Message-ID: <CAKFNMonmuCg56_T-TzrCB4BA60=Y9ZRAtEpqhiFuq_HVe8VmjQ@mail.gmail.com>
Date: Sun, 21 Jul 2024 17:13:11 +0900
From: Ryusuke Konishi <konishi.ryusuke@...il.com>
To: syzbot <syzbot+3961aebd12fe0ea4a3e8@...kaller.appspotmail.com>
Cc: syzkaller-bugs@...glegroups.com, linux-kernel@...r.kernel.org, 
	linux-nilfs <linux-nilfs@...r.kernel.org>
Subject: Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in
 move_to_new_folio (2)

On Sun, Jun 23, 2024 at 8:33 PM Ryusuke Konishi wrote:
>
> On Sun, Jun 23, 2024 at 10:34 AM syzbot
> <syzbot+3961aebd12fe0ea4a3e8@...kaller.appspotmail.com> wrote:
> >
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    563a50672d8a Merge tag 'xfs-6.10-fixes-4' of git://git.ker..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=1599afb1980000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=c3820d4fff43c7a3
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3961aebd12fe0ea4a3e8
> > compiler:       gcc (Debian 12.2.0-14) 12.2.0, GNU ld (GNU Binutils for Debian) 2.40
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > Downloadable assets:
> > disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7bc7510fe41f/non_bootable_disk-563a5067.raw.xz
> > vmlinux: https://storage.googleapis.com/syzbot-assets/6ef95d163dde/vmlinux-563a5067.xz
> > kernel image: https://storage.googleapis.com/syzbot-assets/0102d9e1ac9a/bzImage-563a5067.xz
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+3961aebd12fe0ea4a3e8@...kaller.appspotmail.com
> >
> > ==================================================================
> > BUG: KASAN: slab-use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
> > BUG: KASAN: slab-use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
> > BUG: KASAN: slab-use-after-free in mapping_unmovable include/linux/pagemap.h:325 [inline]
> > BUG: KASAN: slab-use-after-free in move_to_new_folio+0x12a/0x700 mm/migrate.c:968
> > Read of size 8 at addr ffff8880486117e0 by task kcompactd0/44
> >
> > CPU: 3 PID: 44 Comm: kcompactd0 Not tainted 6.10.0-rc4-syzkaller-00283-g563a50672d8a #0
> > Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
> > Call Trace:
> >  <TASK>
> >  __dump_stack lib/dump_stack.c:88 [inline]
> >  dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:114
> >  print_address_description mm/kasan/report.c:377 [inline]
> >  print_report+0xc3/0x620 mm/kasan/report.c:488
> >  kasan_report+0xd9/0x110 mm/kasan/report.c:601
> >  check_region_inline mm/kasan/generic.c:183 [inline]
> >  kasan_check_range+0xef/0x1a0 mm/kasan/generic.c:189
> >  instrument_atomic_read include/linux/instrumented.h:68 [inline]
> >  _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
> >  mapping_unmovable include/linux/pagemap.h:325 [inline]
> >  move_to_new_folio+0x12a/0x700 mm/migrate.c:968
> >  migrate_folio_move mm/migrate.c:1287 [inline]
> >  migrate_pages_batch+0x1e88/0x2f80 mm/migrate.c:1807
> >  migrate_pages_sync mm/migrate.c:1873 [inline]
> >  migrate_pages+0x1b5a/0x27a0 mm/migrate.c:1982
> >  compact_zone+0x1f68/0x4280 mm/compaction.c:2664
> >  compact_node+0x1a2/0x2d0 mm/compaction.c:2928
> >  kcompactd+0x76e/0xde0 mm/compaction.c:3226
> >  kthread+0x2c1/0x3a0 kernel/kthread.c:389
> >  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> >  </TASK>
> >
> > Allocated by task 25044:
> >  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
> >  kasan_save_track+0x14/0x30 mm/kasan/common.c:68
> >  unpoison_slab_object mm/kasan/common.c:312 [inline]
> >  __kasan_slab_alloc+0x89/0x90 mm/kasan/common.c:338
> >  kasan_slab_alloc include/linux/kasan.h:201 [inline]
> >  slab_post_alloc_hook mm/slub.c:3941 [inline]
> >  slab_alloc_node mm/slub.c:4001 [inline]
> >  kmem_cache_alloc_lru_noprof+0x121/0x2f0 mm/slub.c:4020
> >  nilfs_alloc_inode+0x26/0x150 fs/nilfs2/super.c:154
> >  alloc_inode+0x5d/0x230 fs/inode.c:261
> >  iget5_locked fs/inode.c:1235 [inline]
> >  iget5_locked+0x1c9/0x2c0 fs/inode.c:1228
> >  nilfs_iget_locked+0xa1/0xe0 fs/nilfs2/inode.c:606
> >  nilfs_ifile_read+0x2f/0x1e0 fs/nilfs2/ifile.c:192
> >  nilfs_attach_checkpoint+0x12d/0x1d0 fs/nilfs2/super.c:557
> >  nilfs_fill_super fs/nilfs2/super.c:1067 [inline]
> >  nilfs_get_tree+0x951/0x1000 fs/nilfs2/super.c:1211
> >  vfs_get_tree+0x8f/0x380 fs/super.c:1780
> >  do_new_mount fs/namespace.c:3352 [inline]
> >  path_mount+0x14e6/0x1f20 fs/namespace.c:3679
> >  do_mount fs/namespace.c:3692 [inline]
> >  __do_sys_mount fs/namespace.c:3898 [inline]
> >  __se_sys_mount fs/namespace.c:3875 [inline]
> >  __x64_sys_mount+0x297/0x320 fs/namespace.c:3875
> >  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >  do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >
> > Freed by task 34:
> >  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
> >  kasan_save_track+0x14/0x30 mm/kasan/common.c:68
> >  kasan_save_free_info+0x3b/0x60 mm/kasan/generic.c:579
> >  poison_slab_object+0xf7/0x160 mm/kasan/common.c:240
> >  __kasan_slab_free+0x32/0x50 mm/kasan/common.c:256
> >  kasan_slab_free include/linux/kasan.h:184 [inline]
> >  slab_free_hook mm/slub.c:2196 [inline]
> >  slab_free mm/slub.c:4437 [inline]
> >  kmem_cache_free+0x12f/0x3a0 mm/slub.c:4512
> >  i_callback+0x43/0x70 fs/inode.c:250
> >  rcu_do_batch kernel/rcu/tree.c:2535 [inline]
> >  rcu_core+0x828/0x16b0 kernel/rcu/tree.c:2809
> >  handle_softirqs+0x216/0x8f0 kernel/softirq.c:554
> >  run_ksoftirqd kernel/softirq.c:928 [inline]
> >  run_ksoftirqd+0x3a/0x60 kernel/softirq.c:920
> >  smpboot_thread_fn+0x661/0xa10 kernel/smpboot.c:164
> >  kthread+0x2c1/0x3a0 kernel/kthread.c:389
> >  ret_from_fork+0x45/0x80 arch/x86/kernel/process.c:147
> >  ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> >
> > Last potentially related work creation:
> >  kasan_save_stack+0x33/0x60 mm/kasan/common.c:47
> >  __kasan_record_aux_stack+0xba/0xd0 mm/kasan/generic.c:541
> >  __call_rcu_common.constprop.0+0x9a/0x790 kernel/rcu/tree.c:3072
> >  destroy_inode+0x12c/0x1b0 fs/inode.c:316
> >  iput_final fs/inode.c:1741 [inline]
> >  iput.part.0+0x5a8/0x7f0 fs/inode.c:1767
> >  iput+0x5c/0x80 fs/inode.c:1757
> >  nilfs_put_root+0xae/0xe0 fs/nilfs2/the_nilfs.c:925
> >  nilfs_segctor_destroy fs/nilfs2/segment.c:2788 [inline]
> >  nilfs_detach_log_writer+0x5ef/0xaa0 fs/nilfs2/segment.c:2850
> >  nilfs_put_super+0x43/0x1b0 fs/nilfs2/super.c:498
> >  generic_shutdown_super+0x159/0x3d0 fs/super.c:642
> >  kill_block_super+0x3b/0x90 fs/super.c:1676
> >  deactivate_locked_super+0xbe/0x1a0 fs/super.c:473
> >  deactivate_super+0xde/0x100 fs/super.c:506
> >  cleanup_mnt+0x222/0x450 fs/namespace.c:1267
> >  task_work_run+0x14e/0x250 kernel/task_work.c:180
> >  resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
> >  exit_to_user_mode_loop kernel/entry/common.c:114 [inline]
> >  exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline]
> >  __syscall_exit_to_user_mode_work kernel/entry/common.c:207 [inline]
> >  syscall_exit_to_user_mode+0x278/0x2a0 kernel/entry/common.c:218
> >  do_syscall_64+0xda/0x250 arch/x86/entry/common.c:89
> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >
> > The buggy address belongs to the object at ffff888048611338
> >  which belongs to the cache nilfs2_inode_cache of size 1512
> > The buggy address is located 1192 bytes inside of
> >  freed 1512-byte region [ffff888048611338, ffff888048611920)
> >
> > The buggy address belongs to the physical page:
> > page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x48610
> > head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> > memcg:ffff88801d879701
> > flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
> > page_type: 0xffffefff(slab)
> > raw: 00fff00000000040 ffff88801a824780 dead000000000122 0000000000000000
> > raw: 0000000000000000 0000000080130013 00000001ffffefff ffff88801d879701
> > head: 00fff00000000040 ffff88801a824780 dead000000000122 0000000000000000
> > head: 0000000000000000 0000000080130013 00000001ffffefff ffff88801d879701
> > head: 00fff00000000003 ffffea0001218401 ffffffffffffffff 0000000000000000
> > head: ffff888000000008 0000000000000000 00000000ffffffff 0000000000000000
> > page dumped because: kasan: bad access detected
> > page_owner tracks the page as allocated
> > page last allocated via order 3, migratetype Reclaimable, gfp_mask 0x1d2050(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL|__GFP_RECLAIMABLE), pid 5921, tgid 5920 (syz-executor.1), ts 80330288288, free_ts 75951829280
> >  set_page_owner include/linux/page_owner.h:32 [inline]
> >  post_alloc_hook+0x2d1/0x350 mm/page_alloc.c:1468
> >  prep_new_page mm/page_alloc.c:1476 [inline]
> >  get_page_from_freelist+0x136a/0x2e50 mm/page_alloc.c:3420
> >  __alloc_pages_noprof+0x22b/0x2460 mm/page_alloc.c:4678
> >  __alloc_pages_node_noprof include/linux/gfp.h:269 [inline]
> >  alloc_pages_node_noprof include/linux/gfp.h:296 [inline]
> >  alloc_slab_page+0x56/0x110 mm/slub.c:2265
> >  allocate_slab mm/slub.c:2428 [inline]
> >  new_slab+0x84/0x260 mm/slub.c:2481
> >  ___slab_alloc+0xdac/0x1870 mm/slub.c:3667
> >  __slab_alloc.constprop.0+0x56/0xb0 mm/slub.c:3757
> >  __slab_alloc_node mm/slub.c:3810 [inline]
> >  slab_alloc_node mm/slub.c:3989 [inline]
> >  kmem_cache_alloc_lru_noprof+0x2a0/0x2f0 mm/slub.c:4020
> >  nilfs_alloc_inode+0x26/0x150 fs/nilfs2/super.c:154
> >  alloc_inode+0x5d/0x230 fs/inode.c:261
> >  new_inode_pseudo fs/inode.c:1007 [inline]
> >  new_inode+0x22/0x270 fs/inode.c:1033
> >  nilfs_new_inode+0xe0/0x8e0 fs/nilfs2/inode.c:336
> >  nilfs_create fs/nilfs2/namei.c:85 [inline]
> >  nilfs_create+0x121/0x320 fs/nilfs2/namei.c:75
> >  lookup_open.isra.0+0x10a1/0x13c0 fs/namei.c:3505
> >  open_last_lookups fs/namei.c:3574 [inline]
> >  path_openat+0x92f/0x29f0 fs/namei.c:3804
> >  do_filp_open+0x1dc/0x430 fs/namei.c:3834
> > page last free pid 4689 tgid 4689 stack trace:
> >  reset_page_owner include/linux/page_owner.h:25 [inline]
> >  free_pages_prepare mm/page_alloc.c:1088 [inline]
> >  free_unref_page+0x64a/0xe40 mm/page_alloc.c:2583
> >  __put_partials+0x14c/0x170 mm/slub.c:2995
> >  qlink_free mm/kasan/quarantine.c:163 [inline]
> >  qlist_free_all+0x4e/0x140 mm/kasan/quarantine.c:179
> >  kasan_quarantine_reduce+0x192/0x1e0 mm/kasan/quarantine.c:286
> >  __kasan_slab_alloc+0x69/0x90 mm/kasan/common.c:322
> >  kasan_slab_alloc include/linux/kasan.h:201 [inline]
> >  slab_post_alloc_hook mm/slub.c:3941 [inline]
> >  slab_alloc_node mm/slub.c:4001 [inline]
> >  kmem_cache_alloc_noprof+0x121/0x2f0 mm/slub.c:4008
> >  getname_flags.part.0+0x50/0x4f0 fs/namei.c:139
> >  getname_flags+0x9b/0xf0 include/linux/audit.h:322
> >  user_path_at_empty+0x2c/0x60 fs/namei.c:2928
> >  do_readlinkat+0xdd/0x310 fs/stat.c:499
> >  __do_sys_readlink fs/stat.c:532 [inline]
> >  __se_sys_readlink fs/stat.c:529 [inline]
> >  __x64_sys_readlink+0x78/0xc0 fs/stat.c:529
> >  do_syscall_x64 arch/x86/entry/common.c:52 [inline]
> >  do_syscall_64+0xcd/0x250 arch/x86/entry/common.c:83
> >  entry_SYSCALL_64_after_hwframe+0x77/0x7f
> >
> > Memory state around the buggy address:
> >  ffff888048611680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >  ffff888048611700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > >ffff888048611780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >                                                        ^
> >  ffff888048611800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >  ffff888048611880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> > ==================================================================
> >
> >
> > ---
> > 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 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
> >
>
> #syz set subsystems: nilfs
>
> Although I cannot confirm this yet, it appears this is the same issue as below:
>
> https://syzkaller.appspot.com/bug?extid=d79afb004be235636ee8
>
> If so, the following patch (the second in the series) that I just sent
> out today should fix this issue:
>
> https://lkml.kernel.org/r/20240623051135.4180-3-konishi.ryusuke@gmail.com
>
>
> Ryusuke Konishi

#syz dup: KASAN: slab-use-after-free Read in lru_add_fn

The issue doesn't seem to occur anymore after merging the above patch.
So I will close it as it's likely a common issue as expected.

Ryusuke Konishi

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