Date: Wed, 3 Nov 2021 11:25:53 -0400 From: Michael Butler via freebsd-emulation <freebsd-emulation@freebsd.org> To: Konstantin Belousov <kostikbel@gmail.com> Cc: Ed Maste <emaste@freebsd.org>, Cy Schubert <Cy.Schubert@cschubert.com>, Greg V <greg@unrelenting.technology>, "freebsd-emulation@freebsd.org" <freebsd-emulation@freebsd.org>, freebsd-current <freebsd-current@freebsd.org> Subject: Re: current now panics when starting VBox VM Message-ID: <20712a48-03d3-722e-3990-e70b9670af1d@protected-networks.net> In-Reply-To: <YYKm/5rJz9JEdgVY@kib.kiev.ua> References: <d4c79b85-2668-3fe8-7c4a-9304e7fd88d1@protected-networks.net> <36923A7F-23DE-490D-B1FA-A8B064740BD6@unrelenting.technology> <202111022148.1A2LmeHX004930@slippy.cwsent.com> <1ccb6ce3-2cb7-e325-79e3-cda5640f24df@protected-networks.net> <CAPyFy2ADpz-wrFgP_YgmDvnKjoRYaQf3nTEwBpjLU6kBBRmsuQ@mail.gmail.com> <d40fb2c8-020a-d66b-6b4a-1a5acb9937a6@protected-networks.net> <YYKm/5rJz9JEdgVY@kib.kiev.ua>
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On 11/3/21 11:13, Konstantin Belousov wrote:
> On Wed, Nov 03, 2021 at 11:05:11AM -0400, Michael Butler via freebsd-emulation wrote:
>> On 11/3/21 10:36, Ed Maste wrote:
>> The kgdb back-trace isn't any more enlightening to me :-(
>>
>> __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55
>> 55 __asm("movq %%gs:%P1,%0" : "=r" (td) : "n" (offsetof(struct
>> pcpu,
>> (kgdb) bt
>> #0 __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55
>> #1 doadump (textdump=<optimized out>) at
>> /usr/src/sys/kern/kern_shutdown.c:399
>> #2 0xffffffff808cbac5 in kern_reboot (howto=260) at
>> /usr/src/sys/kern/kern_shutdown.c:487
>> #3 0xffffffff808cbedb in vpanic (fmt=<optimized out>,
>> ap=0xfffffe0129a6a8d0) at /usr/src/sys/kern/kern_shutdown.c:920
>> #4 0xffffffff808cbd33 in panic (fmt=<unavailable>) at
>> /usr/src/sys/kern/kern_shutdown.c:844
>> #5 0xffffffff80ca920c in trap_fatal (frame=frame@entry=0xfffffe0129a6aac0,
>> eva=0) at /usr/src/sys/amd64/amd64/trap.c:946
>> #6 0xffffffff80ca95af in trap_pfault (frame=frame@entry=0xfffffe0129a6aac0,
>> usermode=false, signo=<optimized out>, signo@entry=0x0, ucode=<optimized
>> out>, ucode@entry=0x0)
>> at /usr/src/sys/amd64/include/cpufunc.h:417
>> #7 0xffffffff80ca89bc in trap (frame=0xfffffe0129a6aac0) at
>> /usr/src/sys/amd64/amd64/trap.c:443
>> #8 <signal handler called>
>> #9 strlen () at /usr/src/sys/amd64/amd64/support.S:751
>> #10 0xffffffff808b4d79 in sysctl_kern_proc_pathname (oidp=<optimized out>,
>> arg1=0xfffffe0129a6ad8c, arg2=<optimized out>, req=0xfffffe0129a6acc0) at
>> /usr/src/sys/kern/kern_proc.c:2330
>> #11 0xffffffff808dc331 in sysctl_root_handler_locked
>> (oid=oid@entry=0xffffffff810cf0e0 <sysctl___kern_proc_pathname>,
>> arg1=arg1@entry=0xfffffe0129a6ad8c, arg2=arg2@entry=1,
>> req=0xfffffe0129a6acc0, tracker=tracker@entry=0xfffffe0129a6ac38) at
>> /usr/src/sys/kern/kern_sysctl.c:185
>> #12 0xffffffff808db88b in sysctl_root (oidp=<optimized out>,
>> arg1=0xfffffe0129a6ad8c, arg1@entry=0xfffffe0129a6ad80, arg2=1,
>> arg2@entry=4, req=req@entry=0xfffffe0129a6acc0)
>> at /usr/src/sys/kern/kern_sysctl.c:2305
>> #13 0xffffffff808dbdf3 in userland_sysctl (td=td@entry=0xfffffe012991a000,
>> name=name@entry=0xfffffe0129a6ad80, namelen=4, old=<optimized out>,
>> oldlenp=<optimized out>,
>> inkernel=<optimized out>, inkernel@entry=0, new=0x0, newlen=0,
>> retval=0xfffffe0129a6ade8, flags=0) at /usr/src/sys/kern/kern_sysctl.c:2462
>> #14 0xffffffff808dbc3c in sys___sysctl (td=0xfffffe012991a000,
>> uap=0xfffffe012991a3f0) at /usr/src/sys/kern/kern_sysctl.c:2335
>> #15 0xffffffff80ca9b5c in syscallenter (td=0xfffffe012991a000) at
>> /usr/src/sys/amd64/amd64/../../kern/subr_syscall.c:189
>> #16 amd64_syscall (td=0xfffffe012991a000, traced=0) at
>> /usr/src/sys/amd64/amd64/trap.c:1191
>> #17 <signal handler called>
>> #18 0x000000080315a71a in ?? ()
>> Backtrace stopped: Cannot access memory at address 0x7fffffffc778
>> (kgdb)
>>
>
> Try this
>
> commit 2d3f95bd1fd4f71769f60b8037c1ff27c75d8258
> Author: Konstantin Belousov <kib@FreeBSD.org>
> Date: Wed Nov 3 17:11:33 2021 +0200
>
> proc_get_binpath(): return empty string instead of NULL
>
> for strange case where process does not have text.
>
> Sponsored by: The FreeBSD Foundation
> MFC after: 3 days
>
> diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
> index 2156c5c465ba..d11f651960c0 100644
> --- a/sys/kern/kern_proc.c
> +++ b/sys/kern/kern_proc.c
> @@ -2252,7 +2252,7 @@ proc_get_binpath(struct proc *p, char *binname, char **retbuf,
> vp = p->p_textvp;
> if (vp == NULL) {
> PROC_UNLOCK(p);
> - *retbuf = NULL;
> + *retbuf = "";
> *freebuf = NULL;
> return (0);
> }
>
Interestingly, when I went to log out of KDE afer applying this patch
and rebuilding the kernel, it also paniced without VBox ruuning. The log
looks similar but the back-trace points to this possibility .. see
frames 8 through 10 .
__curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55
55 __asm("movq %%gs:%P1,%0" : "=r" (td) : "n"
(offsetof(struct pcpu,
(kgdb) #0 __curthread () at /usr/src/sys/amd64/include/pcpu_aux.h:55
#1 doadump (textdump=<optimized out>)
at /usr/src/sys/kern/kern_shutdown.c:399
#2 0xffffffff808cbac5 in kern_reboot (howto=260)
at /usr/src/sys/kern/kern_shutdown.c:487
#3 0xffffffff808cbedb in vpanic (fmt=<optimized out>,
ap=0xfffffe011c1858d0)
at /usr/src/sys/kern/kern_shutdown.c:920
#4 0xffffffff808cbd33 in panic (fmt=<unavailable>)
at /usr/src/sys/kern/kern_shutdown.c:844
#5 0xffffffff80ca920c in trap_fatal (frame=frame@entry=0xfffffe011c185ac0,
eva=0) at /usr/src/sys/amd64/amd64/trap.c:946
#6 0xffffffff80ca95af in trap_pfault
(frame=frame@entry=0xfffffe011c185ac0,
usermode=false, signo=<optimized out>, signo@entry=0x0,
ucode=<optimized out>, ucode@entry=0x0)
at /usr/src/sys/amd64/include/cpufunc.h:417
#7 0xffffffff80ca89bc in trap (frame=0xfffffe011c185ac0)
at /usr/src/sys/amd64/amd64/trap.c:443
#8 <signal handler called>
#9 strlen () at /usr/src/sys/amd64/amd64/support.S:751
#10 0xffffffff808b4d79 in sysctl_kern_proc_pathname (oidp=<optimized out>,
arg1=0xfffffe011c185d8c, arg2=<optimized out>, req=0xfffffe011c185cc0)
at /usr/src/sys/kern/kern_proc.c:2330
#11 0xffffffff808dc331 in sysctl_root_handler_locked (
oid=oid@entry=0xffffffff810cf0e0 <sysctl___kern_proc_pathname>,
arg1=arg1@entry=0xfffffe011c185d8c, arg2=arg2@entry=1,
req=0xfffffe011c185cc0, tracker=tracker@entry=0xfffffe011c185c38)
at /usr/src/sys/kern/kern_sysctl.c:185
After rebooting with this patch, I can now run a VBox VM without
provoking a panic. Thanks! :-)
Michael
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