Date: Thu, 18 Feb 2010 00:28:30 +0000 From: Rui Paulo <rpaulo@freebsd.org> To: M. Warner Losh <imp@bsdimp.com> Cc: freebsd-arm@freebsd.org Subject: Re: kdump on ARM Message-ID: <987A4BCD-03A9-49ED-9E2E-AA4C2C6CA345@freebsd.org> In-Reply-To: <20100217.121545.260300876949842220.imp@bsdimp.com> References: <6c36ec371002170654n5e441c6eib9a8c9aad61c1e87@mail.gmail.com> <20100217.094559.29593248078653355.imp@bsdimp.com> <6c36ec371002171047m13544419sf8ca5ad283cdc65@mail.gmail.com> <20100217.121545.260300876949842220.imp@bsdimp.com>
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On 17 Feb 2010, at 19:15, M. Warner Losh wrote:
> In message: =
<6c36ec371002171047m13544419sf8ca5ad283cdc65@mail.gmail.com>
> batcilla itself <batcilla@gmail.com> writes:
> : 2010/2/17 M. Warner Losh <imp@bsdimp.com>:
> : > In message: =
<6c36ec371002170654n5e441c6eib9a8c9aad61c1e87@mail.gmail.com>
> : > batcilla itself <batcilla@gmail.com> writes:
> : > : 2010/2/17 Hans Petter Selasky <hselasky@c2i.net>
> : > : >
> : > : > On Wednesday 17 February 2010 15:18:12 Grzegorz Bernacki =
wrote:
> : > : > > Hi,
> : > : > >
> : > : > > I've noticed that kdump on ARM doesn't work properly, it =
generates bus
> : > : > > error. The problem is that structures dumped into =
ktrace.out are not
> : > : > > aligned. Processing such a structure causes Aligment Fault. =
One solution
> : > : > > is to copy structure into local variable and then process =
it, please see
> : > : > > patch below. But I am not sure if this is the best solution =
and maybe
> : > : > > someone has a better idea.
> : > : > >
> : > : > > grzesiek
> : > : > >
> : > : > >
> : > : > > diff --git a/usr.bin/kdump/kdump.c b/usr.bin/kdump/kdump.c
> : > : > > index 386221e..5a15886 100644
> : > : > > --- a/usr.bin/kdump/kdump.c
> : > : > > +++ b/usr.bin/kdump/kdump.c
> : > : > > @@ -1325,6 +1325,10 @@ ktrstat(struct stat *statp)
> : > : > > void
> : > : > > ktrstruct(char *buf, size_t buflen)
> : > : > > {
> : > : > > +#if defined(__arm__)
> : > : > > + struct stat stat;
> : > : > > + struct sockaddr sockaddr;
> : > : > > +#endif
> : > : > > char *name, *data;
> : > : > > size_t namelen, datalen;
> : > : > > int i;
> : > : > > @@ -1348,12 +1352,22 @@ ktrstruct(char *buf, size_t buflen)
> : > : > > if (strcmp(name, "stat") =3D=3D 0) {
> : > : > > if (datalen !=3D sizeof(struct stat))
> : > : > > goto invalid;
> : > : > > +#if defined(__arm__)
> : > : > > + memcpy(&stat, data, sizeof(struct stat));
> : > : > > + ktrstat(&stat);
> : > : > > +#else
> : > : > > ktrstat((struct stat *)data);
> : > : > > +#endif
> : > : > > } else if (strcmp(name, "sockaddr") =3D=3D 0) {
> : > : > > if (datalen < sizeof(struct sockaddr) ||
> : > : > > datalen !=3D ((struct sockaddr =
*)(data))->sa_len)
> : > : > > goto invalid;
> : > : > > +#if defined(__arm__)
> : > : > > + memcpy(&sockaddr, data, sizeof(struct =
sockaddr));
> : > : > > + ktrsockaddr(&sockaddr);
> : > : > > +#else
> : > : > > ktrsockaddr((struct sockaddr *)data);
> : > : > > +#endif
> : > : > > } else {
> : > : > > printf("unknown structure\n");
> : > : > > }
> : > : >
> : > : > I think more than ARM is affected by this.
> : > : >
> : > : > --HPS
> : > : ARM affected definitely, just today had that Align error with =
-current
> : > : while tried to use ng_bridge with wlan0
> : >
> : > Where exactly was the error? Do you have a traceback?
> : It was ARM/Xcale avila custom nanobsd build, error was caused adding
> : wlan0 into ng_bridge, while wlan0 was in tdma master (slot 0) mode,
> : with slot 1 there was no errors. Exact message here:
> :=20
> : Fatal kernel mode data abort: 'Alignment Fault 3'
> : trapframe: 0xc5e38cac
> : FSR=3D00000003, FAR=3Dc10fd1fe, spsr=3D00000013
> : r0 =3Dc0e15080, r1 =3Dc0508288, r2 =3Dc10fd1fe, r3 =3D00000001
> : r4 =3D0000003c, r5 =3Dc0e15080, r6 =3Dc0e15500, r7 =3Dc111a600
> : r8 =3Dc1182a00, r9 =3Dc116dc00, r10=3Dc0e15d80, r11=3D00000001
> : r12=3Dc0e15080, ssp=3Dc5e38cf8, slr=3Dc041cb58, pc =3Dc041ec98
> :=20
> : panic: Fatal abort
> : Uptime: 3h26m17s
> : Cannot dump. Device not defined or unavailable.
> : Automatic reboot in 15 seconds - press a key on the console to abort
> :=20
> : uname: avila ... FreeBSD 9.0-CURRENT #1: Wed Feb 17 12:08:37 UTC =
2010 ... arm
> :=20
> : Not really sure, if this alignment error come from kdump, there is
> : really no dump device in this unit and other debugging facilities =
was
> : turned off to save space.
>=20
> I'd wager that it wasn't caused by kdump, but something in the kernel.
I definitely agree.
--
Rui Paulo
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