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Date:   Thu, 6 Jul 2023 12:54:26 -0400
From:   "Liam R. Howlett" <Liam.Howlett@Oracle.com>
To:     syzbot <syzbot+ca8f1ca3255d1bac5f2f@syzkaller.appspotmail.com>
Cc:     akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
        linux-mm@kvack.org, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in mas_next_slot
Message-ID: <20230706165426.jgwc7s5wolxbbskf@revolver>
Mail-Followup-To: "Liam R. Howlett" <Liam.Howlett@Oracle.com>,
        syzbot <syzbot+ca8f1ca3255d1bac5f2f@syzkaller.appspotmail.com>,
        akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
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This is also a result of the issue on lkml [1].  Should be fixed once
those patches are in tree.

[1] https://lore.kernel.org/lkml/ZKIsoMOT71uwCIZX@xsang-OptiPlex-9020/

* syzbot <syzbot+ca8f1ca3255d1bac5f2f@syzkaller.appspotmail.com> [230706 01:55]:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    a901a3568fd2 Merge tag 'iomap-6.5-merge-1' of git://git.ke..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=11f631fca80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=d787595a482d6a43
> dashboard link: https://syzkaller.appspot.com/bug?extid=ca8f1ca3255d1bac5f2f
> compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
> 
> Unfortunately, I don't have any reproducer for this issue yet.
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/35902c43a7c2/disk-a901a356.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/78b3ce875c7d/vmlinux-a901a356.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/150b1474a952/bzImage-a901a356.xz
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ca8f1ca3255d1bac5f2f@syzkaller.appspotmail.com
> 
> ==================================================================
> BUG: KASAN: slab-use-after-free in ma_data_end lib/maple_tree.c:1459 [inline]
> BUG: KASAN: slab-use-after-free in mas_next_slot+0x184/0x960 lib/maple_tree.c:4725
> Read of size 8 at addr ffff88804b9c5078 by task syz-executor.4/27410
> 
> CPU: 1 PID: 27410 Comm: syz-executor.4 Not tainted 6.4.0-syzkaller-10173-ga901a3568fd2 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
> Call Trace:
>  <TASK>
>  __dump_stack lib/dump_stack.c:88 [inline]
>  dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106
>  print_address_description mm/kasan/report.c:364 [inline]
>  print_report+0x163/0x540 mm/kasan/report.c:475
>  kasan_report+0x175/0x1b0 mm/kasan/report.c:588
>  ma_data_end lib/maple_tree.c:1459 [inline]
>  mas_next_slot+0x184/0x960 lib/maple_tree.c:4725
>  vma_next include/linux/mm.h:865 [inline]
>  validate_mm+0x3e5/0x500 mm/mmap.c:301
>  do_vmi_align_munmap+0x13b1/0x15c0 mm/mmap.c:2561
>  do_vmi_munmap+0x24d/0x2d0 mm/mmap.c:2619
>  __vm_munmap+0x230/0x450 mm/mmap.c:2899
>  __do_sys_munmap mm/mmap.c:2916 [inline]
>  __se_sys_munmap mm/mmap.c:2913 [inline]
>  __x64_sys_munmap+0x69/0x80 mm/mmap.c:2913
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f1076e8c467
> Code: 00 00 00 48 c7 c2 b8 ff ff ff f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb 85 66 2e 0f 1f 84 00 00 00 00 00 90 b8 0b 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f1077b1af38 EFLAGS: 00000246 ORIG_RAX: 000000000000000b
> RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00007f1076e8c467
> RDX: 0000000000040000 RSI: 0000000000040000 RDI: 00007f106d5bd000
> RBP: 00007f106d5bd000 R08: 0000000000000000 R09: 00000000000004a0
> R10: 0000000000040000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007f1077b1afdc R14: 00007f1077b1afe0 R15: 0000000020000582
>  </TASK>
> 
> Allocated by task 27410:
>  kasan_save_stack mm/kasan/common.c:45 [inline]
>  kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
>  __kasan_slab_alloc+0x66/0x70 mm/kasan/common.c:328
>  kasan_slab_alloc include/linux/kasan.h:186 [inline]
>  slab_post_alloc_hook+0x68/0x3a0 mm/slab.h:750
>  slab_alloc_node mm/slub.c:3470 [inline]
>  slab_alloc mm/slub.c:3478 [inline]
>  __kmem_cache_alloc_lru mm/slub.c:3485 [inline]
>  kmem_cache_alloc+0x123/0x300 mm/slub.c:3494
>  mt_alloc_one lib/maple_tree.c:159 [inline]
>  mas_alloc_nodes+0x276/0x800 lib/maple_tree.c:1282
>  mas_node_count_gfp lib/maple_tree.c:1362 [inline]
>  mas_node_count lib/maple_tree.c:1376 [inline]
>  mas_wr_node_store lib/maple_tree.c:4100 [inline]
>  mas_wr_modify+0x1346/0x2290 lib/maple_tree.c:4346
>  mas_store_gfp+0x30d/0x410 lib/maple_tree.c:5506
>  vma_iter_clear_gfp mm/mmap.c:162 [inline]
>  do_vmi_align_munmap+0xfad/0x15c0 mm/mmap.c:2538
>  do_vmi_munmap+0x24d/0x2d0 mm/mmap.c:2619
>  __vm_munmap+0x230/0x450 mm/mmap.c:2899
>  __do_sys_munmap mm/mmap.c:2916 [inline]
>  __se_sys_munmap mm/mmap.c:2913 [inline]
>  __x64_sys_munmap+0x69/0x80 mm/mmap.c:2913
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> Freed by task 21:
>  kasan_save_stack mm/kasan/common.c:45 [inline]
>  kasan_set_track+0x4f/0x70 mm/kasan/common.c:52
>  kasan_save_free_info+0x28/0x40 mm/kasan/generic.c:521
>  ____kasan_slab_free+0xd6/0x120 mm/kasan/common.c:236
>  kasan_slab_free include/linux/kasan.h:162 [inline]
>  slab_free_hook mm/slub.c:1792 [inline]
>  slab_free_freelist_hook mm/slub.c:1818 [inline]
>  slab_free mm/slub.c:3801 [inline]
>  kmem_cache_free+0x292/0x500 mm/slub.c:3823
>  rcu_do_batch kernel/rcu/tree.c:2135 [inline]
>  rcu_core+0xaaa/0x1740 kernel/rcu/tree.c:2399
>  __do_softirq+0x2ab/0x908 kernel/softirq.c:553
> 
> Last potentially related work creation:
>  kasan_save_stack+0x3f/0x60 mm/kasan/common.c:45
>  __kasan_record_aux_stack+0xad/0xc0 mm/kasan/generic.c:491
>  __call_rcu_common kernel/rcu/tree.c:2649 [inline]
>  call_rcu+0x167/0xa70 kernel/rcu/tree.c:2763
>  mas_wr_node_store lib/maple_tree.c:4151 [inline]
>  mas_wr_modify+0x1aec/0x2290 lib/maple_tree.c:4346
>  mas_store_prealloc+0x313/0x650 lib/maple_tree.c:5529
>  mmap_region+0x1680/0x2310 mm/mmap.c:2811
>  do_mmap+0x8cf/0xf80 mm/mmap.c:1362
>  vm_mmap_pgoff+0x1db/0x410 mm/util.c:543
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> 
> The buggy address belongs to the object at ffff88804b9c5000
>  which belongs to the cache maple_node of size 256
> The buggy address is located 120 bytes inside of
>  freed 256-byte region [ffff88804b9c5000, ffff88804b9c5100)
> 
> The buggy address belongs to the physical page:
> page:ffffea00012e7100 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4b9c4
> head:ffffea00012e7100 order:1 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
> page_type: 0xffffffff()
> raw: 00fff00000010200 ffff88801324d000 ffffea0000849c00 dead000000000002
> raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 1, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 26971, tgid 26971 (syz-executor.1), ts 924325306641, free_ts 824783195274
>  set_page_owner include/linux/page_owner.h:31 [inline]
>  post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1570
>  prep_new_page mm/page_alloc.c:1577 [inline]
>  get_page_from_freelist+0x31e8/0x3370 mm/page_alloc.c:3221
>  __alloc_pages+0x255/0x670 mm/page_alloc.c:4477
>  alloc_slab_page+0x6a/0x160 mm/slub.c:1862
>  allocate_slab mm/slub.c:2009 [inline]
>  new_slab+0x84/0x2f0 mm/slub.c:2062
>  ___slab_alloc+0xade/0x1100 mm/slub.c:3215
>  __kmem_cache_alloc_bulk mm/slub.c:3966 [inline]
>  kmem_cache_alloc_bulk+0x196/0x4b0 mm/slub.c:4041
>  mt_alloc_bulk lib/maple_tree.c:164 [inline]
>  mas_alloc_nodes+0x3df/0x800 lib/maple_tree.c:1304
>  mas_node_count_gfp lib/maple_tree.c:1362 [inline]
>  mas_preallocate+0x131/0x350 lib/maple_tree.c:5546
>  vma_iter_prealloc mm/internal.h:1032 [inline]
>  vma_expand+0x41b/0x6d0 mm/mmap.c:665
>  mmap_region+0xaed/0x2310 mm/mmap.c:2711
>  do_mmap+0x8cf/0xf80 mm/mmap.c:1362
>  vm_mmap_pgoff+0x1db/0x410 mm/util.c:543
>  ksys_mmap_pgoff+0x4ff/0x6d0 mm/mmap.c:1408
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x63/0xcd
> page last free stack trace:
>  reset_page_owner include/linux/page_owner.h:24 [inline]
>  free_pages_prepare mm/page_alloc.c:1161 [inline]
>  free_unref_page_prepare+0x903/0xa30 mm/page_alloc.c:2348
>  free_unref_page+0x37/0x3f0 mm/page_alloc.c:2443
>  __slab_free+0x2f6/0x390 mm/slub.c:3707
>  qlist_free_all+0x22/0x60 mm/kasan/quarantine.c:185
>  kasan_quarantine_reduce+0x14b/0x160 mm/kasan/quarantine.c:292
>  __kasan_slab_alloc+0x23/0x70 mm/kasan/common.c:305
>  kasan_slab_alloc include/linux/kasan.h:186 [inline]
>  slab_post_alloc_hook+0x68/0x3a0 mm/slab.h:750
>  slab_alloc_node mm/slub.c:3470 [inline]
>  __kmem_cache_alloc_node+0x141/0x270 mm/slub.c:3509
>  kmalloc_node_trace+0x27/0xe0 mm/slab_common.c:1089
>  kmalloc_node include/linux/slab.h:595 [inline]
>  kzalloc_node include/linux/slab.h:711 [inline]
>  __get_vm_area_node+0x125/0x370 mm/vmalloc.c:2588
>  __vmalloc_node_range+0x3df/0x1490 mm/vmalloc.c:3276
>  __vmalloc_node mm/vmalloc.c:3381 [inline]
>  vzalloc+0x79/0x90 mm/vmalloc.c:3454
>  alloc_counters+0xd7/0x760 net/ipv4/netfilter/ip_tables.c:799
>  copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:837 [inline]
>  get_entries net/ipv6/netfilter/ip6_tables.c:1039 [inline]
>  do_ip6t_get_ctl+0xec4/0x18d0 net/ipv6/netfilter/ip6_tables.c:1669
>  nf_getsockopt+0x292/0x2c0 net/netfilter/nf_sockopt.c:116
>  ipv6_getsockopt+0x25d/0x380 net/ipv6/ipv6_sockglue.c:1500
> 
> Memory state around the buggy address:
>  ffff88804b9c4f00: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>  ffff88804b9c4f80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> >ffff88804b9c5000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>                                                                 ^
>  ffff88804b9c5080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>  ffff88804b9c5100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
> 
> 
> ---
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