Comment 5 for bug 1716767

Ok, I was wrong, there's a whole load of code being included inside the function from a header. The issue seems to be the pread:

20771@1505254578.940000:guest_user_syscall cpu=0x62850620 num=0x00000000000000b4 arg1=0x0000000000000003 arg2=0xfffffffff6fe6798 arg3=0x0000000000000020 arg4=0x0000000000000000 arg5=0x0000000000000034 arg6=0x0000000000000000 arg7=0x0000000000000000 arg8=0x0000000000000000
20771@1505254578.940005:guest_user_syscall_ret cpu=0x62850620 num=0x00000000000000b4 ret=0x0000000000000000

0xb4 (180) is pread(64) on SH, which goes via a special wrapper[0] with a dummy argument that gets stripped. This dummy argument ensures that the 64-bit offset is aligned. However, linux-user doesn't know about this, and so takes (arg4, arg5) as the 64-bit value, rather than (arg5, arg6), leading to the host kernel trying to read 0x340000000000000000 bytes (and rightly returning 0 for EOF).

[0] https://github.com/torvalds/linux/blob/e0d072250a54669dce876d8ade70e417356aae74/arch/sh/kernel/sys_sh32.c#L38