From: Andrew Morton <akpm@osdl.org>
To: Mike Fedyk <mfedyk@matchmail.com>
Cc: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org
Subject: Re: OOps in 2.6.0-test4-mm3-1
Date: Fri, 29 Aug 2003 20:09:26 -0700 [thread overview]
Message-ID: <20030829200926.3e2b7eb6.akpm@osdl.org> (raw)
In-Reply-To: <20030830014309.GA898@matchmail.com>
Mike Fedyk <mfedyk@matchmail.com> wrote:
>
> It's vanilla mm3-1 with this one patch added from Neil Brown. I don't think
> it has anything to do with it (it looks like a driver issue to me). But it
> can't hurt to mention it.
>
No, it is not an MD thing.
You need two patches. It's up to the scsi guys to decide if they're the
right way to go. I think they are.
Some drivers such as aha1542 and aic7xxx_old will call scsi_register() and
then, if some succeeding operations fails they will call scsi_unregister(),
without an intervening scsi_set_host().
This causes an oops in scsi_put_device(), because kobj->parent is NULL.
In other words, scsi_register() immediately followed by scsi_unregister()
is guaranteed to oops.
The patch makes scsi_host_dev_release() more robust against this usage
pattern.
drivers/scsi/hosts.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletion(-)
diff -puN drivers/scsi/hosts.c~aha1542-oops-fix drivers/scsi/hosts.c
--- 25/drivers/scsi/hosts.c~aha1542-oops-fix 2003-08-29 19:48:37.000000000 -0700
+++ 25-akpm/drivers/scsi/hosts.c 2003-08-29 20:02:49.000000000 -0700
@@ -158,7 +158,13 @@ static void scsi_host_dev_release(struct
scsi_proc_hostdir_rm(shost->hostt);
scsi_destroy_command_freelist(shost);
- put_device(parent);
+ /*
+ * Some drivers (eg aha1542) do scsi_register()/scsi_unregister()
+ * during probing without performing a scsi_set_device() in between.
+ * In this case dev->parent is NULL.
+ */
+ if (parent)
+ put_device(parent);
kfree(shost);
}
_
and
scsi_unregister() unconditionally does list_del(&shost->sht_legacy_list).
But scsi_register() leaves that list_head uninitialised if scsi_host_alloc()
returned NULL.
In other words: scsi_unregister() is guaranteed to oops if scsi_host_alloc()
fails.
Fix it by initialising the list_head in scsi_register().
drivers/scsi/hosts.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletion(-)
diff -puN drivers/scsi/hosts.c~scsi_unregister-oops-fix drivers/scsi/hosts.c
--- 25/drivers/scsi/hosts.c~scsi_unregister-oops-fix 2003-08-29 20:02:53.000000000 -0700
+++ 25-akpm/drivers/scsi/hosts.c 2003-08-29 20:02:53.000000000 -0700
@@ -297,8 +297,12 @@ struct Scsi_Host *scsi_register(struct s
dump_stack();
}
- if (shost)
+ if (shost) {
list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
+ } else {
+ /* Do this to keep scsi_unregister() happy */
+ INIT_LIST_HEAD(&shost->sht_legacy_list);
+ }
return shost;
}
_
next prev parent reply other threads:[~2003-08-30 3:06 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-08-29 6:56 2.6.0-test4-mm3 Andrew Morton
2003-08-29 7:45 ` 2.6.0-test4-mm3 Andrew Morton
2003-08-29 15:42 ` 2.6.0-test4-mm3 Ed Sweetman
2003-08-29 15:57 ` 2.6.0-test4-mm3 Andrew Morton
2003-08-29 15:59 ` 2.6.0-test4-mm3 Felipe Alfaro Solana
2003-08-30 1:43 ` OOps in 2.6.0-test4-mm3-1 Mike Fedyk
2003-08-30 3:09 ` Andrew Morton [this message]
2003-08-30 23:20 ` Mike Fedyk
2003-08-30 23:36 ` Andrew Morton
2003-09-10 18:53 ` 2.6.0-test4-mm3 Mike Fedyk
2003-09-10 18:55 ` ide-scsi oops was: 2.6.0-test4-mm3 Mike Fedyk
2003-09-10 18:43 ` Andrew Morton
2003-09-10 19:10 ` Mike Fedyk
2003-09-11 15:24 ` Alan Cox
2003-09-10 20:04 ` Martin J. Bligh
2003-09-10 20:35 ` Murray J. Root
2003-09-10 20:53 ` Paul Larson
2003-09-10 21:11 ` Sandisk WiFi + CF card question J.C. Wren
2003-09-11 8:20 ` ide-scsi oops was: 2.6.0-test4-mm3 Jens Axboe
2003-09-11 15:12 ` Gerhard Mack
2003-09-11 21:52 ` Jens Axboe
2003-09-11 15:27 ` Alan Cox
2003-09-11 21:50 ` Jens Axboe
2003-09-11 18:13 ` Martin J. Bligh
2003-09-11 18:30 ` Mike Fedyk
2003-09-11 21:52 ` Jens Axboe
2003-09-16 0:34 ` Ian Hastie
2003-09-16 9:20 ` Jens Axboe
2003-09-16 18:26 ` Ian Hastie
2003-09-16 18:58 ` Mike Fedyk
2003-09-17 10:31 ` Jens Axboe
2003-09-16 21:41 ` OOps in HFS " Mike Fedyk
2003-09-16 21:40 ` Andrew Morton
2003-09-16 23:59 ` Mike Fedyk
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20030829200926.3e2b7eb6.akpm@osdl.org \
--to=akpm@osdl.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-scsi@vger.kernel.org \
--cc=mfedyk@matchmail.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).