Re: [PATCH] mapletree-vs-khugepaged

[Liam Howlett]

* Heiko Carstens <hca@xxxxxxxxxxxxx> [220429 08:10]:
> On Thu, Apr 28, 2022 at 10:20:40AM -0700, Guenter Roeck wrote:
> > On Wed, Apr 27, 2022 at 03:10:45PM -0700, Andrew Morton wrote:
> > > Fix mapletree for patch series "Make khugepaged collapse readonly FS THP
> > > more consistent", v3.
> > > 
> > > Cc: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> > > Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > 
> > This patch causes all my sparc64 boot tests to fail. Bisect and crash logs
> > attached.
> > 
> > Guenter
> > 
> > ---
> > [   12.624703] Unable to handle kernel paging request at virtual address 0e00000000000000
> > [   12.624793] tsk->{mm,active_mm}->context = 0000000000000005
> > [   12.624823] tsk->{mm,active_mm}->pgd = fffff800048b8000
> > [   12.624849]               \|/ ____ \|/
> > [   12.624849]               "@'/ .. \`@"
> > [   12.624849]               /_| \__/ |_\
> > [   12.624849]                  \__U_/
> > [   12.624874] init(1): Oops [#1]
> > [   12.625194] CPU: 0 PID: 1 Comm: init Not tainted 5.18.0-rc4-next-20220428 #1
> > [   12.625421] TSTATE: 0000009911001606 TPC: 00000000005e6330 TNPC: 00000000005e6334 Y: 00000000    Not tainted
> > [   12.625455] TPC: <mmap_region+0x150/0x700>
> > [   12.625503] g0: 0000000000619a00 g1: 0000000000000000 g2: fffff8000488b200 g3: 0000000000000000
> > [   12.625537] g4: fffff8000414a9a0 g5: fffff8001dd3e000 g6: fffff8000414c000 g7: 0000000000000000
> > [   12.625569] o0: 0000000000000000 o1: 0000000000000000 o2: 0000000001167b68 o3: 0000000000f51bb8
> > [   12.625601] o4: fffff80100301fff o5: fffff8000414fc20 sp: fffff8000414f341 ret_pc: 00000000005e6310
> > [   12.625630] RPC: <mmap_region+0x130/0x700>
> > [   12.625692] l0: fffff8000488b260 l1: 000000000000008b l2: fffff80100302000 l3: 0000000000000000
> > [   12.625725] l4: fffff80100301fff l5: 0000000000000000 l6: 30812c2a1dd8556f l7: fffff8000414b438
> > [   12.625762] i0: fffff800044f58a0 i1: fffff801001ec000 i2: 0e00000000000000 i3: 0000000000000075
> > [   12.625795] i4: 0000000000000000 i5: fffff8000414fde0 i6: fffff8000414f461 i7: 00000000005e6c58
> > [   12.625833] I7: <do_mmap+0x378/0x500>
> > [   12.625906] Call Trace:
> > [   12.626006] [<00000000005e6c58>] do_mmap+0x378/0x500
> > [   12.626092] [<00000000005bdc98>] vm_mmap_pgoff+0x78/0x100
> > [   12.626112] [<00000000005e3d24>] ksys_mmap_pgoff+0x164/0x1c0
> > [   12.626129] [<0000000000406294>] linux_sparc_syscall+0x34/0x44
> > [   12.626198] Disabling lock debugging due to kernel taint
> > [   12.626286] Caller[00000000005e6c58]: do_mmap+0x378/0x500
> > [   12.626335] Caller[00000000005bdc98]: vm_mmap_pgoff+0x78/0x100
> > [   12.626354] Caller[00000000005e3d24]: ksys_mmap_pgoff+0x164/0x1c0
> > [   12.626371] Caller[0000000000406294]: linux_sparc_syscall+0x34/0x44
> > [   12.626390] Caller[fffff8010001d88c]: 0xfffff8010001d88c
> > [   12.626537] Instruction DUMP:
> > [   12.626567]  a6100008
> > [   12.626678]  02c68006
> > [   12.626685]  01000000
> > [   12.626690] <c25e8000>
> > [   12.626696]  80a04012
> > [   12.626701]  22600077
> > [   12.626707]  c25ea088
> > [   12.626712]  22c4c00a
> > [   12.626717]  f277a7c7
> > [   12.626728]
> > [   12.627169] Kernel panic - not syncing: Attempted to kill init! exitcode=0x00000009
> 
> FWIW, same on s390 - linux-next is completely broken. Note: I didn't
> bisect, but given that the call trace, and even the failing address
> match, I'm quite confident it is the same reason.

This is worth a lot to me.  Thanks for the report and the testing.

Regards,
Liam

> 
> Unable to handle kernel pointer dereference in virtual kernel address space
> Failing address: 0e00000000000000 TEID: 0e00000000000803
> Fault in home space mode while using kernel ASCE.
> AS:00000000bac44007 R3:00000001ffff0007 S:00000001fffef800 P:000000000000003d
> Oops: 0038 ilc:3 [#1] SMP
> CPU: 3 PID: 79757 Comm: pt_upgrade_race Tainted: G            E K   5.18.0-20220428.rc4.git500.bdc61aad77fa.300.fc35.s390x+next #1
> Hardware name: IBM 2964 NC9 702 (z/VM 6.4.0)
> Krnl PSW : 0704c00180000000 00000000b912c9a2 (mmap_region+0x1a2/0x8a8)
>            R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:0 PM:0 RI:0 EA:3
> Krnl GPRS: 0000000000000000 0e00000000000000 0000000000000000 0000000000000000
>            ffffffffffffffff 000000000000000f 00000380016b3d98 0000080000100000
>            000000008364c100 0000080000000000 0000000000100077 0e00000000000000
>            00000000909da100 00000380016b3c58 00000000b912c982 00000380016b3b40
> Krnl Code: 00000000b912c992: a774002c          brc     7,00000000b912c9ea
>            00000000b912c996: ecb80225007c      cgij    %r11,0,8,00000000b912cde0
>           #00000000b912c99c: e310f0f80004      lg      %r1,248(%r15)
>           >00000000b912c9a2: e37010000020      cg      %r7,0(%r1)
>            00000000b912c9a8: a784010b          brc     8,00000000b912cbbe
>            00000000b912c9ac: e310f0e80004      lg      %r1,232(%r15)
>            00000000b912c9b2: ec180013007c      cgij    %r1,0,8,00000000b912c9d8
>            00000000b912c9b8: e310f0e80004      lg      %r1,232(%r15)
> Call Trace:
>  [<00000000b912c9a2>] mmap_region+0x1a2/0x8a8
> ([<00000000b912c982>] mmap_region+0x182/0x8a8)
>  [<00000000b912d492>] do_mmap+0x3ea/0x4c8
>  [<00000000b90fb9cc>] vm_mmap_pgoff+0xd4/0x170
>  [<00000000b9129c9a>] ksys_mmap_pgoff+0x62/0x238
>  [<00000000b912a034>] __s390x_sys_old_mmap+0x74/0x98
>  [<00000000b9a78ff8>] __do_syscall+0x1d8/0x200
>  [<00000000b9a872a2>] system_call+0x82/0xb0
> Last Breaking-Event-Address:
>  [<00000000b9b9e678>] __s390_indirect_jump_r14+0x0/0xc
> Kernel panic - not syncing: Fatal exception: panic_on_oops