Bart and I worked through this some off-list and found the problem. The
fix is in cvs trunk now, but I attached the patch in case anyone needs it.
There was an off by one error in a path length test that could cause a
buffer overrun when attempting to access file names that are too long.
I'm not sure what kernel versions it affected. I did not see any side
affects from the bug on newer kernels, but I haven't confirmed if the
vfs added a generic check for this or if I was just lucky. The rhel4
2.6.9 kernel can definitely trigger this condition.
-Phil
Bart Taylor wrote:
It did not seem to make a difference. I do not see any log message,
client or kernel, that indicate what is happening. The pvfs2-client-core
does die after the long file name commands run though.
Bart.
On Mon, Jun 30, 2008 at 2:10 PM, Phil Carns <[EMAIL PROTECTED]
<mailto:[EMAIL PROTECTED]>> wrote:
Hi Bart,
Does the attached patch help this issue any?
-Phil
Phil Carns wrote:
Hi Bart,
I can't get those specific commands to cause a problem for me
(using trunk at least, I haven't tried 2.7.1 yet). However, I
definitely see some problems in LTP. For me it eventually hangs
on the rename06 test, but valgrind is complaining about some
memory problems in the pvfs2-client-core symlink path as well
before reaching that point.
I'll look into it and let you know what turns up.
I might also see if I can cook up a script to include LTP in our
nightly tinderbox builds as well; there are some good tests in here.
-Phil
Bart Taylor wrote:
Hello all,
I have run into a few problems when running some tests
against the 2.7.1 release on RHEL4. They all seem to hinge
around large file names of 256 characters or greater. The
commands fail gracefully - reporting an error that the file
names are too long - but the next access of PVFS (an 'ls'
for instance) hangs the system so that it has to be
rebooted. I ran into them using the LTP test suite, but they
can be reliably repeated with simple commands. Create, open,
rename, and stat are the operations that fail, and some
example commands are provided below. The file does not need
to exist for the open or stat commands. Occasionally it
takes a few seconds after command has been executed for the
problem to show itself. Do these commands cause problems for
anyone else, or is it something unique to my setup or
environment?
Bart.
create: $echo "Hello World" >
1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456
open: $cat
1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456
rename: $mv test.file
1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456
stat: $stat -f
/mnt/pvfs2/test/1234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456
------------------------------------------------------------------------
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? src/kernel/linux-2.6/pvfs2-utils.c.backup
Index: src/kernel/linux-2.6/namei.c
===================================================================
RCS file: /projects/cvsroot/pvfs2-1/src/kernel/linux-2.6/namei.c,v
retrieving revision 1.83
diff -a -u -p -r1.83 namei.c
--- src/kernel/linux-2.6/namei.c 9 Oct 2007 23:02:35 -0000 1.83
+++ src/kernel/linux-2.6/namei.c 18 Jul 2008 19:51:00 -0000
@@ -81,7 +81,7 @@ static struct dentry *pvfs2_lookup(
*/
gossip_debug(GOSSIP_NAME_DEBUG, "pvfs2_lookup called on %s\n", dentry->d_name.name);
- if (dentry->d_name.len > PVFS2_NAME_LEN)
+ if (dentry->d_name.len > (PVFS2_NAME_LEN-1))
{
return ERR_PTR(-ENAMETOOLONG);
}
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