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BUG: KASAN: use-after-free in ib_uverbs_remove_one+0x411/0x4e0 drivers/infiniband/core/uverbs_main.c:1210
Read of size 4 at addr ffff888096324578 by task syz-executor.2/15847

CPU: 1 PID: 15847 Comm: syz-executor.2 Not tainted 5.7.0-rc6-next-20200522-syzkaller #0
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+0x18f/0x20d lib/dump_stack.c:118
 print_address_description.constprop.0.cold+0xd3/0x413 mm/kasan/report.c:383
 __kasan_report mm/kasan/report.c:513 [inline]
 kasan_report.cold+0x1f/0x37 mm/kasan/report.c:530
 ib_uverbs_remove_one+0x411/0x4e0 drivers/infiniband/core/uverbs_main.c:1210
 remove_client_context+0xbe/0x110 drivers/infiniband/core/device.c:732
 disable_device+0x13b/0x230 drivers/infiniband/core/device.c:1278
 __ib_unregister_device+0x91/0x180 drivers/infiniband/core/device.c:1445
 ib_unregister_device_and_put+0x57/0x80 drivers/infiniband/core/device.c:1508
 nldev_dellink+0x20a/0x310 drivers/infiniband/core/nldev.c:1571
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0x586/0x900 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352
 ___sys_sendmsg+0x100/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
Code: 0d 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fd6764d1c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00000000004ffa00 RCX: 000000000045ca29
RDX: 0000000000000000 RSI: 0000000020000180 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000009af R14: 00000000004d61b0 R15: 00007fd6764d26d4

Allocated by task 9061:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc mm/kasan/common.c:494 [inline]
 __kasan_kmalloc.constprop.0+0xbf/0xd0 mm/kasan/common.c:467
 kmem_cache_alloc_trace+0x153/0x7d0 mm/slab.c:3551
 kmalloc include/linux/slab.h:555 [inline]
 kzalloc include/linux/slab.h:669 [inline]
 ib_uverbs_add_one+0x80/0x7c0 drivers/infiniband/core/uverbs_main.c:1107
 add_client_context+0x400/0x5e0 drivers/infiniband/core/device.c:677
 enable_device_and_get+0x1cd/0x3b0 drivers/infiniband/core/device.c:1326
 ib_register_device drivers/infiniband/core/device.c:1392 [inline]
 ib_register_device+0xa12/0xda0 drivers/infiniband/core/device.c:1353
 siw_device_register drivers/infiniband/sw/siw/siw_main.c:70 [inline]
 siw_newlink drivers/infiniband/sw/siw/siw_main.c:565 [inline]
 siw_newlink+0xd37/0x1240 drivers/infiniband/sw/siw/siw_main.c:542
 nldev_newlink+0x29e/0x420 drivers/infiniband/core/nldev.c:1541
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0x586/0x900 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352
 ___sys_sendmsg+0x100/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

Freed by task 15847:
 save_stack+0x1b/0x40 mm/kasan/common.c:48
 set_track mm/kasan/common.c:56 [inline]
 kasan_set_free_info mm/kasan/common.c:316 [inline]
 __kasan_slab_free+0xf7/0x140 mm/kasan/common.c:455
 __cache_free mm/slab.c:3426 [inline]
 kfree+0x109/0x2b0 mm/slab.c:3757
 device_release+0x71/0x200 drivers/base/core.c:1541
 kobject_cleanup lib/kobject.c:701 [inline]
 kobject_release lib/kobject.c:732 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1c8/0x2f0 lib/kobject.c:749
 cdev_device_del+0x69/0x80 fs/char_dev.c:575
 ib_uverbs_remove_one+0x31/0x4e0 drivers/infiniband/core/uverbs_main.c:1209
 remove_client_context+0xbe/0x110 drivers/infiniband/core/device.c:732
 disable_device+0x13b/0x230 drivers/infiniband/core/device.c:1278
 __ib_unregister_device+0x91/0x180 drivers/infiniband/core/device.c:1445
 ib_unregister_device_and_put+0x57/0x80 drivers/infiniband/core/device.c:1508
 nldev_dellink+0x20a/0x310 drivers/infiniband/core/nldev.c:1571
 rdma_nl_rcv_msg drivers/infiniband/core/netlink.c:195 [inline]
 rdma_nl_rcv_skb drivers/infiniband/core/netlink.c:239 [inline]
 rdma_nl_rcv+0x586/0x900 drivers/infiniband/core/netlink.c:259
 netlink_unicast_kernel net/netlink/af_netlink.c:1303 [inline]
 netlink_unicast+0x537/0x740 net/netlink/af_netlink.c:1329
 netlink_sendmsg+0x882/0xe10 net/netlink/af_netlink.c:1918
 sock_sendmsg_nosec net/socket.c:652 [inline]
 sock_sendmsg+0xcf/0x120 net/socket.c:672
 ____sys_sendmsg+0x6e6/0x810 net/socket.c:2352
 ___sys_sendmsg+0x100/0x170 net/socket.c:2406
 __sys_sendmsg+0xe5/0x1b0 net/socket.c:2439
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3

The buggy address belongs to the object at ffff888096324000
 which belongs to the cache kmalloc-4k of size 4096
The buggy address is located 1400 bytes inside of
 4096-byte region [ffff888096324000, ffff888096325000)
The buggy address belongs to the page:
page:ffffea000258c900 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 head:ffffea000258c900 order:1 compound_mapcount:0
flags: 0xfffe0000010200(slab|head)
raw: 00fffe0000010200 ffffea0002429c08 ffffea000173f988 ffff8880aa002000
raw: 0000000000000000 ffff888096324000 0000000100000001 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888096324400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888096324480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888096324500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff888096324580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888096324600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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