syzbot


stack segment fault in mtree_range_walk

Status: upstream: reported C repro on 2025/07/08 17:52
Subsystems: mm
[Documentation on labels]
Reported-by: syzbot+8d7491ac5a289af56d5a@syzkaller.appspotmail.com
First crash: 11d, last: 6d05h
Cause bisection: introduced by (bisect log) :
commit 6772c457a86536f3496bf5b3716f34a5ac125783
Author: Suren Baghdasaryan <surenb@google.com>
Date: Tue Jun 24 19:33:59 2025 +0000

  fs/proc/task_mmu:: execute PROCMAP_QUERY ioctl under per-vma locks

Crash: BUG: unable to handle kernel NULL pointer dereference in lock_next_vma (log)
Repro: C syz .config
  
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [mm?] stack segment fault in mtree_range_walk 1 (2) 2025/07/09 00:11

Sample crash report:
Oops: stack segment: 0000 [#1] SMP KASAN PTI
CPU: 0 UID: 0 PID: 6109 Comm: syz.0.38 Not tainted 6.16.0-rc5-next-20250711-syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:mtree_range_walk+0x2d7/0x840 lib/maple_tree.c:2779
Code: 00 00 48 8d 04 2b 48 83 f8 01 0f 84 b4 00 00 00 e8 7e dd 46 f6 49 83 c4 08 48 ff c3 eb ac e8 70 dd 46 f6 31 db e9 e1 00 00 00 <80> 7d 00 00 74 07 31 ff e8 fc 93 ab f6 4c 8b 2c 25 00 00 00 00 48
RSP: 0018:ffffc9000215f9c0 EFLAGS: 00010297
RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000005
RDX: ffffffff8b79283a RSI: ffffffff8fcb99b0 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffff88802cc40000 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f2ab04846c0(0000) GS:ffff88812578f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2ab0483f98 CR3: 000000007eaf8000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 mas_state_walk lib/maple_tree.c:3636 [inline]
 mas_walk lib/maple_tree.c:4939 [inline]
 mas_find_setup lib/maple_tree.c:6018 [inline]
 mas_find+0x8e9/0xd30 lib/maple_tree.c:6058
 vma_next include/linux/mm.h:864 [inline]
 lock_next_vma+0x101/0xdc0 mm/mmap_lock.c:216
 get_next_vma fs/proc/task_mmu.c:182 [inline]
 query_vma_find_by_addr fs/proc/task_mmu.c:512 [inline]
 query_matching_vma+0x319/0x5c0 fs/proc/task_mmu.c:544
 do_procmap_query fs/proc/task_mmu.c:629 [inline]
 procfs_procmap_ioctl+0x3f9/0xd50 fs/proc/task_mmu.c:747
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:598 [inline]
 __se_sys_ioctl+0xf9/0x170 fs/ioctl.c:584
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f2aaf58e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f2ab0484038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f2aaf7b6080 RCX: 00007f2aaf58e929
RDX: 0000200000000180 RSI: 00000000c0686611 RDI: 0000000000000003
RBP: 00007f2aaf610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000001 R14: 00007f2aaf7b6080 R15: 00007ffc42f08cc8
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:mtree_range_walk+0x2d7/0x840 lib/maple_tree.c:2779
Code: 00 00 48 8d 04 2b 48 83 f8 01 0f 84 b4 00 00 00 e8 7e dd 46 f6 49 83 c4 08 48 ff c3 eb ac e8 70 dd 46 f6 31 db e9 e1 00 00 00 <80> 7d 00 00 74 07 31 ff e8 fc 93 ab f6 4c 8b 2c 25 00 00 00 00 48
RSP: 0018:ffffc9000215f9c0 EFLAGS: 00010297
RAX: 0000000000000003 RBX: 0000000000000000 RCX: 0000000000000005
RDX: ffffffff8b79283a RSI: ffffffff8fcb99b0 RDI: 0000000000000000
RBP: dffffc0000000000 R08: ffff88802cc40000 R09: 0000000000000003
R10: 0000000000000003 R11: 0000000000000000 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f2ab04846c0(0000) GS:ffff88812578f000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f2ab0483f98 CR3: 000000007eaf8000 CR4: 00000000003526f0
----------------
Code disassembly (best guess):
   0:	00 00                	add    %al,(%rax)
   2:	48 8d 04 2b          	lea    (%rbx,%rbp,1),%rax
   6:	48 83 f8 01          	cmp    $0x1,%rax
   a:	0f 84 b4 00 00 00    	je     0xc4
  10:	e8 7e dd 46 f6       	call   0xf646dd93
  15:	49 83 c4 08          	add    $0x8,%r12
  19:	48 ff c3             	inc    %rbx
  1c:	eb ac                	jmp    0xffffffca
  1e:	e8 70 dd 46 f6       	call   0xf646dd93
  23:	31 db                	xor    %ebx,%ebx
  25:	e9 e1 00 00 00       	jmp    0x10b
* 2a:	80 7d 00 00          	cmpb   $0x0,0x0(%rbp) <-- trapping instruction
  2e:	74 07                	je     0x37
  30:	31 ff                	xor    %edi,%edi
  32:	e8 fc 93 ab f6       	call   0xf6ab9433
  37:	4c 8b 2c 25 00 00 00 	mov    0x0,%r13
  3e:	00
  3f:	48                   	rex.W

Crashes (6):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/07/13 20:04 linux-next a62b7a37e6fc 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce stack segment fault in mtree_range_walk
2025/07/13 13:24 linux-next a62b7a37e6fc 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce stack segment fault in mtree_range_walk
2025/07/13 12:35 linux-next a62b7a37e6fc 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root stack segment fault in mtree_range_walk
2025/07/13 07:14 linux-next a62b7a37e6fc 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root stack segment fault in mtree_range_walk
2025/07/11 06:55 linux-next b551c4e2a98a 3cda49cf .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-rust-kasan-gce stack segment fault in mtree_range_walk
2025/07/08 07:49 linux-next 26ffb3d6f02c 4f67c4ae .config console log report syz / log C [disk image] [vmlinux] [kernel image] ci-upstream-linux-next-kasan-gce-root stack segment fault in mtree_range_walk
* Struck through repros no longer work on HEAD.