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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 ffff8880a8a8a588 by task syz-executor.3/11280

CPU: 0 PID: 11280 Comm: syz-executor.3 Not tainted 5.1.0-rc2-next-20190401 #15
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
 cma_bind_addr drivers/infiniband/core/cma.c:3121 [inline]
 rdma_resolve_addr+0x437/0x21f0 drivers/infiniband/core/cma.c:3132
 ucma_resolve_ip+0x153/0x210 drivers/infiniband/core/ucma.c:715
 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: 0033:0x458209
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:00007ff302c81c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000458209
RDX: 0000000000000048 RSI: 00000000200001c0 RDI: 0000000000000008
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007ff302c826d4
R13: 00000000004ce0e8 R14: 00000000004dd828 R15: 00000000ffffffff

Allocated by task 11271:
 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
 cma_bind_addr drivers/infiniband/core/cma.c:3121 [inline]
 rdma_resolve_addr+0x437/0x21f0 drivers/infiniband/core/cma.c:3132
 ucma_resolve_ip+0x153/0x210 drivers/infiniband/core/ucma.c:715
 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 11273:
 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_destroy_id+0x334/0x4a0 drivers/infiniband/core/ucma.c:638
 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

The buggy address belongs to the object at ffff8880a8a8a580
 which belongs to the cache kmalloc-32 of size 32
The buggy address is located 8 bytes inside of
 32-byte region [ffff8880a8a8a580, ffff8880a8a8a5a0)
The buggy address belongs to the page:
page:ffffea0002a2a280 count:1 mapcount:0 mapping:ffff88812c3f01c0 index:0xffff8880a8a8afc1
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00027eb488 ffff88812c3f1248 ffff88812c3f01c0
raw: ffff8880a8a8afc1 ffff8880a8a8a000 000000010000003f 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a8a8a480: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a8a8a500: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
>ffff8880a8a8a580: fb fb fb fb fc fc fc fc 00 00 fc fc fc fc fc fc
                      ^
 ffff8880a8a8a600: fb fb fb fb fc fc fc fc fb fb fb fb fc fc fc fc
 ffff8880a8a8a680: fb fb fb fb fc fc fc fc 00 03 fc fc fc fc fc fc
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