KASAN: use-after-free Read in posix_lock_inode

From: syzbot
Date: Wed Jan 02 2019 - 05:31:21 EST

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Hello,

syzbot found the following crash on:

HEAD commit: e1ef035d272e Merge tag 'armsoc-defconfig' of git://git.ker..
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=16bb4c4b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=9c6a26e22579190b
dashboard link: https://syzkaller.appspot.com/bug?extid=239d99847eb49ecb3899
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=128aa377400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+239d99847eb49ecb3899@xxxxxxxxxxxxxxxxxxxxxxxxx

IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
IPv6: ADDRCONF(NETDEV_UP): vxcan1: link is not ready
8021q: adding VLAN 0 to HW filter on device batadv0
8021q: adding VLAN 0 to HW filter on device batadv0
==================================================================
BUG: KASAN: use-after-free in what_owner_is_waiting_for fs/locks.c:1000 [inline]
BUG: KASAN: use-after-free in posix_locks_deadlock fs/locks.c:1023 [inline]
BUG: KASAN: use-after-free in posix_lock_inode+0x1f9e/0x2750 fs/locks.c:1163
Read of size 8 at addr ffff88808791b000 by task syz-executor2/10100

CPU: 1 PID: 10100 Comm: syz-executor2 Not tainted 4.20.0+ #3
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+0x1db/0x2d0 lib/dump_stack.c:113
print_address_description.cold+0x7c/0x20d mm/kasan/report.c:187
kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
__asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:135
what_owner_is_waiting_for fs/locks.c:1000 [inline]
posix_locks_deadlock fs/locks.c:1023 [inline]
posix_lock_inode+0x1f9e/0x2750 fs/locks.c:1163
posix_lock_file fs/locks.c:1346 [inline]
vfs_lock_file fs/locks.c:2314 [inline]
vfs_lock_file+0xc7/0xf0 fs/locks.c:2309
do_lock_file_wait.part.0+0xe5/0x260 fs/locks.c:2328
do_lock_file_wait fs/locks.c:2324 [inline]
fcntl_setlk+0x2f1/0xfe0 fs/locks.c:2413
do_fcntl+0x843/0x12b0 fs/fcntl.c:370
__do_sys_fcntl fs/fcntl.c:463 [inline]
__se_sys_fcntl fs/fcntl.c:448 [inline]
__x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448
do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457ec9
Code: 6d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 0f 83 3b b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f58bbb50c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000048
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457ec9
RDX: 0000000020000140 RSI: 0000000000000007 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f58bbb516d4
R13: 00000000004be5f0 R14: 00000000004ceab0 R15: 00000000ffffffff

Allocated by task 10100:
save_stack+0x45/0xd0 mm/kasan/common.c:73
set_track mm/kasan/common.c:85 [inline]
kasan_kmalloc mm/kasan/common.c:482 [inline]
kasan_kmalloc+0xcf/0xe0 mm/kasan/common.c:455
kasan_slab_alloc+0xf/0x20 mm/kasan/common.c:397
kmem_cache_alloc+0x12d/0x710 mm/slab.c:3541
kmem_cache_zalloc include/linux/slab.h:730 [inline]
locks_alloc_lock+0x8e/0x2f0 fs/locks.c:344
fcntl_setlk+0xa9/0xfe0 fs/locks.c:2362
do_fcntl+0x843/0x12b0 fs/fcntl.c:370
__do_sys_fcntl fs/fcntl.c:463 [inline]
__se_sys_fcntl fs/fcntl.c:448 [inline]
__x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448
do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 10100:
save_stack+0x45/0xd0 mm/kasan/common.c:73
set_track mm/kasan/common.c:85 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/common.c:444
kasan_slab_free+0xe/0x10 mm/kasan/common.c:452
__cache_free mm/slab.c:3485 [inline]
kmem_cache_free+0x86/0x260 mm/slab.c:3747
locks_free_lock+0x27a/0x3f0 fs/locks.c:381
fcntl_setlk+0x7b5/0xfe0 fs/locks.c:2439
do_fcntl+0x843/0x12b0 fs/fcntl.c:370
__do_sys_fcntl fs/fcntl.c:463 [inline]
__se_sys_fcntl fs/fcntl.c:448 [inline]
__x64_sys_fcntl+0x16d/0x1e0 fs/fcntl.c:448
do_syscall_64+0x1a3/0x800 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff88808791b000
which belongs to the cache file_lock_cache of size 264
The buggy address is located 0 bytes inside of
264-byte region [ffff88808791b000, ffff88808791b108)
The buggy address belongs to the page:
page:ffffea00021e46c0 count:1 mapcount:0 mapping:ffff8880aa16a1c0 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea0002333508 ffffea00021d76c8 ffff8880aa16a1c0
raw: 0000000000000000 ffff88808791b000 000000010000000c 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff88808791af00: fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc fc
ffff88808791af80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc

ffff88808791b000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

^
ffff88808791b080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88808791b100: fb fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb
==================================================================

---
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Next message: Corentin Labbe: "Re: [BUG] net: sungem: device driver frees DMA memory with wrong function"
Previous message: syzbot: "possible deadlock in nr_destroy_socket"
Next in thread: Jeff Layton: "Re: KASAN: use-after-free Read in posix_lock_inode"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]