syzbot


BUG: unable to handle kernel paging request in __process_finished_items

Status: moderation: reported on 2025/01/14 23:11
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+5fafd719e943283c0397@syzkaller.appspotmail.com
First crash: 4d09h, last: 4d09h

Sample crash report:
bcachefs (loop2): starting version 1.7: mi_btree_bitmap opts=errors=continue,metadata_checksum=none,data_checksum=none,compression=lz4,nojournal_transaction_names
bcachefs (loop2): initializing new filesystem
bcachefs (loop2): going read-write
bcachefs (loop2): marking superblocks
Unable to handle kernel paging request at virtual address dfff800000000000
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
Mem abort info:
  ESR = 0x0000000096000005
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x05: level 1 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000005, ISS2 = 0x00000000
  CM = 0, WnR = 0, TnD = 0, TagAccess = 0
  GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
[dfff800000000000] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
Modules linked in:

CPU: 0 UID: 0 PID: 9857 Comm: syz.2.602 Tainted: G        W          6.13.0-rc6-syzkaller-g6251d1776bc5 #0
Tainted: [W]=WARN
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __process_finished_items+0x708/0x7b4 fs/bcachefs/rcu_pending.c:257
lr : __process_finished_items+0x700/0x7b4 fs/bcachefs/rcu_pending.c:252
sp : ffff80009bc86480
x29: ffff80009bc86540 x28: dfff800000000000 x27: ffff80009bc864e0
x26: 1ffff00013790c9d x25: fffffdffbf6eb940 x24: 0000000000000000
x23: ffff80009bc864e8 x22: ffff0000fc904558 x21: 0000000000000003
x20: fffffdffbf6eb840 x19: 1fffe0001f9208ab x18: ffff80009bc85840
x17: 0000000000000000 x16: ffff8000832776d4 x15: 0000000000000001
x14: 1ffff00013790c9c x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000080000 x10: 0000000000000003 x9 : 937ab5ca09c45f00
x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000008 x3 : ffff80008322442c
x2 : 0000000000000001 x1 : ffff80008bcbfe60 x0 : 0000000000000001
Call trace:
 __process_finished_items+0x708/0x7b4 fs/bcachefs/rcu_pending.c:257 (P)
 process_finished_items+0x254/0x27c fs/bcachefs/rcu_pending.c:280
 __rcu_pending_enqueue fs/bcachefs/rcu_pending.c:422 [inline]
 rcu_pending_enqueue+0x1e8/0x898 fs/bcachefs/rcu_pending.c:515
 bkey_cached_free+0xb8/0x214 fs/bcachefs/btree_key_cache.c:115
 bch2_btree_key_cache_drop+0x104/0x210 fs/bcachefs/btree_key_cache.c:586
 bch2_trans_commit_write_locked fs/bcachefs/btree_trans_commit.c:824 [inline]
 do_bch2_trans_commit fs/bcachefs/btree_trans_commit.c:900 [inline]
 __bch2_trans_commit+0x4d64/0x6604 fs/bcachefs/btree_trans_commit.c:1121
 bch2_trans_commit fs/bcachefs/btree_update.h:184 [inline]
 bch2_trans_mark_metadata_bucket+0x3bc/0x1188 fs/bcachefs/buckets.c:1048
 __bch2_trans_mark_dev_sb fs/bcachefs/buckets.c:1120 [inline]
 bch2_trans_mark_dev_sb+0x48c/0x6c8 fs/bcachefs/buckets.c:1133
 bch2_trans_mark_dev_sbs_flags+0x754/0x7b4 fs/bcachefs/buckets.c:1143
 bch2_trans_mark_dev_sbs+0x24/0x34 fs/bcachefs/buckets.c:1155
 bch2_fs_initialize+0xa40/0x1d0c fs/bcachefs/recovery.c:1074
 bch2_fs_start+0x2fc/0x53c fs/bcachefs/super.c:1038
 bch2_fs_get_tree+0x938/0x1030 fs/bcachefs/fs.c:2170
 vfs_get_tree+0x90/0x28c fs/super.c:1814
 do_new_mount+0x278/0x900 fs/namespace.c:3507
 path_mount+0x590/0xe04 fs/namespace.c:3834
 do_mount fs/namespace.c:3847 [inline]
 __do_sys_mount fs/namespace.c:4057 [inline]
 __se_sys_mount fs/namespace.c:4034 [inline]
 __arm64_sys_mount+0x4d4/0x5ac fs/namespace.c:4034
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
Code: aa1b03e0 9418e6c0 b40002b5 d343fea8 (387c6908) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa1b03e0 	mov	x0, x27
   4:	9418e6c0 	bl	0x639b04
   8:	b40002b5 	cbz	x21, 0x5c
   c:	d343fea8 	lsr	x8, x21, #3
* 10:	387c6908 	ldrb	w8, [x8, x28] <-- trapping instruction

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/01/10 23:00 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 6251d1776bc5 67d7ec0a .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 BUG: unable to handle kernel paging request in __process_finished_items
* Struck through repros no longer work on HEAD.