linux-kernel - [syzbot] [mm?] BUG: unable to handle kernel paging request in list_lru

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Message-ID: <0000000000006d415806048a9aee@google.com>
Date:   Mon, 04 Sep 2023 09:00:02 -0700
From:   syzbot <syzbot+2403e3909382fbdeaf6c@...kaller.appspotmail.com>
To:     akpm@...ux-foundation.org, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, syzkaller-bugs@...glegroups.com
Subject: [syzbot] [mm?] BUG: unable to handle kernel paging request in list_lru_add

Hello,

syzbot found the following issue on:

HEAD commit:    708283abf896 Merge tag 'dmaengine-6.6-rc1' of git://git.ke..
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=17424cd0680000
kernel config:  https://syzkaller.appspot.com/x/.config?x=15f37e053f1602f8
dashboard link: https://syzkaller.appspot.com/bug?extid=2403e3909382fbdeaf6c
compiler:       aarch64-linux-gnu-gcc (Debian 12.2.0-14) 12.2.0, 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 (non-bootable): https://storage.googleapis.com/syzbot-assets/384ffdcca292/non_bootable_disk-708283ab.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/ae645c88b07f/vmlinux-708283ab.xz
kernel image: https://storage.googleapis.com/syzbot-assets/32d5997bb055/Image-708283ab.gz.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+2403e3909382fbdeaf6c@...kaller.appspotmail.com

Unable to handle kernel paging request at virtual address dfff800000000001
KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
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
[dfff800000000001] address between user and kernel address ranges
Internal error: Oops: 0000000096000005 [#1] PREEMPT SMP
Modules linked in:
CPU: 1 PID: 2922 Comm: udevd Not tainted 6.5.0-syzkaller-11329-g708283abf896 #0
Hardware name: linux,dummy-virt (DT)
pstate: 60000005 (nZCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : list_add_tail include/linux/list.h:183 [inline]
pc : list_lru_add+0x174/0x464 mm/list_lru.c:129
lr : list_lru_from_memcg_idx mm/list_lru.c:56 [inline]
lr : list_lru_from_memcg_idx mm/list_lru.c:53 [inline]
lr : list_lru_from_kmem mm/list_lru.c:78 [inline]
lr : list_lru_add+0x354/0x464 mm/list_lru.c:128
sp : ffff80008dd57520
x29: ffff80008dd57520 x28: 0000000000000008 x27: ffff0000378c4000
x26: 0000000000000001 x25: 0000000000000000 x24: 0000000000000000
x23: 1fffe0000293550a x22: 0000000000000000 x21: ffff000012d1c7a0
x20: ffff0000149aa850 x19: ffff0000146f7a00 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000 x15: ffff800080915234
x14: ffff800080914c58 x13: ffff800080914c58 x12: 000000000000f1f1
x11: dfff800000000000 x10: 00000000f3000000 x9 : 00000000f3f3f3f3
x8 : ffff700011baae76 x7 : 00000000f1f1f1f1 x6 : dfff800000000000
x5 : ffff700011baae7a x4 : 00000000f204f1f1 x3 : 1fffe0000d51ff28
x2 : 0000000000000000 x1 : 0000000000000000 x0 : dfff800000000000
Call trace:
 list_add_tail include/linux/list.h:183 [inline]
 list_lru_add+0x174/0x464 mm/list_lru.c:129
 d_lru_add+0x180/0x31c fs/dcache.c:431
 retain_dentry fs/dcache.c:685 [inline]
 dput+0x4ac/0x96c fs/dcache.c:908
 handle_mounts fs/namei.c:1554 [inline]
 step_into+0xc18/0x16c4 fs/namei.c:1839
 walk_component+0xa8/0x484 fs/namei.c:2007
 link_path_walk.part.0.constprop.0+0x4cc/0x970 fs/namei.c:2328
 link_path_walk fs/namei.c:2253 [inline]
 path_openat+0x1bc/0x2058 fs/namei.c:3792
 do_filp_open+0x16c/0x330 fs/namei.c:3823
 do_sys_openat2+0x12c/0x160 fs/open.c:1422
 do_sys_open fs/open.c:1437 [inline]
 __do_sys_openat fs/open.c:1453 [inline]
 __se_sys_openat fs/open.c:1448 [inline]
 __arm64_sys_openat+0x12c/0x1b8 fs/open.c:1448
 __invoke_syscall arch/arm64/kernel/syscall.c:37 [inline]
 invoke_syscall+0x6c/0x258 arch/arm64/kernel/syscall.c:51
 el0_svc_common.constprop.0+0xac/0x230 arch/arm64/kernel/syscall.c:136
 do_el0_svc+0x40/0x58 arch/arm64/kernel/syscall.c:155
 el0_svc+0x58/0x140 arch/arm64/kernel/entry-common.c:678
 el0t_64_sync_handler+0x100/0x12c arch/arm64/kernel/entry-common.c:696
 el0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:591
Code: 9100231c d2d00000 f2fbffe0 d343ff9a (38e06b40) 
---[ end trace 0000000000000000 ]---
----------------
Code disassembly (best guess):
   0:	9100231c 	add	x28, x24, #0x8
   4:	d2d00000 	mov	x0, #0x800000000000        	// #140737488355328
   8:	f2fbffe0 	movk	x0, #0xdfff, lsl #48
   c:	d343ff9a 	lsr	x26, x28, #3
* 10:	38e06b40 	ldrsb	w0, [x26, x0] <-- trapping instruction


---
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