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KASAN: use-after-free Read in nilfs_segctor_confirm

Status: upstream: reported C repro on 2022/11/20 06:43
Subsystems: nilfs2
[Documentation on labels]
Reported-by: syzbot+c98e005f97eb5c1e4b5a@syzkaller.appspotmail.com
First crash: 607d, last: 522d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream KASAN: use-after-free Read in nilfs_segctor_confirm nilfs C inconclusive 19 638d 657d 22/27 fixed on 2023/02/24 13:50
linux-4.19 KASAN: use-after-free Read in nilfs_segctor_confirm nilfs2 C error 9 531d 609d 0/1 upstream: reported C repro on 2022/11/18 14:16
Fix bisection attempts (1)
Created Duration User Patch Repo Result
2023/02/13 11:50 29m bisect fix linux-4.14.y OK (0) job log log

Sample crash report:
attempt to access beyond end of device
loop0: rw=0, want=72057594037928010, limit=2048
NILFS (loop0): I/O error reading meta-data file (ino=6, block-offset=1)
==================================================================
BUG: KASAN: use-after-free in nilfs_segctor_confirm+0x147/0x160 fs/nilfs2/segment.c:855
Read of size 8 at addr ffff8880b0b302b0 by task syz-executor228/7987

CPU: 0 PID: 7987 Comm: syz-executor228 Not tainted 4.14.299-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x281 lib/dump_stack.c:58
 print_address_description.cold+0x54/0x1d3 mm/kasan/report.c:252
 kasan_report_error.cold+0x8a/0x191 mm/kasan/report.c:351
 kasan_report mm/kasan/report.c:409 [inline]
 __asan_report_load8_noabort+0x68/0x70 mm/kasan/report.c:430
 nilfs_segctor_confirm+0x147/0x160 fs/nilfs2/segment.c:855
 nilfs_segctor_destroy fs/nilfs2/segment.c:2749 [inline]
 nilfs_detach_log_writer+0x7f9/0x980 fs/nilfs2/segment.c:2829
 nilfs_put_super+0x3f/0x190 fs/nilfs2/super.c:480
 generic_shutdown_super+0x144/0x370 fs/super.c:446
 kill_block_super+0x95/0xe0 fs/super.c:1161
 deactivate_locked_super+0x6c/0xd0 fs/super.c:319
 deactivate_super+0x7f/0xa0 fs/super.c:350
 cleanup_mnt+0x186/0x2c0 fs/namespace.c:1183
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3

Allocated by task 8460:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xeb/0x160 mm/kasan/kasan.c:551
 kmem_cache_alloc_trace+0x131/0x3d0 mm/slab.c:3618
 kmalloc include/linux/slab.h:488 [inline]
 kzalloc include/linux/slab.h:661 [inline]
 nilfs_find_or_create_root+0x84/0x410 fs/nilfs2/the_nilfs.c:761
 nilfs_attach_checkpoint+0xa2/0x420 fs/nilfs2/super.c:531
 nilfs_fill_super fs/nilfs2/super.c:1079 [inline]
 nilfs_mount+0x911/0xd00 fs/nilfs2/super.c:1332
 mount_fs+0x92/0x2a0 fs/super.c:1237
 vfs_kern_mount.part.0+0x5b/0x470 fs/namespace.c:1046
 vfs_kern_mount fs/namespace.c:1036 [inline]
 do_new_mount fs/namespace.c:2572 [inline]
 do_mount+0xe65/0x2a30 fs/namespace.c:2905
 SYSC_mount fs/namespace.c:3121 [inline]
 SyS_mount+0xa8/0x120 fs/namespace.c:3098
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3

Freed by task 7987:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xc3/0x1a0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3496 [inline]
 kfree+0xc9/0x250 mm/slab.c:3815
 nilfs_put_root+0x9a/0xc0 fs/nilfs2/the_nilfs.c:819
 nilfs_clear_inode+0x251/0x2e0 fs/nilfs2/inode.c:934
 nilfs_evict_inode+0x2dd/0x3a0 fs/nilfs2/inode.c:947
 evict+0x2c8/0x700 fs/inode.c:554
 dispose_list+0x109/0x1e0 fs/inode.c:589
 evict_inodes+0x2cd/0x3a0 fs/inode.c:639
 generic_shutdown_super+0xb3/0x370 fs/super.c:438
 kill_block_super+0x95/0xe0 fs/super.c:1161
 deactivate_locked_super+0x6c/0xd0 fs/super.c:319
 deactivate_super+0x7f/0xa0 fs/super.c:350
 cleanup_mnt+0x186/0x2c0 fs/namespace.c:1183
 task_work_run+0x11f/0x190 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:191 [inline]
 exit_to_usermode_loop+0x1ad/0x200 arch/x86/entry/common.c:164
 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:270 [inline]
 do_syscall_64+0x4a3/0x640 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x5e/0xd3

The buggy address belongs to the object at ffff8880b0b30280
 which belongs to the cache kmalloc-256 of size 256
The buggy address is located 48 bytes inside of
 256-byte region [ffff8880b0b30280, ffff8880b0b30380)
The buggy address belongs to the page:
page:ffffea0002c2cc00 count:1 mapcount:0 mapping:ffff8880b0b30000 index:0xffff8880b0b30dc0
flags: 0xfff00000000100(slab)
raw: 00fff00000000100 ffff8880b0b30000 ffff8880b0b30dc0 0000000100000006
raw: ffffea0002bccfa0 ffffea0002c2c7e0 ffff88813fe747c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880b0b30180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b0b30200: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8880b0b30280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                     ^
 ffff8880b0b30300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880b0b30380: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
==================================================================

Crashes (4):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/11/20 06:43 linux-4.14.y e911713e40ca 5bb70014 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-4-14 KASAN: use-after-free Read in nilfs_segctor_confirm
2023/01/14 11:50 linux-4.14.y c4215ee4771b a63719e7 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-4-14 KASAN: use-after-free Read in nilfs_segctor_confirm
2023/01/11 15:44 linux-4.14.y c4215ee4771b 96166539 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-4-14 KASAN: use-after-free Read in nilfs_segctor_confirm
2022/12/14 18:04 linux-4.14.y c4215ee4771b b18f0a64 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-4-14 KASAN: use-after-free Read in nilfs_segctor_confirm
* Struck through repros no longer work on HEAD.