Thread (16 messages) flat view 16 messages, 3 authors, 2019-06-21

Re: [PATCH v3 0/6] mm: Further memory block device cleanups

From: Qian Cai <hidden>
Date: 2019-06-21 19:07:46
Also in: linux-acpi, linux-mm, lkml

On Fri, 2019-06-21 at 20:56 +0200, David Hildenbrand wrote:
On 21.06.19 20:24, David Hildenbrand wrote:
quoted
On 21.06.19 17:15, Qian Cai wrote:
quoted
On Thu, 2019-06-20 at 20:31 +0200, David Hildenbrand wrote:
quoted
@Andrew: Only patch 1, 4 and 6 changed compared to v1.

Some further cleanups around memory block devices. Especially, clean up
and simplify walk_memory_range(). Including some other minor cleanups.

Compiled + tested on x86 with DIMMs under QEMU. Compile-tested on ppc64.

v2 -> v3:
- "mm/memory_hotplug: Rename walk_memory_range() and pass start+size .."
-- Avoid warning on ppc.
- "drivers/base/memory.c: Get rid of find_memory_block_hinted()"
-- Fixup a comment regarding hinted devices.

v1 -> v2:
- "mm: Section numbers use the type "unsigned long""
-- "unsigned long i" -> "unsigned long nr", in one case -> "int i"
- "drivers/base/memory.c: Get rid of find_memory_block_hinted("
-- Fix compilation error
-- Get rid of the "hint" parameter completely

David Hildenbrand (6):
  mm: Section numbers use the type "unsigned long"
  drivers/base/memory: Use "unsigned long" for block ids
  mm: Make register_mem_sect_under_node() static
  mm/memory_hotplug: Rename walk_memory_range() and pass start+size
    instead of pfns
  mm/memory_hotplug: Move and simplify walk_memory_blocks()
  drivers/base/memory.c: Get rid of find_memory_block_hinted()

 arch/powerpc/platforms/powernv/memtrace.c |  23 ++---
 drivers/acpi/acpi_memhotplug.c            |  19 +---
 drivers/base/memory.c                     | 120 +++++++++++++---------
 drivers/base/node.c                       |   8 +-
 include/linux/memory.h                    |   5 +-
 include/linux/memory_hotplug.h            |   2 -
 include/linux/mmzone.h                    |   4 +-
 include/linux/node.h                      |   7 --
 mm/memory_hotplug.c                       |  57 +---------
 mm/sparse.c                               |  12 +--
 10 files changed, 106 insertions(+), 151 deletions(-)
This series causes a few machines are unable to boot triggering endless
soft
lockups. Reverted those commits fixed the issue.

97f4217d1da0 Revert "mm/memory_hotplug: rename walk_memory_range() and
pass
start+size instead of pfns"
c608eebf33c6 Revert "mm-memory_hotplug-rename-walk_memory_range-and-pass-
startsize-instead-of-pfns-fix"
34b5e4ab7558 Revert "mm/memory_hotplug: move and simplify
walk_memory_blocks()"
59a9f3eec5d1 Revert "drivers/base/memory.c: Get rid of
find_memory_block_hinted()"
5cfcd52288b6 Revert "drivers-base-memoryc-get-rid-of-
find_memory_block_hinted-
v3"

[    4.582081][    T1] ACPI FADT declares the system doesn't support PCIe
ASPM,
so disable it
[    4.590405][    T1] ACPI: bus type PCI registered
[    4.592908][    T1] PCI: MMCONFIG for domain 0000 [bus 00-ff] at [mem
0x80000000-0x8fffffff] (base 0x80000000)
[    4.601860][    T1] PCI: MMCONFIG at [mem 0x80000000-0x8fffffff]
reserved in
E820
[    4.601860][    T1] PCI: Using configuration type 1 for base access
[   28.661336][   C16] watchdog: BUG: soft lockup - CPU#16 stuck for 22s!
[swapper/0:1]
[   28.671351][   C16] Modules linked in:
[   28.671354][   C16] CPU: 16 PID: 1 Comm: swapper/0 Not tainted 5.2.0-
rc5-
next-20190621+ #1
[   28.681366][   C16] Hardware name: HPE ProLiant DL385 Gen10/ProLiant
DL385
Gen10, BIOS A40 03/09/2018
[   28.691334][   C16] RIP: 0010:_raw_spin_unlock_irqrestore+0x2f/0x40
[   28.701334][   C16] Code: 55 48 89 e5 41 54 49 89 f4 be 01 00 00 00 53
48 8b
55 08 48 89 fb 48 8d 7f 18 e8 4c 89 7d ff 48 89 df e8 94 f9 7d ff 41 54 9d
<65>
ff 0d c2 44 8d 48 5b 41 5c 5d c3 0f 1f 44 00 00 0f 1f 44 00 00
[   28.711354][   C16] RSP: 0018:ffff888205b27bf8 EFLAGS: 00000246
ORIG_RAX:
ffffffffffffff13
[   28.721372][   C16] RAX: 0000000000000000 RBX: ffff8882053d6138 RCX:
ffffffffb6f2a3b8
[   28.731371][   C16] RDX: 1ffff11040a7ac27 RSI: dffffc0000000000 RDI:
ffff8882053d6138
[   28.741371][   C16] RBP: ffff888205b27c08 R08: ffffed1040a7ac28 R09:
ffffed1040a7ac27
[   28.751334][   C16] R10: ffffed1040a7ac27 R11: ffff8882053d613b R12:
0000000000000246
[   28.751370][   C16] R13: ffff888205b27c98 R14: ffff8884504d0a20 R15:
0000000000000000
[   28.761368][   C16] FS:  0000000000000000(0000)
GS:ffff888454500000(0000)
knlGS:0000000000000000
[   28.771373][   C16] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   28.781334][   C16] CR2: 0000000000000000 CR3: 00000007c9012000 CR4:
00000000001406a0
[   28.791333][   C16] Call Trace:
[   28.791374][   C16]  klist_next+0xd8/0x1c0
[   28.791374][   C16]  subsys_find_device_by_id+0x13b/0x1f0
[   28.801334][   C16]  ? bus_find_device_by_name+0x20/0x20
[   28.801370][   C16]  ? kobject_put+0x23/0x250
[   28.811333][   C16]  walk_memory_blocks+0x6c/0xb8
[   28.811353][   C16]  ? write_policy_show+0x40/0x40
[   28.821334][   C16]  link_mem_sections+0x7e/0xa0
[   28.821369][   C16]  ? unregister_memory_block_under_nodes+0x210/0x210
[   28.831353][   C16]  ? __register_one_node+0x3bd/0x600
[   28.831353][   C16]  topology_init+0xbf/0x126
[   28.841364][   C16]  ? enable_cpu0_hotplug+0x1a/0x1a
[   28.841368][   C16]  do_one_initcall+0xfe/0x45a
[   28.851334][   C16]  ? initcall_blacklisted+0x150/0x150
[   28.851353][   C16]  ? kasan_check_write+0x14/0x20
[   28.861333][   C16]  ? up_write+0x75/0x140
[   28.861369][   C16]  kernel_init_freeable+0x619/0x6ac
[   28.871333][   C16]  ? rest_init+0x188/0x188
[   28.871353][   C16]  kernel_init+0x11/0x138
[   28.881363][   C16]  ? rest_init+0x188/0x188
[   28.881363][   C16]  ret_from_fork+0x22/0x40
[   56.661336][   C16] watchdog: BUG: soft lockup - CPU#16 stuck for 22s!
[swapper/0:1]
[   56.671352][   C16] Modules linked in:
[   56.671354][   C16] CPU: 16 PID: 1 Comm: swapper/0 Tainted:
G             L    5.2.0-rc5-next-20190621+ #1
[   56.681357][   C16] Hardware name: HPE ProLiant DL385 Gen10/ProLiant
DL385
Gen10, BIOS A40 03/09/2018
[   56.691356][   C16] RIP: 0010:subsys_find_device_by_id+0x168/0x1f0
[   56.701334][   C16] Code: 48 85 c0 74 3e 48 8d 78 58 e8 14 77 ca ff 4d
8b 7e
58 4d 85 ff 74 2c 49 8d bf a0 03 00 00 e8 bf 75 ca ff 45 39 a7 a0 03 00 00
<75>
c9 4c 89 ff e8 0e 89 ff ff 48 85 c0 74 bc 48 89 df e8 21 3b 24
[   56.721333][   C16] RSP: 0018:ffff888205b27c68 EFLAGS: 00000287
ORIG_RAX:
ffffffffffffff13
[   56.721370][   C16] RAX: 0000000000000000 RBX: ffff888205b27c90 RCX:
ffffffffb74c9dc1
[   56.731370][   C16] RDX: 0000000000000003 RSI: dffffc0000000000 RDI:
ffff8888774ec3e0
[   56.741371][   C16] RBP: ffff888205b27cf8 R08: ffffed1040a7ac28 R09:
ffffed1040a7ac27
[   56.751335][   C16] R10: ffffed1040a7ac27 R11: ffff8882053d613b R12:
0000000000085c1b
[   56.761334][   C16] R13: 1ffff11040b64f8e R14: ffff888450de4a20 R15:
ffff8888774ec040
[   56.761372][   C16] FS:  0000000000000000(0000)
GS:ffff888454500000(0000)
knlGS:0000000000000000
[   56.771374][   C16] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   56.781370][   C16] CR2: 0000000000000000 CR3: 00000007c9012000 CR4:
00000000001406a0
[   56.791373][   C16] Call Trace:
[   56.791373][   C16]  ? bus_find_device_by_name+0x20/0x20
[   56.801334][   C16]  ? kobject_put+0x23/0x250
[   56.801334][   C16]  walk_memory_blocks+0x6c/0xb8
[   56.811333][   C16]  ? write_policy_show+0x40/0x40
[   56.811353][   C16]  link_mem_sections+0x7e/0xa0
[   56.811353][   C16]  ? unregister_memory_block_under_nodes+0x210/0x210
[   56.821333][   C16]  ? __register_one_node+0x3bd/0x600
[   56.831333][   C16]  topology_init+0xbf/0x126
[   56.831355][   C16]  ? enable_cpu0_hotplug+0x1a/0x1a
[   56.841334][   C16]  do_one_initcall+0xfe/0x45a
[   56.841334][   C16]  ? initcall_blacklisted+0x150/0x150
[   56.851333][   C16]  ? kasan_check_write+0x14/0x20
[   56.851354][   C16]  ? up_write+0x75/0x140
[   56.861333][   C16]  kernel_init_freeable+0x619/0x6ac
[   56.861333][   C16]  ? rest_init+0x188/0x188
[   56.861369][   C16]  kernel_init+0x11/0x138
[   56.871333][   C16]  ? rest_init+0x188/0x188
[   56.871354][   C16]  ret_from_fork+0x22/0x40
[   64.601362][   C16] rcu: INFO: rcu_sched self-detected stall on CPU
[   64.611335][   C16] rcu: 	16-....: (5958 ticks this GP)
idle=37e/1/0x4000000000000002 softirq=27/27 fqs=3000 
[   64.621334][   C16] 	(t=6002 jiffies g=-1079 q=25)
[   64.621334][   C16] NMI backtrace for cpu 16
[   64.621374][   C16] CPU: 16 PID: 1 Comm: swapper/0 Tainted:
G             L    5.2.0-rc5-next-20190621+ #1
[   64.631372][   C16] Hardware name: HPE ProLiant DL385 Gen10/ProLiant
DL385
Gen10, BIOS A40 03/09/2018
[   64.641371][   C16] Call Trace:
[   64.651337][   C16]  <IRQ>
[   64.651376][   C16]  dump_stack+0x62/0x9a
[   64.651376][   C16]  nmi_cpu_backtrace.cold.0+0x2e/0x33
[   64.661337][   C16]  ? nmi_cpu_backtrace_handler+0x20/0x20
[   64.661337][   C16]  nmi_trigger_cpumask_backtrace+0x1a6/0x1b9
[   64.671353][   C16]  arch_trigger_cpumask_backtrace+0x19/0x20
[   64.681366][   C16]  rcu_dump_cpu_stacks+0x18b/0x1d6
[   64.681366][   C16]  rcu_sched_clock_irq.cold.64+0x368/0x791
[   64.691336][   C16]  ? kasan_check_read+0x11/0x20
[   64.691354][   C16]  ? __raise_softirq_irqoff+0x66/0x150
[   64.701336][   C16]  update_process_times+0x2f/0x60
[   64.701362][   C16]  tick_periodic+0x38/0xe0
[   64.711334][   C16]  tick_handle_periodic+0x2e/0x80
[   64.711353][   C16]  smp_apic_timer_interrupt+0xfb/0x370
[   64.721367][   C16]  apic_timer_interrupt+0xf/0x20
[   64.721367][   C16]  </IRQ>
[   64.721367][   C16] RIP: 0010:_raw_spin_unlock_irqrestore+0x2f/0x40
[   64.731370][   C16] Code: 55 48 89 e5 41 54 49 89 f4 be 01 00 00 00 53 
@Qian Cai, unfortunately I can't reproduce.

If you get the chance, it would be great if you could retry with
diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index 972c5336bebf..742f99ddd148 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -868,6 +868,9 @@ int walk_memory_blocks(unsigned long start, unsigned
long size,
        unsigned long block_id;
        int ret = 0;

+       if (!size)
+               return;
+
        for (block_id = start_block_id; block_id <= end_block_id;
block_id++) {
                mem = find_memory_block_by_id(block_id);
                if (!mem)



If both, start and size are 0, we would get a veeeery long loop. This
would mean that we have an online node that does not span any pages at
all (pgdat->node_start_pfn = 0, start_pfn + pgdat->node_spanned_pages = 0).

...trying to reproduce with QEMU (setting 0MB for the second node):

qemu-system-x86_64 --enable-kvm -m 4G,maxmem=20G,slots=2 \
	-smp sockets=2,cores=1 \
	-numa node,nodeid=0,cpus=0,mem=4G \
	-numa node,nodeid=1,cpus=1,mem=0 ...

I can indeed see that the node is online and
"pgdat->node_start_pfn == 0 && start_pfn + pgdat->node_spanned_pages == 0".

However, the kernel segfaults in an unrelated code path, so I can't
verify if this solves this problem:

[    0.313284] BUG: kernel NULL pointer dereference, address: 00000000000000a0
[    0.313479] #PF: supervisor read access in kernel mode
[    0.313479] #PF: error_code(0x0000) - not-present page
[    0.313479] PGD 0 P4D 0 
[    0.313479] Oops: 0000 [#1] SMP PTI
[    0.313479] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 5.2.0-rc5-next-
20190620+ #56
[    0.313479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.4
[    0.313479] RIP: 0010:bus_add_device+0x59/0x110
[    0.313479] Code: 20 48 89 df e8 f8 b4 ff ff 41 89 c4 85 c0 0f 85 81 00 00
00 48 8b 53 50 48 85 d2 75 03 48 8b 135
[    0.313479] RSP: 0000:ffffb4a6c0013e20 EFLAGS: 00010246
[    0.313479] RAX: 0000000000000000 RBX: ffff8b61bac23800 RCX:
0000000000000000
[    0.313479] RDX: ffff8b61bac29038 RSI: ffff8b61bac23800 RDI:
ffff8b61bac23800
[    0.313479] RBP: ffffffff9d2f4500 R08: 0000000000000000 R09:
0000000000000001
[    0.313479] R10: 0000000000000000 R11: ffff8b61bad20878 R12:
0000000000000000
[    0.313479] R13: 0000000000000000 R14: 0000000000000000 R15:
0000000000000000
[    0.313479] FS:  0000000000000000(0000) GS:ffff8b61bba00000(0000)
knlGS:0000000000000000
[    0.313479] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[    0.313479] CR2: 00000000000000a0 CR3: 0000000013c24000 CR4:
00000000000006f0
[    0.313479] DR0: 0000000000000000 DR1: 0000000000000000 DR2:
0000000000000000
[    0.313479] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7:
0000000000000400
[    0.313479] Call Trace:
[    0.313479]  device_add+0x304/0x660
[    0.313479]  ? __init_waitqueue_head+0x31/0x50
[    0.313479]  __register_one_node+0x67/0x170
[    0.313479]  __try_online_node.cold+0x3e/0x78
[    0.313479]  try_online_node+0x25/0x40
[    0.313479]  do_cpu_up+0x36/0xc0
[    0.313479]  smp_init+0x59/0xb3
[    0.313479]  kernel_init_freeable+0x11a/0x247
[    0.313479]  ? rest_init+0x23f/0x23f
[    0.313479]  kernel_init+0x5/0xf1
[    0.313479]  ret_from_fork+0x3a/0x50
[    0.313479] Modules linked in:

Figuring out what goes wrong here (maybe QEMU creating a weird
system configuration) is a different journey :)
That is a separate issue need to revert,

"x86, numa: always initialize all possible nodes"

and then, you should be able to reproduce.
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