Message-ID: <0000000000007ab192060ec3a224@google.com>
Date: Fri, 12 Jan 2024 10:14:27 -0800
From: syzbot <syzbot+8f477ac014ff5b32d81f@...kaller.appspotmail.com>
To: chao@...nel.org, jaegeuk@...nel.org, 
	linux-f2fs-devel@...ts.sourceforge.net, linux-fsdevel@...r.kernel.org, 
	linux-kernel@...r.kernel.org, syzkaller-bugs@...glegroups.com
Subject: Re: [syzbot] [f2fs?] KASAN: slab-use-after-free Read in kill_f2fs_super

syzbot has found a reproducer for the following issue on:

HEAD commit:    70d201a40823 Merge tag 'f2fs-for-6.8-rc1' of git://git.ker..
git tree:       upstream
console+strace: https://syzkaller.appspot.com/x/log.txt?x=13973ca5e80000
kernel config:  https://syzkaller.appspot.com/x/.config?x=4607bc15d1c4bb90
dashboard link: https://syzkaller.appspot.com/bug?extid=8f477ac014ff5b32d81f
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=16b910ede80000

Downloadable assets:
disk image: https://storage.googleapis.com/syzbot-assets/4faf0f99e43c/disk-70d201a4.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/23f59e40d2ef/vmlinux-70d201a4.xz
kernel image: https://storage.googleapis.com/syzbot-assets/a0bc6007f0a4/bzImage-70d201a4.xz
mounted in repro #1: https://storage.googleapis.com/syzbot-assets/47520ebdcfe6/mount_0.gz
mounted in repro #2: https://storage.googleapis.com/syzbot-assets/bc946d522410/mount_1.gz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+8f477ac014ff5b32d81f@...kaller.appspotmail.com

==================================================================
BUG: KASAN: slab-use-after-free in destroy_device_list fs/f2fs/super.c:1606 [inline]
BUG: KASAN: slab-use-after-free in kill_f2fs_super+0x618/0x690 fs/f2fs/super.c:4932
Read of size 4 at addr ffff88801c6bd77c by task syz-executor.0/5218

CPU: 1 PID: 5218 Comm: syz-executor.0 Not tainted 6.7.0-syzkaller-06264-g70d201a40823 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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:377 [inline]
 print_report+0x163/0x540 mm/kasan/report.c:488
 kasan_report+0x142/0x170 mm/kasan/report.c:601
 destroy_device_list fs/f2fs/super.c:1606 [inline]
 kill_f2fs_super+0x618/0x690 fs/f2fs/super.c:4932
 deactivate_locked_super+0xc1/0x130 fs/super.c:477
 mount_bdev+0x222/0x2d0 fs/super.c:1665
 legacy_get_tree+0xef/0x190 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x2a0 fs/super.c:1784
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7ff92ca7e4aa
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 09 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffd484f9b8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fffd484fa40 RCX: 00007ff92ca7e4aa
RDX: 0000000020000040 RSI: 0000000020000080 RDI: 00007fffd484fa00
RBP: 0000000020000040 R08: 00007fffd484fa40 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000020000080
R13: 00007fffd484fa00 R14: 00000000000054f9 R15: 00000000200004c0
 </TASK>

Allocated by task 5218:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x70 mm/kasan/common.c:68
 poison_kmalloc_redzone mm/kasan/common.c:372 [inline]
 __kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:389
 kasan_kmalloc include/linux/kasan.h:211 [inline]
 kmalloc_trace+0x1d6/0x360 mm/slub.c:4012
 kmalloc include/linux/slab.h:590 [inline]
 kzalloc include/linux/slab.h:711 [inline]
 f2fs_fill_super+0xce/0x8170 fs/f2fs/super.c:4397
 mount_bdev+0x206/0x2d0 fs/super.c:1663
 legacy_get_tree+0xef/0x190 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x2a0 fs/super.c:1784
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Freed by task 5218:
 kasan_save_stack mm/kasan/common.c:47 [inline]
 kasan_save_track+0x3f/0x70 mm/kasan/common.c:68
 kasan_save_free_info+0x4e/0x60 mm/kasan/generic.c:634
 poison_slab_object+0xa6/0xe0 mm/kasan/common.c:241
 __kasan_slab_free+0x34/0x60 mm/kasan/common.c:257
 kasan_slab_free include/linux/kasan.h:184 [inline]
 slab_free_hook mm/slub.c:2121 [inline]
 slab_free mm/slub.c:4299 [inline]
 kfree+0x14a/0x380 mm/slub.c:4409
 f2fs_fill_super+0x6b04/0x8170 fs/f2fs/super.c:4882
 mount_bdev+0x206/0x2d0 fs/super.c:1663
 legacy_get_tree+0xef/0x190 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x2a0 fs/super.c:1784
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

The buggy address belongs to the object at ffff88801c6bc000
 which belongs to the cache kmalloc-8k of size 8192
The buggy address is located 6012 bytes inside of
 freed 8192-byte region [ffff88801c6bc000, ffff88801c6be000)

The buggy address belongs to the physical page:
page:ffffea000071ae00 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1c6b8
head:ffffea000071ae00 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0
flags: 0xfff00000000840(slab|head|node=0|zone=1|lastcpupid=0x7ff)
page_type: 0xffffffff()
raw: 00fff00000000840 ffff888012c42280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000020002 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Unmovable, gfp_mask 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 5217, tgid 5217 (syz-executor.2), ts 94314184798, free_ts 94276562119
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x1e6/0x210 mm/page_alloc.c:1533
 prep_new_page mm/page_alloc.c:1540 [inline]
 get_page_from_freelist+0x33ea/0x3570 mm/page_alloc.c:3311
 __alloc_pages+0x255/0x680 mm/page_alloc.c:4567
 __alloc_pages_node include/linux/gfp.h:238 [inline]
 alloc_pages_node include/linux/gfp.h:261 [inline]
 alloc_slab_page+0x5f/0x160 mm/slub.c:2190
 allocate_slab mm/slub.c:2354 [inline]
 new_slab+0x84/0x2f0 mm/slub.c:2407
 ___slab_alloc+0xd17/0x13d0 mm/slub.c:3540
 __slab_alloc mm/slub.c:3625 [inline]
 __slab_alloc_node mm/slub.c:3678 [inline]
 slab_alloc_node mm/slub.c:3850 [inline]
 __do_kmalloc_node mm/slub.c:3980 [inline]
 __kmalloc_node+0x2d2/0x4e0 mm/slub.c:3988
 kmalloc_node include/linux/slab.h:610 [inline]
 kvmalloc_node+0x72/0x180 mm/util.c:617
 build_sit_info fs/f2fs/segment.c:4402 [inline]
 f2fs_build_segment_manager+0x1036/0x3270 fs/f2fs/segment.c:5252
 f2fs_fill_super+0x5792/0x8170 fs/f2fs/super.c:4609
 mount_bdev+0x206/0x2d0 fs/super.c:1663
 legacy_get_tree+0xef/0x190 fs/fs_context.c:662
 vfs_get_tree+0x8c/0x2a0 fs/super.c:1784
 do_new_mount+0x2be/0xb40 fs/namespace.c:3352
 do_mount fs/namespace.c:3692 [inline]
 __do_sys_mount fs/namespace.c:3898 [inline]
 __se_sys_mount+0x2d9/0x3c0 fs/namespace.c:3875
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
page last free pid 4503 tgid 4503 stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1140 [inline]
 free_unref_page_prepare+0x959/0xa80 mm/page_alloc.c:2346
 free_unref_page+0x37/0x3f0 mm/page_alloc.c:2486
 discard_slab mm/slub.c:2453 [inline]
 __put_partials+0xeb/0x130 mm/slub.c:2922
 put_cpu_partial+0x17b/0x250 mm/slub.c:2997
 __slab_free+0x2fe/0x410 mm/slub.c:4166
 qlink_free mm/kasan/quarantine.c:160 [inline]
 qlist_free_all+0x6d/0xd0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x14b/0x160 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x23/0x70 mm/kasan/common.c:324
 kasan_slab_alloc include/linux/kasan.h:201 [inline]
 slab_post_alloc_hook mm/slub.c:3813 [inline]
 slab_alloc_node mm/slub.c:3860 [inline]
 kmem_cache_alloc+0x16f/0x340 mm/slub.c:3867
 getname_flags+0xbc/0x4f0 fs/namei.c:140
 user_path_at_empty+0x2c/0x60 fs/namei.c:2909
 do_readlinkat+0x118/0x3b0 fs/stat.c:499
 __do_sys_readlink fs/stat.c:532 [inline]
 __se_sys_readlink fs/stat.c:529 [inline]
 __x64_sys_readlink+0x7f/0x90 fs/stat.c:529
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0xf5/0x230 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Memory state around the buggy address:
 ffff88801c6bd600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801c6bd680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88801c6bd700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff88801c6bd780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff88801c6bd800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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.

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