[Bengt Ahlgren] 8.3-PRERELEASE panic in linux emulation

[Bengt Ahlgren]

Konstantin Belousov <kostikbel at gmail.com> writes:

> On Fri, Feb 24, 2012 at 01:27:24PM +0100, Bengt Ahlgren wrote:
>> Hello!
>> 
>> Perhaps emulation@ is a better place to report this problem?
>> 
>> Bengt
>> 
>
>> From: Bengt Ahlgren <bengta at sics.se>
>> To: stable at freebsd.org
>> Subject: 8.3-PRERELEASE panic in linux emulation
>> Date: Thu, 23 Feb 2012 17:26:32 +0100
>> 
>> Hi!
>> 
>> I get a consistent panic when starting acroread after updating to
>> 8.3-PRERELEASE.  An 8.2-STABLE from Feb 4th was OK.  Can provide more
>> info if needed.
>> 
>> Bengt
>> 
>> FreeBSD xx.yy.zz 8.3-PRERELEASE FreeBSD 8.3-PRERELEASE #13 r231999: Wed Feb 22 21:01:38 CET 2012     bengta at P142.sics.se:/usr/obj/usr/src/sys/P142-82  i386
>> 
>> Fatal trap 12: page fault while in kernel mode
>> fault virtual address   = 0xbfbfdffc
>> fault code              = supervisor write, page not present
>> instruction pointer     = 0x20:0xc50b396c
>> stack pointer           = 0x28:0xe7481a6c
>> frame pointer           = 0x28:0xe7481a90
>> code segment            = base 0x0, limit 0xfffff, type 0x1b
>>                         = DPL 0, pres 1, def32 1, gran 1
>> processor eflags        = interrupt enabled, resume, IOPL = 0
>> current process         = 1997 (bash)
>> trap number             = 12
>> panic: page fault
>> KDB: stack backtrace:
>> db_trace_self_wrapper(c091af2a,70797420,78302065,a0d6231,c5d6b600,...) at db_trace_self_wrapper+0x26
>> kdb_backtrace(c0919061,c09b49a0,c0900251,e7481910,e7481910,...) at kdb_backtrace+0x2a
>> panic(c0900251,c0941cab,c5c246e8,1,1,...) at panic+0xaf
>> trap_fatal(c0670d02,0,e7481964,80400,c5c24580,...) at trap_fatal+0x353
>> trap_pfault(e74819cc,bfbfe190,c5c24580,202,c5cecac0,...) at trap_pfault+0x87
>> trap(e7481a2c) at trap+0x453
>> calltrap() at calltrap+0x6
>> --- trap 0xc, eip = 0xc50b396c, esp = 0xe7481a6c, ebp = 0xe7481a90 ---
>> elf_linux_fixup(e7481c0c,e7481b98,c065ca92,c60ffce8,100000,...) at elf_linux_fixup+0x33c
>> kern_execve(c5c24580,e7481c3c,0,8112710,8116cd8,...) at kern_execve+0x7d6
>> linux_execve(c5c24580,e7481cec,c,c,c,...) at linux_execve+0xa7
>> syscall(e7481d28) at syscall+0x372
>> Xint0x80_syscall() at Xint0x80_syscall+0x21
>> --- syscall (11, Linux ELF, linux_execve), eip = 0x281e0d4a, esp = 0xbfbfd644, ebp = 0xbfbfd7e8 ---
>> 
>> #0  doadump () at pcpu.h:244
>> #1  0xc05de609 in boot (howto=260) at /usr/src/sys/kern/kern_shutdown.c:441
>> #2  0xc05de84f in panic (fmt=Variable "fmt" is not available.
>> ) at /usr/src/sys/kern/kern_shutdown.c:614
>> #3  0xc08b22c3 in trap_fatal (frame=0xe7481a2c, eva=3217022972) at /usr/src/sys/i386/i386/trap.c:981
>> #4  0xc08b2357 in trap_pfault (frame=0xe7481a2c, usermode=0, eva=3217022972) at /usr/src/sys/i386/i386/trap.c:843
>> #5  0xc08b3133 in trap (frame=0xe7481a2c) at /usr/src/sys/i386/i386/trap.c:562
>> #6  0xc089bedc in calltrap () at /usr/src/sys/i386/i386/exception.s:168
>> #7  0xc50b396c in elf_linux_fixup (stack_base=0xe7481c0c, imgp=0xe7481b98) at /usr/src/sys/modules/linux/../../i386/linux/linux_sysvec.c:288
>> #8  0xc05ac636 in kern_execve (td=0xc5c24580, args=0xe7481c3c, mac_p=0x0) at /usr/src/sys/kern/kern_exec.c:551
>> #9  0xc50ab387 in linux_execve (td=0xc5c24580, args=0xe7481cec) at /usr/src/sys/modules/linux/../../i386/linux/linux_machdep.c:143
>> #10 0xc08b2902 in syscall (frame=0xe7481d28) at subr_syscall.c:114
>> #11 0xc089bf41 in Xint0x80_syscall () at /usr/src/sys/i386/i386/exception.s:266
>> #12 0x00000033 in ?? ()
>> 
> I am not sure if this is the real cause of your panic, but the line from
> the backtrace indeed has a bug. Please try the change below.
>
> diff --git a/sys/i386/linux/linux_sysvec.c b/sys/i386/linux/linux_sysvec.c
> index 7634138..d4e23e1 100644
> --- a/sys/i386/linux/linux_sysvec.c
> +++ b/sys/i386/linux/linux_sysvec.c
> @@ -227,11 +227,11 @@ linux_fixup(register_t **stack_base, struct image_params *imgp)
>  	argv = *stack_base;
>  	envp = *stack_base + (imgp->args->argc + 1);
>  	(*stack_base)--;
> -	**stack_base = (intptr_t)(void *)envp;
> +	suword(*stack_base, (intptr_t)(void *)envp);
>  	(*stack_base)--;
> -	**stack_base = (intptr_t)(void *)argv;
> +	suword(*stack_base, (intptr_t)(void *)argv);
>  	(*stack_base)--;
> -	**stack_base = imgp->args->argc;
> +	suword(*stack_base, imgp->args->argc);
>  	return (0);
>  }
>  
> @@ -286,7 +286,7 @@ elf_linux_fixup(register_t **stack_base, struct image_params *imgp)
>  	imgp->auxargs = NULL;
>  
>  	(*stack_base)--;
> -	**stack_base = (register_t)imgp->args->argc;
> +	suword(*stack_base, (register_t)imgp->args->argc);
>  	return (0);
>  }
>  

Thanks for the response!  I will try the patch, but that file has not
been touched since June 2011.  I was suspecting the changes in r231146
and r231148.  If there is no change with your patch I will roll back
those to see what happens.

Bengt