On Thu, 2012-06-14 at 16:57 -0700, Yinghai Lu wrote: > On Thu, Jun 14, 2012 at 2:34 PM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote: > > On Thu, 2012-06-14 at 13:56 -0700, Yinghai Lu wrote: > >> On Thu, Jun 14, 2012 at 2:50 AM, Sasha Levin <levinsasha928@xxxxxxxxx> wrote: > >> > On Thu, 2012-06-14 at 12:20 +0900, Tejun Heo wrote: > >> >> On Wed, Jun 13, 2012 at 11:38:55PM +0200, Sasha Levin wrote: > >> >> > Hi all, > >> >> > > >> >> > I'm seeing the following when booting a KVM guest with 65gb of RAM, on latest linux-next. > >> >> > > >> >> > Note that it happens with numa=off. > >> >> > > >> >> > [ 0.000000] BUG: unable to handle kernel paging request at ffff88102febd948 > >> >> > [ 0.000000] IP: [<ffffffff836a6f37>] __next_free_mem_range+0x9b/0x155 > >> >> > >> >> Can you map it back to the source line please? > >> > > >> > mm/memblock.c:583 > >> > > >> > phys_addr_t r_start = ri ? r[-1].base + r[-1].size : 0; > >> > 97: 85 d2 test %edx,%edx > >> > 99: 74 08 je a3 <__next_free_mem_range+0xa3> > >> > 9b: 49 8b 48 f0 mov -0x10(%r8),%rcx > >> > 9f: 49 03 48 e8 add -0x18(%r8),%rcx > >> > > >> > It's the deref on 9b (r8=ffff88102febd958). > >> > >> that reserved.region is allocated by memblock. > >> > >> can you boot with "memblock=debug debug ignore_loglevel" and post > >> whole boot log? > > > > Attached below. I've also noticed it doesn't always happen, but > > increasing the vcpu count (to something around 254) makes it happen > > almost every time. > > > ... > [ 0.000000] memblock: reserved array is doubled to 512 at > [0x102febc080-0x102febf07f] > [ 0.000000] memblock_free: [0x0000102febf080-0x0000102fec0880] > memblock_double_array+0x1b0/0x1e2 > [ 0.000000] memblock_reserve: [0x0000102febc080-0x0000102febf080] > memblock_double_array+0x1c5/0x1e2 > > the reserved regions get double two times to 512. > .... > > [ 0.000000] memblock_free: [0x0000102febc080-0x0000102febf080] memblock_free_reserved_regions+0x37/0x39 > > [ 0.000000] BUG: unable to handle kernel paging request at ffff88102febd948 > > [ 0.000000] IP: [<ffffffff836a5774>] __next_free_mem_range+0x9b/0x155 > > [ 0.000000] PGD 4826063 PUD cf67a067 PMD cf7fa067 PTE 800000102febd160 > > that page table for them is > > [ 0.000000] kernel direct mapping tables up to 0x102fffffff @ [mem > 0xc7e3e000-0xcfffffff] > [ 0.000000] memblock_reserve: [0x000000c7e3e000-0x000000cf7fb000] > native_pagetable_reserve+0xc/0xe > > only near by allocation is swiotlb. > > [ 0.000000] __ex_table already sorted, skipping sort > [ 0.000000] memblock_reserve: [0x000000c3e3e000-0x000000c7e3e000] > __alloc_memory_core_early+0x5c/0x73 > ... > [ 0.000000] memblock_reserve: [0x000000cfff8000-0x000000d0000000] > __alloc_memory_core_early+0x5c/0x73 > [ 0.000000] Checking aperture... > > so the memblock allocation is ok... > > can you please boot with "memtest" to see if there is any memory problem? The host got a memtest treatment, nothing found. (I'll cc the KVM folks as well.) -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>