10.0 BETA 3 with redports kernel panic

[Sean Bruno]

On Fri, 2013-12-20 at 18:22 +0200, Konstantin Belousov wrote:
> On Fri, Dec 20, 2013 at 07:45:55AM -0800, Sean Bruno wrote:
> > With this change to pmap.c we blow up in keg_alloc_slab() now:
> > 
> > FreeBSD clang version 3.3 (tags/RELEASE_33/final 183502) 20130610
> > kernel trap 12 with interrupts disabled
> > 
> > 
> > Fatal trap 12: page fault while in kernel mode
> > cpuid = 0; apic id = 00
> > fault virtual address	= 0x8
> > fault code		= supervisor write data, page not present
> > instruction pointer	= 0x20:0xffffffff80b2602a
> > stack pointer	        = 0x28:0xffffffff81a90a50
> > frame pointer	        = 0x28:0xffffffff81a90ac0
> > code segment		= base 0x0, limit 0xfffff, type 0x1b
> > 			= DPL 0, pres 1, long 1, def32 0, gran 1
> > processor eflags	= resume, IOPL = 0
> > current process		= 0 ()
> > [ thread pid 0 tid 0 ]
> > Stopped at      keg_alloc_slab+0x13a:   movq    %r13,0x8(%rax)
> > db> whe
> > Tracing pid 0 tid 0 td 0xffffffff81527500
> > keg_alloc_slab() at keg_alloc_slab+0x13a/frame 0xffffffff81a90ac0
> > keg_fetch_slab() at keg_fetch_slab+0x152/frame 0xffffffff81a90b10
> > zone_fetch_slab() at zone_fetch_slab+0x7e/frame 0xffffffff81a90b50
> > zone_import() at zone_import+0x3c/frame 0xffffffff81a90b90
> > uma_zalloc_arg() at uma_zalloc_arg+0x33e/frame 0xffffffff81a90c10
> > malloc() at malloc+0x6a/frame 0xffffffff81a90c60
> > init_dynamic_kenv() at init_dynamic_kenv+0x8d/frame 0xffffffff81a90c90
> > mi_startup() at mi_startup+0x118/frame 0xffffffff81a90cb0
> > btext() at btext+0x2c
> > db> bt
> > Tracing pid 0 tid 0 td 0xffffffff81527500
> > keg_alloc_slab() at keg_alloc_slab+0x13a/frame 0xffffffff81a90ac0
> > keg_fetch_slab() at keg_fetch_slab+0x152/frame 0xffffffff81a90b10
> > zone_fetch_slab() at zone_fetch_slab+0x7e/frame 0xffffffff81a90b50
> > zone_import() at zone_import+0x3c/frame 0xffffffff81a90b90
> > uma_zalloc_arg() at uma_zalloc_arg+0x33e/frame 0xffffffff81a90c10
> > malloc() at malloc+0x6a/frame 0xffffffff81a90c60
> > init_dynamic_kenv() at init_dynamic_kenv+0x8d/frame 0xffffffff81a90c90
> > mi_startup() at mi_startup+0x118/frame 0xffffffff81a90cb0
> > btext() at btext+0x2c
> > 
> 
> This could be related, indeed.
> 
> Lets limit the impact to the /dev/{,k}mem only.  Please try this.
> 
> diff --git a/sys/amd64/amd64/mem.c b/sys/amd64/amd64/mem.c
> index abbbb21..2a9b7c1 100644
> --- a/sys/amd64/amd64/mem.c
> +++ b/sys/amd64/amd64/mem.c
> @@ -98,7 +98,11 @@ memrw(struct cdev *dev, struct uio *uio, int flags)
>  kmemphys:
>  			o = v & PAGE_MASK;
>  			c = min(uio->uio_resid, (u_int)(PAGE_SIZE - o));
> -			error = uiomove((void *)PHYS_TO_DMAP(v), (int)c, uio);
> +			v = PHYS_TO_DMAP(v);
> +			if (v < DMAP_MIN_ADDRESS || v >= dmaplimit ||
> +			    pmap_kextract(v) == 0)
> +				return (EFAULT);
> +			error = uiomove((void *)v, (int)c, uio);
>  			continue;
>  		}
>  		else if (dev2unit(dev) == CDEV_MINOR_KMEM) {
> diff --git a/sys/amd64/amd64/pmap.c b/sys/amd64/amd64/pmap.c
> index 014020b..13404b0 100644
> --- a/sys/amd64/amd64/pmap.c
> +++ b/sys/amd64/amd64/pmap.c
> @@ -321,7 +321,7 @@ SYSCTL_INT(_machdep, OID_AUTO, nkpt, CTLFLAG_RD, &nkpt, 0,
>      "Number of kernel page table pages allocated on bootup");
>  
>  static int ndmpdp;
> -static vm_paddr_t dmaplimit;
> +vm_paddr_t dmaplimit;
>  vm_offset_t kernel_vm_end = VM_MIN_KERNEL_ADDRESS;
>  pt_entry_t pg_nx;
>  
> diff --git a/sys/amd64/include/pmap.h b/sys/amd64/include/pmap.h
> index 3918282..e83e07e 100644
> --- a/sys/amd64/include/pmap.h
> +++ b/sys/amd64/include/pmap.h
> @@ -369,6 +369,7 @@ extern vm_paddr_t phys_avail[];
>  extern vm_paddr_t dump_avail[];
>  extern vm_offset_t virtual_avail;
>  extern vm_offset_t virtual_end;
> +extern vm_paddr_t dmaplimit;
>  
>  #define	pmap_page_get_memattr(m)	((vm_memattr_t)(m)->md.pat_mode)
>  #define	pmap_page_is_write_mapped(m)	(((m)->aflags & PGA_WRITEABLE) != 0)



Ok, we can boot again.  System is up at this time and running.

sean