Date: Thu, 21 Dec 2023 04:15:04 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 272965] 14.0-ALPHA1 too: armv7 'Alignment Fault' on read panic during udp_input for kyua's sys/netinet6/exthdr:exthdr ; other udp_input related panics Message-ID: <bug-272965-227-Re1D1GBK3K@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-272965-227@https.bugs.freebsd.org/bugzilla/> References: <bug-272965-227@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D272965 --- Comment #10 from Michal Meloun <mmel@FreeBSD.org> --- (In reply to Warner Losh from comment #8) Unfortunately, I can't agree with that. Aligning the input mbuf is only papering over the real problem and can only work for trivial cases. It doe= sn't help for vlans (unless HW strips header), for various protocol encapsulatio= ns and most importantly it doesn't work at all for IPv6 :( The real problem is that our network stack uses undefined behavior. We can alias a byte buffer to a structure only if the given buffer pointer is conf= orm with the desired structure alignment, otherwise the behavior is undefined. = This is, strictly speaking , required for every architecture. The only way we can reduce the required alignment is by using the packed attribute for the affe= cted structures... --=20 You are receiving this mail because: You are the assignee for the bug.=
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