Re: [syzbot] [mm?] KASAN: slab-use-after-free Read in folio_evictable (3)

Yu Zhao
2024-12-13T19:21:29Z

On Fri, Dec 13, 2024 at 9:18 AM syzbot
<syzbot+4c7590f1cee06597e43a@syzkaller.appspotmail.com> wrote:
>
> syzbot has found a reproducer for the following issue on:
>
> HEAD commit: f932fb9b4074 Merge tag 'v6.13-rc2-ksmbd-server-fixes' of g..
> git tree: upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=101e24f8580000
> kernel config: https://syzkaller.appspot.com/x/.config?x=fee25f93665c89ac
> dashboard link: https://syzkaller.appspot.com/bug?extid=4c7590f1cee06597e43a
> 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=14654730580000
>
> Downloadable assets:
> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-f932fb9b.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/1982926f01cf/vmlinux-f932fb9b.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/56ef2ef1e465/bzImage-f932fb9b.xz
> mounted in repro #1: https://storage.googleapis.com/syzbot-assets/7e9b5cd91eeb/mount_0.gz
> mounted in repro #2: https://storage.googleapis.com/syzbot-assets/87ff98e190e4/mount_1.gz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+4c7590f1cee06597e43a@syzkaller.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_unevictable include/linux/pagemap.h:269 [inline]
> BUG: KASAN: slab-use-after-free in folio_evictable+0xe3/0x250 mm/internal.h:435
> Read of size 8 at addr ffff88804e4813a0 by task kswapd1/81

This doesn't seem like an MM bug -- folio_evictable() should be safe
to use on a folio as long as it's on LRU, i.e., after it's exposed on
LRU and before page_cache_release() finishes.

There might have been a dangling folio_mappping()?

> CPU: 0 UID: 0 PID: 81 Comm: kswapd1 Not tainted 6.13.0-rc2-syzkaller-00159-gf932fb9b4074 #0
> 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 lib/dump_stack.c:94 [inline]
> dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
> print_address_description mm/kasan/report.c:378 [inline]
> print_report+0x169/0x550 mm/kasan/report.c:489
> kasan_report+0x143/0x180 mm/kasan/report.c:602
> kasan_check_range+0x282/0x290 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_unevictable include/linux/pagemap.h:269 [inline]
> folio_evictable+0xe3/0x250 mm/internal.h:435
> sort_folio mm/vmscan.c:4299 [inline]
> scan_folios mm/vmscan.c:4424 [inline]
> isolate_folios mm/vmscan.c:4550 [inline]
> evict_folios+0xff2/0x5800 mm/vmscan.c:4581
> try_to_shrink_lruvec+0x9a6/0xc70 mm/vmscan.c:4789
> shrink_one+0x3b9/0x850 mm/vmscan.c:4834
> shrink_many mm/vmscan.c:4897 [inline]
> lru_gen_shrink_node mm/vmscan.c:4975 [inline]
> shrink_node+0x37c5/0x3e50 mm/vmscan.c:5956
> kswapd_shrink_node mm/vmscan.c:6785 [inline]
> balance_pgdat mm/vmscan.c:6977 [inline]
> kswapd+0x1ca9/0x36f0 mm/vmscan.c:7246
> kthread+0x2f0/0x390 kernel/kthread.c:389
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
> </TASK>
>
> Allocated by task 5580:
> 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:319 [inline]
> __kasan_slab_alloc+0x66/0x80 mm/kasan/common.c:345
> kasan_slab_alloc include/linux/kasan.h:250 [inline]
> slab_post_alloc_hook mm/slub.c:4104 [inline]
> slab_alloc_node mm/slub.c:4153 [inline]
> kmem_cache_alloc_noprof+0x1d9/0x380 mm/slub.c:4160
> gfs2_glock_get+0x309/0x1010 fs/gfs2/glock.c:1178
> gfs2_inode_lookup+0x2a3/0xc90 fs/gfs2/inode.c:135
> gfs2_dir_search+0x229/0x2f0 fs/gfs2/dir.c:1667
> gfs2_lookupi+0x461/0x5e0 fs/gfs2/inode.c:340
> gfs2_jindex_hold fs/gfs2/ops_fstype.c:587 [inline]
> init_journal+0x5fa/0x2410 fs/gfs2/ops_fstype.c:729
> init_inodes+0xdc/0x320 fs/gfs2/ops_fstype.c:864
> gfs2_fill_super+0x1bd1/0x24d0 fs/gfs2/ops_fstype.c:1249
> get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636
> gfs2_get_tree+0x54/0x220 fs/gfs2/ops_fstype.c:1330
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3507
> do_mount fs/namespace.c:3847 [inline]
> __do_sys_mount fs/namespace.c:4057 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
> 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 16:
> 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:582
> poison_slab_object mm/kasan/common.c:247 [inline]
> __kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
> kasan_slab_free include/linux/kasan.h:233 [inline]
> slab_free_hook mm/slub.c:2338 [inline]
> slab_free mm/slub.c:4598 [inline]
> kmem_cache_free+0x195/0x410 mm/slub.c:4700
> rcu_do_batch kernel/rcu/tree.c:2567 [inline]
> rcu_core+0xaaa/0x17a0 kernel/rcu/tree.c:2823
> handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
> run_ksoftirqd+0xca/0x130 kernel/softirq.c:950
> smpboot_thread_fn+0x544/0xa30 kernel/smpboot.c:164
> kthread+0x2f0/0x390 kernel/kthread.c:389
> ret_from_fork+0x4b/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+0x3f/0x60 mm/kasan/common.c:47
> __kasan_record_aux_stack+0xac/0xc0 mm/kasan/generic.c:544
> __call_rcu_common kernel/rcu/tree.c:3086 [inline]
> call_rcu+0x167/0xa70 kernel/rcu/tree.c:3190
> __gfs2_glock_free+0xda0/0xef0 fs/gfs2/glock.c:172
> gfs2_glock_free+0x3c/0xb0 fs/gfs2/glock.c:178
> gfs2_glock_put_eventually fs/gfs2/super.c:1257 [inline]
> gfs2_evict_inode+0x6e2/0x13c0 fs/gfs2/super.c:1546
> evict+0x4e8/0x9a0 fs/inode.c:796
> gfs2_jindex_free+0x3f6/0x4b0 fs/gfs2/super.c:79
> init_journal+0x9fb/0x2410 fs/gfs2/ops_fstype.c:846
> init_inodes+0xdc/0x320 fs/gfs2/ops_fstype.c:864
> gfs2_fill_super+0x1bd1/0x24d0 fs/gfs2/ops_fstype.c:1249
> get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636
> gfs2_get_tree+0x54/0x220 fs/gfs2/ops_fstype.c:1330
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> do_new_mount+0x2be/0xb40 fs/namespace.c:3507
> do_mount fs/namespace.c:3847 [inline]
> __do_sys_mount fs/namespace.c:4057 [inline]
> __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:4034
> 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
>
> Second to 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:544
> insert_work+0x3e/0x330 kernel/workqueue.c:2183
> __queue_work+0xc8b/0xf50 kernel/workqueue.c:2339
> queue_delayed_work_on+0x1ca/0x390 kernel/workqueue.c:2552
> queue_delayed_work include/linux/workqueue.h:677 [inline]
> gfs2_glock_queue_work fs/gfs2/glock.c:250 [inline]
> do_xmote+0xaf8/0x1250 fs/gfs2/glock.c:832
> glock_work_func+0x343/0x5c0 fs/gfs2/glock.c:1090
> process_one_work kernel/workqueue.c:3229 [inline]
> process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
> worker_thread+0x870/0xd30 kernel/workqueue.c:3391
> kthread+0x2f0/0x390 kernel/kthread.c:389
> ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
> ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
>
> The buggy address belongs to the object at ffff88804e480fd8
> which belongs to the cache gfs2_glock(aspace) of size 1224
> The buggy address is located 968 bytes inside of
> freed 1224-byte region [ffff88804e480fd8, ffff88804e4814a0)
>
> The buggy address belongs to the physical page:
> page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x4e480
> head: order:2 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
> flags: 0x4fff00000000040(head|node=1|zone=1|lastcpupid=0x7ff)
> page_type: f5(slab)
> raw: 04fff00000000040 ffff88801fa3d000 dead000000000122 0000000000000000
> raw: 0000000000000000 00000000800c000c 00000001f5000000 0000000000000000
> head: 04fff00000000040 ffff88801fa3d000 dead000000000122 0000000000000000
> head: 0000000000000000 00000000800c000c 00000001f5000000 0000000000000000
> head: 04fff00000000002 ffffea0001392001 ffffffffffffffff 0000000000000000
> head: 0000000700000004 0000000000000000 00000000ffffffff 0000000000000000
> page dumped because: kasan: bad access detected
> page_owner tracks the page as allocated
> page last allocated via order 2, migratetype Unmovable, gfp_mask 0xd2040(__GFP_IO|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 5580, tgid 5580 (syz.0.16), ts 92534711834, free_ts 92373479633
> set_page_owner include/linux/page_owner.h:32 [inline]
> post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1556
> prep_new_page mm/page_alloc.c:1564 [inline]
> get_page_from_freelist+0x365c/0x37a0 mm/page_alloc.c:3474
> __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4751
> alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2269
> alloc_slab_page+0x6a/0x110 mm/slub.c:2408
> allocate_slab+0x5a/0x2b0 mm/slub.c:2574
> new_slab mm/slub.c:2627 [inline]
> ___slab_alloc+0xc27/0x14a0 mm/slub.c:3815
> __slab_alloc+0x58/0xa0 mm/slub.c:3905
> __slab_alloc_node mm/slub.c:3980 [inline]
> slab_alloc_node mm/slub.c:4141 [inline]
> kmem_cache_alloc_noprof+0x268/0x380 mm/slub.c:4160
> gfs2_glock_get+0x309/0x1010 fs/gfs2/glock.c:1178
> gfs2_inode_lookup+0x2a3/0xc90 fs/gfs2/inode.c:135
> gfs2_lookup_root fs/gfs2/ops_fstype.c:440 [inline]
> init_sb+0xa2a/0x1270 fs/gfs2/ops_fstype.c:507
> gfs2_fill_super+0x19b3/0x24d0 fs/gfs2/ops_fstype.c:1216
> get_tree_bdev_flags+0x48c/0x5c0 fs/super.c:1636
> gfs2_get_tree+0x54/0x220 fs/gfs2/ops_fstype.c:1330
> vfs_get_tree+0x90/0x2b0 fs/super.c:1814
> page last free pid 52 tgid 52 stack trace:
> reset_page_owner include/linux/page_owner.h:25 [inline]
> free_pages_prepare mm/page_alloc.c:1127 [inline]
> free_unref_page+0xd3f/0x1010 mm/page_alloc.c:2657
> discard_slab mm/slub.c:2673 [inline]
> __put_partials+0x160/0x1c0 mm/slub.c:3142
> put_cpu_partial+0x17c/0x250 mm/slub.c:3217
> __slab_free+0x290/0x380 mm/slub.c:4468
> qlink_free mm/kasan/quarantine.c:163 [inline]
> qlist_free_all+0x9a/0x140 mm/kasan/quarantine.c:179
> kasan_quarantine_reduce+0x14f/0x170 mm/kasan/quarantine.c:286
> __kasan_slab_alloc+0x23/0x80 mm/kasan/common.c:329
> kasan_slab_alloc include/linux/kasan.h:250 [inline]
> slab_post_alloc_hook mm/slub.c:4104 [inline]
> slab_alloc_node mm/slub.c:4153 [inline]
> kmem_cache_alloc_node_noprof+0x1d9/0x380 mm/slub.c:4205
> __alloc_skb+0x1c3/0x440 net/core/skbuff.c:668
> alloc_skb include/linux/skbuff.h:1323 [inline]
> alloc_skb_with_frags+0xc3/0x820 net/core/skbuff.c:6612
> sock_alloc_send_pskb+0x91a/0xa60 net/core/sock.c:2881
> sock_alloc_send_skb include/net/sock.h:1797 [inline]
> mld_newpack+0x1c3/0xaf0 net/ipv6/mcast.c:1747
> add_grhead net/ipv6/mcast.c:1850 [inline]
> add_grec+0x1492/0x19a0 net/ipv6/mcast.c:1988
> mld_send_cr net/ipv6/mcast.c:2114 [inline]
> mld_ifc_work+0x691/0xd90 net/ipv6/mcast.c:2651
> process_one_work kernel/workqueue.c:3229 [inline]
> process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
> worker_thread+0x870/0xd30 kernel/workqueue.c:3391
>
> Memory state around the buggy address:
> ffff88804e481280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88804e481300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> >ffff88804e481380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ^
> ffff88804e481400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
> ffff88804e481480: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
> ==================================================================
>
>
> ---
> 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.
>