Date: Tue, 1 Feb 2011 20:04:54 +0100 From: Monthadar Al Jaberi <monthadar@gmail.com> To: Julian Elischer <julian@freebsd.org> Cc: freebsd-virtualization@freebsd.org Subject: Re: simulating wireless device (if_alloc panic, VirtualBox, VIMAGE) Message-ID: <AANLkTikJKZLQVA5X2PQs0oT4iFsZYBw7K07kjQTc9iGD@mail.gmail.com> In-Reply-To: <4D484213.6050100@freebsd.org> References: <AANLkTik8D_bLwcUKZdBT-kpkJdDXtPTLvAqfUe0cLoSz@mail.gmail.com> <4D484213.6050100@freebsd.org>
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On Tue, Feb 1, 2011 at 6:25 PM, Julian Elischer <julian@freebsd.org> wrote: > On 2/1/11 8:40 AM, Monthadar Al Jaberi wrote: >> >> Hi, >> >> I hope I am on the write place, second try... >> >> I have written a module that loads fake wifi devices (wtap?) and >> distributes packets between them. For now I use route command to route >> packets between them from upper layers (TCP,...). >> I want to take it to next step and create jails with VNET. I started >> reading Julian Elischer's "Vimage: what is it?" and he says that if I >> am writing hardware drivers I dont need to make any changes when I >> enable VIMAGE option on the kernel, because each one will have their >> own stack. >> >> I can give a more detailed explanation on how my module works. But for >> now I get a panic when calling if_alloc() when using option VIMAGE. >> >> Thank you, > > while this =A0was true to some extent it i snot 100% true now. > during allocation we now try to have separate interface indexes per vimag= e > which means that the setup routines do need to know the current vnet. so I cant call if_alloc directly? > > it looks like wtap_ioctl or wtap_attach should have the following: > (copied from the tun driver) > > this should not be needed from real hardware based drivers as far as I ca= n > tell. > > =A0 =A0 =A0 =A0CURVNET_SET(CRED_TO_VNET(cred)); > =A0 =A0 =A0 =A0/* find any existing device, or allocate new unit number *= / > =A0 =A0 =A0 =A0i =3D clone_create(&tunclones, &tun_cdevsw, &u, dev, 0); > =A0 =A0 =A0 =A0[blah] > =A0 =A0 =A0 =A0if_clone_create(name, namelen, NULL); > =A0 =A0 =A0 =A0CURVNET_RESTORE(); My wtap is based on ath driver code (if_ath.c) which should look like a real device right? if_ath.c is not using VNET, as far as I can tell.... Currently my module creates a couple of wtaps, which I then create a corresponding wlan. These wtaps are interconnected together, so no out world yet... so I dont have struct cdev *dev.... Basic idea is my module have a main queue (simulating air) and each wtap have a rx_task which sends packets up to higher layers, plus callout timer for generation beacons... I will try to use CURVET_SET(...) tomo >> >> My setup: >> FreeBSD Current 201010 guest on VirtualBox on Ubuntu 10.04. >> >> Kernel page fault with the following non-sleepable locks held: >> exclusive rw ifnet_rw (ifnet_rw) r =3D 0 (0xc0fc8284) locked @ >> /usr/src/sys/net/if.c:414 >> KDB: stack backtrace: >> db_trace_self_wrapper(c0cf3cdb,1,0,0,0,...) at db_trace_self_wrapper+0x2= 6 >> kdb_backtrace(19e,1,ffffffff,c0f9b194,c2fc9a1c,...) at kdb_backtrace+0x2= a >> _witness_debugger(c0cf6408,c2fc9a30,4,1,0,...) at _witness_debugger+0x25 >> witness_warn(5,0,c0d2c479,3,c4070d48,...) at witness_warn+0x1fe >> trap(c2fc9abc) at trap+0x195 >> calltrap() at calltrap+0x6 >> --- trap 0xc, eip =3D 0xc0970999, esp =3D 0xc2fc9afc, ebp =3D 0xc2fc9b1c= --- >> ifindex_alloc_locked(c0d003cf,c2fc9b36,19e,19e,c15ab714,...) at >> ifindex_alloc_locked+0x19 >> if_alloc(47,c4085a16,3,c0de9614,c32aa780,...) at if_alloc+0x85 >> wtap_attach(c31a7800,c40857c0,0,4,0,...) at wtap_attach+0x29 >> new_wtap(c32aa780,0,c2fc9bf0,c083ac9b,c3cbb200,...) at new_wtap+0x9b >> wtap_ioctl(c3cbb200,80045701,c31edaa0,1,c3f90b40,...) at wtap_ioctl+0x36 >> devfs_ioctl_f(c3cfe3b8,80045701,c31edaa0,c3185d00,c3f90b40,...) at >> devfs_ioctl_f+0x10b >> kern_ioctl(c3f90b40,3,80045701,c31edaa0,fc9cec,...) at kern_ioctl+0x20d >> ioctl(c3f90b40,c2fc9cec,c2fc9d28,c0cf5783,0,...) at ioctl+0x134 >> syscallenter(c3f90b40,c2fc9ce4,c2fc9ce4,0,0,...) at syscallenter+0x263 >> syscall(c2fc9d28) at syscall+0x34 >> Xint0x80_syscall() at Xint0x80_syscall+0x21 >> --- syscall (54, FreeBSD ELF32, ioctl), eip =3D 0x28181203, esp =3D >> 0xbfbfec3c, ebp =3D 0xbfbfec58 --- >> >> >> Fatal trap 12: page fault while in kernel mode >> cpuid =3D 0; apic id =3D 00 >> fault virtual address =A0 =3D 0x18 >> fault code =A0 =A0 =A0 =A0 =A0 =A0 =A0=3D supervisor read, page not pres= ent >> instruction pointer =A0 =A0 =3D 0x20:0xc0970999 >> stack pointer =A0 =A0 =A0 =A0 =A0 =3D 0x28:0xc2fc9afc >> frame pointer =A0 =A0 =A0 =A0 =A0 =3D 0x28:0xc2fc9b1c >> code segment =A0 =A0 =A0 =A0 =A0 =A0=3D base 0x0, limit 0xfffff, type 0x= 1b >> =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0=3D DPL 0, pres 1, def32 = 1, gran 1 >> processor eflags =A0 =A0 =A0 =A0=3D interrupt enabled, resume, IOPL =3D = 0 >> current process =A0 =A0 =A0 =A0 =3D 1203 (ioctl) >> panic: from debugger >> cpuid =3D 0 >> Uptime: 21s >> Physical memory: 495 MB >> Dumping 55 MB: 40 24 8 >> > > --=20 //Monthadar Al Jaberi
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