KASAN: use-after-free Read in f2fs_evict_inode

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: b09c3451 Linux 4.19.149
git tree: linux-4.19.y
console output: https://syzkaller.appspot.com/x/log.txt?x=154e7d6d900000
kernel config: https://syzkaller.appspot.com/x/.config?x=d7c6dfb55644e8fd
dashboard link: https://syzkaller.appspot.com/bug?extid=641d482b73464dd5d56e
compiler: gcc (GCC) 10.1.0-syz 20200507

Unfortunately, I don't have any reproducer for this issue yet.

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+641d48...@syzkaller.appspotmail.com

F2FS-fs (loop4): Cannot turn on quotas: -2 on 2
==================================================================
BUG: KASAN: use-after-free in f2fs_evict_inode+0x1058/0x1380 fs/f2fs/inode.c:650
Read of size 4 at addr ffff888094cb5950 by task syz-executor.4/11409

CPU: 1 PID: 11409 Comm: syz-executor.4 Not tainted 4.19.149-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x22c/0x33e lib/dump_stack.c:118
print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354
kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432
f2fs_evict_inode+0x1058/0x1380 fs/f2fs/inode.c:650
evict+0x2ed/0x780 fs/inode.c:559
iput_final fs/inode.c:1555 [inline]
iput+0x511/0x890 fs/inode.c:1581
dentry_unlink_inode+0x265/0x320 fs/dcache.c:374
__dentry_kill+0x3c0/0x640 fs/dcache.c:566
dentry_kill+0xc4/0x510 fs/dcache.c:685
shrink_dentry_list+0x2eb/0x740 fs/dcache.c:1092
shrink_dcache_sb+0x144/0x220 fs/dcache.c:1212
f2fs_fill_super+0x2d89/0x7920 fs/f2fs/super.c:3225
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x318 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799
ksys_mount+0xcf/0x130 fs/namespace.c:3015
__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026
do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4607ea
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad 89 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a 89 fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f786c4eea88 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f786c4eeb20 RCX: 00000000004607ea
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007f786c4eeae0
RBP: 00007f786c4eeae0 R08: 00007f786c4eeb20 R09: 0000000020000000
R10: 0000000000000000 R11: 0000000000000202 R12: 0000000020000000
R13: 0000000020000100 R14: 0000000020000200 R15: 0000000020000880

Allocated by task 11409:
kmem_cache_alloc_trace+0x12f/0x4b0 mm/slab.c:3625
kmalloc include/linux/slab.h:515 [inline]
kzalloc include/linux/slab.h:709 [inline]
f2fs_fill_super+0x145/0x7920 fs/f2fs/super.c:2821
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x318 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799
ksys_mount+0xcf/0x130 fs/namespace.c:3015
__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026
do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 11409:
__cache_free mm/slab.c:3503 [inline]
kfree+0xcc/0x250 mm/slab.c:3822
f2fs_fill_super+0x2d5e/0x7920 fs/f2fs/super.c:3220
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x318 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799
ksys_mount+0xcf/0x130 fs/namespace.c:3015
__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026
do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888094cb4c00
which belongs to the cache kmalloc-8192 of size 8192
The buggy address is located 3408 bytes inside of
8192-byte region [ffff888094cb4c00, ffff888094cb6c00)
The buggy address belongs to the page:
page:ffffea0002532d00 count:1 mapcount:0 mapping:ffff88812c3f5080 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffffea00010fb408 ffffea000125d008 ffff88812c3f5080
raw: 0000000000000000 ffff888094cb4c00 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff888094cb5800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888094cb5880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888094cb5900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff888094cb5980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff888094cb5a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: b09c3451 Linux 4.19.149
git tree: linux-4.19.y

console output: https://syzkaller.appspot.com/x/log.txt?x=1411e72f900000

kernel config: https://syzkaller.appspot.com/x/.config?x=d7c6dfb55644e8fd
dashboard link: https://syzkaller.appspot.com/bug?extid=641d482b73464dd5d56e
compiler: gcc (GCC) 10.1.0-syz 20200507

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=124c06ff900000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=128f9ab7900000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+641d48...@syzkaller.appspotmail.com

F2FS-fs (loop3): Can't find valid F2FS filesystem in 2th superblock
F2FS-fs (loop2): Can't find valid F2FS filesystem in 2th superblock
F2FS-fs (loop4): invalid crc value
F2FS-fs (loop1): Can't find valid F2FS filesystem in 2th superblock

==================================================================
BUG: KASAN: use-after-free in f2fs_evict_inode+0x1058/0x1380 fs/f2fs/inode.c:650

Read of size 4 at addr ffff8880a4281ad0 by task syz-executor953/6500

CPU: 0 PID: 6500 Comm: syz-executor953 Not tainted 4.19.149-syzkaller #0

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:

kasan: CONFIG_KASAN_INLINE enabled

__dump_stack lib/dump_stack.c:77 [inline]
dump_stack+0x22c/0x33e lib/dump_stack.c:118
print_address_description.cold+0x56/0x25c mm/kasan/report.c:256
kasan_report_error.cold+0x66/0xb9 mm/kasan/report.c:354

kasan: GPF could be caused by NULL-ptr deref or user memory access

kasan_report mm/kasan/report.c:412 [inline]
__asan_report_load4_noabort+0x88/0x90 mm/kasan/report.c:432
f2fs_evict_inode+0x1058/0x1380 fs/f2fs/inode.c:650
evict+0x2ed/0x780 fs/inode.c:559
iput_final fs/inode.c:1555 [inline]
iput+0x511/0x890 fs/inode.c:1581

kasan: CONFIG_KASAN_INLINE enabled

dentry_unlink_inode+0x265/0x320 fs/dcache.c:374
__dentry_kill+0x3c0/0x640 fs/dcache.c:566

kasan: GPF could be caused by NULL-ptr deref or user memory access

dentry_kill+0xc4/0x510 fs/dcache.c:685
shrink_dentry_list+0x2eb/0x740 fs/dcache.c:1092
shrink_dcache_sb+0x144/0x220 fs/dcache.c:1212

general protection fault: 0000 [#1] PREEMPT SMP KASAN
CPU: 1 PID: 6496 Comm: syz-executor953 Not tainted 4.19.149-syzkaller #0
f2fs_fill_super+0x2d89/0x7920 fs/f2fs/super.c:3225

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:1501 [inline]
RIP: 0010:f2fs_evict_inode+0xedf/0x1380 fs/f2fs/inode.c:712
Code: c1 ea 03 80 3c 02 00 0f 85 dc 03 00 00 49 8b 9c 24 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 30 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 ab 03 00 00 48 8b 7b 30 4c 89 f2 4c 89 f6 e8 68
RSP: 0018:ffff8880a416f768 EFLAGS: 00010206
RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff83321989
mount_bdev+0x2fc/0x3b0 fs/super.c:1158
RDX: 0000000000000006 RSI: ffffffff8332237f RDI: 0000000000000030
RBP: ffff88807fd8f400 R08: 0000000000000000 R09: 0000000000000000
mount_fs+0xa3/0x318 fs/super.c:1261
R10: 0000000000000007 R11: 0000000000000001 R12: ffff888084a48dc0
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
R13: ffff88807fd8f7d0 R14: 0000000000000003 R15: ffff8880a3e2e9b8

vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799

FS: 00007fac44338700(0000) GS:ffff8880ae300000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055ea2e9fd658 CR3: 00000000a386e000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:

ksys_mount+0xcf/0x130 fs/namespace.c:3015
__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026

evict+0x2ed/0x780 fs/inode.c:559
iput_final fs/inode.c:1555 [inline]
iput+0x511/0x890 fs/inode.c:1581

do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
dentry_unlink_inode+0x265/0x320 fs/dcache.c:374
entry_SYSCALL_64_after_hwframe+0x49/0xbe
__dentry_kill+0x3c0/0x640 fs/dcache.c:566
RIP: 0033:0x44d83a
dentry_kill+0xc4/0x510 fs/dcache.c:685
Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad a0 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a a0 fb ff c3 66 0f 1f 84 00 00 00 00 00
shrink_dentry_list+0x2eb/0x740 fs/dcache.c:1092
RSP: 002b:00007fac44337bf8 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5
shrink_dcache_sb+0x144/0x220 fs/dcache.c:1212
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000044d83a
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fac44337c10
RBP: 00007fac44337c10 R08: 00007fac44337c50 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000297 R12: 000000000000000d
f2fs_fill_super+0x2d89/0x7920 fs/f2fs/super.c:3225
R13: 00007fac44337c50 R14: 00007fac443386d0 R15: 0000000000000003

Allocated by task 6500:

kmem_cache_alloc_trace+0x12f/0x4b0 mm/slab.c:3625
kmalloc include/linux/slab.h:515 [inline]
kzalloc include/linux/slab.h:709 [inline]
f2fs_fill_super+0x145/0x7920 fs/f2fs/super.c:2821
mount_bdev+0x2fc/0x3b0 fs/super.c:1158

mount_bdev+0x2fc/0x3b0 fs/super.c:1158
mount_fs+0xa3/0x318 fs/super.c:1261
mount_fs+0xa3/0x318 fs/super.c:1261
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799

vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799
ksys_mount+0xcf/0x130 fs/namespace.c:3015
__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026
do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 6500:
ksys_mount+0xcf/0x130 fs/namespace.c:3015

__cache_free mm/slab.c:3503 [inline]
kfree+0xcc/0x250 mm/slab.c:3822

__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026

f2fs_fill_super+0x2d5e/0x7920 fs/f2fs/super.c:3220
mount_bdev+0x2fc/0x3b0 fs/super.c:1158

do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
mount_fs+0xa3/0x318 fs/super.c:1261
entry_SYSCALL_64_after_hwframe+0x49/0xbe
vfs_kern_mount.part.0+0x68/0x470 fs/namespace.c:961
RIP: 0033:0x44d83a

vfs_kern_mount fs/namespace.c:951 [inline]
do_new_mount fs/namespace.c:2469 [inline]
do_mount+0x51c/0x2f10 fs/namespace.c:2799

Code: b8 08 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 ad a0 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 8a a0 fb ff c3 66 0f 1f 84 00 00 00 00 00
ksys_mount+0xcf/0x130 fs/namespace.c:3015
RSP: 002b:00007fac44337bf8 EFLAGS: 00000297 ORIG_RAX: 00000000000000a5

__do_sys_mount fs/namespace.c:3029 [inline]
__se_sys_mount fs/namespace.c:3026 [inline]
__x64_sys_mount+0xba/0x150 fs/namespace.c:3026

RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 000000000044d83a
do_syscall_64+0xf9/0x670 arch/x86/entry/common.c:293
RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007fac44337c10
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RBP: 00007fac44337c10 R08: 00007fac44337c50 R09: 0000000000000000

R10: 0000000000000000 R11: 0000000000000297 R12: 000000000000000d
The buggy address belongs to the object at ffff8880a4280d80

which belongs to the cache kmalloc-8192 of size 8192

R13: 00007fac44337c50 R14: 00007fac443386d0 R15: 0000000000000003

The buggy address is located 3408 bytes inside of

8192-byte region [ffff8880a4280d80, ffff8880a4282d80)
Modules linked in:

The buggy address belongs to the page:

general protection fault: 0000 [#2] PREEMPT SMP KASAN
page:ffffea000290a000 count:1 mapcount:0 mapping:ffff88812c3f5080 index:0x0 compound_mapcount: 0
CPU: 1 PID: 6501 Comm: syz-executor953 Tainted: G D 4.19.149-syzkaller #0
flags: 0xfffe0000008100(slab|head)

Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011

raw: 00fffe0000008100 ffffea0002127308 ffffea0002129208 ffff88812c3f5080
RIP: 0010:NODE_MAPPING fs/f2fs/f2fs.h:1501 [inline]
RIP: 0010:f2fs_evict_inode+0xedf/0x1380 fs/f2fs/inode.c:712
raw: 0000000000000000 ffff8880a4280d80 0000000100000001 0000000000000000
Code: c1 ea 03 80 3c 02 00 0f 85 dc 03 00 00 49 8b 9c 24 38 01 00 00 48 b8 00 00 00 00 00 fc ff df 48 8d 7b 30 48 89 fa 48 c1 ea 03 <80> 3c 02 00 0f 85 ab 03 00 00 48 8b 7b 30 4c 89 f2 4c 89 f6 e8 68

page dumped because: kasan: bad access detected

RSP: 0018:ffff888084ac7768 EFLAGS: 00010206

RAX: dffffc0000000000 RBX: 0000000000000000 RCX: ffffffff83321989

Memory state around the buggy address:

RDX: 0000000000000006 RSI: ffffffff8332237f RDI: 0000000000000030
ffff8880a4281980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
RBP: ffff88807fd9a480 R08: 0000000000000000 R09: 0000000000000000
ffff8880a4281a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
R10: 0000000000000007 R11: 0000000000000001 R12: ffff8880a4238e00
>ffff8880a4281a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
R13: ffff88807fd9a850 R14: 0000000000000003 R15: ffff8880a4666c38
^
FS: 00007fac44338700(0000) GS:ffff8880ae300000(0000) knlGS:0000000000000000
ffff8880a4281b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
ffff8880a4281b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
CR2: 000055ea2e9fd658 CR3: 00000000a7fa8000 CR4: 00000000001406e0
==================================================================
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000