Message-ID: <4842ef8c-bcf1-4cb8-942a-68591332c948@lucifer.local>
Date: Sun, 17 Nov 2024 18:49:50 +0000
From: Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
To: syzbot <syzbot+bc6bfc25a68b7a020ee1@...kaller.appspotmail.com>
Cc: Liam.Howlett@...cle.com, akpm@...ux-foundation.org, jannh@...gle.com,
        linux-kernel@...r.kernel.org, linux-mm@...ck.org,
        syzkaller-bugs@...glegroups.com, vbabka@...e.cz
Subject: Re: [syzbot] [mm?] general protection fault in mas_store_prealloc

On Sun, Nov 17, 2024 at 02:42:26AM -0800, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    8e9a54d7181b Merge remote-tracking branch 'iommu/arm/smmu'..

Will take a look properly tomorrow, but this commit doesn't exist in the
tree any more.

Let's try this again in the actual existing branch...

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git 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=17b0ace8580000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=a1eb85a42cb8ccec
> dashboard link: https://syzkaller.appspot.com/bug?extid=bc6bfc25a68b7a020ee1
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> userspace arch: arm64
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=147521a7980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=102e14c0580000
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/ad658fb4d0a2/disk-8e9a54d7.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/1b7754fa8c67/vmlinux-8e9a54d7.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/50315382fefb/Image-8e9a54d7.gz.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+bc6bfc25a68b7a020ee1@...kaller.appspotmail.com
>
>  __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
>  invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
>  el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
>  do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
>  el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
>  el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
> 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 UID: 0 PID: 6421 Comm: syz-executor374 Not tainted 6.12.0-rc7-syzkaller-g8e9a54d7181b #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
> pstate: 80400005 (Nzcv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
> pc : mt_slot_locked lib/maple_tree.c:795 [inline]
> pc : mas_slot_locked lib/maple_tree.c:808 [inline]
> pc : mas_store_prealloc+0x870/0x1068 lib/maple_tree.c:5514
> lr : mt_slot_locked lib/maple_tree.c:795 [inline]
> lr : mas_slot_locked lib/maple_tree.c:808 [inline]
> lr : mas_store_prealloc+0x778/0x1068 lib/maple_tree.c:5514
> sp : ffff8000a3e57440
> x29: ffff8000a3e57560 x28: ffff8000a3e574c0 x27: dfff800000000000
> x26: ffff7000147cae94 x25: 0000000000000008 x24: 0000000000000000
> x23: 0000000000000008 x22: ffff0000daed1040 x21: 0000000000000008
> x20: ffff8000a3e578e0 x19: 0000000000000000 x18: 0000000000000008
> x17: 0000000000000000 x16: ffff800080585ea8 x15: 0000000000000009
> x14: 1ffff000147cae99 x13: 0000000000000000 x12: 0000000000000000
> x11: ffff7000147caea2 x10: 0000000000ff0100 x9 : 0000000000000000
> x8 : 0000000000000001 x7 : 0000000000000000 x6 : 0000000000000001
> x5 : ffff8000a3e565f8 x4 : 0000000000000008 x3 : ffff80008b4208f0
> x2 : ffffffffffffffc0 x1 : 0000000000000001 x0 : 0000000000000000
> Call trace:
>  mt_slot_locked lib/maple_tree.c:795 [inline] (P)
>  mas_slot_locked lib/maple_tree.c:808 [inline] (P)
>  mas_store_prealloc+0x870/0x1068 lib/maple_tree.c:5514 (P)
>  mt_slot_locked lib/maple_tree.c:795 [inline] (L)
>  mas_slot_locked lib/maple_tree.c:808 [inline] (L)
>  mas_store_prealloc+0x778/0x1068 lib/maple_tree.c:5514 (L)
>  vma_iter_store+0x2e8/0x81c mm/vma.h:476
>  __mmap_region mm/mmap.c:1513 [inline]
>  mmap_region+0x1650/0x1d44 mm/mmap.c:1603
>  do_mmap+0x8c4/0xfac mm/mmap.c:496
>  vm_mmap_pgoff+0x1a0/0x38c mm/util.c:588
>  ksys_mmap_pgoff+0x3a4/0x5c8 mm/mmap.c:542
>  __do_sys_mmap arch/arm64/kernel/sys.c:28 [inline]
>  __se_sys_mmap arch/arm64/kernel/sys.c:21 [inline]
>  __arm64_sys_mmap+0xf8/0x110 arch/arm64/kernel/sys.c:21
>  __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
>  invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49
>  el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132
>  do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
>  el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744
>  el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762
>  el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600
> Code: 393b2668 972c43de 8b180ef5 d343fea8 (387b6908)
> ---[ end trace 0000000000000000 ]---
> ----------------
> Code disassembly (best guess):
>    0:	393b2668 	strb	w8, [x19, #3785]
>    4:	972c43de 	bl	0xfffffffffcb10f7c
>    8:	8b180ef5 	add	x21, x23, x24, lsl #3
>    c:	d343fea8 	lsr	x8, x21, #3
> * 10:	387b6908 	ldrb	w8, [x8, x27] <-- trapping instruction
>
>
> ---
> This report is generated by a bot. It may contain errors.
> See https://goo.gl/tpsmEJ for more information about syzbot.
> syzbot engineers can be reached at syzkaller@...glegroups.com.
>
> syzbot will keep track of this issue. See:
> https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
>
> If the report is already addressed, let syzbot know by replying with:
> #syz fix: exact-commit-title
>
> If you want syzbot to run the reproducer, reply with:
> #syz test: git://repo/address.git branch-or-commit-hash
> If you attach or paste a git patch, syzbot will apply it before testing.
>
> If you want to overwrite report's subsystems, reply with:
> #syz set subsystems: new-subsystem
> (See the list of subsystem names on the web dashboard)
>
> If the report is a duplicate of another one, reply with:
> #syz dup: exact-subject-of-another-report
>
> If you want to undo deduplication, reply with:
> #syz undup

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