[Qemu-devel] Re: [REGRESSION] mprotect in guest makes qemu-i386 crash

[Jan Kiszka <jan.kiszka@siemens.com>]

Jan Kiszka wrote:
> Hi,
> 
> this fragment from a code self-modification test of mine used to work a
> few weeks ago with qemu-i386 userspace emulation. Now it causes a segfault.
> 
> #include <sys/mman.h>
> main()
> {
> 	mprotect((void *)((unsigned long)main & ~0xfff), 0x1000,
> 		 PROT_READ|PROT_WRITE|PROT_EXEC);
> }
> 
> qemu-x86_64 even complains about an "Unsupported syscall: 221", while
> the same 64-bit binary works fine with 0.9.1 (I don't recall anymore if
> it worked recently with SVN head).

Some clarification: mprotect is fine with qemu-x86_64, that syscall
warning is another, unrelated issue (it pops up with every x86_64
application in userland emu).

That leaves us with mprotect being broken in qemu-i386 on x86_64 hosts.

Jan

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