KASAN: use-after-free Read in __free_vmap_area

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: 3242aa3a Linux 4.14.222
git tree: linux-4.14.y
console output: https://syzkaller.appspot.com/x/log.txt?x=1122d9b6d00000
kernel config: https://syzkaller.appspot.com/x/.config?x=d6fee509440d713f
dashboard link: https://syzkaller.appspot.com/bug?extid=fa3ed26b9c024833250a

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+fa3ed2...@syzkaller.appspotmail.com

==================================================================
BUG: KASAN: use-after-free in ____rb_erase_color lib/rbtree.c:384 [inline]
BUG: KASAN: use-after-free in rb_erase+0xf1f/0x1290 lib/rbtree.c:462
Read of size 8 at addr ffff88800010c018 by task syz-executor.3/7991

CPU: 1 PID: 7991 Comm: syz-executor.3 Not tainted 4.14.222-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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
____rb_erase_color lib/rbtree.c:384 [inline]
rb_erase+0xf1f/0x1290 lib/rbtree.c:462
__free_vmap_area+0xe7/0x310 mm/vmalloc.c:577
__purge_vmap_area_lazy+0x162/0x250 mm/vmalloc.c:707
try_purge_vmap_area_lazy mm/vmalloc.c:722 [inline]
free_vmap_area_noflush+0xa9/0xd0 mm/vmalloc.c:754
free_unmap_vmap_area mm/vmalloc.c:764 [inline]
remove_vm_area+0x22b/0x2c0 mm/vmalloc.c:1509
__vunmap+0x114/0x300 mm/vmalloc.c:1537
vfree+0x4b/0xd0 mm/vmalloc.c:1612
copy_entries_to_user net/ipv6/netfilter/ip6_tables.c:885 [inline]
get_entries net/ipv6/netfilter/ip6_tables.c:1044 [inline]
do_ip6t_get_ctl+0x5fc/0x7d0 net/ipv6/netfilter/ip6_tables.c:1713
nf_sockopt net/netfilter/nf_sockopt.c:104 [inline]
nf_getsockopt+0x62/0xc0 net/netfilter/nf_sockopt.c:122
ipv6_getsockopt+0x146/0x1e0 net/ipv6/ipv6_sockglue.c:1376
tcp_getsockopt+0x7b/0xc0 net/ipv4/tcp.c:3257
SYSC_getsockopt net/socket.c:1896 [inline]
SyS_getsockopt+0x102/0x1c0 net/socket.c:1878
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x46750a
RSP: 002b:00007ffc912872e8 EFLAGS: 00000212 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 0000000000000029 RCX: 000000000046750a
RDX: 0000000000000041 RSI: 0000000000000029 RDI: 0000000000000003
RBP: 00007ffc91287310 R08: 00007ffc9128730c R09: 0079746972756365
R10: 00007ffc91287370 R11: 0000000000000212 R12: 00007ffc91287370
R13: 0000000000000003 R14: 00007ffc9128730c R15: 000000000053df80

Allocated by task 4630:
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]
aa_alloc_file_ctx security/apparmor/include/file.h:60 [inline]
apparmor_file_alloc_security+0x129/0x800 security/apparmor/lsm.c:431
security_file_alloc+0x66/0xa0 security/security.c:874
get_empty_filp+0x15c/0x3e0 fs/file_table.c:129
path_openat+0x84/0x2970 fs/namei.c:3545
do_filp_open+0x179/0x3c0 fs/namei.c:3603
do_sys_open+0x296/0x410 fs/open.c:1081
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x46/0xbb

Freed by task 4630:
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
aa_free_file_ctx security/apparmor/include/file.h:76 [inline]
apparmor_file_free_security+0x7e/0xb0 security/apparmor/lsm.c:441
security_file_free+0x42/0x80 security/security.c:879
__fput+0x26c/0x7a0 fs/file_table.c:211
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+0x46/0xbb

The buggy address belongs to the object at ffff88800010c000
which belongs to the cache kmalloc-96 of size 96
The buggy address is located 24 bytes inside of
96-byte region [ffff88800010c000, ffff88800010c060)
The buggy address belongs to the page:
page:ffffea0000004300 count:1 mapcount:0 mapping:ffff88800010c000 index:0x0
flags: 0x7ff00000000100(slab)
raw: 007ff00000000100 ffff88800010c000 0000000000000000 0000000100000020
raw: ffffea0002d84a20 ffffea00026b1ba0 ffff88813fe804c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88800010bf00: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
ffff88800010bf80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff88800010c000: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
^
ffff88800010c080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
ffff88800010c100: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
==================================================================


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[syzbot]

Auto-closing this bug as obsolete.
Crashes did not happen for a while, no reproducer and no activity.