syzbot


general protection fault in pagemap_scan_hugetlb_entry

Status: upstream: reported C repro on 2023/12/03 02:17
Subsystems: fs
[Documentation on labels]
Reported-by: syzbot+6e2ccedb96d1174e6a5f@syzkaller.appspotmail.com
First crash: 90d, last: 88d
Cause bisection: introduced by (bisect log) :
commit a08c7193e4f18dc8508f2d07d0de2c5b94cb39a3
Author: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Date: Tue Sep 26 19:20:17 2023 +0000

  mm/filemap: remove hugetlb special casing in filemap.c

Crash: invalid opcode in __filemap_add_folio (log)
Repro: C syz .config
  
Fix bisection: fixed by (bisect log) :
commit 4a3ef6be03e6700037fc20e63aa5ffd972e435ca
Author: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Date: Mon Dec 4 18:32:34 2023 +0000

  mm/hugetlb: have CONFIG_HUGETLB_PAGE select CONFIG_XARRAY_MULTI

  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [fs?] general protection fault in pagemap_scan_hugetlb_entry 0 (4) 2023/12/30 18:24
Last patch testing requests (4)
Created Duration User Patch Repo Result
2023/12/14 16:11 20m retest repro upstream OK log
2023/12/06 19:46 49m sidhartha.kumar@oracle.com git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-hotfixes-unstable OK log
2023/12/06 19:18 21m sidhartha.kumar@oracle.com git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm.git mm-hotfixes-unstable OK log
2023/12/06 18:58 7m sidhartha.kumar@oracle.com patch upstream error OK

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
CPU: 0 PID: 5072 Comm: syz-executor107 Not tainted 6.7.0-rc3-syzkaller-00014-gdf60cee26a2e #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/10/2023
RIP: 0010:pagemap_scan_backout_range fs/proc/task_mmu.c:1946 [inline]
RIP: 0010:pagemap_scan_hugetlb_entry+0x6ca/0x1130 fs/proc/task_mmu.c:2254
Code: 3c 02 00 0f 85 68 09 00 00 48 8b 83 80 00 00 00 48 8d 04 40 4d 8d 6c c5 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 51 09 00 00 4d 8b 75 00 48 8b 7c 24 08 4c 89 f6
RSP: 0018:ffffc90003a2fa50 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffc90003a2fdb0 RCX: ffffffff82111e46
RDX: 0000000000000000 RSI: ffffffff82111e54 RDI: ffffc90003a2fe30
RBP: 1ffff92000745f52 R08: 0000000000000006 R09: 0000000020ffc000
R10: 00000000211f9000 R11: ffffffff915f5de8 R12: ffff8880299e0300
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020ffc000
FS:  0000555555c7b380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005fdeb8 CR3: 00000000752b4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 walk_hugetlb_range mm/pagewalk.c:326 [inline]
 __walk_page_range+0x36c/0x770 mm/pagewalk.c:393
 walk_page_range+0x626/0xa80 mm/pagewalk.c:521
 do_pagemap_scan+0x40d/0xcd0 fs/proc/task_mmu.c:2437
 do_pagemap_cmd+0x5e/0x80 fs/proc/task_mmu.c:2478
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:871 [inline]
 __se_sys_ioctl fs/ioctl.c:857 [inline]
 __x64_sys_ioctl+0x18f/0x210 fs/ioctl.c:857
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x40/0x110 arch/x86/entry/common.c:82
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f171819d669
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffbe81bb68 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fffbe81bb80 RCX: 00007f171819d669
RDX: 0000000020000040 RSI: 00000000c0606610 RDI: 0000000000000003
RBP: 00007f1718210610 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000286 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fffbe81bdb8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:pagemap_scan_backout_range fs/proc/task_mmu.c:1946 [inline]
RIP: 0010:pagemap_scan_hugetlb_entry+0x6ca/0x1130 fs/proc/task_mmu.c:2254
Code: 3c 02 00 0f 85 68 09 00 00 48 8b 83 80 00 00 00 48 8d 04 40 4d 8d 6c c5 00 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 51 09 00 00 4d 8b 75 00 48 8b 7c 24 08 4c 89 f6
RSP: 0018:ffffc90003a2fa50 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffffc90003a2fdb0 RCX: ffffffff82111e46
RDX: 0000000000000000 RSI: ffffffff82111e54 RDI: ffffc90003a2fe30
RBP: 1ffff92000745f52 R08: 0000000000000006 R09: 0000000020ffc000
R10: 00000000211f9000 R11: ffffffff915f5de8 R12: ffff8880299e0300
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000020ffc000
FS:  0000555555c7b380(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00000000005fdeb8 CR3: 00000000752b4000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	3c 02                	cmp    $0x2,%al
   2:	00 0f                	add    %cl,(%rdi)
   4:	85 68 09             	test   %ebp,0x9(%rax)
   7:	00 00                	add    %al,(%rax)
   9:	48 8b 83 80 00 00 00 	mov    0x80(%rbx),%rax
  10:	48 8d 04 40          	lea    (%rax,%rax,2),%rax
  14:	4d 8d 6c c5 00       	lea    0x0(%r13,%rax,8),%r13
  19:	48 b8 00 00 00 00 00 	movabs $0xdffffc0000000000,%rax
  20:	fc ff df
  23:	4c 89 ea             	mov    %r13,%rdx
  26:	48 c1 ea 03          	shr    $0x3,%rdx
* 2a:	80 3c 02 00          	cmpb   $0x0,(%rdx,%rax,1) <-- trapping instruction
  2e:	0f 85 51 09 00 00    	jne    0x985
  34:	4d 8b 75 00          	mov    0x0(%r13),%r14
  38:	48 8b 7c 24 08       	mov    0x8(%rsp),%rdi
  3d:	4c 89 f6             	mov    %r14,%rsi

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/11/29 02:43 upstream df60cee26a2e 1adfb6f6 .config strace log report syz C [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce general protection fault in pagemap_scan_hugetlb_entry
2023/11/30 15:27 upstream 3b47bc037bd4 f819d6f7 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce-selinux-root general protection fault in pagemap_scan_hugetlb_entry
2023/11/29 02:12 upstream df60cee26a2e 1adfb6f6 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-gce general protection fault in pagemap_scan_hugetlb_entry
* Struck through repros no longer work on HEAD.