[syzbot ci] Re: dcache: fully initialize the inline name in __d_alloc()

[syzbot ci <syzbot+cif320737e2d884f65@syzkaller.appspotmail.com>]

syzbot ci has tested the following series

[v1] dcache: fully initialize the inline name in __d_alloc()
https://lore.kernel.org/all/20260913152802.13413-1-drifabdelmalekmohamedsaid@gmail.com
* [PATCH] dcache: fully initialize the inline name in __d_alloc()

and found the following issue:
KASAN: null-ptr-deref Read in __d_alloc

Full report is available here:
https://ci.syzbot.org/series/5b221ae6-70dc-4b99-963a-3d9e7db97db0

***

KASAN: null-ptr-deref Read in __d_alloc

tree:      vfs
URL:       https://kernel.googlesource.com/pub/scm/linux/kernel/git/vfs/vfs.git
base:      f5d607b8091438d8416d0e3ae02532a18539b48b
arch:      amd64
compiler:  Debian clang version 22.1.8 (++20260613092233+e80beda6e255-1~exp1~20260613092250.77), Debian LLD 22.1.8
config:    https://ci.syzbot.org/builds/9b8e9369-7fc0-4fbd-a090-6f785f103d1b/config

kfence: initialized - using 2097152 bytes for 255 objects at 0xffff88823c400000-0xffff88823c600000
Console: colour VGA+ 80x25
printk: console [ttyS0] enabled
printk: console [ttyS0] enabled
printk: legacy bootconsole [earlyser0] disabled
printk: legacy bootconsole [earlyser0] disabled
Lock dependency validator: Copyright (c) 2006 Red Hat, Inc., Ingo Molnar
... MAX_LOCKDEP_SUBCLASSES:  8
... MAX_LOCK_DEPTH:          48
... MAX_LOCKDEP_KEYS:        8192
... CLASSHASH_SIZE:          4096
... MAX_LOCKDEP_ENTRIES:     1048576
... MAX_LOCKDEP_CHAINS:      1048576
... CHAINHASH_SIZE:          524288
 memory used by lock dependency info: 106625 kB
 memory used for stack traces: 8320 kB
 per task-struct memory footprint: 1920 bytes
mempolicy: Enabling automatic NUMA balancing. Configure with numa_balancing= or the kernel.numa_balancing sysctl
ACPI: Core revision 20260408
clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 19112604467 ns
APIC: Switch to symmetric I/O mode setup
x2apic enabled
APIC: Switched APIC routing to: physical x2apic
..TIMER: vector=0x30 apic1=0 pin1=2 apic2=-1 pin2=-1
clocksource: tsc-early: mask: 0xffffffffffffffff max_cycles: 0x285c3ee517e, max_idle_ns: 440795257231 ns
Calibrating delay loop (skipped) preset value.. 5599.99 BogoMIPS (lpj=27999980)
Last level iTLB entries: 4KB 0, 2MB 0, 4MB 0
Last level dTLB entries: 4KB 0, 2MB 0, 4MB 0, 1GB 0
mitigations: Enabled attack vectors: user_kernel, user_user, guest_host, guest_guest, SMT mitigations: auto
Speculative Store Bypass: Vulnerable
Spectre V2 : Mitigation: Retpolines
ITS: Mitigation: Aligned branch/return thunks
MDS: Vulnerable: Clear CPU buffers attempted, no microcode
Spectre V1 : Mitigation: usercopy/swapgs barriers and __user pointer sanitization
Spectre V2 : Spectre v2 / SpectreRSB: Filling RSB on context switch and VMEXIT
active return thunk: its_return_thunk
x86/fpu: x87 FPU will use FXSAVE
pid_max: default: 32768 minimum: 301
landlock: Up and running.
Yama: becoming mindful.
TOMOYO Linux initialized
AppArmor: AppArmor initialized
LSM support for eBPF active
debugfs: Unable to create file 'net_refcnt@ffffffff9aedda40', debugfs is not initialized yet
debugfs: Unable to create file 'net_notrefcnt@ffffffff9aeddab8', debugfs is not initialized yet
Dentry cache hash table entries: 1048576 (order: 11, 8388608 bytes, vmalloc hugepage)
Inode-cache hash table entries: 524288 (order: 10, 4194304 bytes, vmalloc hugepage)
Mount-cache hash table entries: 16384 (order: 5, 131072 bytes, vmalloc)
Mountpoint-cache hash table entries: 16384 (order: 5, 131072 bytes, vmalloc)
==================================================================
BUG: KASAN: null-ptr-deref in __d_alloc+0x65/0x7b0
Read of size 40 at addr 0000000000000000 by task swapper/0/0

CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 kasan_report+0x117/0x150
 kasan_check_range+0x264/0x2c0
 __asan_memcpy+0x29/0x70
 __d_alloc+0x65/0x7b0
 d_make_root+0x41/0x80
 shmem_fill_super+0xc07/0x1090
 get_tree_nodev+0xbb/0x150
 vfs_get_tree+0x92/0x2a0
 vfs_kern_mount+0x15b/0x220
 kern_mount+0x43/0x90
 shmem_init+0x37/0x170
 mnt_init+0x19b/0x1f0
 vfs_caches_init+0x22/0x30
 start_kernel+0x34c/0x3e0
 x86_64_start_reservations+0x24/0x30
 x86_64_start_kernel+0x137/0x1b0
 common_startup_64+0x13e/0x157
 </TASK>
==================================================================


***

If these findings have caused you to resend the series or submit a
separate fix, please add the following tag to your commit message:
  Tested-by: syzbot@syzkaller.appspotmail.com

---
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