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Date:   Sun, 11 Sep 2022 00:00:28 -0700
Message-ID: <000000000000922a2105e8615576@google.com>
Subject: [syzbot] BUG: unable to handle kernel paging request in alloc_nilfs
From:   syzbot <syzbot+19d51a2ee09e1cb9ba06@syzkaller.appspotmail.com>
To:     konishi.ryusuke@gmail.com, linux-kernel@vger.kernel.org,
        linux-nilfs@vger.kernel.org, syzkaller-bugs@googlegroups.com
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Hello,

syzbot found the following issue on:

HEAD commit:    25050c56fa3c Merge branch 'for-next/fixes' 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=176f0273080000
kernel config:  https://syzkaller.appspot.com/x/.config?x=db8b30b83a444315
dashboard link: https://syzkaller.appspot.com/bug?extid=19d51a2ee09e1cb9ba06
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, GNU ld (GNU Binutils for Debian) 2.35.2
userspace arch: arm64
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=152b3417080000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ded8f5080000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+19d51a2ee09e1cb9ba06@syzkaller.appspotmail.com

loop0: detected capacity change from 0 to 200
Unable to handle kernel paging request at virtual address dead4ead00000400
Mem abort info:
  ESR = 0x0000000096000004
  EC = 0x25: DABT (current EL), IL = 32 bits
  SET = 0, FnV = 0
  EA = 0, S1PTW = 0
  FSC = 0x04: level 0 translation fault
Data abort info:
  ISV = 0, ISS = 0x00000004
  CM = 0, WnR = 0
[dead4ead00000400] address between user and kernel address ranges
Internal error: Oops: 96000004 [#1] PREEMPT SMP
Modules linked in:
CPU: 0 PID: 3066 Comm: syz-executor208 Not tainted 6.0.0-rc4-syzkaller-17186-g25050c56fa3c #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
pstate: 40400005 (nZcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : slab_alloc mm/slub.c:3251 [inline]
pc : kmem_cache_alloc_trace+0x184/0x324 mm/slub.c:3282
lr : slab_pre_alloc_hook mm/slab.h:702 [inline]
lr : slab_alloc_node mm/slub.c:3157 [inline]
lr : slab_alloc mm/slub.c:3251 [inline]
lr : kmem_cache_alloc_trace+0x8c/0x324 mm/slub.c:3282
sp : ffff8000127f3a80
x29: ffff8000127f3a90 x28: ffff0000c58c0000 x27: ffff80000d379000
x26: ffff80000cdb4419 x25: 0000000000000083 x24: dead4ead00000000
x23: 0000000000000000 x22: ffff800008f7bda0 x21: ffff0000c0001600
x20: 00000000000004d0 x19: 0000000000000dc0 x18: 0000000000000000
x17: 0000000000000000 x16: ffff80000dbb8658 x15: ffff0000c58c0000
x14: 0000000000000010 x13: 0000000000000000 x12: ffff0000c58c0000
x11: 0000000000000001 x10: 0000000000000000 x9 : 0000000000000400
x8 : 0000000000001ec8 x7 : ffff8000084b7800 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000001 x3 : 0000000000001ed0
x2 : 0000000000000000 x1 : 0000000000000800 x0 : 0000000000000000
Call trace:
 next_tid mm/slub.c:2311 [inline]
 slab_alloc_node mm/slub.c:3227 [inline]
 slab_alloc mm/slub.c:3251 [inline]
 kmem_cache_alloc_trace+0x184/0x324 mm/slub.c:3282
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 alloc_nilfs+0x2c/0x13c fs/nilfs2/the_nilfs.c:59
 nilfs_fill_super+0x40/0x2e8 fs/nilfs2/super.c:1041
 nilfs_mount+0x370/0x52c fs/nilfs2/super.c:1317
 legacy_get_tree+0x30/0x74 fs/fs_context.c:610
 vfs_get_tree+0x40/0x140 fs/super.c:1530
 do_new_mount+0x1dc/0x4e4 fs/namespace.c:3040
 path_mount+0x358/0x914 fs/namespace.c:3370
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount fs/namespace.c:3568 [inline]
 __arm64_sys_mount+0x2f8/0x408 fs/namespace.c:3568
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall arch/arm64/kernel/syscall.c:52 [inline]
 el0_svc_common+0x138/0x220 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x48/0x154 arch/arm64/kernel/syscall.c:206
 el0_svc+0x58/0x150 arch/arm64/kernel/entry-common.c:624
 el0t_64_sync_handler+0x84/0xf0 arch/arm64/kernel/entry-common.c:642
 el0t_64_sync+0x18c/0x190
Code: 54000d41 34000d4b b9402aa9 91002103 (f8696b19) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	54000d41 	b.ne	0x1a8  // b.any
   4:	34000d4b 	cbz	w11, 0x1ac
   8:	b9402aa9 	ldr	w9, [x21, #40]
   c:	91002103 	add	x3, x8, #0x8
* 10:	f8696b19 	ldr	x25, [x24, x9] <-- trapping instruction


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