I suppose another question related to the first, is 'limit' checking
part of the 'standard linux security' that embedded Linux users might
find to be a waste of precious code-space?
-l
--
The above thoughts and| I know I don't know the opinions
writings are my own. | of
I've seen some people saying that user-limits are an essential part of a
secure system to prevent local DoS attacks. Given that, should
a system call like 'fork' return -EPERM if the user has reached their
limit?
My local manpage (SuSE 7.2 system) says this under fork:
ERRORS
EAGAIN fork
"Eric W. Biederman" wrote:
> LA Walsh <[EMAIL PROTECTED]> writes:
>
> > Now for whatever reason, since 2.4, I consistently use at least
> > a few Mb of swap -- stands at 5Meg now. Weird -- but I notice things
> > like nscd running 7 copies that
"Eric W. Biederman" wrote:
> There are cetain scenario's where you can't avoid virtual mem =
> min(RAM,swap). Which is what I was trying to say, (bad formula). What
> happens is that pages get referenced evenly enough and quickly enough
> that you simply cannot reuse the on disk pages. Basical
"Eric W. Biederman" wrote:
> The hard rule will always be that to cover all pathological cases swap
> must be greater than RAM. Because in the worse case all RAM will be
> in thes swap cache. That this is more than just the worse case in 2.4
> is problematic. I.e. In the worst case:
> Virtual
Marcus Meissner wrote:
> $ ln -s fupp/bar bar
> $ ls -la bar
---
Is it peculiar to a specific architecture?
What does strace show for args to the symlink cmd?
-l
--
The above thoughts and | They may have nothing to do with
writings are my own. | the opinions of my e
I've been seeing these for a while now (2.4.4 - <=2.4.2) also coincidental
with a change to XFree86 X 4.0.3 from "MetroX" in the time frame. Am not sure
exactly when they started but was wondering if they were significant. It
seems some app is trying to delete or modify something. On console an
"Mohammad A. Haque" wrote:
> This was answered several hours ago. Check the list archives.
---
Many thanks -- it was in my neverending backlog
-l
-
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In 2.4.4, the define, in
include/linux/skbuff.h
and corresponding structure in
net/core/skbuff.c
, "skb_datarefp" disappeared.
I'm not reporting this as a 'bug' as kernel internal interfaces are subject
to change, but more as an "FYI". I haven't had a chance to try to
debug or figure out
Rik van Riel wrote:
> On Fri, 27 Apr 2001, LA Walsh wrote:
>
> > An interesting option (though with less-than-stellar performance
> > characteristics) would be a dynamically expanding swapfile. If you're
> > going to be hit with swap penalties, it may be
Rogier Wolff wrote:
> > > On Linux any swap adds to the memory pool, so 1xRAM would be
> > > equivalent to 2xRAM with the old old OS's.
> >
> > no more true AFAIK
>
> I've always been trying to convice people that 2x RAM remains a good
> rule-of-thumb.
---
Ug. I like to view swap as "low gr
Andrzej Krzysztofowicz wrote:
> I know a few people that often do:
>
> dd if=/dev/hda1 of=/dev/hdc1
> e2fsck /dev/hdc1
>
> to make an "exact" copy of a currently working system.
---
Presumably this isn't a problem is the source disks are either unmounted or
mounted 'read-only' ?
--
The ab
Quim K Holland wrote:
>
> > "BS" == BERECZ Szabolcs <[EMAIL PROTECTED]> writes:
>
> BS> ... a setiathome running at nice level 19, and a bladeenc at
> BS> nice level 0. setiathome uses 14 percent, and bladeenc uses
> BS> 84 percent of the processor. I think, setiathome should use
> BS> max 2
Andreas Schwab wrote:
> Don't use kernel headers in user programs. Just use syscall(3).
>
> Andreas.
---
I'm on a SuSE71 system and have all the manpages installed:
law> man syscall
No manual entry for syscall
The problem is not so much for user programs as library
writers that
I have a question. Some architectures have "system calls"
implemented as library calls (calls that are "system calls" on ia32)
For example, the expectation on 'arm', seems to be that sys_sync
is in a library. On alpha, sys_open appears to be in a library.
Is this correct?
Is it
Jan Harkes wrote:
>
> On Tue, Mar 27, 2001 at 01:57:42PM -0600, Jesse Pollard wrote:
> > > Using similar numbers as presented. If we are working our way through
> > > every single block in a Pentabyte filesystem, and the blocksize is 512
> > > bytes. Then the 1us in extra CPU cycles because of 64
Ion Badulescu wrote:
> Are you being deliberately insulting, "L", or are you one of those users
> who bitch and scream for features they *need* at *any cost*, and who
> have never even opened up the book for Computer Architecture 101?
---
Sorry, I was borderline insulting. I'm getting pre
Manfred Spraul wrote:
> Which field do you access? bh->b_blocknr instead of bh->r_sector?
---
Yes.
>
> There were plans to split the buffer_head into 2 structures: buffer
> cache data and the block io data.
> b_blocknr is buffer cache only, no driver should access them.
---
My 'de
Manfred Spraul wrote:
>
> >4k page size * 2GB = 8TB.
>
> Try it.
> If your drive (array) is larger than 512byte*4G (4TB) linux will eat
> your data.
---
I have a block device that doesn't use 'sectors'. It
only uses the logical block size (which is currently set for
1K). Seems I could
Matthew Wilcox wrote:
>
> On Mon, Mar 26, 2001 at 08:39:21AM -0800, LA Walsh wrote:
> > I vaguely remember a discussion about this a few months back.
> > If I remember, the reasoning was it would unnecessarily slow
> > down smaller systems that would never have block
I vaguely remember a discussion about this a few months back.
If I remember, the reasoning was it would unnecessarily slow
down smaller systems that would never have block devices in
the 4-28T range attached.
However, isn't it possible there will continue to be a series
of P-IV,V,VI,VII ...etc,
Here is the 'alternate' output when the ncr53c8xx driver is
compiled in:
SCSI subsystem driver Revision: 1.00
scsi-ncr53c7,8xx : at PCI bus 0, device 8, function 0
scsi-ncr53c7,8xx : warning : revision of 35 is greater than 2.
scsi-ncr53c7,8xx : NCR53c810 at memory 0xfa101000, io 0x2000, irq 58
s
I have a machine with 3 of these controllers (a 4 CPU server). The
3 controllers are:
ncr53c810a-0: rev=0x23, base=0xfa101000, io_port=0x2000, irq=58
ncr53c810a-0: ID 7, Fast-10, Parity Checking
ncr53c896-1: rev=0x01, base=0xfe004000, io_port=0x3000, irq=57
ncr53c896-1: ID 7, Fast-40, Parity Chec
The not reclaiming swap space is flawed in more than once instance.
Suppose my P1 and P2 have their swap reserved -- now both grow.
P3 is idle but can't fit in swap. This is going to result in fragmentation
no? How is this fragmentation less worse than just freeing swap.
Ever since Ram sizes go
Alexander Viro wrote:
> No such thing. The same fs may be present in many places. Please,
> describe the situation - where do you get that dentry from?
> Cheers,
> Al
---
Al,
Could someone enlighten me as to the purpose of this field in the
dentry struct? There is no elucidating comment in the header for this
particular field and the name/type only indicate it is pointing to
a list of vfsmounts. Can a dentry belong to more than one vfsmount?
If I have a 'dentry' and
I hate when that happens...
LA Walsh wrote:
> If you ask for code from me, it'll be a while -- My read and write
...Q's are rather full right now with some higher priority I/O...:-)
-l
--
L A Walsh| Trust Technology, Core Linux, SGI
[EM
I have a few comments/questions on the elv. alg. as it is now. Some
of them may be based on a flawed understanding, but please be patient
anyway :-).
1) read-ahead is given the same 'latency' [max-wait priority] as 'read'
I can see r-a as being less important than 'read' -- 'read' means
so
Why doesn't setfsuid return -EPERM when it can't perform the operation?
file: kernel/sys.c, 'sys_setfsuid' around line 779 depending on your
source version.
There is a check if capable(CAP_SETUID), that if it fails, doesn't
return an error. This seems inconsistent. In fact the manpage
I have on
Alan Cox wrote:
>
> > support to function efficiently -- perhaps that technology needs to be further
>developed
> > on Linux so app writers don't also have to be kernel experts and experts in all the
> > various bus and device types out there?
>
> You mean someone should write a libcdrom that h
Alan Cox wrote:
>
> > Then it seems the less ideal question is what is the "approved and
>recommended
> > way for a program to "poll" such devices to check for 'changes' and 'media type'
> > without the kernel generating spurious WARNINGS/ERRORS?
>
> The answer to that could probably fill
God wrote:
>
> On Mon, 5 Mar 2001, Alan Cox wrote:
>
> > > > this isnt a kernel problem, its a _very_ stupid app
> > > ---
> > > Must be more than one stupid app...
> >
> > Could well be. You have something continually trying to open your cdrom and
> > see if there is media in it
>
> Gnome
Alan Cox wrote:
>
> > > this isnt a kernel problem, its a _very_ stupid app
> > ---
> > Must be more than one stupid app...
>
> Could well be. You have something continually trying to open your cdrom and
> see if there is media in it
---
Is there some feature they *should* be using
LA Walsh wrote:
>
> > this isnt a kernel problem, its a _very_ stupid app
> ---
> Must be more than one stupid app...
>
> xena:/var/log# rpm -q magicdev
> package magicdev is not installed
> xena:/var/log# locate magicdev
> xena:/var/log#
> xena
> this isnt a kernel problem, its a _very_ stupid app
---
Must be more than one stupid app...
xena:/var/log# rpm -q magicdev
package magicdev is not installed
xena:/var/log# locate magicdev
xena:/var/log#
xena:/var/log# rpm -qa |grep -i magic
ImageMagick-5.2.6-4
--
L A Walsh
Slightly less annoying -- when no CD is in the drive, I'm getting:
Mar 5 09:30:42 xena kernel: VFS: Disk change detected on device ide1(22,0)
Mar 5 09:31:17 xena last message repeated 7 times
Mar 5 09:32:18 xena last message repeated 12 times
Mar 5 09:33:23 xena last message repeated 13 time
I have a music play program (freeamp) playing MP3's running. It has the
feature in that it scans to see if a CD is in the drive and tries to look it up
in CDDB. Well, I don't have a CD in the drive -- I have a DVD-ROM with UDF file
system on it. Freeamp doesn't complain, but in my syslog/warnin
I have a kernel driver that has a variable (surprise) 'audit_state'. It's statically
initialized to 0 in the C code. The only way it can get set on is if the audit modules
are loaded and one makes a system call to enable it.
There is no 'driver' initialization performed.
This code seemed to wo
A problem that I seem to have noticed to some extent or another in the 2.4 series
is that while the elevator algorithm may achieve best disk bandwidth utilization,
it seems to be heavily at the expense of interactive use.
I was running a disk intensive program over nfs, so the nfsd's were quite b
"David D.W. Downey" wrote:
>
> Seriously though folks, look at who's doing this!
>
> They've already tried once to sue 'Linux', were told they couldn't because
> Linux is a non-entity (or at least one that they can not effectively sue
> due to the classification Linux holds), ...
---
Not
I'm wondering about the possibility of re-examining the idea of a kernel debugger
option distributed with 2.4.
I'm thinking that it could be a great teaching tool to break and examine structures,
variables, process states, as well as an aid to people who may not have a grasp
of the entire kerne
I have a block driver I inherited that I working on that has a problem and
was wondering for cleaner solutions.
The driver can accept written characters from either userspace programs or from
the kernel. From userspace it uses sys_write. That in turn calls block_write.
There's almost 100 lines
Excuse my ignorance, but in file include/linux/fs.h, 2.4.x source
in the struct buffer_head, there is a member:
unsigned short b_size; /* block size */
later there is a member:
char * b_data; /* pointer to data block (512 byte) */
Is the "(512 byte)"
Another oddity -- I notice things taking alot more memory
in 2.4. This coincides with 'top' consistently showing I have 0 shared
memory. These two observations would have me wondering if I
have somehow misconfigured my system to disallow sharing. Note
that /proc/meminfo also shows 0 shared mem
In trying to apply Jens's patch I upgraded to 2.4.2-pre1. The figures on it(242-p1)
look
better at this point: a vmstat dump, same data...notice this time it only took maybe 45
seconds to write out the data. I also got better interactive performance.
So write speed is up to about 3.5Mb/s. Fast
Alan Cox wrote:
> But try 2.4.1 before worrying too much. That fixed a lot of the block
> performance problems I was seeing (2.4.1 ruins the VM performance under paging
> loads but the I/O speed is fixed ;))
---
Seems to have gotten a bit worse. Vmstat output after 'vmware' had completed
I've noticed less responsive disk response on 2.4.0 vs. 2.2.17. For example --
I run vmware and suspend it frequently when I'm not using it. One of them requires
a 158Mb save file. Before, I could suspend that one, then start another which
reads in a smaller 50M save file. The smaller one woul
Keith Owens wrote:
>
> On Wed, 31 Jan 2001 19:02:03 -0800,
> LA Walsh <[EMAIL PROTECTED]> wrote:
> >This seems to serialize the delete, run the mod-installs in parallel, then run the
> >depmod when they are done.
>
> It works, until somebody does this
>
Keith Owens wrote:
>
> The only bit that could run in parallel is this one.
>
> .PHONY: $(patsubst %, _modinst_%, $(SUBDIRS))
> $(patsubst %, _modinst_%, $(SUBDIRS)) :
> $(MAKE) -C $(patsubst _modinst_%, %, $@) modules_install
>
> The erase must be done first (serial), then make modules_
I remember reading some time back that on a pentium the difference between a
pentium in HLT vs. running was about 2-3 watts vs. 15-20 watts. Does anyone
know the difference for today's CPU's? P-III/P-IV or other archs?
How about the difference when calling the BIOS power-save feature? With
the
Try "freeamp". It uses darn close to 0 CPU and may not be affected by setiathome.
2nd -- renice setiathome to '19' -- you only want it to use up 'background' cputime
anyway
Rainer Wiener wrote:
>
> Hi,
>
> I hope you can help me. I have a problem with my on board soundcard and
> seti
This seems to have fixed the 66% slowdown -- disk speeds w/hdparm. They are
reading in the same range.
For others -- my problem was that I upgraded from a 2.2.x config -- I
thought 'make xconfig' would add additional new params as needed as
'make config' does. Guess I thought wrong.
Thanks,
I decided put 2.4 on my laptop. After getting config issues seemingly
sorted out, still have some things I can't explain. VMware seems to run
about 30% slower. X was even sluggish at times. When I'm doing 'nothing',
top shows about 67% IDLE and 30% in 'system time'. I notice that
the process
FYI -
Another use sendfile(2) might be used for. Suppose you were to generate
large amounts of data -- maybe kernel profiling data, audit data, whatever,
in the kernel.
You want to pull that data out as fast as possible and write it to
a disk or network socket. Normally, I think
> From: Werner Almesberger [mailto:[EMAIL PROTECTED]]
> Sent: Friday, December 15, 2000 1:21 PM
> I don't think restructuring the headers in this way would cause
> a long period of instability. The main problem seems to be to
> decide what is officially private and what isn't.
---
If someo
> From: Werner Almesberger [mailto:[EMAIL PROTECTED]]
>
> I think there are three possible directions wrt visibility of kernel
> headers:
>
> - non at all - anything that needs kernel headers needs to provide them
>itself
> - kernel-specific extentions only; libc is self-contained, but user
> Huh?
> % ls -ld /usr/include/linux
> drwxr-xr-x6 root root18432 Sep 2 22:35
> /usr/include/linux/
>
> > So if we create a separate /usr/src/linux/include/kernel dir, does that
> > imply that we'll have a 2nd link:
>
> What 2nd link? There should be _no_ links from /usr/include t
So, I brought up the idea of a linux/sys for kernel level include files.
A few other people came up with a desire of a 'kernel' dir under
include, parallel w/linux.
So I ran into a snag with that scenario. Let's suppose we have
a module developer or a company developing a driver in their own
/
Linus has mentioned a desire to move kernel internal interfaces into
a separate kernel include directory. In creating some code, I'm wondering
what the name of this should/will be. Does it follow that convention
would point toward a linux/sys directory?
-l
--
L A Walsh|
Again, the math
says it's a rate near 5. So it still doesn't make sense.
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Andries Brouwer
> Sent: Monday, November 13, 2000 4:59 PM
> To: LA Walsh
> Cc: lkml
> Subject:
According to hdparm, dma was already on. It was also suggested I try
setting
32-bit mode and multcount (which I had tried before and not noticed much
difference).
Here's the current settings and results. Note that the timings still don't
make
alot of sense when comparing them to the vmstat numbe
cks/sec. Again, the
math
says it's a rate near 5m/s. So it still doesn't make sense.
> -Original Message-
> From: [EMAIL PROTECTED]
> [mailto:[EMAIL PROTECTED]]On Behalf Of Andries Brouwer
> Sent: Monday, November 13, 2000 4:59 PM
> To: LA Walsh
> Cc: lkml
>
Some further information in response to a private email, I did hdparm -ti
under both
2216 and 2217 -- they are identical -- this may be something weird
w/extended
partitions...
/dev/hda:
multcount= 0 (off)
I/O support = 0 (default 16-bit)
unmaskirq= 0 (off)
using_dma= 1 (on)
Another question that's been bugging me -- this is behavior that seems
identical in 2216/2217 and not related to my ealier performance degredation
post.
I run VMware. It runs w/144Mg and writes out a 153M suspend file when I
suspend it to disk. My system has a total of 512M, so the entire
suspe
I skimmed over the archives and didn't find a mention of this. I thought
I'd noticed this when I first installed 2217, but I was too busy to verify
it at the time.
Simple case:
Under 2216, I can do a 'badblocks /dev/hda1 X'. Vmstat shows about
10,000K/s average. This is consistent with 'dd
> One problem here is that you might end up with a weightless
> process having grabbed a superblock lock, after which a
> normal priority CPU hog kicks in and starves the weightless
> process.
---
One way would be to set a flag "I'm holding a lock" and when
it releases the lock(s), desc
I had another thought regarding resource scheduling -- has the idea
of a "weightless" process been brought up? Weightless means it doesn't
count toward 'load' and the class strictly has lowest priority in the
system and gets *no* CPU unless there are "idle" cycles. So even a
process niced to -19
needed.
-l
> -Original Message-
> From: Alexander Viro [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, October 01, 2000 1:52 PM
> To: Rik van Riel
> Cc: LA Walsh; lkml
> Subject: Re: Disk priorities...
>
>
>
>
> On Sun, 1 Oct 2000, Rik van Riel wrote:
>
&
Forgive me if this has been asked before, but has there ever been any
thought of having a 'nice' value for disk accesses?. I was on a
server with 4 CPU's but only 2 SCSI disks. Many times I'll see 4 processes
on disk wait, 3 of them at a cpu-nice of 19 while the foreground processes
get bogged d
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