On 2/22/21 9:25 AM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: f40ddce8 Linux 5.11 > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=179e8d22d00000 > kernel config: https://syzkaller.appspot.com/x/.config?x=e53d04227c52a0df > dashboard link: https://syzkaller.appspot.com/bug?extid=429d3f82d757c211bff3 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=10d190cad00000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13dc8a82d00000 > > Bisection is inconclusive: the issue happens on the oldest tested release. > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1128ae60d00000 > final oops: https://syzkaller.appspot.com/x/report.txt?x=1328ae60d00000 > console output: https://syzkaller.appspot.com/x/log.txt?x=1528ae60d00000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+429d3f82d757c211bff3@xxxxxxxxxxxxxxxxxxxxxxxxx > > ================================================================== > BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline] > BUG: KASAN: use-after-free in atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] > BUG: KASAN: use-after-free in refcount_dec_not_one+0x71/0x1e0 lib/refcount.c:76 > Read of size 4 at addr ffff888014ca19a0 by task syz-executor980/8540 > > CPU: 0 PID: 8540 Comm: syz-executor980 Not tainted 5.11.0-syzkaller #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 > Call Trace: > __dump_stack lib/dump_stack.c:79 [inline] > dump_stack+0x107/0x163 lib/dump_stack.c:120 > print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:230 > __kasan_report mm/kasan/report.c:396 [inline] > kasan_report.cold+0x79/0xd5 mm/kasan/report.c:413 > check_memory_region_inline mm/kasan/generic.c:179 [inline] > check_memory_region+0x13d/0x180 mm/kasan/generic.c:185 > instrument_atomic_read include/linux/instrumented.h:71 [inline] > atomic_read include/asm-generic/atomic-instrumented.h:27 [inline] > refcount_dec_not_one+0x71/0x1e0 lib/refcount.c:76 > refcount_dec_and_mutex_lock+0x19/0x140 lib/refcount.c:115 > nbd_put drivers/block/nbd.c:248 [inline] > nbd_genl_connect+0xee7/0x1560 drivers/block/nbd.c:1980 > genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 > genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] > genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 > genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 > netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 > netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:672 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2399 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > RIP: 0033:0x440709 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 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 73 01 c3 48 c7 c1 c0 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffd63e9cc88 EFLAGS: 00000246 ORIG_RAX: 000000000000002e > RAX: ffffffffffffffda RBX: 000000000000e3fb RCX: 0000000000440709 > RDX: 0000000000000000 RSI: 0000000020000340 RDI: 0000000000000003 > RBP: 0000000000000000 R08: 0000000000000000 R09: 00007ffd63e9ce28 > R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffd63e9cc9c > R13: 431bde82d7b634db R14: 00000000004ae018 R15: 00000000004004a0 > > Allocated by task 8536: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 > kasan_set_track mm/kasan/common.c:46 [inline] > set_alloc_info mm/kasan/common.c:401 [inline] > ____kasan_kmalloc.constprop.0+0x82/0xa0 mm/kasan/common.c:429 > kmalloc include/linux/slab.h:552 [inline] > kzalloc include/linux/slab.h:682 [inline] > nbd_dev_add+0x44/0x8e0 drivers/block/nbd.c:1673 > nbd_genl_connect+0x59c/0x1560 drivers/block/nbd.c:1838 > genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 > genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] > genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 > genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 > netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 > netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:672 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2399 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > Freed by task 8540: > kasan_save_stack+0x1b/0x40 mm/kasan/common.c:38 > kasan_set_track+0x1c/0x30 mm/kasan/common.c:46 > kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:356 > ____kasan_slab_free+0xe1/0x110 mm/kasan/common.c:362 > kasan_slab_free include/linux/kasan.h:192 [inline] > slab_free_hook mm/slub.c:1547 [inline] > slab_free_freelist_hook+0x5d/0x150 mm/slub.c:1580 > slab_free mm/slub.c:3143 [inline] > kfree+0xdb/0x3b0 mm/slub.c:4139 > nbd_dev_remove drivers/block/nbd.c:243 [inline] > nbd_put.part.0+0x180/0x1d0 drivers/block/nbd.c:251 > nbd_put drivers/block/nbd.c:295 [inline] > nbd_config_put+0x6dd/0x8c0 drivers/block/nbd.c:1242 > nbd_genl_connect+0xeb7/0x1560 drivers/block/nbd.c:1978 > genl_family_rcv_msg_doit+0x228/0x320 net/netlink/genetlink.c:739 > genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] > genl_rcv_msg+0x328/0x580 net/netlink/genetlink.c:800 > netlink_rcv_skb+0x153/0x420 net/netlink/af_netlink.c:2494 > genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 > netlink_unicast_kernel net/netlink/af_netlink.c:1304 [inline] > netlink_unicast+0x533/0x7d0 net/netlink/af_netlink.c:1330 > netlink_sendmsg+0x856/0xd90 net/netlink/af_netlink.c:1919 > sock_sendmsg_nosec net/socket.c:652 [inline] > sock_sendmsg+0xcf/0x120 net/socket.c:672 > ____sys_sendmsg+0x6e8/0x810 net/socket.c:2345 > ___sys_sendmsg+0xf3/0x170 net/socket.c:2399 > __sys_sendmsg+0xe5/0x1b0 net/socket.c:2432 > do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 > entry_SYSCALL_64_after_hwframe+0x44/0xa9 > > The buggy address belongs to the object at ffff888014ca1800 > which belongs to the cache kmalloc-1k of size 1024 > The buggy address is located 416 bytes inside of > 1024-byte region [ffff888014ca1800, ffff888014ca1c00) > The buggy address belongs to the page: > page:0000000086766889 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x14ca0 > head:0000000086766889 order:3 compound_mapcount:0 compound_pincount:0 > flags: 0xfff00000010200(slab|head) > raw: 00fff00000010200 ffffea0000929400 0000000200000002 ffff888010c41140 > raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 > page dumped because: kasan: bad access detected > > Memory state around the buggy address: > ffff888014ca1880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888014ca1900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >> ffff888014ca1980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ^ > ffff888014ca1a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888014ca1a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ================================================================== > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > syzbot can test patches for this issue, for details see: > https://goo.gl/tpsmEJ#testing-patches > This might be caused by : commit a2c97909f97ef32b76e856572fba4f77e1885fe6 Author: Josef Bacik <josef@xxxxxxxxxxxxxx> Date: Thu Apr 6 17:02:07 2017 -0400 nbd: add a flag to destroy an nbd device on disconnect For ease of management it would be nice for users to specify that the device node for a nbd device is destroyed once it is disconnected and there are no more users. Add a client flag and enable this operation to happen. Signed-off-by: Josef Bacik <jbacik@xxxxxx> Signed-off-by: Jens Axboe <axboe@xxxxxx>
