Bug 745

Summary:	ping with ipv6 crashes on arm
Product:	Busybox	Reporter:	Nikos Mavrogianopoulos <nmav>
Component:	Networking	Assignee:	unassigned
Status:	RESOLVED FIXED
Severity:	normal	CC:	aldot, busybox-cvs
Priority:	P5
Version:	1.15.x
Target Milestone:	---
Hardware:	PC
OS:	Linux
Host:		Target:
Build:
Attachments:	ping ipv6 fix Patch which went into git

Description Nikos Mavrogianopoulos 2009-11-26 09:50:28 UTC

ARM does not allow unaligned memory access thus the following code from ping:
hoplimit = *(int*)CMSG_DATA(mp);
crashes. The attached patch fixes the issue for me.

Comment 1 Nikos Mavrogianopoulos 2009-11-26 09:51:29 UTC

Created attachment 763 [details]
ping ipv6 fix

Comment 2 Bernhard Reutner-Fischer 2009-11-26 11:23:40 UTC

What's your
$ gcc -v
$ as --version
and what CFLAGS (EXTRA_CFLAGS) were used to build busybox?

Doesn't the compiler convert unaligned accesses into aligned ones on CPUs that are known not to support certain unaligned accesses?

Comment 3 Denys Vlasenko 2009-11-26 14:29:04 UTC

(In reply to comment #2)
> Doesn't the compiler convert unaligned accesses into aligned ones on CPUs that
> are known not to support certain unaligned accesses?

I think compiler usually assumes we know what we are doing. It will only handle attribute(packed) structure members and such. Simple casts assumed to result in aligned ptrs.

I pushed a fix in 57be1ee, will be in 1.16.x. Please test current git.

Comment 4 Denys Vlasenko 2009-11-26 14:33:42 UTC

Created attachment 765 [details]
Patch which went into git

Comment 5 Denys Vlasenko 2009-11-29 02:14:05 UTC

Please reopen if current git still doesn't work.