syzbot


general protection fault in nilfs_btree_insert (2)

Status: upstream: reported C repro on 2024/09/01 20:39
Subsystems: nilfs
[Documentation on labels]
Reported-by: syzbot+9bff4c7b992038a7409f@syzkaller.appspotmail.com
First crash: 18d, last: 4d18h
Cause bisection: the issue happens on the oldest tested release (bisect log)
Crash: BUG: unable to handle kernel NULL pointer dereference in nilfs_btree_insert (log)
Repro: C syz .config
  
Discussions (2)
Title Replies (including bot) Last reply
[PATCH 0/3] nilfs2: fix potential issues with empty b-tree nodes 4 (4) 2024/09/04 08:13
[syzbot] [nilfs?] general protection fault in nilfs_btree_insert (2) 2 (4) 2024/09/02 19:40
Similar bugs (3)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 general protection fault in nilfs_btree_insert nilfs2 C 1 561d 624d 0/1 upstream: reported C repro on 2022/12/31 23:33
upstream general protection fault in nilfs_btree_insert nilfs C error 2 630d 628d 22/28 fixed on 2023/06/08 14:41
linux-5.15 BUG: unable to handle kernel paging request in nilfs_btree_insert origin:upstream C 3 21d 21d 0/3 upstream: reported C repro on 2024/08/26 10:25
Last patch testing requests (2)
Created Duration User Patch Repo Result
2024/09/12 00:35 15m retest repro upstream report log
2024/09/02 08:41 20m lizhi.xu@windriver.com patch upstream OK log

Sample crash report:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000005: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]
CPU: 1 UID: 0 PID: 5220 Comm: syz-executor243 Not tainted 6.11.0-rc5-syzkaller-00057-g86987d84b968 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:nilfs_btree_get_nonroot_node fs/nilfs2/btree.c:418 [inline]
RIP: 0010:nilfs_btree_prepare_insert fs/nilfs2/btree.c:1091 [inline]
RIP: 0010:nilfs_btree_insert+0x6d3/0x1c10 fs/nilfs2/btree.c:1252
Code: 8d 9f 80 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ab 89 8a fe 48 8b 1b 48 83 c3 28 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 8e 89 8a fe 4c 89 64 24 28 48 8b
RSP: 0018:ffffc9000352f4e0 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000028 RCX: 1ffff1100f66a0ee
RDX: ffff88807d6f9e00 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffffc9000352f670 R08: ffffffff836d1ea6 R09: 1ffff1100469939a
R10: dffffc0000000000 R11: ffffed100469939b R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000002 R15: ffff88807fbd9680
FS:  0000555573e9d380(0000) GS:ffff8880b9300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc785a110f8 CR3: 000000007ea40000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 nilfs_bmap_do_insert fs/nilfs2/bmap.c:129 [inline]
 nilfs_bmap_insert+0x25e/0x3c0 fs/nilfs2/bmap.c:155
 nilfs_get_block+0x428/0x8e0 fs/nilfs2/inode.c:101
 __block_write_begin_int+0x50c/0x1a70 fs/buffer.c:2125
 __block_write_begin fs/buffer.c:2174 [inline]
 block_write_begin+0x9b/0x1e0 fs/buffer.c:2235
 nilfs_write_begin+0xa0/0x110 fs/nilfs2/inode.c:262
 generic_perform_write+0x399/0x840 mm/filemap.c:4019
 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4147
 new_sync_write fs/read_write.c:497 [inline]
 vfs_write+0xa72/0xc90 fs/read_write.c:590
 ksys_write+0x1a0/0x2c0 fs/read_write.c:643
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc785999a99
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 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 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff8363c328 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fc785999a99
RDX: 0000000000004000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007fc785a0d5f0 R08: 0000555573e9e4c0 R09: 0000555573e9e4c0
R10: 0000000000000a83 R11: 0000000000000246 R12: 00007fff8363c350
R13: 00007fff8363c578 R14: 431bde82d7b634db R15: 00007fc7859e203b
 </TASK>
Modules linked in:
---[ end trace 0000000000000000 ]---
RIP: 0010:nilfs_btree_get_nonroot_node fs/nilfs2/btree.c:418 [inline]
RIP: 0010:nilfs_btree_prepare_insert fs/nilfs2/btree.c:1091 [inline]
RIP: 0010:nilfs_btree_insert+0x6d3/0x1c10 fs/nilfs2/btree.c:1252
Code: 8d 9f 80 00 00 00 48 89 d8 48 c1 e8 03 42 80 3c 28 00 74 08 48 89 df e8 ab 89 8a fe 48 8b 1b 48 83 c3 28 48 89 d8 48 c1 e8 03 <42> 80 3c 28 00 74 08 48 89 df e8 8e 89 8a fe 4c 89 64 24 28 48 8b
RSP: 0018:ffffc9000352f4e0 EFLAGS: 00010206
RAX: 0000000000000005 RBX: 0000000000000028 RCX: 1ffff1100f66a0ee
RDX: ffff88807d6f9e00 RSI: 0000000000000002 RDI: 0000000000000001
RBP: ffffc9000352f670 R08: ffffffff836d1ea6 R09: 1ffff1100469939a
R10: dffffc0000000000 R11: ffffed100469939b R12: 0000000000000000
R13: dffffc0000000000 R14: 0000000000000002 R15: ffff88807fbd9680
FS:  0000555573e9d380(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005582b0414000 CR3: 000000007ea40000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
----------------
Code disassembly (best guess):
   0:	8d 9f 80 00 00 00    	lea    0x80(%rdi),%ebx
   6:	48 89 d8             	mov    %rbx,%rax
   9:	48 c1 e8 03          	shr    $0x3,%rax
   d:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1)
  12:	74 08                	je     0x1c
  14:	48 89 df             	mov    %rbx,%rdi
  17:	e8 ab 89 8a fe       	call   0xfe8a89c7
  1c:	48 8b 1b             	mov    (%rbx),%rbx
  1f:	48 83 c3 28          	add    $0x28,%rbx
  23:	48 89 d8             	mov    %rbx,%rax
  26:	48 c1 e8 03          	shr    $0x3,%rax
* 2a:	42 80 3c 28 00       	cmpb   $0x0,(%rax,%r13,1) <-- trapping instruction
  2f:	74 08                	je     0x39
  31:	48 89 df             	mov    %rbx,%rdi
  34:	e8 8e 89 8a fe       	call   0xfe8a89c7
  39:	4c 89 64 24 28       	mov    %r12,0x28(%rsp)
  3e:	48                   	rex.W
  3f:	8b                   	.byte 0x8b

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/08/28 20:30 upstream 86987d84b968 ef3de9e8 .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs general protection fault in nilfs_btree_insert
* Struck through repros no longer work on HEAD.