Date: Tue, 26 Feb 2013 01:49:42 -0600 From: Alan Cox <alc@rice.edu> To: Andrew Turner <andrew@fubar.geek.nz> Cc: Konstantin Belousov <kostikbel@gmail.com>, svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, John Baldwin <jhb@FreeBSD.org> Subject: Re: svn commit: r247116 - in head/sys: fs/nfs fs/nfsclient kern nfsclient sys tools Message-ID: <512C6916.5010608@rice.edu> In-Reply-To: <20130226202707.026ad226@bender> References: <201302211902.r1LJ2o5T033708@svn.freebsd.org> <20130225201313.2050da18@bender> <20130225085019.GU2454@kib.kiev.ua> <20130225233603.49a5d4a5@bender> <8006325C-B281-4F4D-BE1A-C3B444FE979F@rice.edu> <20130226202707.026ad226@bender>
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On 02/26/2013 01:27, Andrew Turner wrote: > On Mon, 25 Feb 2013 15:00:41 -0600 > Alan Cox <alc@rice.edu> wrote: > >> On Feb 25, 2013, at 4:36 AM, Andrew Turner wrote: >> >>> On Mon, 25 Feb 2013 10:50:19 +0200 >>> Konstantin Belousov <kostikbel@gmail.com> wrote: >>> >>>> On Mon, Feb 25, 2013 at 08:13:13PM +1300, Andrew Turner wrote: >>>>> On Thu, 21 Feb 2013 19:02:50 +0000 (UTC) >>>>> John Baldwin <jhb@FreeBSD.org> wrote: >>>>> >>>>>> Author: jhb >>>>>> Date: Thu Feb 21 19:02:50 2013 >>>>>> New Revision: 247116 >>>>>> URL: http://svnweb.freebsd.org/changeset/base/247116 >>>>>> >>>>>> Log: >>>>>> Further refine the handling of stop signals in the NFS client. >>>>>> The changes in r246417 were incomplete as they did not add >>>>>> explicit calls to sigdeferstop() around all the places that >>>>>> previously passed SBDRY to _sleep(). In addition, >>>>>> nfs_getcacheblk() could trigger a write RPC from getblk() >>>>>> resulting in sigdeferstop() recursing. Rather than manually >>>>>> deferring stop signals in specific places, change the VFS_*() and >>>>>> VOP_*() methods to defer stop signals for filesystems which >>>>>> request this behavior via a new VFCF_SBDRY flag. Note that this >>>>>> has to be a VFC flag rather than a MNTK flag so that it works >>>>>> properly with VFS_MOUNT() when the mount is not yet fully >>>>>> constructed. For now, only the NFS clients are set this new flag >>>>>> in VFS_SET(). A few other related changes: >>>>>> - Add an assertion to ensure that TDF_SBDRY doesn't leak to >>>>>> userland. >>>>>> - When a lookup request uses VOP_READLINK() to follow a symlink, >>>>>> mark the request as being on behalf of the thread performing the >>>>>> lookup (cnp_thread) rather than using a NULL thread pointer. >>>>>> This causes NFS to properly handle signals during this VOP on an >>>>>> interruptible mount. >>>>>> >>>>>> PR: kern/176179 >>>>>> Reported by: Russell Cattelan (sigdeferstop() recursion) >>>>>> Reviewed by: kib >>>>>> MFC after: 1 month >>>>> This change is causing init to crash for me on armv6. I'm >>>>> netbooting a PandaBoard and it appears init is receiving a SIGABRT >>>>> before it gets into main(). >>>>> >>>>> Do you have any idea where I could look to track down why it is >>>>> doing this? >>>> It is weird. SIGABRT sent by the kernel usually means that >>>> execve(2) already destroyed the previous address space of the >>>> process, but the new image cannot be activated, most likely due to >>>> image format error discovered too late, or resource shortage. >>>> >>>> Could it be that some NFS RPC fails after the patch, but I cannot >>>> imagine why. You would need to track this. Also, verify that the >>>> init binary is correct. >>>> >>>> I tried amd64 netboot, and it worked fine. >>> It looks like this change is not the issue, it just changed the >>> symptom enough for me to not realise I was seeing an issue where >>> it would crash the kernel before. I reinstated this change but only >>> allowed the kernel to access half the memory and it booted >>> correctly. >>> >>> The real issue appears to be related to something in the vm layer >>> not working on ARM boards with too much memory (somewhere between >>> 512MiB and 1GiB). >> >> The recently introduced auto-sizing and cap may be too optimistic. >> In fact, they are greater than what we allow on 32-bit x86 and 32-bit >> MIPS. Try the following. >> >> Index: arm/include/vmparam.h >> =================================================================== >> --- arm/include/vmparam.h (revision 247249) >> +++ arm/include/vmparam.h (working copy) >> @@ -142,15 +142,15 @@ >> #define VM_KMEM_SIZE (12*1024*1024) >> #endif >> #ifndef VM_KMEM_SIZE_SCALE >> -#define VM_KMEM_SIZE_SCALE (2) >> +#define VM_KMEM_SIZE_SCALE (3) >> #endif >> >> /* >> - * Ceiling on the size of the kmem submap: 60% of the kernel map. >> + * Ceiling on the size of the kmem submap: 40% of the kernel map. >> */ >> #ifndef VM_KMEM_SIZE_MAX >> #define VM_KMEM_SIZE_MAX ((vm_max_kernel_address - \ >> - VM_MIN_KERNEL_ADDRESS + 1) * 3 / 5) >> + VM_MIN_KERNEL_ADDRESS + 1) * 2 / 5) >> #endif >> >> #define MAXTSIZ (16*1024*1024) >> > This patch fixes the boot for me. Is it likely we will see similar > issues with boards with more memory with this? I know of ARM boards > with 2GiB of ram, and I would expect to see some with more soon. > The kmem submap should be fine, but other things might become a problem. What do "sysctl -x vm.min_kernel_address" and "sysctl -x vm.max_kernel_address" report on your machine? Alan
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