From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1O3pJb-0002nZ-0y for qemu-devel@nongnu.org; Mon, 19 Apr 2010 07:38:59 -0400 Received: from [140.186.70.92] (port=46981 helo=eggs.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1O3pJY-0002ls-G0 for qemu-devel@nongnu.org; Mon, 19 Apr 2010 07:38:58 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.69) (envelope-from ) id 1O3pJV-0005Ur-Ea for qemu-devel@nongnu.org; Mon, 19 Apr 2010 07:38:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:50586) by eggs.gnu.org with esmtp (Exim 4.69) (envelope-from ) id 1O3pJS-0005Tf-QI for qemu-devel@nongnu.org; Mon, 19 Apr 2010 07:38:52 -0400 Message-ID: <4BCC40C6.1040203@redhat.com> Date: Mon, 19 Apr 2010 14:38:46 +0300 From: Avi Kivity MIME-Version: 1.0 Subject: Re: [Qemu-devel] Re: [PATCH v3 2/6] Introduce bit-based phys_ram_dirty for VGA, CODE, MIGRATION and MASTER. References: <1271670198-12793-1-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> <1271670198-12793-3-git-send-email-tamura.yoshiaki@lab.ntt.co.jp> <4BCC2DBA.4000602@redhat.com> <4BCC3226.20305@lab.ntt.co.jp> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Yoshiaki Tamura Cc: aliguori@us.ibm.com, mtosatti@redhat.com, qemu-devel@nongnu.org, ohmura.kei@lab.ntt.co.jp On 04/19/2010 02:31 PM, Yoshiaki Tamura wrote: > >>>> typedef struct RAMBlock { >>>> @@ -2825,10 +2825,16 @@ ram_addr_t qemu_ram_alloc(ram_addr_t size) >>>> new_block->next = ram_blocks; >>>> ram_blocks = new_block; >>>> >>>> - phys_ram_dirty = qemu_realloc(phys_ram_dirty, >>>> - (last_ram_offset + size)>> TARGET_PAGE_BITS); >>>> - memset(phys_ram_dirty + (last_ram_offset>> TARGET_PAGE_BITS), >>>> - 0xff, size>> TARGET_PAGE_BITS); >>>> + if (BITMAP_SIZE(last_ram_offset + size) != >>>> BITMAP_SIZE(last_ram_offset)) { >>>> >>> This check is unneeded - the code will work fine even if the bitmap size >>> doesn't change. >>> >> OK. I'll remove it. >> > I have a problem here. > If I remove this check, glibc reports an error as below. > > *** glibc detected *** /usr/local/qemu/bin/qemu-system-x86_64: > realloc(): invalid pointer: 0x0000000001f0e450 *** > ======= Backtrace: ========= > /lib64/libc.so.6[0x369fa75a96] > /lib64/libc.so.6(realloc+0x2a1)[0x369fa7b881] > /usr/local/qemu/bin/qemu-system-x86_64[0x437d93] > /usr/local/qemu/bin/qemu-system-x86_64[0x4f03f6] > /usr/local/qemu/bin/qemu-system-x86_64[0x5b052c] > /usr/local/qemu/bin/qemu-system-x86_64[0x5b0d8b] > /usr/local/qemu/bin/qemu-system-x86_64[0x41ec2b] > /lib64/libc.so.6(__libc_start_main+0xfd)[0x369fa1ea2d] > /usr/local/qemu/bin/qemu-system-x86_64[0x406479] > ======= Memory map: ======== > > I reminded that I put this check to avoid reallocating same size to the bitmap. > qemu goes this routine at start up, and extends last_ram_offset at > small numbers. > The error above is reported at the extension phase. > > This probably means that an old bitmap pointer leaked somewhere, and we realloc() it after free? Or perhaps a glibc bug. -- error compiling committee.c: too many arguments to function