syzbot


general protection fault in khugepaged (3)

Status: moderation: reported on 2024/02/07 00:07
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+45f744a1e9371de016b0@syzkaller.appspotmail.com
First crash: 73d, last: 73d
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream general protection fault in khugepaged mm C done 3 1364d 1376d 15/26 fixed on 2020/09/16 22:51
upstream general protection fault in khugepaged (2) mm 1 139d 135d 0/26 auto-obsoleted due to no activity on 2024/01/27 04:37
linux-4.19 general protection fault in khugepaged 1 882d 882d 0/1 auto-closed as invalid on 2022/03/15 05:26

Sample crash report:
general protection fault, probably for non-canonical address 0xdffffc0000000084: 0000 [#1] PREEMPT SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000420-0x0000000000000427]
CPU: 1 PID: 36 Comm: khugepaged Not tainted 6.8.0-rc2-syzkaller-00199-g021533194476 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2375 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2508 [inline]
RIP: 0010:khugepaged+0x5bf/0x1620 mm/khugepaged.c:2564
Code: 00 89 de e8 e3 02 a0 ff 85 db 0f 84 68 0d 00 00 e8 f6 07 a0 ff 49 8d 7e 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 21 0f 00 00 49 8d 7e 78 49 8b 6e 20 48 b9 00 00
RSP: 0018:ffffc90000acfcf8 EFLAGS: 00010217
RAX: 0000000000000084 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffff88801b6c8000 RSI: ffffffff81ec61ca RDI: 0000000000000426
RBP: 0000000020000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: 0000000020400000
R13: 0000000000000003 R14: 0000000000000406 R15: 1ffff92000159faf
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fcb49ad56c6 CR3: 000000004c8d0000 CR4: 0000000000350ef0
Call Trace:
 <TASK>
 kthread+0x2c9/0x3b0 kernel/kthread.c:388
 ret_from_fork+0x48/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:242
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:khugepaged_scan_mm_slot mm/khugepaged.c:2375 [inline]
RIP: 0010:khugepaged_do_scan mm/khugepaged.c:2508 [inline]
RIP: 0010:khugepaged+0x5bf/0x1620 mm/khugepaged.c:2564
Code: 00 89 de e8 e3 02 a0 ff 85 db 0f 84 68 0d 00 00 e8 f6 07 a0 ff 49 8d 7e 20 48 b9 00 00 00 00 00 fc ff df 48 89 f8 48 c1 e8 03 <80> 3c 08 00 0f 85 21 0f 00 00 49 8d 7e 78 49 8b 6e 20 48 b9 00 00
RSP: 0018:ffffc90000acfcf8 EFLAGS: 00010217
RAX: 0000000000000084 RBX: 0000000000000001 RCX: dffffc0000000000
RDX: ffff88801b6c8000 RSI: ffffffff81ec61ca RDI: 0000000000000426
RBP: 0000000020000000 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000002 R12: 0000000020400000
R13: 0000000000000003 R14: 0000000000000406 R15: 1ffff92000159faf
FS:  0000000000000000(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9a414b4440 CR3: 000000002d3ae000 CR4: 0000000000350ef0
----------------
Code disassembly (best guess):
   0:	00 89 de e8 e3 02    	add    %cl,0x2e3e8de(%rcx)
   6:	a0 ff 85 db 0f 84 68 	movabs 0xd68840fdb85ff,%al
   d:	0d 00
   f:	00 e8                	add    %ch,%al
  11:	f6 07 a0             	testb  $0xa0,(%rdi)
  14:	ff 49 8d             	decl   -0x73(%rcx)
  17:	7e 20                	jle    0x39
  19:	48 b9 00 00 00 00 00 	movabs $0xdffffc0000000000,%rcx
  20:	fc ff df
  23:	48 89 f8             	mov    %rdi,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	80 3c 08 00          	cmpb   $0x0,(%rax,%rcx,1) <-- trapping instruction
  2e:	0f 85 21 0f 00 00    	jne    0xf55
  34:	49 8d 7e 78          	lea    0x78(%r14),%rdi
  38:	49 8b 6e 20          	mov    0x20(%r14),%rbp
  3c:	48                   	rex.W
  3d:	b9                   	.byte 0xb9

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/02/02 12:37 upstream 021533194476 60bf9982 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-kasan-badwrites-root general protection fault in khugepaged
* Struck through repros no longer work on HEAD.