Date: Mon, 18 Nov 2002 09:20:02 -0800 (PST) From: Cinek <cinekcvs@gmx.net> To: freebsd-bugs@FreeBSD.org Subject: Re: i386/45391: /usr/bin/cmp coredumps while reading a faulty CD-R Message-ID: <200211181720.gAIHK2cJ049263@freefall.freebsd.org>
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The following reply was made to PR i386/45391; it has been noted by GNATS. From: Cinek <cinekcvs@gmx.net> To: Bruce Evans <bde@zeta.org.au> Cc: FreeBSD-gnats-submit@FreeBSD.org Subject: Re: i386/45391: /usr/bin/cmp coredumps while reading a faulty CD-R Date: Mon, 18 Nov 2002 18:16:37 +0100 On Monday 18 November 2002 12:21, Bruce Evans wrote: > I think there is a problem with mmap() on files with i/o errors in > them. Pages should not be mapped if some part of them is unreadable, > and this should result in the application getting signals. cmp makes > no attempt to handle signals. I see. I guess I cannot help much about it. > Not much, but you might be able to see that the fauilting instruction > is an ordinary memory access, which would indicate that the problem is > just unmapped memory. I have disassembled the part and indeed a memory access is causing the segfault. I will paste some lines here: Program terminated with signal 11, Segmentation fault. 0x8048e17 in open () 0x8048e14 <open+1904>: mov 0xfffffff8(%ebp),%edx 0x8048e17 <open+1907>: mov (%edx),%dl 0x8048e19 <open+1909>: mov %dl,0xffffffff(%ebp) 0x8048e1c <open+1912>: mov 0xfffffff4(%ebp),%eax 0x8048e1f <open+1915>: cmp (%eax),%dl 0x8048e21 <open+1917>: je 0x8048eb7 <open+2067> 0x8048e27 <open+1923>: cmpl $0x0,0x804a80c 0x8048e2e <open+1930>: je 0x8048e60 <open+1980> Martin To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-bugs" in the body of the message
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