Re: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4

From: Evgeny Baskakov
Date: Mon Jul 10 2017 - 19:44:44 EST

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In reply to: Jerome Glisse: "Re: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4"
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On 6/30/17 5:57 PM, Jerome Glisse wrote:

...

Hi Jerome,

I am working on a sporadic data corruption seen in highly contented use cases. So far, I've been able to re-create a sporadic hang that happens when multiple threads compete to migrate the same page to and from device memory. The reproducer uses only the dummy driver from hmm-next.

Please find attached. This is how it hangs on my 12-core Intel i7-5930K SMT system:

&&& 2 migrate threads, 2 read threads: STARTING
(EE:84) hmm_buffer_mirror_read error -1
&&& 2 migrate threads, 2 read threads: PASSED
&&& 2 migrate threads, 3 read threads: STARTING
&&& 2 migrate threads, 3 read threads: PASSED
&&& 2 migrate threads, 4 read threads: STARTING
&&& 2 migrate threads, 4 read threads: PASSED
&&& 3 migrate threads, 2 read threads: STARTING

The kernel log (also attached) shows multiple threads blocked in hmm_vma_fault() and migrate_vma():

[ 139.054907] sanity_rmem004 D13528 3997 3818 0x00000000
[ 139.054912] Call Trace:
[ 139.054914] __schedule+0x20b/0x6c0
[ 139.054916] schedule+0x36/0x80
[ 139.054920] io_schedule+0x16/0x40
[ 139.054923] __lock_page+0xf2/0x130
[ 139.054929] migrate_vma+0x48a/0xee0
[ 139.054933] dummy_migrate.isra.10+0xd9/0x110 [hmm_dmirror]
[ 139.054945] dummy_fops_unlocked_ioctl+0x1e8/0x330 [hmm_dmirror]
[ 139.054954] do_vfs_ioctl+0x96/0x5a0
[ 139.054957] SyS_ioctl+0x79/0x90
[ 139.054960] entry_SYSCALL_64_fastpath+0x13/0x94
...
[ 139.055067] sanity_rmem004 D13136 3999 3818 0x00000000
[ 139.055072] Call Trace:
[ 139.055074] __schedule+0x20b/0x6c0
[ 139.055076] schedule+0x36/0x80
[ 139.055079] io_schedule+0x16/0x40
[ 139.055083] wait_on_page_bit+0xee/0x120
[ 139.055089] __migration_entry_wait+0xe8/0x190
[ 139.055091] migration_entry_wait+0x5f/0x70
[ 139.055094] do_swap_page+0x4c7/0x4e0
[ 139.055096] __handle_mm_fault+0x347/0x9d0
[ 139.055099] handle_mm_fault+0x88/0x150
[ 139.055103] hmm_vma_walk_clear+0x8f/0xd0
[ 139.055105] hmm_vma_walk_pmd+0x1ba/0x250
[ 139.055109] __walk_page_range+0x1e8/0x420
[ 139.055112] walk_page_range+0x73/0xf0
[ 139.055114] hmm_vma_fault+0x180/0x260
[ 139.055121] dummy_fault+0xda/0x1f0 [hmm_dmirror]
[ 139.055138] dummy_fops_unlocked_ioctl+0x12c/0x330 [hmm_dmirror]
[ 139.055142] do_vfs_ioctl+0x96/0x5a0
[ 139.055145] SyS_ioctl+0x79/0x90
[ 139.055148] entry_SYSCALL_64_fastpath+0x13/0x94

Please compile and run the attached program this way:

$ ./build.sh
$ sudo ./kload.sh
$ sudo ./run.sh

Thanks!

Evgeny Baskakov
NVIDIA

Attachment: sanity_rmem004_repeated_faults_threaded.tgz
Description: GNU Zip compressed data

[ 107.703099] hmm_dmirror loaded THIS IS A DANGEROUS MODULE !!!
[ 114.236862] DEVICE PAGE 20400 20400 (0)
[ 114.845967] DEVICE PAGE 53323 53323 (0)
[ 115.536446] DEVICE PAGE 87401 87401 (0)
[ 139.054579] sysrq: SysRq : Show Blocked State
[ 139.054658] task PC stack pid father
[ 139.054661] rcu_sched D15024 8 2 0x00000000
[ 139.054669] Call Trace:
[ 139.054676] __schedule+0x20b/0x6c0
[ 139.054679] schedule+0x36/0x80
[ 139.054687] rcu_gp_kthread+0x74/0x770
[ 139.054693] kthread+0x109/0x140
[ 139.054697] ? force_qs_rnp+0x180/0x180
[ 139.054700] ? kthread_park+0x60/0x60
[ 139.054705] ret_from_fork+0x22/0x30
[ 139.054707] rcu_bh D15424 9 2 0x00000000
[ 139.054713] Call Trace:
[ 139.054716] __schedule+0x20b/0x6c0
[ 139.054718] schedule+0x36/0x80
[ 139.054721] rcu_gp_kthread+0x74/0x770
[ 139.054725] kthread+0x109/0x140
[ 139.054728] ? force_qs_rnp+0x180/0x180
[ 139.054731] ? kthread_park+0x60/0x60
[ 139.054734] ret_from_fork+0x22/0x30
[ 139.054762] sanity_rmem004 D13528 3995 3818 0x00000000
[ 139.054767] Call Trace:
[ 139.054769] __schedule+0x20b/0x6c0
[ 139.054776] ? wake_up_q+0x80/0x80
[ 139.054778] schedule+0x36/0x80
[ 139.054782] io_schedule+0x16/0x40
[ 139.054789] __lock_page+0xf2/0x130
[ 139.054792] ? page_cache_tree_insert+0x90/0x90
[ 139.054798] migrate_vma+0x48a/0xee0
[ 139.054803] dummy_migrate.isra.10+0xd9/0x110 [hmm_dmirror]
[ 139.054812] dummy_fops_unlocked_ioctl+0x1e8/0x330 [hmm_dmirror]
[ 139.054814] ? _cond_resched+0x19/0x30
[ 139.054819] ? selinux_file_ioctl+0x114/0x1e0
[ 139.054823] do_vfs_ioctl+0x96/0x5a0
[ 139.054826] SyS_ioctl+0x79/0x90
[ 139.054830] entry_SYSCALL_64_fastpath+0x13/0x94
[ 139.054832] RIP: 0033:0x7fc07add61e7
[ 139.054834] RSP: 002b:00007fc078cdfd78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 139.054836] RAX: ffffffffffffffda RBX: 00007fc078cdfdf0 RCX: 00007fc07add61e7
[ 139.054837] RDX: 00007fc078cdfdf0 RSI: 00000000c0104802 RDI: 0000000000000003
[ 139.054839] RBP: 00007ffde7ffd470 R08: 0000000000000000 R09: 00007fc078ce0700
[ 139.054840] R10: 00007fc078ce09d0 R11: 0000000000000246 R12: 00007fc078cdfdf8
[ 139.054841] R13: 0000000000000000 R14: 0000000000000010 R15: 00007fc078ce0700
[ 139.054843] sanity_rmem004 D13304 3996 3818 0x00000000
[ 139.054848] Call Trace:
[ 139.054851] __schedule+0x20b/0x6c0
[ 139.054853] schedule+0x36/0x80
[ 139.054856] io_schedule+0x16/0x40
[ 139.054860] __lock_page+0xf2/0x130
[ 139.054863] ? page_cache_tree_insert+0x90/0x90
[ 139.054866] migrate_vma+0x48a/0xee0
[ 139.054870] dummy_migrate.isra.10+0xd9/0x110 [hmm_dmirror]
[ 139.054877] ? avc_has_extended_perms+0xda/0x480
[ 139.054881] dummy_fops_unlocked_ioctl+0x1e8/0x330 [hmm_dmirror]
[ 139.054883] ? _cond_resched+0x19/0x30
[ 139.054887] ? selinux_file_ioctl+0x114/0x1e0
[ 139.054890] do_vfs_ioctl+0x96/0x5a0
[ 139.054893] SyS_ioctl+0x79/0x90
[ 139.054896] entry_SYSCALL_64_fastpath+0x13/0x94
[ 139.054897] RIP: 0033:0x7fc07add61e7
[ 139.054898] RSP: 002b:00007fc0794e0d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 139.054901] RAX: ffffffffffffffda RBX: 00007fc0794e0df0 RCX: 00007fc07add61e7
[ 139.054902] RDX: 00007fc0794e0df0 RSI: 00000000c0104802 RDI: 0000000000000003
[ 139.054903] RBP: 00007ffde7ffd470 R08: 0000000000000000 R09: 00007fc0794e1700
[ 139.054904] R10: 00007fc0794e19d0 R11: 0000000000000246 R12: 00007fc0794e0df8
[ 139.054905] R13: 0000000000000000 R14: 0000000000000010 R15: 00007fc0794e1700
[ 139.054907] sanity_rmem004 D13528 3997 3818 0x00000000
[ 139.054912] Call Trace:
[ 139.054914] __schedule+0x20b/0x6c0
[ 139.054916] schedule+0x36/0x80
[ 139.054920] io_schedule+0x16/0x40
[ 139.054923] __lock_page+0xf2/0x130
[ 139.054927] ? page_cache_tree_insert+0x90/0x90
[ 139.054929] migrate_vma+0x48a/0xee0
[ 139.054933] dummy_migrate.isra.10+0xd9/0x110 [hmm_dmirror]
[ 139.054942] ? copy_user_enhanced_fast_string+0x7/0x10
[ 139.054945] dummy_fops_unlocked_ioctl+0x1e8/0x330 [hmm_dmirror]
[ 139.054947] ? _cond_resched+0x19/0x30
[ 139.054951] ? selinux_file_ioctl+0x114/0x1e0
[ 139.054954] do_vfs_ioctl+0x96/0x5a0
[ 139.054957] SyS_ioctl+0x79/0x90
[ 139.054960] entry_SYSCALL_64_fastpath+0x13/0x94
[ 139.054961] RIP: 0033:0x7fc07add61e7
[ 139.054962] RSP: 002b:00007fc079ce1d78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 139.054964] RAX: ffffffffffffffda RBX: 00007fc079ce1df0 RCX: 00007fc07add61e7
[ 139.054965] RDX: 00007fc079ce1df0 RSI: 00000000c0104802 RDI: 0000000000000003
[ 139.054966] RBP: 00007ffde7ffd470 R08: 0000000000000000 R09: 00007fc079ce2700
[ 139.054968] R10: 00007fc079ce29d0 R11: 0000000000000246 R12: 00007fc079ce1df8
[ 139.054969] R13: 0000000000000000 R14: 0000000000000010 R15: 00007fc079ce2700
[ 139.054971] sanity_rmem004 D13136 3998 3818 0x00000000
[ 139.054975] Call Trace:
[ 139.054977] __schedule+0x20b/0x6c0
[ 139.054979] schedule+0x36/0x80
[ 139.054983] io_schedule+0x16/0x40
[ 139.054986] wait_on_page_bit+0xee/0x120
[ 139.054990] ? page_cache_tree_insert+0x90/0x90
[ 139.054993] __migration_entry_wait+0xe8/0x190
[ 139.054995] migration_entry_wait+0x5f/0x70
[ 139.054998] do_swap_page+0x4c7/0x4e0
[ 139.055001] __handle_mm_fault+0x347/0x9d0
[ 139.055004] handle_mm_fault+0x88/0x150
[ 139.055008] hmm_vma_walk_clear+0x8f/0xd0
[ 139.055010] hmm_vma_walk_pmd+0x1ba/0x250
[ 139.055015] __walk_page_range+0x1e8/0x420
[ 139.055018] walk_page_range+0x73/0xf0
[ 139.055020] hmm_vma_fault+0x180/0x260
[ 139.055023] ? hmm_vma_walk_hole+0xd0/0xd0
[ 139.055024] ? hmm_vma_get_pfns+0x1b0/0x1b0
[ 139.055028] dummy_fault+0xda/0x1f0 [hmm_dmirror]
[ 139.055033] ? __kernel_map_pages+0x70/0xe0
[ 139.055038] ? __alloc_pages_nodemask+0x11b/0x240
[ 139.055041] ? dummy_pt_walk+0x209/0x2f0 [hmm_dmirror]
[ 139.055044] ? dummy_update+0x60/0x60 [hmm_dmirror]
[ 139.055047] dummy_fops_unlocked_ioctl+0x12c/0x330 [hmm_dmirror]
[ 139.055050] do_vfs_ioctl+0x96/0x5a0
[ 139.055054] SyS_ioctl+0x79/0x90
[ 139.055057] entry_SYSCALL_64_fastpath+0x13/0x94
[ 139.055058] RIP: 0033:0x7fc07add61e7
[ 139.055059] RSP: 002b:00007fc07ace3c38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 139.055061] RAX: ffffffffffffffda RBX: 00007fc07ace4700 RCX: 00007fc07add61e7
[ 139.055062] RDX: 00007fc07ace3cd0 RSI: 00000000c0284800 RDI: 0000000000000003
[ 139.055063] RBP: 00007ffde7ffd3b0 R08: 00007fc07ace3ef0 R09: 00007fc07ace4700
[ 139.055064] R10: 00007ffde7ffd470 R11: 0000000000000246 R12: 0000000000000000
[ 139.055066] R13: 0000000000000000 R14: 00007fc07ace49c0 R15: 00007fc07ace4700
[ 139.055067] sanity_rmem004 D13136 3999 3818 0x00000000
[ 139.055072] Call Trace:
[ 139.055074] __schedule+0x20b/0x6c0
[ 139.055076] schedule+0x36/0x80
[ 139.055079] io_schedule+0x16/0x40
[ 139.055083] wait_on_page_bit+0xee/0x120
[ 139.055086] ? page_cache_tree_insert+0x90/0x90
[ 139.055089] __migration_entry_wait+0xe8/0x190
[ 139.055091] migration_entry_wait+0x5f/0x70
[ 139.055094] do_swap_page+0x4c7/0x4e0
[ 139.055096] __handle_mm_fault+0x347/0x9d0
[ 139.055099] handle_mm_fault+0x88/0x150
[ 139.055103] hmm_vma_walk_clear+0x8f/0xd0
[ 139.055105] hmm_vma_walk_pmd+0x1ba/0x250
[ 139.055109] __walk_page_range+0x1e8/0x420
[ 139.055112] walk_page_range+0x73/0xf0
[ 139.055114] hmm_vma_fault+0x180/0x260
[ 139.055116] ? hmm_vma_walk_hole+0xd0/0xd0
[ 139.055118] ? hmm_vma_get_pfns+0x1b0/0x1b0
[ 139.055121] dummy_fault+0xda/0x1f0 [hmm_dmirror]
[ 139.055125] ? __kernel_map_pages+0x70/0xe0
[ 139.055129] ? __alloc_pages_nodemask+0x11b/0x240
[ 139.055133] ? dummy_pt_walk+0x209/0x2f0 [hmm_dmirror]
[ 139.055135] ? dummy_update+0x60/0x60 [hmm_dmirror]
[ 139.055138] dummy_fops_unlocked_ioctl+0x12c/0x330 [hmm_dmirror]
[ 139.055142] do_vfs_ioctl+0x96/0x5a0
[ 139.055145] SyS_ioctl+0x79/0x90
[ 139.055148] entry_SYSCALL_64_fastpath+0x13/0x94
[ 139.055149] RIP: 0033:0x7fc07add61e7
[ 139.055150] RSP: 002b:00007fc07a4e2c38 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
[ 139.055152] RAX: ffffffffffffffda RBX: 00007fc07a4e3700 RCX: 00007fc07add61e7
[ 139.055153] RDX: 00007fc07a4e2cd0 RSI: 00000000c0284800 RDI: 0000000000000003
[ 139.055154] RBP: 00007ffde7ffd3b0 R08: 00007fc07a4e2ef0 R09: 00007fc07a4e3700
[ 139.055155] R10: 00007ffde7ffd470 R11: 0000000000000246 R12: 0000000000000000
[ 139.055156] R13: 0000000000000000 R14: 00007fc07a4e39c0 R15: 00007fc07a4e3700

Next message: David Rientjes: "Re: [RFC PATCH] mm, oom: allow oom reaper to race with exit_mmap"
Previous message: Bjorn Andersson: "Re: [PATCH v6 1/4] firmware: scm: Add new SCM call API for switching memory ownership"
In reply to: Jerome Glisse: "Re: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4"
Next in thread: Jerome Glisse: "Re: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4"
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