osandov

8 ms·

1.
Calling Linux Kernel Functions from Userspace Using Drgn(blog.osandov.com)
5 points by osandov 2y ago|0 comments
2.
Making Debuginfod Viable for the Linux Kernel(blog.osandov.com)
1 points by osandov 2y ago|0 comments
3.
Recovering a dm-crypt Encryption Key with drgn(drgn.readthedocs.io)
82 points by osandov 3y ago|2 comments
4.
by osandov 4y ago
This was great. Before Powder Game, there were several games in this genre, and a very active Falling Sand Game BBS forum. I got my start in programming by writing mods for one of those games, Burning Sand. I wonder if anyone from those for
5.
by osandov 5y ago
It should work on ARM with a couple of caveats: * Stack tracing needs architecture-specific support which is currently only implemented for x86-64 and ppc64. It's not too hard to add for other architectures, so if this is a feature you
6.
by osandov 5y ago
Some folks at Delphix implemented a debugger based on mdb that's powered by drgn: https://github.com/delphix/sdb
7.
by osandov 7y ago
Absolutely, same goes for anyone else who comes across this and is interested in kernel development.
8.
by osandov 7y ago
Feel free to email me at $my_username@$my_username.com. I'd be happy to help you get started.
9.
by osandov 7y ago
It was actually fixed in Python 3.4 with the switch to use SipHash, as the randomization introduced in Python 3.3 was still susceptible to some attacks. See https://www.python.org/dev/peps/pep-0456/
10.
by osandov 7y ago
The filesystem track at LSF/MM tends to focus on topics which impact more of the kernel than one specific filesystem, and we didn't have any of those topics for Btrfs this year. Plus, only a couple of the Btrfs developers were at
11.
by osandov 9y ago
Every subsystem is tested differently. Because of the wide variety of subsystems and workflows in the kernel, it's pretty much impossible to have a single test suite you can run and call good. For example, some subsystems have unit tes
12.
by osandov 9y ago
What problems have you had with Btrfs recently?
13.
by osandov 9y ago
-fstrict-overflow is the opposite of what the parent comment was asking about. You want -fwrapv or -fno-strict-overflow.
14.
by osandov 9y ago
File modes are typically written in octal, not hex.
15.
Two new block I/O schedulers for Linux 4.12(lwn.net)
2 points by osandov 9y ago|0 comments
16.
by osandov 10y ago
> I don't get why BFQ hasn't been mainlined yet BFQ hasn't been mainlined because it is written for the legacy block layer in the Linux kernel, which will be replaced entirely with the new block multiqueue implementation.
17.
by osandov 10y ago
I'm curious about your NBD performance issues. When you say large number of blocks, are you talking a large filesystem? The free space cache tends to be a performance bottleneck for large filesystems, you might want to try out space_ca
18.
by osandov 11y ago
Cool! I did something very similar to this a couple of years back: https://github.com/osandov/asmase . Instead of assembling to a file, I used the LLVM libraries to assemble in memory, then used ptrace to get a child pr
19.
by osandov 11y ago
> BTW, for the specific problem of dealing with child processes, I really hope Linux adopts the Capsicum interface as FreeBSD has: > https://www.freebsd.org/cgi/man.cgi?query=pdfork&sektion=2 Whoops, I mentio
20.
by osandov 11y ago
> You could certainly imagine some kernel extensions that take all of this useful functionality and make it available in ways other than signals, leaving just signals for things you have to deal with immediately like SIGSEGV (so you can
21.
by osandov 11y ago
Great article on LWN about this: http://lwn.net/Articles/642166/
22.
by osandov 12y ago
Wow, that's pretty sweet. Any plans for trying to get that upstream?
23.
by osandov 12y ago
There's also f2fs [1][2], which has a similar design but runs on flash devices with an FTL and thus takes a more middle road. It still has a log structure and tries to make things easy for the FTL by doing large, sequential, out-of-pla
24.
by osandov 12y ago
This is orthogonal to the argument in the article, but the "buffer overflow" example in C is incorrect. Even if sizeof(b) is smaller in the receiver than in the sender, the receiver will only read at most as many bytes as it (the
25.
by osandov 12y ago
This is cool! Nitpick about examples 2 and 3 - the code should return something in the else case.
26.
by osandov 12y ago
Cool! Back in 2012, I got impatient and put together my own resistive touch screen for the Raspberry Pi: https://www.youtube.com/watch?v=uwEwHFglq8M . I just got a small LCD, a resistive touch panel, soldered up a microcontr
27.
by osandov 12y ago
A nitpicky tip: --help is normal execution, not an error, so the usage information should be printed to stdout, not stderr (and it should exit with a successful status). Nothing is more annoying than trying to use a convoluted program with
28.
by osandov 12y ago
I expected to see more night owls in the "Computer and mathematical" category, but it looks like we're more conventional than the average.