KASAN: invalid-free in x25_asy_free

From: syzbot
Date: Fri Dec 28 2018 - 19:21:13 EST

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Hello,

syzbot found the following crash on:

HEAD commit: 8fe28cb58bcb Linux 4.20
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=13c11a3b400000
kernel config: https://syzkaller.appspot.com/x/.config?x=7d581260bae0899a
dashboard link: https://syzkaller.appspot.com/bug?extid=5e5e969e525129229052
compiler: gcc (GCC) 8.0.1 20180413 (experimental)
syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1574eeaf400000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1417cd8b400000

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+5e5e969e525129229052@xxxxxxxxxxxxxxxxxxxxxxxxx

__alloc_pages include/linux/gfp.h:473 [inline]
__alloc_pages_node include/linux/gfp.h:486 [inline]
kmem_getpages mm/slab.c:1409 [inline]
cache_grow_begin+0x91/0x8c0 mm/slab.c:2677
==================================================================
cache_alloc_refill mm/slab.c:3044 [inline]
____cache_alloc mm/slab.c:3127 [inline]
slab_alloc_node mm/slab.c:3322 [inline]
kmem_cache_alloc_node_trace+0x670/0x740 mm/slab.c:3661
BUG: KASAN: double-free or invalid-free in x25_asy_free+0x37/0x140 drivers/net/wan/x25_asy.c:111

__do_kmalloc_node mm/slab.c:3683 [inline]
__kmalloc_node+0x3c/0x70 mm/slab.c:3691
kmalloc_node include/linux/slab.h:589 [inline]
kvmalloc_node+0x65/0xf0 mm/util.c:416
kvmalloc include/linux/mm.h:577 [inline]
kvzalloc include/linux/mm.h:585 [inline]
alloc_netdev_mqs+0x17b/0xfe0 net/core/dev.c:8949
x25_asy_alloc drivers/net/wan/x25_asy.c:83 [inline]
x25_asy_open_tty+0x551/0x7e7 drivers/net/wan/x25_asy.c:556
tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453
tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578
tiocsetd drivers/tty/tty_io.c:2321 [inline]
tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4410e9
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffc32511548 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004410e9
RDX: 0000000020000000 RSI: 0000000000005423 RDI: 0000000000000003
RBP: 00007ffc32511560 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000
CPU: 0 PID: 7925 Comm: syz-executor081 Not tainted 4.20.0 #387
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+0x1d3/0x2c6 lib/dump_stack.c:113
print_address_description.cold.8+0x9/0x1ff mm/kasan/report.c:256
kasan_report_invalid_free+0x64/0xa0 mm/kasan/report.c:336
__kasan_slab_free+0x13a/0x150 mm/kasan/kasan.c:501
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3817
x25_asy_free+0x37/0x140 drivers/net/wan/x25_asy.c:111
x25_asy_open_tty+0x6ad/0x7e7 drivers/net/wan/x25_asy.c:572
tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453
tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578
tiocsetd drivers/tty/tty_io.c:2321 [inline]
tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4410e9
Code: e8 ac e8 ff ff 48 83 c4 18 c3 0f 1f 80 00 00 00 00 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 0b 0a fc ff c3 66 2e 0f 1f 84 00 00 00 00
kobject: 'queues' (000000001e78d271): kobject_uevent_env: filter function caused the event to drop!
RSP: 002b:00007ffc32511548 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004410e9
RDX: 0000000020000000 RSI: 0000000000005423 RDI: 0000000000000003
RBP: 00007ffc32511560 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: ffffffffffffffff
R13: 0000000000000004 R14: 0000000000000000 R15: 0000000000000000

kobject: 'rx-0' (00000000b3577da5): kobject_add_internal: parent: 'queues', set: 'queues'
Allocated by task 7925:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:553
__do_kmalloc mm/slab.c:3722 [inline]
__kmalloc+0x15b/0x770 mm/slab.c:3731
kmalloc include/linux/slab.h:551 [inline]
x25_asy_open drivers/net/wan/x25_asy.c:465 [inline]
x25_asy_open_tty+0x32a/0x7e7 drivers/net/wan/x25_asy.c:570
tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453
tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578
tiocsetd drivers/tty/tty_io.c:2321 [inline]
tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581
kobject: 'rx-0' (00000000b3577da5): kobject_uevent_env
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 7925:
save_stack+0x43/0xd0 mm/kasan/kasan.c:448
set_track mm/kasan/kasan.c:460 [inline]
__kasan_slab_free+0x102/0x150 mm/kasan/kasan.c:521
kobject: 'rx-0' (00000000b3577da5): fill_kobj_path: path = '/devices/virtual/net/x25asy1/queues/rx-0'
kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
__cache_free mm/slab.c:3498 [inline]
kfree+0xcf/0x230 mm/slab.c:3817
x25_asy_open drivers/net/wan/x25_asy.c:489 [inline]
x25_asy_open_tty+0x6a0/0x7e7 drivers/net/wan/x25_asy.c:570
tty_ldisc_open.isra.1+0x8b/0xe0 drivers/tty/tty_ldisc.c:453
tty_set_ldisc+0x2dc/0x6a0 drivers/tty/tty_ldisc.c:578
tiocsetd drivers/tty/tty_io.c:2321 [inline]
tty_ioctl+0x39d/0x17d0 drivers/tty/tty_io.c:2581
vfs_ioctl fs/ioctl.c:46 [inline]
file_ioctl fs/ioctl.c:509 [inline]
do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
kobject: 'tx-0' (00000000ae272600): kobject_add_internal: parent: 'queues', set: 'queues'
__do_sys_ioctl fs/ioctl.c:720 [inline]
__se_sys_ioctl fs/ioctl.c:718 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8881afc12000
which belongs to the cache kmalloc-1k of size 1024
The buggy address is located 0 bytes inside of
1024-byte region [ffff8881afc12000, ffff8881afc12400)
The buggy address belongs to the page:
page:ffffea0006bf0480 count:1 mapcount:0 mapping:ffff8881da800ac0 index:0x0 compound_mapcount: 0
kobject: 'tx-0' (00000000ae272600): kobject_uevent_env
flags: 0x2fffc0000010200(slab|head)
raw: 02fffc0000010200 ffffea0007511e08 ffffea0007551288 ffff8881da800ac0
raw: 0000000000000000 ffff8881afc12000 0000000100000007 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
ffff8881afc11f00: fb fb fb fb fb fb fc fc fc fc fb fb fb fb fb fb
ffff8881afc11f80: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc

ffff8881afc12000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb

kobject: 'tx-0' (00000000ae272600): fill_kobj_path: path = '/devices/virtual/net/x25asy1/queues/tx-0'
^
ffff8881afc12080: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff8881afc12100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================

---
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Next message: syzbot: "WARNING in __might_sleep (2)"
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