469] __alloc_pages_nodemask+0xfd/0x280
[ 809.149472] alloc_pages_vma+0x88/0x1c0
[ 809.149475] do_swap_page+0x346/0x910
[ 809.149477] __handle_mm_fault+0x815/0x1170
[ 809.149479] handle_mm_fault+0x102/0x200
[ 809.149481] __get_user_pages+0x131/0x680
[ 809.149483] get_user_pages_unlocked+0x145/0x1e0
[ 809.149488] __gfn_to_pfn_memslot+0x10b/0x3c0
[ 809.149491] try_async_pf+0x86/0x230
[ 809.149494] tdp_page_fault+0x12d/0x290
[ 809.149496] kvm_mmu_page_fault+0x74/0x5d0
[ 809.149499] ? call_function_interrupt+0xa/0x20
[ 809.149502] ? vmexit_fill_RSB+0x10/0x40
[ 809.149503] ? vmexit_fill_RSB+0x1c/0x40
[ 809.149504] ? vmexit_fill_RSB+0x10/0x40
[ 809.149505] ? vmexit_fill_RSB+0x1c/0x40
[ 809.149506] ? vmexit_fill_RSB+0x10/0x40
[ 809.149507] ? vmexit_fill_RSB+0x1c/0x40
[ 809.149508] ? vmexit_fill_RSB+0x10/0x40
[ 809.149509] ? vmexit_fill_RSB+0x1c/0x40
[ 809.149510] ? vmexit_fill_RSB+0x10/0x40
[ 809.149513] handle_ept_violation+0xdf/0x1a0
[ 809.149514] vmx_handle_exit+0xa5/0x11c0
[ 809.149516] ? vmx_vcpu_run+0x3bb/0x620
[ 809.149519] kvm_arch_vcpu_ioctl_run+0x9b3/0x1980
[ 809.149522] kvm_vcpu_ioctl+0x3a0/0x5e0
[ 809.149523] ? kvm_vcpu_ioctl+0x3a0/0x5e0
[ 809.149526] do_vfs_ioctl+0xa6/0x620
[ 809.149527] ksys_ioctl+0x75/0x80
[ 809.149529] __x64_sys_ioctl+0x1a/0x20
[ 809.149532] do_syscall_64+0x5a/0x110
[ 809.149534] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 809.149536] RIP: 0033:0x7fd3c5572dd7
[ 809.149536] Code: 00 00 00 48 8b 05 c1 80 2b 00 64 c7 00 26 00 00 00
48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f
05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 91 80 2b 00 f7 d8 64 89 01 48
[ 809.149563] RSP: 002b:00007fd3b07fc538 EFLAGS: 00000246 ORIG_RAX:
0000000000000010
[ 809.149565] RAX: ffffffffffffffda RBX: 000000000000ae80 RCX:
00007fd3c5572dd7
[ 809.149566] RDX: 0000000000000000 RSI: 000000000000ae80 RDI:
0000000000000014
[ 809.149566] RBP: 00007fd3b9b13000 R08: 0000558cb94bb350 R09:
00000000ffffffff
[ 809.149567] R10: 0005577fd3b06fe6 R11: 0000000000000246 R12:
0000000000000000
[ 809.149568] R13: 00007fd3ba146000 R14: 0000000000000000 R15:
00007fd3b9b13000
[ 809.149570] Disabling lock debugging due to kernel taint
--
Kind regards,
Tino Lehnig