Hello,
syzbot found the following crash on:
HEAD commit: 78d697fc Linux 4.14.172
git tree: linux-4.14.y
console output:
https://syzkaller.appspot.com/x/log.txt?x=17b7f7ede00000
kernel config:
https://syzkaller.appspot.com/x/.config?x=31ad682bcda9b93f
dashboard link:
https://syzkaller.appspot.com/bug?extid=d11c860b0130db28056e
compiler: gcc (GCC) 9.0.0 20181231 (experimental)
Unfortunately, I don't have any reproducer for this crash yet.
IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by:
syzbot+d11c86...@syzkaller.appspotmail.com
==================================================================
BUG: KASAN: use-after-free in macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1095
Read of size 4 at addr ffff88802911a508 by task syz-executor.5/2114
CPU: 1 PID: 2114 Comm: syz-executor.5 Not tainted 4.14.172-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+0x13e/0x194 lib/dump_stack.c:58
print_address_description.cold+0x7c/0x1e2 mm/kasan/report.c:252
kasan_report_error mm/kasan/report.c:351 [inline]
kasan_report mm/kasan/report.c:409 [inline]
kasan_report.cold+0xa9/0x2ae mm/kasan/report.c:393
macvlan_dev_get_iflink+0x5f/0x70 drivers/net/macvlan.c:1095
dev_get_iflink+0x73/0xe0 net/core/dev.c:690
rfc2863_policy+0x17e/0x1e0 net/core/link_watch.c:43
linkwatch_do_dev+0x16/0xe0 net/core/link_watch.c:157
linkwatch_forget_dev+0x15c/0x1f0 net/core/link_watch.c:223
netdev_wait_allrefs net/core/dev.c:7831 [inline]
netdev_run_todo+0x234/0x710 net/core/dev.c:7932
rtnl_unlock net/core/rtnetlink.c:106 [inline]
rtnetlink_rcv_msg+0x3cb/0xb10 net/core/rtnetlink.c:4317
netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2432
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xc5/0x100 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x45c479
RSP: 002b:00007fcfc82f0c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fcfc82f16d4 RCX: 000000000045c479
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000006
RBP: 000000000076bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009f9 R14: 00000000004cc71a R15: 000000000076bf2c
Allocated by task 2114:
save_stack+0x32/0xa0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_kmalloc mm/kasan/kasan.c:551 [inline]
kasan_kmalloc+0xbf/0xe0 mm/kasan/kasan.c:529
__do_kmalloc_node mm/slab.c:3682 [inline]
__kmalloc_node+0x4c/0x70 mm/slab.c:3689
kmalloc_node include/linux/slab.h:530 [inline]
kvmalloc_node+0x46/0xd0 mm/util.c:397
kvmalloc include/linux/mm.h:531 [inline]
kvzalloc include/linux/mm.h:539 [inline]
alloc_netdev_mqs+0x76/0xb70 net/core/dev.c:8097
rtnl_create_link+0x1ab/0x880 net/core/rtnetlink.c:2460
rtnl_newlink+0xdd0/0x1720 net/core/rtnetlink.c:2718
rtnetlink_rcv_msg+0x3be/0xb10 net/core/rtnetlink.c:4315
netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2432
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xc5/0x100 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
Freed by task 2118:
save_stack+0x32/0xa0 mm/kasan/kasan.c:447
set_track mm/kasan/kasan.c:459 [inline]
kasan_slab_free+0x75/0xc0 mm/kasan/kasan.c:524
__cache_free mm/slab.c:3496 [inline]
kfree+0xcb/0x260 mm/slab.c:3815
kvfree+0x45/0x50 mm/util.c:416
device_release+0x15f/0x1a0 drivers/base/core.c:833
kobject_cleanup lib/kobject.c:646 [inline]
kobject_release lib/kobject.c:675 [inline]
kref_put include/linux/kref.h:70 [inline]
kobject_put+0x13e/0x1f0 lib/kobject.c:692
netdev_run_todo+0x4a9/0x710 net/core/dev.c:7954
rtnl_unlock net/core/rtnetlink.c:106 [inline]
rtnetlink_rcv_msg+0x3cb/0xb10 net/core/rtnetlink.c:4317
netlink_rcv_skb+0x127/0x370 net/netlink/af_netlink.c:2432
netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
netlink_unicast+0x437/0x620 net/netlink/af_netlink.c:1312
netlink_sendmsg+0x733/0xbe0 net/netlink/af_netlink.c:1877
sock_sendmsg_nosec net/socket.c:646 [inline]
sock_sendmsg+0xc5/0x100 net/socket.c:656
___sys_sendmsg+0x70a/0x840 net/socket.c:2062
__sys_sendmsg+0xa3/0x120 net/socket.c:2096
SYSC_sendmsg net/socket.c:2107 [inline]
SyS_sendmsg+0x27/0x40 net/socket.c:2103
do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
entry_SYSCALL_64_after_hwframe+0x42/0xb7
The buggy address belongs to the object at ffff88802911a400
which belongs to the cache kmalloc-4096 of size 4096
The buggy address is located 264 bytes inside of
4096-byte region [ffff88802911a400, ffff88802911b400)
The buggy address belongs to the page:
page:ffffea0000a44680 count:1 mapcount:0 mapping:ffff88802911a400 index:0x0 compound_mapcount: 0
flags: 0xfffe0000008100(slab|head)
raw: 00fffe0000008100 ffff88802911a400 0000000000000000 0000000100000001
raw: ffffea0001374aa0 ffffea0002816c20 ffff88812fe56dc0 0000000000000000
page dumped because: kasan: bad access detected
Memory state around the buggy address:
ffff88802911a400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802911a480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88802911a500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
^
ffff88802911a580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
ffff88802911a600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================
---
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