On 12 March 2018 at 17:56, Sudeep Holla sudeep.holla@arm.com wrote:
Hi,
I couldn't find the exact mail corresponding to the patch merged in v4.16-rc5 but commit 864b75f9d6b01 "mm/page_alloc: fix memmap_init_zone pageblock alignment" cause boot hang on my ARM64 platform.
I have also noticed this problem on hi6220 Hikey - arm64.
LKFT: linux-next: Hikey boot failed linux-next-20180308 https://bugs.linaro.org/show_bug.cgi?id=3676
- Naresh
Log: [ 0.000000] NUMA: No NUMA configuration found [ 0.000000] NUMA: Faking a node at [mem 0x0000000000000000-0x00000009ffffffff] [ 0.000000] NUMA: NODE_DATA [mem 0x9fffcb480-0x9fffccf7f] [ 0.000000] Zone ranges: [ 0.000000] DMA32 [mem 0x0000000080000000-0x00000000ffffffff] [ 0.000000] Normal [mem 0x0000000100000000-0x00000009ffffffff] [ 0.000000] Movable zone start for each node [ 0.000000] Early memory node ranges [ 0.000000] node 0: [mem 0x0000000080000000-0x00000000f8f9afff] [ 0.000000] node 0: [mem 0x00000000f8f9b000-0x00000000f908ffff] [ 0.000000] node 0: [mem 0x00000000f9090000-0x00000000f914ffff] [ 0.000000] node 0: [mem 0x00000000f9150000-0x00000000f920ffff] [ 0.000000] node 0: [mem 0x00000000f9210000-0x00000000f922ffff] [ 0.000000] node 0: [mem 0x00000000f9230000-0x00000000f95bffff] [ 0.000000] node 0: [mem 0x00000000f95c0000-0x00000000fe58ffff] [ 0.000000] node 0: [mem 0x00000000fe590000-0x00000000fe5cffff] [ 0.000000] node 0: [mem 0x00000000fe5d0000-0x00000000fe5dffff] [ 0.000000] node 0: [mem 0x00000000fe5e0000-0x00000000fe62ffff] [ 0.000000] node 0: [mem 0x00000000fe630000-0x00000000feffffff] [ 0.000000] node 0: [mem 0x0000000880000000-0x00000009ffffffff] [ 0.000000] Initmem setup node 0 [mem 0x0000000080000000-0x00000009ffffffff]
On Sat, Mar 3, 2018 at 1:08 AM, Daniel Vacek neelx@redhat.com wrote:
On Sat, Mar 3, 2018 at 1:40 AM, Andrew Morton akpm@linux-foundation.org wrote:
On Sat, 3 Mar 2018 01:12:26 +0100 Daniel Vacek neelx@redhat.com wrote:
Commit b92df1de5d28 ("mm: page_alloc: skip over regions of invalid pfns where possible") introduced a bug where move_freepages() triggers a VM_BUG_ON() on uninitialized page structure due to pageblock alignment.
b92df1de5d28 was merged a year ago. Can you suggest why this hasn't been reported before now?
Yeah. I was surprised myself I couldn't find a fix to backport to RHEL. But actually customers started to report this as soon as 7.4 (where b92df1de5d28 was merged in RHEL) was released. I remember reports from September/October-ish times. It's not easily reproduced and happens on a handful of machines only. I guess that's why. But that does not make it less serious, I think.
Though there actually is a report here: https://bugzilla.kernel.org/show_bug.cgi?id=196443
And there are reports for Fedora from July: https://bugzilla.redhat.com/show_bug.cgi?id=1473242 and CentOS: https://bugs.centos.org/view.php?id=13964 and we internally track several dozens reports for RHEL bug https://bugzilla.redhat.com/show_bug.cgi?id=1525121
Enough? ;-)
This makes me wonder whether a -stable backport is really needed...
For some machines it definitely is. Won't hurt either, IMHO.
--nX