Message-ID: <46f44064-255b-4a1e-9317-f4b168706d65@kernel.org>
Date: Thu, 18 Jul 2024 12:59:45 +0200
From: "Vlastimil Babka (SUSE)" <vbabka@...nel.org>
To: syzbot <syzbot+4c882a4a0697c4a25364@...kaller.appspotmail.com>,
 akpm@...ux-foundation.org, davem@...emloft.net, herbert@...dor.apana.org.au,
 linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org,
 linux-mm@...ck.org, syzkaller-bugs@...glegroups.com
Cc: Suren Baghdasaryan <surenb@...gle.com>,
 "Liam R. Howlett" <Liam.Howlett@...cle.com>,
 Lorenzo Stoakes <lorenzo.stoakes@...cle.com>
Subject: Re: [syzbot] [crypto?] KASAN: slab-use-after-free Read in
 handle_mm_fault

On 7/16/24 10:29 AM, syzbot wrote:
> Hello,

dunno about the [crypto?] parts, sounds rather something for Suren or Liam
or maybe it's due to some changes to gup?

> syzbot found the following issue on:
> 
> HEAD commit:    3fe121b62282 Add linux-next specific files for 20240712
> git tree:       linux-next
> console output: https://syzkaller.appspot.com/x/log.txt?x=1097ebed980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=98dd8c4bab5cdce
> dashboard link: https://syzkaller.appspot.com/bug?extid=4c882a4a0697c4a25364
> compiler:       Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
> syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=11d611a5980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=13ce3259980000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/8c6fbf69718d/disk-3fe121b6.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/39fc7e43dfc1/vmlinux-3fe121b6.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/0a78e70e4b4e/bzImage-3fe121b6.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/66cfe5a679f2/mount_0.gz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+4c882a4a0697c4a25364@...kaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: slab-use-after-free in handle_mm_fault+0x14f0/0x19a0 mm/memory.c:5842
> Read of size 8 at addr ffff88802c4719d0 by task syz-executor125/5235
> 
> CPU: 1 UID: 0 PID: 5235 Comm: syz-executor125 Not tainted 6.10.0-rc7-next-20240712-syzkaller #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:94 [inline]
>  dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
>  print_address_description mm/kasan/report.c:377 [inline]
>  print_report+0x169/0x550 mm/kasan/report.c:488
>  kasan_report+0x143/0x180 mm/kasan/report.c:601
>  handle_mm_fault+0x14f0/0x19a0 mm/memory.c:5842
>  faultin_page mm/gup.c:1194 [inline]
>  __get_user_pages+0x6ec/0x16a0 mm/gup.c:1493
>  populate_vma_page_range+0x264/0x330 mm/gup.c:1932
>  __mm_populate+0x27a/0x460 mm/gup.c:2035
>  mm_populate include/linux/mm.h:3429 [inline]
>  vm_mmap_pgoff+0x2c3/0x3d0 mm/util.c:593
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> RIP: 0033:0x7f093ce17fe9
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 1d 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f093cd9e158 EFLAGS: 00000246 ORIG_RAX: 0000000000000009
> RAX: ffffffffffffffda RBX: 00007f093ce9f4b8 RCX: 00007f093ce17fe9
> RDX: 0000000000000002 RSI: 0000000000b36000 RDI: 0000000020000000
> RBP: 00007f093ce9f4b0 R08: 00000000ffffffff R09: 0000000000000000
> R10: 0000000000008031 R11: 0000000000000246 R12: 00007f093ce9f4bc
> R13: 000000000000006e R14: 00007ffe8008cc30 R15: 00007ffe8008cd18
>  </TASK>
> 
> Allocated by task 5235:
>  kasan_save_stack mm/kasan/common.c:47 [inline]
>  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>  unpoison_slab_object mm/kasan/common.c:312 [inline]
>  __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:338
>  kasan_slab_alloc include/linux/kasan.h:201 [inline]
>  slab_post_alloc_hook mm/slub.c:3988 [inline]
>  slab_alloc_node mm/slub.c:4037 [inline]
>  kmem_cache_alloc_noprof+0x135/0x2a0 mm/slub.c:4044
>  vm_area_alloc+0x24/0x1d0 kernel/fork.c:472
>  mmap_region+0xc3d/0x2090 mm/mmap.c:2944
>  do_mmap+0x8f9/0x1010 mm/mmap.c:1468
>  vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Freed by task 5237:
>  kasan_save_stack mm/kasan/common.c:47 [inline]
>  kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
>  kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
>  poison_slab_object+0xe0/0x150 mm/kasan/common.c:240
>  __kasan_slab_free+0x37/0x60 mm/kasan/common.c:256
>  kasan_slab_free include/linux/kasan.h:184 [inline]
>  slab_free_hook mm/slub.c:2252 [inline]
>  slab_free mm/slub.c:4473 [inline]
>  kmem_cache_free+0x145/0x350 mm/slub.c:4548
>  rcu_do_batch kernel/rcu/tree.c:2569 [inline]
>  rcu_core+0xafd/0x1830 kernel/rcu/tree.c:2843
>  handle_softirqs+0x2c4/0x970 kernel/softirq.c:554
>  __do_softirq kernel/softirq.c:588 [inline]
>  invoke_softirq kernel/softirq.c:428 [inline]
>  __irq_exit_rcu+0xf4/0x1c0 kernel/softirq.c:637
>  irq_exit_rcu+0x9/0x30 kernel/softirq.c:649
>  instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1043 [inline]
>  sysvec_apic_timer_interrupt+0xa6/0xc0 arch/x86/kernel/apic/apic.c:1043
>  asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
> 
> Last potentially related work creation:
>  kasan_save_stack+0x3f/0x60 mm/kasan/common.c:47
>  __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:541
>  __call_rcu_common kernel/rcu/tree.c:3106 [inline]
>  call_rcu+0x167/0xa70 kernel/rcu/tree.c:3210
>  remove_vma mm/mmap.c:189 [inline]
>  remove_mt mm/mmap.c:2415 [inline]
>  do_vmi_align_munmap+0x155c/0x18c0 mm/mmap.c:2758
>  do_vmi_munmap+0x261/0x2f0 mm/mmap.c:2830
>  mmap_region+0x72f/0x2090 mm/mmap.c:2881
>  do_mmap+0x8f9/0x1010 mm/mmap.c:1468
>  vm_mmap_pgoff+0x1dd/0x3d0 mm/util.c:588
>  ksys_mmap_pgoff+0x544/0x720 mm/mmap.c:1514
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> The buggy address belongs to the object at ffff88802c4719b0
>  which belongs to the cache vm_area_struct of size 184
> The buggy address is located 32 bytes inside of
>  freed 184-byte region [ffff88802c4719b0, ffff88802c471a68)
> 
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2c471
> memcg:ffff888024312e01
> flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
> page_type: 0xfdffffff(slab)
> raw: 00fff00000000000 ffff888015eefb40 ffffea000091a480 0000000000000008
> raw: 0000000000000000 0000000080100010 00000001fdffffff ffff888024312e01
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 4769, tgid 4769 (S41dhcpcd), ts 42147845478, free_ts 42112307396
>  set_page_owner include/linux/page_owner.h:32 [inline]
>  post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1493
>  prep_new_page mm/page_alloc.c:1501 [inline]
>  get_page_from_freelist+0x2ccb/0x2d80 mm/page_alloc.c:3474
>  __alloc_pages_noprof+0x256/0x6c0 mm/page_alloc.c:4732
>  __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
>  alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
>  alloc_slab_page+0x5f/0x120 mm/slub.c:2321
>  allocate_slab+0x5a/0x2f0 mm/slub.c:2484
>  new_slab mm/slub.c:2537 [inline]
>  ___slab_alloc+0xcd1/0x14b0 mm/slub.c:3723
>  __slab_alloc+0x58/0xa0 mm/slub.c:3813
>  __slab_alloc_node mm/slub.c:3866 [inline]
>  slab_alloc_node mm/slub.c:4025 [inline]
>  kmem_cache_alloc_noprof+0x1c1/0x2a0 mm/slub.c:4044
>  vm_area_dup+0x27/0x290 kernel/fork.c:487
>  dup_mmap kernel/fork.c:696 [inline]
>  dup_mm kernel/fork.c:1674 [inline]
>  copy_mm+0xc7b/0x1f30 kernel/fork.c:1723
>  copy_process+0x186b/0x3d90 kernel/fork.c:2376
>  kernel_clone+0x226/0x8f0 kernel/fork.c:2788
>  __do_sys_clone kernel/fork.c:2931 [inline]
>  __se_sys_clone kernel/fork.c:2915 [inline]
>  __x64_sys_clone+0x258/0x2a0 kernel/fork.c:2915
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> page last free pid 4768 tgid 4768 stack trace:
>  reset_page_owner include/linux/page_owner.h:25 [inline]
>  free_pages_prepare mm/page_alloc.c:1094 [inline]
>  free_unref_folios+0x103a/0x1b00 mm/page_alloc.c:2692
>  folios_put_refs+0x76e/0x860 mm/swap.c:1039
>  free_pages_and_swap_cache+0x5c8/0x690 mm/swap_state.c:335
>  __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:366 [inline]
>  tlb_flush_mmu+0x3a3/0x680 mm/mmu_gather.c:373
>  tlb_finish_mmu+0xd4/0x200 mm/mmu_gather.c:465
>  exit_mmap+0x44f/0xc80 mm/mmap.c:3425
>  __mmput+0x115/0x390 kernel/fork.c:1347
>  exit_mm+0x220/0x310 kernel/exit.c:571
>  do_exit+0x9b2/0x27f0 kernel/exit.c:869
>  do_group_exit+0x207/0x2c0 kernel/exit.c:1031
>  __do_sys_exit_group kernel/exit.c:1042 [inline]
>  __se_sys_exit_group kernel/exit.c:1040 [inline]
>  __x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1040
>  x64_sys_call+0x26c3/0x26d0 arch/x86/include/generated/asm/syscalls_64.h:232
>  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
>  do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
>  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> 
> Memory state around the buggy address:
>  ffff88802c471880: fc fc fc fc fc fc fc 00 00 00 00 00 00 00 00 00
>  ffff88802c471900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 fc fc
>>ffff88802c471980: fc fc fc fc fc fc fa fb fb fb fb fb fb fb fb fb
>                                                  ^
>  ffff88802c471a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
>  ffff88802c471a80: fc fc fc fc fc 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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