usercopy: kernel memory overwrite attempt detected to 00000000056dec9b (kmalloc-1024) (983 bytes)
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kernel BUG at mm/usercopy.c:84!
invalid opcode: 0000 [#1] SMP
Dumping ftrace buffer:
   (ftrace buffer empty)
Modules linked in:
CPU: 0 PID: 31345 Comm: syz-executor7 Not tainted 4.15.0-rc3-next-20171214+ #67
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:report_usercopy mm/usercopy.c:76 [inline]
RIP: 0010:__check_object_size+0x1e2/0x250 mm/usercopy.c:276
RSP: 0018:ffffc90000dbf9c8 EFLAGS: 00010296
RAX: 0000000000000061 RBX: ffffffff82e57be7 RCX: ffffffff8123dede
RDX: 00000000000051be RSI: ffffc90002616000 RDI: ffff88021fc136f8
RBP: ffffc90000dbfa00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8801fca28050
R13: 00000000000003d7 R14: 0000000000000000 R15: ffffffff82edf8a5
FS:  00007f506151b700(0000) GS:ffff88021fc00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000071c000 CR3: 00000001fb4ca004 CR4: 00000000001626f0
DR0: 0000000020000000 DR1: 0000000020001000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600
Call Trace:
 check_object_size include/linux/thread_info.h:112 [inline]
 check_copy_size include/linux/thread_info.h:143 [inline]
 copy_from_user include/linux/uaccess.h:146 [inline]
 memdup_user_nul+0x48/0xe0 mm/util.c:227
 map_write+0x19d/0x920 kernel/user_namespace.c:903
 proc_projid_map_write+0x91/0xc0 kernel/user_namespace.c:1085
 __vfs_write+0x43/0x1e0 fs/read_write.c:480
 __kernel_write+0x72/0x140 fs/read_write.c:501
 write_pipe_buf+0x77/0x90 fs/splice.c:797
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x138/0x250 fs/splice.c:626
 splice_from_pipe+0x66/0x90 fs/splice.c:661
 default_file_splice_write+0x40/0x70 fs/splice.c:809
 do_splice_from fs/splice.c:851 [inline]
 direct_splice_actor+0x60/0x70 fs/splice.c:1018
 splice_direct_to_actor+0xfb/0x280 fs/splice.c:973
 do_splice_direct+0xac/0xe0 fs/splice.c:1061
 do_sendfile+0x216/0x440 fs/read_write.c:1413
 SYSC_sendfile64 fs/read_write.c:1468 [inline]
 SyS_sendfile64+0x59/0xc0 fs/read_write.c:1460
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x452a09
RSP: 002b:00007f506151ac58 EFLAGS: 00000212 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 00007f506151a950 RCX: 0000000000452a09
RDX: 000000002030f000 RSI: 0000000000000013 RDI: 0000000000000014
RBP: 00007f506151a940 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000007563 R11: 0000000000000212 R12: 00000000004b7366
R13: 00007f506151aac8 R14: 00000000004b7371 R15: 0000000000000000
Code: 7b e5 82 48 0f 44 da e8 8d 82 eb ff 48 8b 45 d0 4d 89 e9 4c 89 e1 4c 89 fa 48 89 de 48 c7 c7 a8 51 e6 82 49 89 c0 e8 76 b7 e3 ff <0f> 0b 48 c7 c0 43 51 e6 82 eb a1 48 c7 c0 53 51 e6 82 eb 98 48 
RIP: report_usercopy mm/usercopy.c:76 [inline] RSP: ffffc90000dbf9c8
RIP: __check_object_size+0x1e2/0x250 mm/usercopy.c:276 RSP: ffffc90000dbf9c8
---[ end trace dbe6ffc74bf4afa4 ]---