| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Thu, 04 Mar 2010 09:41:48 -0500 From: Mark Lord <kernel@...savvy.com> To: Greg Freemyer <greg.freemyer@...il.com> CC: Andrew Morton <akpm@...ux-foundation.org>, foo saa <foosaa@...il.com>, linux-kernel@...r.kernel.org, linux-ide@...r.kernel.org, Jens Axboe <jens.axboe@...cle.com>, linux-mm@...ck.org Subject: Re: Linux kernel - Libata bad block error handling to user mode program On 03/04/10 09:17, Greg Freemyer wrote: .. > I think / suspect your major problem is you say above that you use a > 512-byte buffer to wipe with. The kernel is using 4K pages. So when > you write to a 4K section of the drive for the first time, the kernel > implements read-modify-write logic. > > Your i/o failures are almost certainly on the read cycle of the above, > not the write cycle. You need to move to 4K buffers and you need to > ensure your 4K writes are aligned with how the kernel is working with > the disk. ie. You need your 4K buffer to perfectly align with the > kernels 4K block handling so you never have a read-modify-write cycle. .. You'll also need to disable Linux read-ahead for the drive, or it may try reading beyond even the 4KB block. But really.. isn't "hdparm --security-erase NULL /dev/sdX" good enough ??? Cheers -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Powered by blists - more mailing lists