Lars Nooden <[email protected]> writes:
> On 12/13/16, Stuart Henderson wrote:
>> On 2016/12/13 12:23, Lars Nooden wrote:
>>> On a BeagleBone Black (one that has not been used for GPIO), I have
>>> been getting segfaults with tcpdump since the last four or so
>>> snapshots. Running tcpdump in any way triggers the fault.
>>
>> A backtrace would be nice, or even better build with symbols and get
>> a backtrace from that.
>>
>> if you don't have a full source checkout handy, you can just fetch tcpdump:
>> cd /usr; cvs get -P src/usr.sbin/tcpdump
>>
>> then:
>> cd /usr/src/usr.sbin/tcpdump
>> make obj; make clean; make DEBUG=-g
>> gdb obj/tcpdump
>> run
>> bt
>>
>> You can also do a date-based checkout ("cvs up -D 2016/11/23" etc) to
>> narrow
>> down the commit that broke it.
>
> Ok. 'make obj' failed without having the full source tree. So now I have
> everything and did:
>
> $ cd /usr/src/usr.sbin/tcpdump
> $ make obj; make clean; make DEBUG=-g
>
> Then I ran gdb with the following results:
>
> # cd /usr/src/usr.sbin/tcpdump/
> # gdb obj/tcpdump
> GNU gdb 6.3
> Copyright 2004 Free Software Foundation, Inc.
> GDB is free software, covered by the GNU General Public License, and you are
> welcome to change it and/or distribute copies of it under certain conditions.
> Type "show copying" to see the conditions.
> There is absolutely no warranty for GDB. Type "show warranty" for details.
> This GDB was configured as "arm-unknown-openbsd6.0"...
> (gdb) run
> Starting program: /usr/obj/usr.sbin/tcpdump/tcpdump
>
> Program received signal SIGSEGV, Segmentation fault.
> *_libc_strlen (str=0x200 "\020@-\001")
> at /usr/src/lib/libc/string/strlen.c:39
> 39 for (s = str; *s; ++s)
> (gdb) bt
> #0 *_libc_strlen (str=0x200 "\020@-\001")
> at /usr/src/lib/libc/string/strlen.c:39
> #1 0x2fb1ffb8 in savestr (str=0x200 "\020@-\001")
> at /usr/src/usr.sbin/tcpdump/savestr.c:45
> #2 0x2fae57e8 in init_addrtoname (localnet=Variable "localnet" is not
> available.
> )
> at /usr/src/usr.sbin/tcpdump/addrtoname.c:738
> #3 0x2fae34c8 in main (argc=-1073903148, argv=Variable "argv" is not
> available.
> )
> at /usr/src/usr.sbin/tcpdump/tcpdump.c:460
>
Thanks for the report. I couldn't reproduce your issue at first since
I kinda always use -n. With the diff below I can't reproduce your
issue even without -n. The fallout is due to a change I made in
libpcap; I had such a commit in mind for tcpdump but kinda forgot,
since I didn't expect extern array vs. pointer to make a difference
here. *shrug*
oks?
Index: addrtoname.c
===================================================================
RCS file: /d/cvs/src/usr.sbin/tcpdump/addrtoname.c,v
retrieving revision 1.36
diff -u -p -p -u -r1.36 addrtoname.c
--- addrtoname.c 18 Nov 2015 15:36:20 -0000 1.36
+++ addrtoname.c 13 Dec 2016 19:38:48 -0000
@@ -693,11 +693,11 @@ init_ipprotoarray(void)
}
}
-/*XXX from libbpfc.a */
+/* XXX from libpcap */
extern struct eproto {
char *s;
u_short p;
-} eproto_db[];
+} *eproto_db;
static void
init_eprotoarray(void)
--
jca | PGP : 0x1524E7EE / 5135 92C1 AD36 5293 2BDF DDCC 0DFA 74AE 1524 E7EE
