On Mon, Jan 07, 2019 at 07:57:38PM +0300, Konstantin Khlebnikov wrote: > On 03.01.2019 13:43, syzbot wrote: > > Hello, > > > > syzbot found the following crash on: > > > > HEAD commit: 4cd1b60def51 Add linux-next specific files for 20190102 > > git tree: linux-next > > console output: https://syzkaller.appspot.com/x/log.txt?x=147760d3400000 > > kernel config: https://syzkaller.appspot.com/x/.config?x=e8ea56601353001c > > dashboard link: https://syzkaller.appspot.com/bug?extid=8e075128f7db8555391a > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > > Unfortunately, I don't have any reproducer for this crash yet. > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > Reported-by: syzbot+8e075128f7db8555391a@xxxxxxxxxxxxxxxxxxxxxxxxx > > > Few more lines from "console output" > > [ 549.659441] page:ffffea0000e80000 count:512 mapcount:0 mapping:ffff88809a33f5b1 index:0x20000 compound_mapcount: -1 > [ 549.746649] anon > [ 549.746665] flags: 0x1fffc000009000d(locked|uptodate|dirty|head|swapbacked) That's obviously underflow of compound_mapcount, but I don't see a possible cause for it. Ying, you've looked recently into THP rmap code. Maybe you have any insight on the problem? > > > > raw: 01fffc000009000d dead000000000100 dead000000000200 ffff88809a33f5b1 > > raw: 0000000000020000 0000000000000000 0000020000000000 ffff888095368000 > > page dumped because: VM_BUG_ON_PAGE(compound_mapcount(head)) > > page->mem_cgroup:ffff888095368000 > > ------------[ cut here ]------------ > > kernel BUG at mm/huge_memory.c:2683! > > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > > CPU: 0 PID: 1551 Comm: kswapd0 Not tainted 4.20.0-next-20190102 #3 > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > > RIP: 0010:split_huge_page_to_list+0x2161/0x2ac0 mm/huge_memory.c:2683 > > Code: ff e8 33 35 b8 ff 48 8b 85 10 fc ff ff 4c 8d 70 ff e9 1e ea ff ff > > e8 1e 35 b8 ff 48 c7 c6 a0 a3 54 88 4c 89 ef e8 0f 15 ea ff <0f> 0b 48 > > 89 85 10 fc ff ff e8 01 35 b8 ff 48 8b 85 10 fc ff ff 4c > > RSP: 0018:ffff8880a5f36de8 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: ffff8880a5f371d8 RCX: 0000000000000000 > > RDX: ffffed1014be6d6e RSI: ffffffff81b3831e RDI: ffffed1014be6dae > > RBP: ffff8880a5f37200 R08: 0000000000000021 R09: ffffed1015cc5021 > > R10: ffffed1015cc5020 R11: ffff8880ae628107 R12: ffffea0000e80080 > > R13: ffffea0000e80000 R14: 00000000fffffffe R15: 01fffc000009000d > > FS: 0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000 > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 0000000020003030 CR3: 0000000219267000 CR4: 00000000001426f0 > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > Call Trace: > > split_huge_page include/linux/huge_mm.h:148 [inline] > > deferred_split_scan+0xa47/0x11d0 mm/huge_memory.c:2820 > > do_shrink_slab+0x4e5/0xd30 mm/vmscan.c:561 > > shrink_slab mm/vmscan.c:710 [inline] > > shrink_slab+0x6bb/0x8c0 mm/vmscan.c:690 > > shrink_node+0x61a/0x17e0 mm/vmscan.c:2776 > > kswapd_shrink_node mm/vmscan.c:3535 [inline] > > balance_pgdat+0xb00/0x18b0 mm/vmscan.c:3693 > > kswapd+0x839/0x1330 mm/vmscan.c:3948 > > kthread+0x357/0x430 kernel/kthread.c:246 > > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 > > Modules linked in: > > kobject: 'loop1' (000000002d2ad2ad): kobject_uevent_env > > kobject: 'loop1' (000000002d2ad2ad): fill_kobj_path: path = '/devices/virtual/block/loop1' > > kobject: 'loop3' (000000003c94a079): kobject_uevent_env > > kobject: 'loop3' (000000003c94a079): fill_kobj_path: path = '/devices/virtual/block/loop3' > > kobject: 'loop5' (0000000000e89d9d): kobject_uevent_env > > kobject: 'loop5' (0000000000e89d9d): fill_kobj_path: path = '/devices/virtual/block/loop5' > > kobject: 'loop2' (000000001a685ee7): kobject_uevent_env > > kobject: 'loop2' (000000001a685ee7): fill_kobj_path: path = '/devices/virtual/block/loop2' > > kobject: 'loop3' (000000003c94a079): kobject_uevent_env > > kobject: 'loop3' (000000003c94a079): fill_kobj_path: path = '/devices/virtual/block/loop3' > > ---[ end trace a543f5c1741fca97 ]--- > > kobject: 'loop0' (00000000aa59ea1f): kobject_uevent_env > > RIP: 0010:split_huge_page_to_list+0x2161/0x2ac0 mm/huge_memory.c:2683 > > Code: ff e8 33 35 b8 ff 48 8b 85 10 fc ff ff 4c 8d 70 ff e9 1e ea ff ff > > e8 1e 35 b8 ff 48 c7 c6 a0 a3 54 88 4c 89 ef e8 0f 15 ea ff <0f> 0b 48 > > 89 85 10 fc ff ff e8 01 35 b8 ff 48 8b 85 10 fc ff ff 4c > > kobject: 'loop0' (00000000aa59ea1f): fill_kobj_path: path = '/devices/virtual/block/loop0' > > RSP: 0018:ffff8880a5f36de8 EFLAGS: 00010246 > > RAX: 0000000000000000 RBX: ffff8880a5f371d8 RCX: 0000000000000000 > > RDX: ffffed1014be6d6e RSI: ffffffff81b3831e RDI: ffffed1014be6dae > > RBP: ffff8880a5f37200 R08: 0000000000000021 R09: ffffed1015cc5021 > > netlink: 'syz-executor0': attribute type 22 has an invalid length. > > R10: ffffed1015cc5020 R11: ffff8880ae628107 R12: ffffea0000e80080 > > R13: ffffea0000e80000 R14: 00000000fffffffe R15: 01fffc000009000d > > FS: 0000000000000000(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000 > > kobject: 'loop1' (000000002d2ad2ad): kobject_uevent_env > > kobject: 'loop1' (000000002d2ad2ad): fill_kobj_path: path = '/devices/virtual/block/loop1' > > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > > CR2: 00000000004efb18 CR3: 00000000702a7000 CR4: 00000000001426e0 > > kobject: 'loop5' (0000000000e89d9d): kobject_uevent_env > > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > > kobject: 'loop5' (0000000000e89d9d): fill_kobj_path: path = '/devices/virtual/block/loop5' > > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > > kobject: 'loop3' (000000003c94a079): kobject_uevent_env > > > > > I've got couple of these for 4.14. > Maybe related but this happened with THP tmpfs. > > > <1>[220723.475439] huge_memory: total_mapcount: 63, page_count(): 576 > <0>[220723.475474] page:ffffea0024ee8000 count:576 mapcount:0 mapping:ffff881813235550 index:0x0 compound_mapcount: 0 > <0>[220723.475512] flags: 0x10000000004807d(locked|referenced|uptodate|dirty|lru|active|head|swapbacked) > <1>[220723.475545] raw: 010000000004807d ffff881813235550 0000000000000000 00000240ffffffff > <1>[220723.475573] raw: ffffea004c099a20 ffffea002bd9e020 0000000000000000 ffff883018044800 > <1>[220723.475601] page dumped because: total_mapcount(head) > 0 > <1>[220723.475621] page->mem_cgroup:ffff883018044800 > <4>[220723.475644] ------------[ cut here ]------------ > <2>[220723.475645] kernel BUG at mm/huge_memory.c:2652! > <4>[220723.475667] invalid opcode: 0000 [#1] SMP PTI > <4>[220723.475684] Modules linked in: xt_nat xt_limit overlay ip6table_nat > nf_nat_ipv6 nf_nat veth tcp_diag inet_diag unix_diag xt_NFLOG nfnetlink_log > nfnetlink ip6t_REJECT nf_reject_ipv6 nf_log_ipv6 nf_log_common xt_LOG > nf_conntrack_ipv6 nf_defrag_ipv6 xt_u32 ip6table_raw xt_conntrack > ip6table_filter xt_tcpudp xt_CT nf_conntrack iptable_raw xt_multiport > iptable_filter bridge ip6_tables ip_tables x_tables sch_fq_codel sch_hfsc > netconsole configfs 8021q mrp garp stp llc intel_rapl sb_edac > x86_pkg_temp_thermal intel_powerclamp mgag200 coretemp ttm kvm_intel > drm_kms_helper drm kvm fb_sys_fops sysimgblt input_leds sysfillrect > syscopyarea irqbypass lpc_ich mfd_core ghash_clmulni_intel shpchp ioatdma > wmi tcp_bbr ip6_tunnel tunnel6 mlx4_en mlx4_core devlink tcp_nv tcp_htcp > raid456 async_raid6_recov async_pq async_xor > <4>[220723.475954] xor async_memcpy async_tx raid10 igb isci dca libsas > i2c_algo_bit ptp scsi_transport_sas pps_core raid6_pq libcrc32c raid1 raid0 > multipath linear [last unloaded: ipmi_msghandler] > <4>[220723.476021] CPU: 5 PID: 529913 Comm: qpipe-updater Not tainted 4.14.80-33 #1 > <4>[220723.476047] Hardware name: Aquarius Aquarius Server/X9DRW, BIOS 3.0c 10/30/2014 > <4>[220723.476074] task: ffff8817b98f3900 task.stack: ffffc900311d4000 > <4>[220723.476099] RIP: 0010:split_huge_page_to_list+0x7b5/0x8d0 > <4>[220723.476120] RSP: 0018:ffffc900311d76a0 EFLAGS: 00010086 > <4>[220723.476140] RAX: 0000000000000021 RBX: ffff881813235550 RCX: 0000000000000006 > <4>[220723.476165] RDX: 0000000000000007 RSI: 0000000000000082 RDI: ffff88181fb55730 > <4>[220723.476190] RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000c20 > <4>[220723.476216] R10: ffffc900311d7690 R11: 0000000000000001 R12: 0000000000000000 > <4>[220723.476241] R13: ffffea0024ee8000 R14: ffff88187fffb000 R15: ffffea0024ee8000 > <4>[220723.476267] FS: 00007fe7a69097c0(0000) GS:ffff88181fb40000(0000) knlGS:0000000000000000 > <4>[220723.476296] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > <4>[220723.476317] CR2: 00007fe78c1e1000 CR3: 0000001815530005 CR4: 00000000000606e0 > <4>[220723.476342] Call Trace: > <4>[220723.476358] ? find_get_entry+0x20/0x140 > <4>[220723.476377] shmem_unused_huge_shrink+0x184/0x3f0 > <4>[220723.476398] super_cache_scan+0x184/0x190 > <4>[220723.476416] shrink_slab.part.54+0x1ec/0x430 > <4>[220723.476434] shrink_node+0x300/0x310 > <4>[220723.476451] do_try_to_free_pages+0xe3/0x350 > <4>[220723.476469] try_to_free_pages+0xe4/0x1d0 > <4>[220723.476487] __alloc_pages_slowpath+0x3a5/0xe70 > <4>[220723.476507] __alloc_pages_nodemask+0x25c/0x2a0 > <4>[220723.476526] shmem_alloc_hugepage+0xc7/0x110 > <4>[220723.476545] ? __radix_tree_create+0x168/0x1f0 > <4>[220723.476563] ? release_pages+0x2c8/0x3a0 > <4>[220723.476579] ? release_pages+0x2c8/0x3a0 > <4>[220723.477420] ? __activate_page+0x200/0x2d0 > <4>[220723.478254] ? percpu_counter_add_batch+0x52/0x70 > <4>[220723.479095] shmem_alloc_and_acct_page+0x108/0x1d0 > <4>[220723.479926] shmem_getpage_gfp+0x4ef/0xdf0 > <4>[220723.480736] shmem_write_begin+0x35/0x60 > <4>[220723.481514] generic_perform_write+0xaf/0x1b0 > <4>[220723.482293] __generic_file_write_iter+0x196/0x1e0 > <4>[220723.483061] generic_file_write_iter+0xe6/0x1f0 > <4>[220723.483820] __vfs_write+0xdc/0x150 > <4>[220723.484573] vfs_write+0xc5/0x1c0 > <4>[220723.485324] SyS_write+0x42/0x90 > <4>[220723.486067] do_syscall_64+0x67/0x120 > <4>[220723.486790] entry_SYSCALL_64_after_hwframe+0x3d/0xa2 > <4>[220723.487496] RIP: 0033:0x7fe7a60d8330 > <4>[220723.488175] RSP: 002b:00007ffc05104af8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 > <4>[220723.488851] RAX: ffffffffffffffda RBX: 00007fe785e00000 RCX: 00007fe7a60d8330 > <4>[220723.489511] RDX: 0000000011be3b28 RSI: 00007fe785e00000 RDI: 0000000000000003 > <4>[220723.490156] RBP: 0000000011be3b28 R08: 00007fe7a69097c0 R09: 00007ffc05104bb7 > <4>[220723.490770] R10: 00007ffc051048c0 R11: 0000000000000246 R12: 0000000107b88c00 > <4>[220723.491364] R13: 00007ffc051057b8 R14: 0000000011be3b28 R15: 00000001072886b8 > <4>[220723.491933] Code: 8b 54 24 08 48 c7 c7 28 54 06 82 e8 51 59 eb ff 49 > 8b 45 20 a8 01 0f 85 1b 01 00 00 48 c7 c6 8c 50 06 82 4c 89 ef e8 cb 64 fb > ff <0f> 0b 48 c7 c6 60 53 06 82 4c 89 ff e8 ba 64 fb ff 0f 0b e8 23 > <1>[220723.493137] RIP: split_huge_page_to_list+0x7b5/0x8d0 RSP: ffffc900311d76a0 > <4>[220723.493731] ---[ end trace 74a2900540d3546c ]--- > <5>[220723.494322] ---[ now 2018-12-24 07:08:37+03 ]--- > > > > > > > --- > > This bug is generated by a bot. It may contain errors. > > See https://goo.gl/tpsmEJ for more information about syzbot. > > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > > > syzbot will keep track of this bug report. See: > > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with syzbot. > -- Kirill A. Shutemov
