On Thu, Jul 09, 2020 at 09:21:13PM +0100, Matthew Wilcox (Oracle) wrote:
> Simplify both the implementation and the output by splitting all the
> compound page information onto a second line.
>
> Reported-by: John Hubbard <jhubbard@xxxxxxxxxx>
> Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
dump_page() starts to crash occasionally. The offset below points to this
patch. Any thought?
[ 2999.340055][ T5516] page:0000000084997a23 refcount:1 mapcount:0 mapping:0000000000000000 index:0xffff888bf243bf40 pfn:0xbf2438
[ 2999.398824][ T5516] page:0000000084997a23 refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888bf243ad40 pfn:0xbf2438
[ 2999.455037][ T5516] flags: 0x1bfffc000000000()
[ 2999.476870][ T5516] raw: 01bfffc000000000 dead000000000100 dead000000000122 0000000000000000
[ 2999.518459][ T5516] raw: ffff888bf243ad40 00000000002a0000 00000000ffffffff 0000000000000000
[ 2999.560177][ T5516] page dumped because: VM_BUG_ON_PAGE(!PageCompound(page))
[ 2999.595087][ T5516] ------------[ cut here ]------------
[ 2999.625075][ T5516] kernel BUG at include/linux/mm.h:786!
[ 2999.652433][ T5516] invalid opcode: 0000 [#1] SMP KASAN PTI
[ 2999.679523][ T5516] CPU: 35 PID: 5516 Comm: test.sh Not tainted 5.8.0-next-20200804 #2
[ 2999.718652][ T5516] Hardware name: HP ProLiant ML350 Gen9, BIOS P92 07/11/2014
[ 2999.755698][ T5516] RIP: 0010:__dump_page+0xe8b/0x12f0
compound_mapcount at include/linux/mm.h:786
(inlined by) compound_mapcount at include/linux/mm.h:784
(inlined by) __dump_page at mm/debug.c:108
[ 2999.784590][ T5516] Code: 06 49 01 c1 e9 72 f4 ff ff 48 89 df e8 5e 12 16 00 e9 09 fe ff ff 48 c7 c6 80 41 cc a8 48 89 df e8 7a f1 ff ff 0f 1f 44 00 00 <0f> 0b 48 c7 c7 80 25 cb ad e8 33 f5 71 00 48 c7 c6 80 41 cc a8 48
[ 2999.890974][ T5516] RSP: 0018:ffffc9000a3c78d0 EFLAGS: 00010282
[ 2999.920196][ T5516] RAX: 0000000000000000 RBX: ffffea002fc90e00 RCX: ffffffffa8095282
[ 2999.958834][ T5516] RDX: 1ffffd4005f921c7 RSI: 0000000000000000 RDI: ffffea002fc90e38
[ 2999.997374][ T5516] RBP: 1ffff92001478f22 R08: ffffed118cf0de7a R09: ffffed118cf0de7a
[ 3000.035972][ T5516] R10: ffff888c6786f3cf R11: ffffed118cf0de79 R12: ffffea002fc90e08
[ 3000.074836][ T5516] R13: ffffea002fc90e00 R14: ffffea002fc90e08 R15: ffffea002fc90e00
[ 3000.113842][ T5516] FS: 00007fae1ff5e740(0000) GS:ffff888c67840000(0000) knlGS:0000000000000000
[ 3000.156525][ T5516] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3000.189099][ T5516] CR2: 00005578d493a1b8 CR3: 0000000610836005 CR4: 00000000001706e0
[ 3000.227643][ T5516] Call Trace:
[ 3000.243118][ T5516] ? page_init_poison+0x40/0x40
[ 3000.266242][ T5516] ? lockdep_hardirqs_on_prepare+0x33e/0x4e0
[ 3000.294621][ T5516] ? _raw_spin_unlock_irq+0x1f/0x30
[ 3000.322775][ T5516] ? trace_hardirqs_on+0x20/0x1b5
[ 3000.350565][ T5516] ? lockdep_hardirqs_on_prepare+0x4e0/0x4e0
[ 3000.383465][ T5516] ? start_isolate_page_range+0x301/0x690
[ 3000.416514][ T5516] ? drain_all_pages+0x4a/0x7a0
[ 3000.441585][ T5516] ? mark_lock+0x147/0x1800
[ 3000.463184][ T5516] ? init_pwq+0x340/0x340
[ 3000.483738][ T5516] ? find_held_lock+0x33/0x1c0
[ 3000.506497][ T5516] ? print_irqtrace_events+0x270/0x270
[ 3000.532505][ T5516] ? start_isolate_page_range+0x344/0x690
[ 3000.560632][ T5516] ? mark_held_locks+0xb0/0x110
[ 3000.583751][ T5516] ? rwlock_bug.part.1+0x90/0x90
[ 3000.610492][ T5516] ? lockdep_hardirqs_on_prepare+0x33e/0x4e0
[ 3000.640146][ T5516] ? _raw_spin_unlock_irqrestore+0x39/0x40
[ 3000.671680][ T5516] dump_page+0x9/0x20
[ 3000.690807][ T5516] start_isolate_page_range+0x4ac/0x690
[ 3000.717529][ T5516] ? state_show+0xc0/0xc0
[ 3000.738137][ T5516] __offline_pages+0x199/0xe30
[ 3000.761471][ T5516] ? __mutex_lock+0x4aa/0x1390
[ 3000.784203][ T5516] ? rwlock_bug.part.1+0x90/0x90
[ 3000.807941][ T5516] ? device_offline+0x75/0x1c0
[ 3000.833233][ T5516] ? __add_memory+0x60/0x60
[ 3000.857530][ T5516] ? mutex_lock_io_nested+0x1270/0x1270
[ 3000.886608][ T5516] ? klist_next+0x253/0x430
[ 3000.911512][ T5516] ? device_is_dependent+0x140/0x140
[ 3000.937751][ T5516] ? device_for_each_child+0xe1/0x140
[ 3000.963576][ T5516] ? device_remove_class_symlinks+0x1a0/0x1a0
[ 3000.992753][ T5516] ? state_show+0xc0/0xc0
[ 3001.013490][ T5516] memory_subsys_offline+0xcb/0x160
[ 3001.038346][ T5516] device_offline+0x131/0x1c0
[ 3001.060614][ T5516] ? sysfs_file_ops+0x160/0x160
[ 3001.083866][ T5516] state_store+0x78/0xa0
[ 3001.103882][ T5516] kernfs_fop_write+0x208/0x410
[ 3001.127602][ T5516] ? __sb_start_write+0x1f8/0x2e0
[ 3001.151596][ T5516] vfs_write+0x1a3/0x5d0
[ 3001.171713][ T5516] ksys_write+0xec/0x1c0
[ 3001.192625][ T5516] ? __x64_sys_read+0xa0/0xa0
[ 3001.215692][ T5516] ? syscall_enter_from_user_mode+0x20/0x210
[ 3001.245499][ T5516] ? trace_hardirqs_on+0x20/0x1b5
[ 3001.269466][ T5516] do_syscall_64+0x33/0x40
[ 3001.290710][ T5516] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 3001.319164][ T5516] RIP: 0033:0x7fae1f63fb28
[ 3001.340214][ T5516] Code: 89 02 48 c7 c0 ff ff ff ff eb b3 0f 1f 80 00 00 00 00 f3 0f 1e fa 48 8d 05 35 4b 2d 00 8b 00 85 c0 75 17 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 41 54 49 89 d4 55
[ 3001.448642][ T5516] RSP: 002b:00007ffdad11d068 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
[ 3001.492000][ T5516] RAX: ffffffffffffffda RBX: 0000000000000008 RCX: 00007fae1f63fb28
[ 3001.531309][ T5516] RDX: 0000000000000008 RSI: 00005649a73b6240 RDI: 0000000000000001
[ 3001.571310][ T5516] RBP: 00005649a73b6240 R08: 000000000000000a R09: 00007fae1f6d0c80
[ 3001.610126][ T5516] R10: 000000000000000a R11: 0000000000000246 R12: 00007fae1f9106c0
[ 3001.648869][ T5516] R13: 0000000000000008 R14: 00007fae1f90b880 R15: 0000000000000008
[ 3001.687284][ T5516] Modules linked in: loop kvm_intel kvm irqbypass ip_tables x_tables sd_mod ahci libahci tg3 firmware_class libata libphy hpsa scsi_transport_sas dm_mirror dm_region_hash dm_log dm_mod
[ 3001.776222][ T5516] ---[ end trace 263095a22deddb65 ]---
[ 3001.802318][ T5516] RIP: 0010:__dump_page+0xe8b/0x12f0
[ 3001.828306][ T5516] Code: 06 49 01 c1 e9 72 f4 ff ff 48 89 df e8 5e 12 16 00 e9 09 fe ff ff 48 c7 c6 80 41 cc a8 48 89 df e8 7a f1 ff ff 0f 1f 44 00 00 <0f> 0b 48 c7 c7 80 25 cb ad e8 33 f5 71 00 48 c7 c6 80 41 cc a8 48
[ 3001.931924][ T5516] RSP: 0018:ffffc9000a3c78d0 EFLAGS: 00010282
[ 3001.965478][ T5516] RAX: 0000000000000000 RBX: ffffea002fc90e00 RCX: ffffffffa8095282
[ 3002.005570][ T5516] RDX: 1ffffd4005f921c7 RSI: 0000000000000000 RDI: ffffea002fc90e38
[ 3002.044022][ T5516] RBP: 1ffff92001478f22 R08: ffffed118cf0de7a R09: ffffed118cf0de7a
[ 3002.082857][ T5516] R10: ffff888c6786f3cf R11: ffffed118cf0de79 R12: ffffea002fc90e08
[ 3002.121273][ T5516] R13: ffffea002fc90e00 R14: ffffea002fc90e08 R15: ffffea002fc90e00
[ 3002.160008][ T5516] FS: 00007fae1ff5e740(0000) GS:ffff888c67840000(0000) knlGS:0000000000000000
[ 3002.204033][ T5516] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3002.235743][ T5516] CR2: 00005578d493a1b8 CR3: 0000000610836005 CR4: 00000000001706e0
[ 3002.274246][ T5516] Kernel panic - not syncing: Fatal exception
[ 3002.303579][ T5516] Kernel Offset: 0x26400000 from 0xffffffff81000000 (relocation range: 0xffffffff80000000-0xffffffffbfffffff)
[ 3002.360369][ T5516] ---[ end Kernel panic - not syncing: Fatal exception ]---
> ---
> mm/debug.c | 30 ++++++++++++------------------
> 1 file changed, 12 insertions(+), 18 deletions(-)
>
> diff --git a/mm/debug.c b/mm/debug.c
> index e5de63406b59..f35c1ae1a7a5 100644
> --- a/mm/debug.c
> +++ b/mm/debug.c
> @@ -89,27 +89,21 @@ void __dump_page(struct page *page, const char *reason)
> */
> mapcount = PageSlab(head) ? 0 : page_mapcount(page);
>
> - if (compound)
> + pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n",
> + page, page_ref_count(head), mapcount, mapping,
> + page_to_pgoff(page));
> + if (compound) {
> if (hpage_pincount_available(page)) {
> - pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
> - "index:%#lx head:%px order:%u "
> - "compound_mapcount:%d compound_pincount:%d\n",
> - page, page_ref_count(head), mapcount,
> - mapping, page_to_pgoff(page), head,
> - compound_order(head), compound_mapcount(page),
> - compound_pincount(page));
> + pr_warn("head:%px order:%u compound_mapcount:%d compound_pincount:%d\n",
> + head, compound_order(head),
> + compound_mapcount(head),
> + compound_pincount(head));
> } else {
> - pr_warn("page:%px refcount:%d mapcount:%d mapping:%p "
> - "index:%#lx head:%px order:%u "
> - "compound_mapcount:%d\n",
> - page, page_ref_count(head), mapcount,
> - mapping, page_to_pgoff(page), head,
> - compound_order(head), compound_mapcount(page));
> + pr_warn("head:%px order:%u compound_mapcount:%d\n",
> + head, compound_order(head),
> + compound_mapcount(head));
> }
> - else
> - pr_warn("page:%px refcount:%d mapcount:%d mapping:%p index:%#lx\n",
> - page, page_ref_count(page), mapcount,
> - mapping, page_to_pgoff(page));
> + }
> if (PageKsm(page))
> type = "ksm ";
> else if (PageAnon(page))
> --
> 2.27.0
>
>
