Date: Thu, 12 Jul 2012 21:33:26 -0400 From: Justin Hibbits <chmeeedalf@gmail.com> To: mdf@freebsd.org Cc: freebsd-current <freebsd-current@freebsd.org>, FreeBSD PowerPC ML <freebsd-ppc@freebsd.org> Subject: Re: panic with DEBUG_MEMGUARD on PowerPC Message-ID: <307005B6-C8E5-4DCF-BD10-6BC79D8C2FE3@gmail.com> In-Reply-To: <CAMBSHm-5Xix46MaYAwBek6hWvcOHZ7%2BR_4cpdG5SH_5RD7difQ@mail.gmail.com> References: <A3CD63CD-694A-48F5-B0F7-9C8923AFCB90@gmail.com> <CAMBSHm-5Xix46MaYAwBek6hWvcOHZ7%2BR_4cpdG5SH_5RD7difQ@mail.gmail.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Jul 12, 2012, at 9:11 PM, mdf@freebsd.org wrote: > On Thu, Jul 12, 2012 at 4:43 PM, Justin Hibbits > <chmeeedalf@gmail.com> wrote: >> When tracking down a panic exposed by INVARIANTS, I tried setting >> DEBUG_MEMGUARD, so I could find the culprit that's trashing freed >> memory. >> However, this causes a panic at bootup. It shows up right after >> the first >> WARNING: WITNESS message, with the following: >> >> panic: kmem_suballoc: bad status return of 3 >> cpuid = 0 >> KDB: stack backtrace: >> 0xd0004ad0: at kdb_backtrace+0x4c >> 0xd0004b40: at panic+0x224 >> 0xd0004ba0: at kmem_suballoc+0x8c >> 0xd0004bd0: at kmeminit+0x1ac >> 0xd0004c20: at mi_startup+0x13c >> 0xd0004c50: at btext+0xc0 >> >> Tracing, and printf() debugging, I see arguments to >> vm_map_findspace(): >> start: 0xD0000000, length: 4246446080, and map->max_offset = >> 4026531839. >> >> Beyond that, I'm lost with tracking this down. Machine is a dual >> processor >> PowerPC G4, with 2GB RAM. > > The length is 0xFD1BA000 which is almost 4GB. Asking for 4GB of > virtual space for 2GB of RAM sounds about right (it's been a while > since I was in this code), unless this is a 32-bit kernel, in which > case it'd be too much since there isn't that much virtual space > available. > > So, is the kernel 32-bit? What are the values used and returned by > memguard_fudge()? The intent of that routine is to get kmeminit() to > allocate a larger map so memguard can use part of it for private > virtual addresses. But it shouldn't be asking for "too much"; i.e. > the intent was to check both physical and virtual space available and > be greedy, but not too greedy. > > There were some issues with that code for some platforms that e.g. > didn't define a VM_KMEM_SIZE_MAX, but alc@ fixed that in r216425. > > Thanks, > matthew It is a 32-bit kernel, on 32-bit hardware. The values for memguard_fudge are (defaults): tmp: 4246446080, vm_kmem_size: 117440512, vm_kmem_size_max: 0 When setting vm.kmem_size/vm.kmem_size_max to 2GB they are: tmp: 2147483648, vm_kmem_size: 214793648, vm_kmem_sizee_max: 2147483648 (all 2GB). But the start and map->max_offset remain the same on all runs I make. - Justin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?307005B6-C8E5-4DCF-BD10-6BC79D8C2FE3>