Date: Tue, 6 Aug 2013 03:31:37 GMT From: Brandon Gooch <jamesbrandongooch@gmail.com> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/181078: Loading tun(4) from loader.conf(5) causes panic when kernel already contains device tun(4) Message-ID: <201308060331.r763Vbtw036264@oldred.freebsd.org> Resent-Message-ID: <201308060340.r763e08n042734@freefall.freebsd.org>
next in thread | raw e-mail | index | archive | help
>Number: 181078
>Category: kern
>Synopsis: Loading tun(4) from loader.conf(5) causes panic when kernel already contains device tun(4)
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue Aug 06 03:40:00 UTC 2013
>Closed-Date:
>Last-Modified:
>Originator: Brandon Gooch
>Release: 10-CURRENT
>Organization:
>Environment:
FreeBSD m6500.m6500 10.0-CURRENT FreeBSD 10.0-CURRENT #3 r253950M: Mon Aug 5 21:16:19 CDT 2013 root@m6500.m6500:/usr/obj/usr/home/brandon/wc/freebsd-base-head/sys/DELL_M6500 amd64
>Description:
As per the subject, loading tun(4) via loader.conf(5) results in a panic if the tun(4) device already exists in the kernel.
Properly registering the tun(4) driver via MODULE_VERSION(9) fixes the issue, disallowing double-registering the module (patch attached).
Sure, this is on the edge of user error, but it's still a POLA violation and incorrect behavior...
Here's the stack trace from the panic:
#0 doadump (textdump=682654720) at pcpu.h:236
236 pcpu.h: No such file or directory.
in pcpu.h
(kgdb) #0 doadump (textdump=682654720) at pcpu.h:236
#1 0xffffffff803050a5 in db_fncall (dummy1=<value optimized out>,
dummy2=<value optimized out>, dummy3=<value optimized out>,
dummy4=<value optimized out>)
at /usr/home/brandon/wc/freebsd-base-head/sys/ddb/db_command.c:578
#2 0xffffffff80304d8d in db_command (cmd_table=<value optimized out>)
at /usr/home/brandon/wc/freebsd-base-head/sys/ddb/db_command.c:449
#3 0xffffffff80304b04 in db_command_loop ()
at /usr/home/brandon/wc/freebsd-base-head/sys/ddb/db_command.c:502
#4 0xffffffff80307470 in db_trap (type=<value optimized out>, code=0)
at /usr/home/brandon/wc/freebsd-base-head/sys/ddb/db_main.c:231
#5 0xffffffff804b92c3 in kdb_trap (type=9, code=0, tf=<value optimized out>)
at /usr/home/brandon/wc/freebsd-base-head/sys/kern/subr_kdb.c:654
#6 0xffffffff8082954a in trap_fatal (frame=0xffffff84655c4860,
eva=<value optimized out>)
at /usr/home/brandon/wc/freebsd-base-head/sys/amd64/amd64/trap.c:868
#7 0xffffffff808291ef in trap (frame=<value optimized out>)
at /usr/home/brandon/wc/freebsd-base-head/sys/amd64/amd64/trap.c:224
#8 0xffffffff80812ed2 in calltrap ()
at /usr/home/brandon/wc/freebsd-base-head/sys/amd64/amd64/exception.S:232
#9 0xffffffff8053e696 in if_clone_create (name=0xfffffe0032b7aec0 "wlan0",
len=16, params=0x627300 <Address 0x627300 out of bounds>)
at /usr/home/brandon/wc/freebsd-base-head/sys/net/if_clone.c:193
#10 0xffffffff8053ba10 in ifioctl (so=0xfffffe0032e50550,
cmd=<value optimized out>, data=0xfffffe0032b7aec0 "wlan0",
td=0xfffffe0032eb1920)
at /usr/home/brandon/wc/freebsd-base-head/sys/net/if.c:2505
#11 0xffffffff804d072e in kern_ioctl (td=0xfffffe0032eb1920,
fd=<value optimized out>, com=18446741875537194688) at file.h:306
#12 0xffffffff804d04af in sys_ioctl (td=0xfffffe0032eb1920,
uap=0xffffff84655c4b80)
at /usr/home/brandon/wc/freebsd-base-head/sys/kern/sys_generic.c:693
#13 0xffffffff80829e77 in amd64_syscall (td=0xfffffe0032eb1920, traced=0)
at subr_syscall.c:134
#14 0xffffffff808131bb in Xfast_syscall ()
at /usr/home/brandon/wc/freebsd-base-head/sys/amd64/amd64/exception.S:391
#15 0x000000080119b45a in ?? ()
Previous frame inner to this frame (corrupt stack?)
Current language: auto; currently minimal
>How-To-Repeat:
Load tun(4) via loader.conf(5) while having the tun(4) device compiled in to the kernel.
>Fix:
Patch attached.
Patch attached with submission follows:
Index: sys/net/if_tun.c
===================================================================
--- sys/net/if_tun.c (revision 253950)
+++ sys/net/if_tun.c (working copy)
@@ -321,6 +321,7 @@
};
DECLARE_MODULE(if_tun, tun_mod, SI_SUB_PSEUDO, SI_ORDER_ANY);
+MODULE_VERSION(if_tun, 1);
static void
tunstart(struct ifnet *ifp)
>Release-Note:
>Audit-Trail:
>Unformatted:
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201308060331.r763Vbtw036264>