syzbot


KASAN: use-after-free Read in nilfs_iget

Status: closed as dup on 2022/10/21 23:19
Subsystems: nilfs
[Documentation on labels]
Reported-by: syzbot+e7b15dcc1051f8b99e58@syzkaller.appspotmail.com
First crash: 769d, last: 765d
Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
KASAN: use-after-free Read in nilfs_segctor_confirm nilfs C inconclusive 19 765d 783d
Discussions (1)
Title Replies (including bot) Last reply
[syzbot] KASAN: use-after-free Read in nilfs_iget 1 (2) 2022/10/17 23:26

Sample crash report:
==================================================================
BUG: KASAN: use-after-free in __nilfs_read_inode fs/nilfs2/inode.c:477 [inline]
BUG: KASAN: use-after-free in nilfs_iget+0x242/0x8b0 fs/nilfs2/inode.c:603
Read of size 8 at addr ffff888078c35630 by task syz-executor.3/7167

CPU: 1 PID: 7167 Comm: syz-executor.3 Not tainted 6.0.0-syzkaller-09423-g493ffd6605b2 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1b1/0x28e lib/dump_stack.c:106
 print_address_description+0x65/0x4b0 mm/kasan/report.c:317
 print_report+0x108/0x1f0 mm/kasan/report.c:433
 kasan_report+0xc3/0xf0 mm/kasan/report.c:495
 __nilfs_read_inode fs/nilfs2/inode.c:477 [inline]
 nilfs_iget+0x242/0x8b0 fs/nilfs2/inode.c:603
 nilfs_lookup+0xca/0x110 fs/nilfs2/namei.c:63
 __lookup_slow+0x266/0x3a0 fs/namei.c:1685
 lookup_slow+0x53/0x70 fs/namei.c:1702
 walk_component+0x2e1/0x410 fs/namei.c:1993
 lookup_last fs/namei.c:2450 [inline]
 path_lookupat+0x17d/0x450 fs/namei.c:2474
 filename_lookup+0x274/0x650 fs/namei.c:2503
 user_path_at_empty+0x40/0x1a0 fs/namei.c:2876
 user_path_at include/linux/namei.h:57 [inline]
 do_fchmodat fs/open.c:643 [inline]
 __do_sys_chmod fs/open.c:663 [inline]
 __se_sys_chmod fs/open.c:661 [inline]
 __x64_sys_chmod+0xd6/0x180 fs/open.c:661
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7fb72328b5a9
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fb724407168 EFLAGS: 00000246 ORIG_RAX: 000000000000005a
RAX: ffffffffffffffda RBX: 00007fb7233abf80 RCX: 00007fb72328b5a9
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000020000100
RBP: 00007fb7232e6580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffe2696b2ef R14: 00007fb724407300 R15: 0000000000022000
 </TASK>

Allocated by task 7167:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:45 [inline]
 set_alloc_info mm/kasan/common.c:437 [inline]
 ____kasan_kmalloc+0xcd/0x100 mm/kasan/common.c:516
 kasan_kmalloc include/linux/kasan.h:234 [inline]
 kmem_cache_alloc_trace+0x97/0x310 mm/slub.c:3289
 kmalloc include/linux/slab.h:600 [inline]
 kzalloc include/linux/slab.h:733 [inline]
 nilfs_find_or_create_root+0x142/0x4f0 fs/nilfs2/the_nilfs.c:747
 nilfs_attach_checkpoint+0xcd/0x4a0 fs/nilfs2/super.c:519
 nilfs_fill_super+0x2e8/0x5d0 fs/nilfs2/super.c:1064
 nilfs_mount+0x613/0x9b0 fs/nilfs2/super.c:1317
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Freed by task 7167:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x3d/0x60 mm/kasan/common.c:45
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:370
 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:367
 kasan_slab_free include/linux/kasan.h:200 [inline]
 slab_free_hook mm/slub.c:1759 [inline]
 slab_free_freelist_hook+0x12e/0x1a0 mm/slub.c:1785
 slab_free mm/slub.c:3539 [inline]
 kfree+0xda/0x210 mm/slub.c:4567
 nilfs_evict_inode+0x253/0x3d0 fs/nilfs2/inode.c:924
 evict+0x2a4/0x620 fs/inode.c:664
 nilfs_new_inode+0x6b8/0x8a0
 nilfs_create+0xdc/0x2d0 fs/nilfs2/namei.c:85
 lookup_open fs/namei.c:3413 [inline]
 open_last_lookups fs/namei.c:3481 [inline]
 path_openat+0x12d0/0x2df0 fs/namei.c:3688
 do_filp_open+0x264/0x4f0 fs/namei.c:3718
 do_sys_openat2+0x124/0x4e0 fs/open.c:1310
 do_sys_open fs/open.c:1326 [inline]
 __do_sys_openat fs/open.c:1342 [inline]
 __se_sys_openat fs/open.c:1337 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1337
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

The buggy address belongs to the object at ffff888078c35600
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 48 bytes inside of
 256-byte region [ffff888078c35600, ffff888078c35700)

The buggy address belongs to the physical page:
page:ffffea0001e30d00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x78c34
head:ffffea0001e30d00 order:1 compound_mapcount:0 compound_pincount:0
flags: 0xfff00000010200(slab|head|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000010200 dead000000000100 dead000000000122 ffff888012041b40
raw: 0000000000000000 0000000080100010 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 3880, tgid 3879 (syz-executor.4), ts 143958418417, free_ts 141490355425
 prep_new_page mm/page_alloc.c:2532 [inline]
 get_page_from_freelist+0x742/0x7c0 mm/page_alloc.c:4283
 __alloc_pages+0x259/0x560 mm/page_alloc.c:5549
 alloc_slab_page+0x70/0xf0 mm/slub.c:1829
 allocate_slab+0x5e/0x520 mm/slub.c:1974
 new_slab mm/slub.c:2034 [inline]
 ___slab_alloc+0x3ee/0xc40 mm/slub.c:3036
 __slab_alloc mm/slub.c:3123 [inline]
 slab_alloc_node mm/slub.c:3214 [inline]
 slab_alloc mm/slub.c:3256 [inline]
 __kmalloc+0x2bd/0x370 mm/slub.c:4425
 kmalloc_array include/linux/slab.h:640 [inline]
 kcalloc include/linux/slab.h:671 [inline]
 __list_lru_init+0xa0/0x5f0 mm/list_lru.c:571
 alloc_super+0x7a7/0x920 fs/super.c:272
 sget+0x20e/0x560 fs/super.c:642
 mount_bdev+0xe8/0x3a0 fs/super.c:1371
 legacy_get_tree+0xea/0x180 fs/fs_context.c:610
 vfs_get_tree+0x88/0x270 fs/super.c:1530
 do_new_mount+0x289/0xad0 fs/namespace.c:3040
 do_mount fs/namespace.c:3383 [inline]
 __do_sys_mount fs/namespace.c:3591 [inline]
 __se_sys_mount+0x2d3/0x3c0 fs/namespace.c:3568
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 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:1449 [inline]
 free_pcp_prepare+0x812/0x900 mm/page_alloc.c:1499
 free_unref_page_prepare mm/page_alloc.c:3380 [inline]
 free_unref_page_list+0xb4/0x7b0 mm/page_alloc.c:3522
 release_pages+0x22c3/0x2540 mm/swap.c:1012
 __pagevec_release+0x7d/0xf0 mm/swap.c:1032
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 truncate_inode_pages_range+0x472/0x1780 mm/truncate.c:373
 kill_bdev block/bdev.c:76 [inline]
 blkdev_flush_mapping+0x153/0x2c0 block/bdev.c:662
 blkdev_put_whole block/bdev.c:693 [inline]
 blkdev_put+0x4a5/0x730 block/bdev.c:953
 deactivate_locked_super+0xa7/0xf0 fs/super.c:331
 cleanup_mnt+0x4ce/0x560 fs/namespace.c:1186
 task_work_run+0x146/0x1c0 kernel/task_work.c:177
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0x124/0x150 kernel/entry/common.c:169
 exit_to_user_mode_prepare+0xb2/0x140 kernel/entry/common.c:201
 __syscall_exit_to_user_mode_work kernel/entry/common.c:283 [inline]
 syscall_exit_to_user_mode+0x26/0x60 kernel/entry/common.c:294
 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:86
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

Memory state around the buggy address:
 ffff888078c35500: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff888078c35580: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff888078c35600: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff888078c35680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888078c35700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/10/19 16:55 upstream 493ffd6605b2 b31320fc .config console log report info [disk image] [vmlinux] ci2-upstream-fs KASAN: use-after-free Read in nilfs_iget
2022/10/16 11:02 upstream 493ffd6605b2 67cb024c .config console log report info ci2-upstream-fs KASAN: use-after-free Read in nilfs_iget
* Struck through repros no longer work on HEAD.