Re: WARNING: CPU: 0 PID: 2777 at arch/powerpc/mm/hugetlbpage.c:354 h,ugetlb_free_pgd_range+0xc8/0x1e4

[Christophe LEROY <christophe.leroy@c-s.fr>]

Le 20/12/2017 à 13:17, Christophe LEROY a écrit :
> Trying to malloc() with libhugetlbfs, it runs indefinitly doing page 
> faults in do_page_fault()/hugetlb_fault().
> When interrupting the blocked app with CTRL+C, I get the following WARNING:
> 
> Any idea of what can be wrong ? I'm on a 8xx with 512k huge pages.


It looks like something goes wrong when the app tries to mmap a 
hugetlbpage at a given address.
When it requests the page with a NULL address, it works well.

Any idea ?

Christophe

> 
> [162980.035629] WARNING: CPU: 0 PID: 2777 at 
> arch/powerpc/mm/hugetlbpage.c:354 h
> ugetlb_free_pgd_range+0xc8/0x1e4
> [162980.035699] CPU: 0 PID: 2777 Comm: malloc Tainted: G W       4.14.6-s
> 3k-dev-ga8e8e8b176-svn9134 #85
> [162980.035744] task: c67e2c00 task.stack: c668e000
> [162980.035783] NIP:  c000fe18 LR: c00e1eec CTR: c00f90c0
> [162980.035830] REGS: c668fc20 TRAP: 0700   Tainted: G W        (4.14.6-s
> 3k-dev-ga8e8e8b176-svn9134)
> [162980.035854] MSR:  00029032 <EE,ME,IR,DR,RI>  CR: 24044224 XER: 20000000
> [162980.036003]
> [162980.036003] GPR00: c00e1eec c668fcd0 c67e2c00 00000010 c6869410 
> 10080000 000
> 00000 77fb4000
> [162980.036003] GPR08: ffff0001 0683c001 00000000 ffffff80 44028228 
> 10018a34 000
> 04008 418004fc
> [162980.036003] GPR16: c668e000 00040100 c668e000 c06c0000 c668fe78 
> c668e000 c68
> 35ba0 c668fd48
> [162980.036003] GPR24: 00000000 73ffffff 74000000 00000001 77fb4000 
> 100fffff 101
> 00000 10100000
> [162980.036743] NIP [c000fe18] hugetlb_free_pgd_range+0xc8/0x1e4
> [162980.036839] LR [c00e1eec] free_pgtables+0x12c/0x150
> [162980.036861] Call Trace:
> [162980.036939] [c668fcd0] [c00f0774] unlink_anon_vmas+0x1c4/0x214 
> (unreliable)
> [162980.037040] [c668fd10] [c00e1eec] free_pgtables+0x12c/0x150
> [162980.037118] [c668fd40] [c00eabac] exit_mmap+0xe8/0x1b4
> [162980.037210] [c668fda0] [c0019710] mmput.part.9+0x20/0xd8
> [162980.037301] [c668fdb0] [c001ecb0] do_exit+0x1f0/0x93c
> [162980.037386] [c668fe00] [c001f478] do_group_exit+0x40/0xcc
> [162980.037479] [c668fe10] [c002a76c] get_signal+0x47c/0x614
> [162980.037570] [c668fe70] [c0007840] do_signal+0x54/0x244
> [162980.037654] [c668ff30] [c0007ae8] do_notify_resume+0x34/0x88
> [162980.037744] [c668ff40] [c000dae8] do_user_signal+0x74/0xc4
> [162980.037781] Instruction dump:
> [162980.037821] 7fdff378 81370000 54a3463a 80890020 7d24182e 7c841a14 
> 712a0004 4
> 082ff94
> [162980.038014] 2f890000 419e0010 712a0ff0 408200e0 <0fe00000> 54a9000a 
> 7f984840
>   419d0094
> [162980.038216] ---[ end trace c0ceeca8e7a5800a ]---
> [162980.038754] BUG: non-zero nr_ptes on freeing mm: 1
> [162985.363322] BUG: non-zero nr_ptes on freeing mm: -1
> 
> Christophe