BUG: unable to handle kernel paging request in isolate_freepages_block

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    baf76f0c slip: make slhc_free() silently accept an error p..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16dbe6cca00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a42d110b47dd6b36
dashboard link: https://syzkaller.appspot.com/bug?extid=d84c80f9fe26a0f7a734
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+d84c80f9fe26a0f7a734@xxxxxxxxxxxxxxxxxxxxxxxxx

BUG: unable to handle kernel paging request at ffffea0003348000
#PF error: [normal kernel read fault]
PGD 12c3f9067 P4D 12c3f9067 PUD 12c3f8067 PMD 0
Oops: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 28916 Comm: syz-executor.2 Not tainted 5.1.0-rc6+ #89
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:314 [inline]
RIP: 0010:PageCompound include/linux/page-flags.h:186 [inline]
RIP: 0010:isolate_freepages_block+0x1c0/0xd40 mm/compaction.c:579
Code: 01 d8 ff 4d 85 ed 0f 84 ef 07 00 00 e8 29 00 d8 ff 4c 89 e0 83 85 38  
ff ff ff 01 48 c1 e8 03 42 80 3c 38 00 0f 85 31 0a 00 00 <4d> 8b 2c 24 31  
ff 49 c1 ed 10 41 83 e5 01 44 89 ee e8 3a 01 d8 ff
RSP: 0018:ffff88802b31eab8 EFLAGS: 00010246
RAX: 1ffffd4000669000 RBX: 00000000000cd200 RCX: ffffc9000a235000
RDX: 000000000001ca5e RSI: ffffffff81988cc7 RDI: 0000000000000001
RBP: ffff88802b31ebd8 R08: ffff88805af700c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0003348000
R13: 0000000000000000 R14: ffff88802b31f030 R15: dffffc0000000000
FS:  00007f61648dc700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffea0003348000 CR3: 0000000037c64000 CR4: 00000000001426e0
Call Trace:
 fast_isolate_around mm/compaction.c:1243 [inline]
 fast_isolate_freepages mm/compaction.c:1418 [inline]
 isolate_freepages mm/compaction.c:1438 [inline]
 compaction_alloc+0x1aee/0x22e0 mm/compaction.c:1550
 unmap_and_move mm/migrate.c:1180 [inline]
 migrate_pages+0x484/0x2cd0 mm/migrate.c:1431
 compact_zone+0x1b4f/0x38f0 mm/compaction.c:2181
 compact_zone_order+0x1af/0x2a0 mm/compaction.c:2306
 try_to_compact_pages+0x268/0xaf0 mm/compaction.c:2358
 __alloc_pages_direct_compact+0x154/0x460 mm/page_alloc.c:3786
 __alloc_pages_slowpath+0xb14/0x28b0 mm/page_alloc.c:4425
 __alloc_pages_nodemask+0x602/0x8d0 mm/page_alloc.c:4633
 __alloc_pages include/linux/gfp.h:473 [inline]
 __alloc_pages_node include/linux/gfp.h:486 [inline]
 alloc_pages_vma+0x39a/0x540 mm/mempolicy.c:2088
 do_huge_pmd_anonymous_page+0x509/0x1730 mm/huge_memory.c:740
 create_huge_pmd mm/memory.c:3701 [inline]
 __handle_mm_fault+0x2d5e/0x3ec0 mm/memory.c:3905
 handle_mm_fault+0x43f/0xb30 mm/memory.c:3971
 faultin_page mm/gup.c:548 [inline]
 __get_user_pages+0x7b6/0x1a40 mm/gup.c:751
 __get_user_pages_locked mm/gup.c:927 [inline]
 get_user_pages_remote+0x21d/0x440 mm/gup.c:1119
 process_vm_rw_single_vec mm/process_vm_access.c:113 [inline]
 process_vm_rw_core.isra.0+0x464/0xb10 mm/process_vm_access.c:220
 process_vm_rw+0x21f/0x240 mm/process_vm_access.c:288
 __do_sys_process_vm_writev mm/process_vm_access.c:310 [inline]
 __se_sys_process_vm_writev mm/process_vm_access.c:305 [inline]
 __x64_sys_process_vm_writev+0xe3/0x1a0 mm/process_vm_access.c:305
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x458da9
Code: ad b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7  
48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff  
ff 0f 83 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f61648dbc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000137
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000458da9
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000004a77
RBP: 000000000073bf00 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000020000040 R11: 0000000000000246 R12: 00007f61648dc6d4
R13: 00000000004c5b1e R14: 00000000004d9e90 R15: 00000000ffffffff
Modules linked in:
CR2: ffffea0003348000
---[ end trace 50f8738754fa12f3 ]---
RIP: 0010:constant_test_bit arch/x86/include/asm/bitops.h:314 [inline]
RIP: 0010:PageCompound include/linux/page-flags.h:186 [inline]
RIP: 0010:isolate_freepages_block+0x1c0/0xd40 mm/compaction.c:579
Code: 01 d8 ff 4d 85 ed 0f 84 ef 07 00 00 e8 29 00 d8 ff 4c 89 e0 83 85 38  
ff ff ff 01 48 c1 e8 03 42 80 3c 38 00 0f 85 31 0a 00 00 <4d> 8b 2c 24 31  
ff 49 c1 ed 10 41 83 e5 01 44 89 ee e8 3a 01 d8 ff
RSP: 0018:ffff88802b31eab8 EFLAGS: 00010246
RAX: 1ffffd4000669000 RBX: 00000000000cd200 RCX: ffffc9000a235000
RDX: 000000000001ca5e RSI: ffffffff81988cc7 RDI: 0000000000000001
RBP: ffff88802b31ebd8 R08: ffff88805af700c0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffffea0003348000
R13: 0000000000000000 R14: ffff88802b31f030 R15: dffffc0000000000
FS:  00007f61648dc700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffea0003348000 CR3: 0000000037c64000 CR4: 00000000001426e0


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