linux-kernel - Re: [PATCH] Save command pool address of Scsi

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

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20140804110747.GB19109@infradead.org>
Date:	Mon, 4 Aug 2014 04:07:47 -0700
From:	Christoph Hellwig <hch@...radead.org>
To:	James Bottomley <James.Bottomley@...senPartnership.com>
Cc:	Christoph Hellwig <hch@...radead.org>, jgross@...e.com,
	linux-scsi@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] Save command pool address of Scsi_Host

On Sat, Aug 02, 2014 at 12:24:34AM +0400, James Bottomley wrote:
> Wait, that's not right at all.  There looks to be a thinko in the
> command pool handling code.  We have both a cmd_pool in the host
> structure and in the host template structure, but there's confusion
> about which one we're supposed to be using.

For anything in the I/O path: shost->cmd_pool, for finding a pool
created for a specific host template: template->cmd_pool.

> The origin of confusion seems to be the reference counting in the pool
> itself ... you want the same pool for all hosts, since they can only
> have one cmd_size, but you want it created on first host use and
> destroyed again on the last one.
> 
> If you take this patch, a host that attached, detaches and then attaches
> a host will panic because it will use a freed pool structure.

Yes, it also needs to set hostt->cmd_pool to NULL when the last
reference goes away.

--
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/