Message-ID: <485fb3da73d92f47fda626f176d65dfbeac9a6d8.camel@dubeyko.com>
Date: Wed, 23 Jul 2025 10:26:21 -0700
From: Viacheslav Dubeyko <slava@...eyko.com>
To: syzbot <syzbot+41ba9c82bce8d7101765@...kaller.appspotmail.com>, 
	frank.li@...o.com, glaubitz@...sik.fu-berlin.de,
 linux-fsdevel@...r.kernel.org, 	linux-kernel@...r.kernel.org,
 syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [hfs?] KASAN: out-of-bounds Read in hfs_bnode_move

On Wed, 2025-07-23 at 10:18 -0700, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 

Issue has been created:
https://github.com/hfs-linux-kernel/hfs-linux-kernel/issues/227

Thanks,
Slava.

> HEAD commit:    89be9a83ccf1 Linux 6.16-rc7
> git tree:       upstream
> console output:
> https://syzkaller.appspot.com/x/log.txt?x=17ac1b82580000
> kernel config: 
> https://syzkaller.appspot.com/x/.config?x=8adfe52da0de2761
> dashboard link:
> https://syzkaller.appspot.com/bug?extid=41ba9c82bce8d7101765
> compiler:       Debian clang version 20.1.7
> (++20250616065708+6146a88f6049-1~exp1~20250616065826.132), Debian LLD
> 20.1.7
> syz repro:     
> https://syzkaller.appspot.com/x/repro.syz?x=1771ef22580000
> C reproducer:  
> https://syzkaller.appspot.com/x/repro.c?x=11f764f0580000
> 
> Downloadable assets:
> disk image (non-bootable):
> https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-89be9a83.raw.xz
> vmlinux:
> https://storage.googleapis.com/syzbot-assets/a3f5f507f252/vmlinux-89be9a83.xz
> kernel image:
> https://storage.googleapis.com/syzbot-assets/a8f9b92c57a6/bzImage-89be9a83.xz
> mounted in repro:
> https://storage.googleapis.com/syzbot-assets/f02d92e4771f/mount_0.gz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the
> commit:
> Reported-by: syzbot+41ba9c82bce8d7101765@...kaller.appspotmail.com
> 
> loop0: detected capacity change from 0 to 64
> ==================================================================
> BUG: KASAN: out-of-bounds in hfs_bnode_move+0xea/0x130
> fs/hfs/bnode.c:143
> Read of size 18446744073709486080 at addr ffff888000994400 by task
> syz.0.16/5547
> 
> CPU: 0 UID: 0 PID: 5547 Comm: syz.0.16 Not tainted 6.16.0-rc7-
> syzkaller #0 PREEMPT(full) 
> Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-
> debian-1.16.3-2~bpo12+1 04/01/2014
> Call Trace:
>  <TASK>
>  dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
>  print_address_description mm/kasan/report.c:378 [inline]
>  print_report+0xca/0x230 mm/kasan/report.c:480
>  kasan_report+0x118/0x150 mm/kasan/report.c:593
>  check_region_inline mm/kasan/generic.c:-1 [inline]
>  kasan_check_range+0x2b0/0x2c0 mm/kasan/generic.c:189
>  __asan_memmove+0x29/0x70 mm/kasan/shadow.c:94
>  hfs_bnode_move+0xea/0x130 fs/hfs/bnode.c:143
>  hfs_brec_remove+0x467/0x550 fs/hfs/brec.c:222
>  hfs_cat_move+0x6fb/0x960 fs/hfs/catalog.c:364
>  hfs_rename+0x1dc/0x2d0 fs/hfs/dir.c:299
>  vfs_rename+0xb99/0xec0 fs/namei.c:5137
>  do_renameat2+0x878/0xc50 fs/namei.c:5286
>  __do_sys_rename fs/namei.c:5333 [inline]
>  __se_sys_rename fs/namei.c:5331 [inline]
>  __x64_sys_rename+0x82/0x90 fs/namei.c:5331
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f11db18e9a9
> Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48
> 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48>
> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007ffd56ec9fe8 EFLAGS: 00000246 ORIG_RAX:
> 0000000000000052
> RAX: ffffffffffffffda RBX: 00007f11db3b5fa0 RCX: 00007f11db18e9a9
> RDX: 0000000000000000 RSI: 0000200000000780 RDI: 00002000000003c0
> RBP: 00007f11db210d69 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f11db3b5fa0 R14: 00007f11db3b5fa0 R15: 0000000000000002
>  </TASK>
> 
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x35
> pfn:0x994
> memcg:ffff888030a98000
> anon flags:
> 0x7ff00000020908(uptodate|active|owner_2|swapbacked|node=0|zone=0|las
> tcpupid=0x7ff)
> raw: 007ff00000020908 0000000000000000 dead000000000122
> ffff888059a96cc1
> raw: 0000000000000035 0000000000000000 00000001ffffffff
> ffff888030a98000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Movable, gfp_mask
> 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 5548, tgid 5548
> (dhcpcd-run-hook), ts 123108746961, free_ts 121368908469
>  set_page_owner include/linux/page_owner.h:32 [inline]
>  post_alloc_hook+0x240/0x2a0 mm/page_alloc.c:1704
>  prep_new_page mm/page_alloc.c:1712 [inline]
>  get_page_from_freelist+0x21e4/0x22c0 mm/page_alloc.c:3669
>  __alloc_frozen_pages_noprof+0x181/0x370 mm/page_alloc.c:4959
>  alloc_pages_mpol+0x232/0x4a0 mm/mempolicy.c:2419
>  folio_alloc_mpol_noprof mm/mempolicy.c:2438 [inline]
>  vma_alloc_folio_noprof+0xe4/0x200 mm/mempolicy.c:2473
>  folio_prealloc+0x30/0x180 mm/memory.c:-1
>  wp_page_copy mm/memory.c:3569 [inline]
>  do_wp_page+0x1231/0x5800 mm/memory.c:4030
>  handle_pte_fault mm/memory.c:6085 [inline]
>  __handle_mm_fault+0x1144/0x5620 mm/memory.c:6212
>  handle_mm_fault+0x40a/0x8e0 mm/memory.c:6381
>  do_user_addr_fault+0xa81/0x1390 arch/x86/mm/fault.c:1336
>  handle_page_fault arch/x86/mm/fault.c:1476 [inline]
>  exc_page_fault+0x76/0xf0 arch/x86/mm/fault.c:1532
>  asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:623
> page last free pid 5509 tgid 5509 stack trace:
>  reset_page_owner include/linux/page_owner.h:25 [inline]
>  free_pages_prepare mm/page_alloc.c:1248 [inline]
>  free_unref_folios+0xc66/0x14d0 mm/page_alloc.c:2763
>  folios_put_refs+0x559/0x640 mm/swap.c:992
>  free_pages_and_swap_cache+0x4be/0x520 mm/swap_state.c:267
>  __tlb_batch_free_encoded_pages mm/mmu_gather.c:136 [inline]
>  tlb_batch_pages_flush mm/mmu_gather.c:149 [inline]
>  tlb_flush_mmu_free mm/mmu_gather.c:397 [inline]
>  tlb_flush_mmu+0x3a0/0x680 mm/mmu_gather.c:404
>  tlb_finish_mmu+0xc3/0x1d0 mm/mmu_gather.c:497
>  exit_mmap+0x44c/0xb50 mm/mmap.c:1297
>  __mmput+0x118/0x420 kernel/fork.c:1121
>  exit_mm+0x1da/0x2c0 kernel/exit.c:581
>  do_exit+0x648/0x22e0 kernel/exit.c:952
>  do_group_exit+0x21c/0x2d0 kernel/exit.c:1105
>  __do_sys_exit_group kernel/exit.c:1116 [inline]
>  __se_sys_exit_group kernel/exit.c:1114 [inline]
>  __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1114
>  x64_sys_call+0x21ba/0x21c0
> arch/x86/include/generated/asm/syscalls_64.h:232
>  do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
>  do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Memory state around the buggy address:
>  ffff888000994300: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffff888000994380: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> > ffff888000994400: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>                    ^
>  ffff888000994480: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>  ffff888000994500: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
> ==================================================================
> 
> 
> ---
> 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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