Is remount racy?
jfs_rename did not expect dtDelete to return rc = -2
ERROR: (device (efault)): txAbort: 
Unable to handle kernel paging request at virtual address dfff80000000000a
KASAN: null-ptr-deref in range [0x0000000000000050-0x0000000000000057]
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
[dfff80000000000a] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 7990 Comm: syz-executor.2 Not tainted 6.9.0-rc7-syzkaller-gfda5695d692c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/27/2024
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : sb_rdonly include/linux/fs.h:2234 [inline]
pc : jfs_handle_error fs/jfs/super.c:66 [inline]
pc : jfs_error+0x120/0x274 fs/jfs/super.c:98
lr : jfs_error+0x118/0x274 fs/jfs/super.c:93
sp : ffff800099297420
x29: ffff800099297500 x28: 00000000fffffffe x27: 1fffe0001e0512de
x26: 1ffff00012e48a05 x25: dfff800000000000 x24: ffff700013252e8c
x23: ffff8000992974a0 x22: 000000000000000a x21: 0000000000000668
x20: 0000000000000050 x19: 0000000000000000 x18: 1fffe000367bd196
x17: ffff80008eead000 x16: ffff80008ae89e3c x15: 0000000000000001
x14: 1ffff00013252dd8 x13: 0000000000000000 x12: 0000000000000000
x11: 0000000000040000 x10: 000000000000e936 x9 : 8c016e96ab9f9b00
x8 : 8c016e96ab9f9b00 x7 : ffff8000802aa2c0 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000001 x3 : ffff800082f22378
x2 : 0000000000000001 x1 : 0000000100000000 x0 : 0000000000000024
Call trace:
 sb_rdonly include/linux/fs.h:2234 [inline]
 jfs_handle_error fs/jfs/super.c:66 [inline]
 jfs_error+0x120/0x274 fs/jfs/super.c:98
 txAbort+0x4b0/0x570 fs/jfs/jfs_txnmgr.c:2637
 jfs_rename+0xc50/0x17c4 fs/jfs/namei.c:1243
 vfs_rename+0x9bc/0xc84 fs/namei.c:4880
 do_renameat2+0x9c8/0xe40 fs/namei.c:5037
 __do_sys_renameat2 fs/namei.c:5071 [inline]
 __se_sys_renameat2 fs/namei.c:5068 [inline]
 __arm64_sys_renameat2+0xe0/0xfc fs/namei.c:5068
 __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: aa1e03e2 9593f019 91014274 d343fe96 (38796ac8) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	aa1e03e2 	mov	x2, x30
   4:	9593f019 	bl	0x64fc068
   8:	91014274 	add	x20, x19, #0x50
   c:	d343fe96 	lsr	x22, x20, #3
* 10:	38796ac8 	ldrb	w8, [x22, x25] <-- trapping instruction