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BUG: KASAN: use-after-free in cma_check_port+0x8ce/0x8f0 drivers/infiniband/core/cma.c:3354
Read of size 8 at addr ffff888099736448 by task syz-executor.3/16129

CPU: 1 PID: 16129 Comm: syz-executor.3 Not tainted 5.1.0-rc3-next-20190402 #16
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+0x172/0x1f0 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:132
 cma_check_port+0x8ce/0x8f0 drivers/infiniband/core/cma.c:3354
 cma_use_port drivers/infiniband/core/cma.c:3391 [inline]
 cma_get_port drivers/infiniband/core/cma.c:3473 [inline]
 rdma_bind_addr+0x19c3/0x1f80 drivers/infiniband/core/cma.c:3591
 ucma_bind+0x17f/0x210 drivers/infiniband/core/ucma.c:691
 ucma_write+0x2da/0x3c0 drivers/infiniband/core/ucma.c:1696
 __vfs_write+0x8d/0x110 fs/read_write.c:485
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0xea/0x1f0 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4582b9
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f4b431fac78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000004582b9
RDX: 0000000000000090 RSI: 0000000020000100 RDI: 0000000000000003
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f4b431fb6d4
R13: 00000000004c7846 R14: 00000000004dd718 R15: 00000000ffffffff

Allocated by task 16107:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_kmalloc mm/kasan/common.c:497 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:470
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:511
 kmem_cache_alloc_trace+0x151/0x760 mm/slab.c:3622
 kmalloc include/linux/slab.h:547 [inline]
 kzalloc include/linux/slab.h:742 [inline]
 cma_alloc_port+0x4f/0x1a0 drivers/infiniband/core/cma.c:3241
 cma_use_port drivers/infiniband/core/cma.c:3389 [inline]
 cma_get_port drivers/infiniband/core/cma.c:3473 [inline]
 rdma_bind_addr+0x1bc0/0x1f80 drivers/infiniband/core/cma.c:3591
 ucma_bind+0x17f/0x210 drivers/infiniband/core/ucma.c:691
 ucma_write+0x2da/0x3c0 drivers/infiniband/core/ucma.c:1696
 __vfs_write+0x8d/0x110 fs/read_write.c:485
 vfs_write+0x20c/0x580 fs/read_write.c:549
 ksys_write+0xea/0x1f0 fs/read_write.c:598
 __do_sys_write fs/read_write.c:610 [inline]
 __se_sys_write fs/read_write.c:607 [inline]
 __x64_sys_write+0x73/0xb0 fs/read_write.c:607
 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 16102:
 save_stack+0x45/0xd0 mm/kasan/common.c:75
 set_track mm/kasan/common.c:87 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:459
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:467
 __cache_free mm/slab.c:3499 [inline]
 kfree+0xcf/0x230 mm/slab.c:3822
 cma_release_port drivers/infiniband/core/cma.c:1773 [inline]
 rdma_destroy_id+0x7fc/0xaa0 drivers/infiniband/core/cma.c:1840
 ucma_close+0x115/0x320 drivers/infiniband/core/ucma.c:1777
 __fput+0x2e5/0x8d0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff888099736440
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff888099736440, ffff888099736460)
The buggy address belongs to the page:
page:ffffea000265cd80 count:1 mapcount:0 mapping:ffff88812c3f01c0 index:0xffff888099736fc1
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00027c3188 ffffea0002a0e1c8 ffff88812c3f01c0
raw: ffff888099736fc1 ffff888099736000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff888099736300: 00 00 07 fc fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888099736380: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff888099736400: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
                                              ^
 ffff888099736480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff888099736500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
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