[syzbot] [bcachefs?] BUG: unable to handle kernel paging request in bch2_fs_btree_key_cache_exit

syzbot
2024-05-03T11:38:48Z

Hello,

syzbot found the following issue on:

HEAD commit: 6a71d2909427 Merge branch 'for-next/core' into for-kernelci
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci
console output: https://syzkaller.appspot.com/x/log.txt?x=11889a4c980000
kernel config: https://syzkaller.appspot.com/x/.config?x=fca646cf17cc616b
dashboard link: https://syzkaller.appspot.com/bug?extid=a35cdb62ec34d44fb062
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
userspace arch: arm64

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/c77d21fa1405/disk-6a71d290.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/429fcd369816/vmlinux-6a71d290.xz
kernel image: https://storage.googleapis.com/syzbot-assets/d3d8a4b85112/Image-6a71d290.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+a35cdb62ec34d44fb062@syzkaller.appspotmail.com

Unable to handle kernel paging request at virtual address ffff7000249ff210
KASAN: probably wild-memory-access in range [0xffff800124ff9080-0xffff800124ff9087]
Mem abort info:
ESR = 0x0000000096000006
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x06: level 2 translation fault
Data abort info:
ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
swapper pgtable: 4k pages, 48-bit VAs, pgdp=00000001ad5bd000
[ffff7000249ff210] pgd=0000000000000000, p4d=000000023e882003, pud=000000023e880003, pmd=0000000000000000
Internal error: Oops: 0000000096000006 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 7242 Comm: syz-executor.4 Not tainted 6.9.0-rc4-syzkaller-g6a71d2909427 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
pstate: 80401005 (Nzcv daif +PAN -UAO -TCO -DIT +SSBS BTYPE=--)
pc : bch2_fs_btree_key_cache_exit+0x7ec/0xfcc fs/bcachefs/btree_key_cache.c:974
lr : bch2_fs_btree_key_cache_exit+0x78c/0xfcc fs/bcachefs/btree_key_cache.c:970
sp : ffff8000aa1d6e80
x29: ffff8000aa1d6f50 x28: 1fffe0001c790010 x27: ffff0000e3c844b0
x26: 1ffff0001543ade0 x25: dfff800000000000 x24: 1ffff0001168e5d4
x23: 0000000000000000 x22: ffff800124ff9080 x21: ffff8000aa1d6f00
x20: ffff80008ee81218 x19: dfff800000000000 x18: 1fffe000367b9596
x17: ffff80008ee7d000 x16: ffff8000802896e4 x15: 0000000000000001
x14: 1fffe0001c790898 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000040000 x10: 0000000000ff0100 x9 : 0000000000000003
x8 : 1ffff000249ff210 x7 : ffff80008275d4e8 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : ffff80008275d4f8
x2 : 0000000000000000 x1 : 0000000000000000 x0 : 0000000000000008
Call trace:
bch2_fs_btree_key_cache_exit+0x7ec/0xfcc fs/bcachefs/btree_key_cache.c:974
__bch2_fs_free fs/bcachefs/super.c:562 [inline]
bch2_fs_release+0x1e0/0x564 fs/bcachefs/super.c:609
kobject_cleanup lib/kobject.c:689 [inline]
kobject_release lib/kobject.c:720 [inline]
kref_put include/linux/kref.h:65 [inline]
kobject_put+0x2a8/0x41c lib/kobject.c:737
bch2_fs_free+0x288/0x2f0 fs/bcachefs/super.c:674
bch2_fs_alloc+0xe4c/0x1c60 fs/bcachefs/super.c:965
bch2_fs_open+0x740/0xb64 fs/bcachefs/super.c:2080
bch2_mount+0x558/0xe10 fs/bcachefs/fs.c:1900
legacy_get_tree+0xd4/0x16c fs/fs_context.c:662
vfs_get_tree+0x90/0x288 fs/super.c:1779
do_new_mount+0x278/0x900 fs/namespace.c:3352
path_mount+0x590/0xe04 fs/namespace.c:3679
do_mount fs/namespace.c:3692 [inline]
__do_sys_mount fs/namespace.c:3898 [inline]
__se_sys_mount fs/namespace.c:3875 [inline]
__arm64_sys_mount+0x45c/0x594 fs/namespace.c:3875
__invoke_syscall arch/arm64/kernel/syscall.c:34 [inline]
invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:48
el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:133
do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:152
el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712
el0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730
el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598
Code: f90027e8 d343fec8 11000d29 f9002be8 (38f36908)
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
0: f90027e8 str x8, [sp, #72]
4: d343fec8 lsr x8, x22, #3
8: 11000d29 add w9, w9, #0x3
c: f9002be8 str x8, [sp, #80]
* 10: 38f36908 ldrsb w8, [x8, x19] <-- trapping instruction

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