Re: [Bugme-new] [Bug 15709] New: swapper page allocation failure

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Apr 22, 2010 at 01:31:06PM +0200, kernel wrote:
> Maybe some comments to my former mail about what I've done:
> I started with a fresh clone (deleted the old /usr/src/linux
> of course). 
> 
> git clone
> git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6.git linux
> 
> Then I started bisect
> 
> git bisect start 'v2.6.31' 'v2.6.30'
> 
> and build the first kernel and then marked kernels which
> "crashed" with "soft lockup" or "swapper page allocation failure"
> as bad and the other ones as good. Before I've compiled
> a new kernel I've always done a "make mrproper". I don't know
> if this is needed but thought it wouldn't hurt.
> 
> For me it was not clear that maybe I should have had stopped
> testing after the first commit that came up with a "swapper
> page allocation failure". It was only one commit which cased
> the allocation failure. All the other commits marked as bad
> came up with a soft lockup. But I thought it is important to
> find the earliest commit which crashes. So should I find out
> the commit with the allocation failure?

I think you did the right thing. We'll have to
figure out soft lockup thing, then if page allocation failure
turns out to be a different issue, look at it.

> As you requested I've now done now a
> 
> git checkout c02d7adf8c5429727a98bad1d039bccad4c61c50
> 
> which ended with a soft lockup within 3 min. after starting
> the VM (see
> https://bugzilla.kernel.org/attachment.cgi?id=26089&action=edit)
> with this kernel.

I'm not sure why the lockup backtrace does not show function names -
is the kernel stripped?

> 
> Then I've done a
> 
> git checkout cf8d2c11cb77f129675478792122f50827e5b0ae
> 
> compiled and restarted the VM with this kernel version
> (BTW: Of course I've always used the same .config for 
> all kernels I've build.). cf8d2c11cb77f129675478792122f50827e5b0ae
> is running fine.
> 
> Thanks!
> Robert

Well, so the soft lockup issue seems NFS-related?
Trond, commit cf8d2c11cb77f129675478792122f50827e5b0ae seems to
be causing problems on some old kernels (See bisect below). Any idea why?


> On Wed, 21 Apr 2010 12:42:49 +0300, "Michael S. Tsirkin" <mst@redhat.com>
> wrote:
> > On Wed, Apr 21, 2010 at 01:23:12PM +0200, kernel wrote:
> >> So after the compiler was running hot I've now the following result:
> >> 
> >> server10:/usr/src/linux # git bisect log 
> >> # bad: [74fca6a42863ffacaf7ba6f1936a9f228950f657] Linux 2.6.31
> >> # good: [07a2039b8eb0af4ff464efd3dfd95de5c02648c6] Linux 2.6.30
> >> git bisect start 'v2.6.31' 'v2.6.30'
> >> # good: [925d74ae717c9a12d3618eb4b36b9fb632e2cef3] V4L/DVB (11736):
> >> videobuf: modify return value of VIDIOC_REQBUFS ioctl
> >> git bisect good 925d74ae717c9a12d3618eb4b36b9fb632e2cef3
> >> # bad: [a380137900fca5c79e6daa9500bdb6ea5649188e] ixgbe: Fix device
> >> capabilities of 82599 single speed fiber NICs.
> >> git bisect bad a380137900fca5c79e6daa9500bdb6ea5649188e
> >> # good: [1dbb5765acc7a6fe4bc1957c001037cc9d02ae03] Staging: android:
> >> lowmemorykiller: fix up remaining checkpatch warnings
> >> git bisect good 1dbb5765acc7a6fe4bc1957c001037cc9d02ae03
> >> # good: [df36b439c5fedefe013d4449cb6a50d15e2f4d70] Merge branch
> >> 'for-2.6.31' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
> >> git bisect good df36b439c5fedefe013d4449cb6a50d15e2f4d70
> >> # bad: [a800faec1b21d7133b5f0c8c6dac593b7c4e118d] Merge branch
> >> 'for-linus'
> >> of git://www.jni.nu/cris
> >> git bisect bad a800faec1b21d7133b5f0c8c6dac593b7c4e118d
> >> # good: [ac1b7c378ef26fba6694d5f118fe7fc16fee2fe2] Merge
> >> git://git.infradead.org/mtd-2.6
> >> git bisect good ac1b7c378ef26fba6694d5f118fe7fc16fee2fe2
> >> # bad: [37c6dbe290c05023b47f52528e30ce51336b93eb] V4L/DVB (12091):
> >> gspca_sonixj: Add light frequency control
> >> git bisect bad 37c6dbe290c05023b47f52528e30ce51336b93eb
> >> # bad: [687d680985b1438360a9ba470ece8b57cd205c3b] Merge
> >> git://git.infradead.org/~dwmw2/iommu-2.6.31
> >> git bisect bad 687d680985b1438360a9ba470ece8b57cd205c3b
> >> # bad: [1053414068bad659479e6efa62a67403b8b1ec0a] Merge branch
> >> 'for-linus'
> >> of git://git.kernel.org/pub/scm/linux/kernel/git/ieee1394/linux1394-2.6
> >> git bisect bad 1053414068bad659479e6efa62a67403b8b1ec0a
> >> # good: [b01b4babbf204443b5a846a7494546501614cefc] firewire: net: fix
> >> card
> >> driver reloading
> >> git bisect good b01b4babbf204443b5a846a7494546501614cefc
> >> # bad: [c02d7adf8c5429727a98bad1d039bccad4c61c50] NFSv4: Replace
> >> nfs4_path_walk() with VFS path lookup in a private namespace
> >> git bisect bad c02d7adf8c5429727a98bad1d039bccad4c61c50
> >> # good: [616511d039af402670de8500d0e24495113a9cab] VFS: Uninline the
> >> function put_mnt_ns()
> >> git bisect good 616511d039af402670de8500d0e24495113a9cab
> >> # good: [cf8d2c11cb77f129675478792122f50827e5b0ae] VFS: Add VFS helper
> >> functions for setting up private namespaces
> >> git bisect good cf8d2c11cb77f129675478792122f50827e5b0ae
> >> 
> >> 
> >> The last "git bisect good" prints out:
> >> 
> >> server10:/usr/src/linux # git bisect good
> >> c02d7adf8c5429727a98bad1d039bccad4c61c50 is the first bad commit
> >> commit c02d7adf8c5429727a98bad1d039bccad4c61c50
> >> Author: Trond Myklebust <Trond.Myklebust@netapp.com>
> >> Date:   Mon Jun 22 15:09:14 2009 -0400
> >> 
> >>     NFSv4: Replace nfs4_path_walk() with VFS path lookup in a private
> >> namespace
> >>     
> >>     As noted in the previous patch, the NFSv4 client mount code
> currently
> >>     has several limitations. If the mount path contains symlinks, or
> >>     referrals, or even if it just contains a '..', then the client code
> >>     in
> >>     nfs4_path_walk() will fail with an error.
> >>     
> >>     This patch replaces the nfs4_path_walk()-based lookup with a helper
> >>     function that sets up a private namespace to represent the
> namespace
> >> on the
> >>     server, then uses the ordinary VFS and NFS path lookup code to walk
> >> down the
> >>     mount path in that namespace.
> >>     
> >>     Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
> >>     Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
> >> 
> >> :040000 040000 97a18818f26ab9a0987f157257eb6f399c3cc1cc
> >> 9ab6c712bb64f1349b5ac9f2020191abb5780ca0 M      fs
> >> 
> >> Does this help you any further?
> >> 
> >> Thanks!
> >> Robert
> > 
> > Looks suspiciously like some error in testing.
> > Could you pls retest and verify again that
> > cf8d2c11cb77f129675478792122f50827e5b0ae
> > is good and c02d7adf8c5429727a98bad1d039bccad4c61c50 is bad?

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