On 12 March 2018 at 17:56, Sudeep Holla <sudeep.holla@xxxxxxx> 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@xxxxxxxxxx> wrote: >> On Sat, Mar 3, 2018 at 1:40 AM, Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: >>> On Sat, 3 Mar 2018 01:12:26 +0100 Daniel Vacek <neelx@xxxxxxxxxx> 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