* [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd
@ 2012-07-23 17:32 Jörn Engel
2012-07-23 19:45 ` James Bottomley
0 siblings, 1 reply; 5+ messages in thread
From: Jörn Engel @ 2012-07-23 17:32 UTC (permalink / raw)
To: James Bottomley; +Cc: linux-scsi
At least two slightly different paths can lead to a NULL pointer
dereference in scsi_prep_state_check and have been hit in practice.
1.
Call Trace:
[<ffffffff812f8c4b>] scsi_setup_blk_pc_cmnd+0x2b/0x170
[<ffffffff81305108>] sd_prep_fn+0x568/0xdd0
[<ffffffff8121c594>] blk_peek_request+0xb4/0x240
[<ffffffff812f94fe>] scsi_request_fn+0x43e/0x4a0
[<ffffffff8121621b>] __blk_run_queue+0x1b/0x20
[<ffffffff81220638>] blk_execute_rq_nowait+0x68/0xc0
[<ffffffff812206fd>] blk_execute_rq+0x6d/0x100
[<ffffffff812f8f8c>] scsi_execute+0xfc/0x160
[<ffffffff812f975a>] scsi_execute_req+0xca/0x140
[<ffffffff81305a4e>] sd_revalidate_disk+0xde/0x1a00
[<ffffffff8130749b>] sd_probe_async+0x12b/0x1d0
...
2.
Call Trace:
[<ffffffff8130078b>] scsi_setup_blk_pc_cmnd+0x2b/0x170
[<ffffffff8130091d>] scsi_prep_fn+0x4d/0x60
[<ffffffff81227794>] blk_peek_request+0xb4/0x240
[<ffffffff813010cd>] scsi_request_fn+0x47d/0x4b0
[<ffffffff81223bff>] __blk_run_queue+0x1f/0x80
[<ffffffff8122b808>] blk_execute_rq_nowait+0x68/0xc0
...
This patch should fix both cases.
Signed-off-by: Joern Engel <joern@logfs.org>
---
drivers/scsi/scsi_lib.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index bb216ff..5fb5a1c 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -1079,8 +1079,11 @@ static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev,
int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
{
struct scsi_cmnd *cmd;
- int ret = scsi_prep_state_check(sdev, req);
+ int ret;
+ if (!sdev)
+ return BLKPREP_KILL;
+ ret = scsi_prep_state_check(sdev, req);
if (ret != BLKPREP_OK)
return ret;
--
1.7.10.4
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd
2012-07-23 17:32 [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd Jörn Engel
@ 2012-07-23 19:45 ` James Bottomley
2012-07-23 19:24 ` Jörn Engel
0 siblings, 1 reply; 5+ messages in thread
From: James Bottomley @ 2012-07-23 19:45 UTC (permalink / raw)
To: Jörn Engel; +Cc: linux-scsi
On Mon, 2012-07-23 at 13:32 -0400, Jörn Engel wrote:
> At least two slightly different paths can lead to a NULL pointer
> dereference in scsi_prep_state_check and have been hit in practice.
Have you checked this with the patches in scsi-misc? There's a series
of patches in there that alters the way sdev handling is done.
James
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd
2012-07-23 19:45 ` James Bottomley
@ 2012-07-23 19:24 ` Jörn Engel
2012-07-24 5:01 ` James Bottomley
0 siblings, 1 reply; 5+ messages in thread
From: Jörn Engel @ 2012-07-23 19:24 UTC (permalink / raw)
To: James Bottomley; +Cc: linux-scsi
On Mon, 23 July 2012 23:45:55 +0400, James Bottomley wrote:
> On Mon, 2012-07-23 at 13:32 -0400, Jörn Engel wrote:
> > At least two slightly different paths can lead to a NULL pointer
> > dereference in scsi_prep_state_check and have been hit in practice.
>
> Have you checked this with the patches in scsi-misc? There's a series
> of patches in there that alters the way sdev handling is done.
I would have liked to, but the tree referenced in MAINTAINERS does not
appear to exist:
git clone git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
Cloning into 'scsi-misc-2.6'...
fatal: The remote end hung up unexpectedly
Jörn
--
The object-oriented version of 'Spaghetti code' is, of course, 'Lasagna code'.
(Too many layers).
-- Roberto Waltman.
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd
2012-07-23 19:24 ` Jörn Engel
@ 2012-07-24 5:01 ` James Bottomley
2012-07-25 19:13 ` Jörn Engel
0 siblings, 1 reply; 5+ messages in thread
From: James Bottomley @ 2012-07-24 5:01 UTC (permalink / raw)
To: Jörn Engel; +Cc: linux-scsi
On Mon, 2012-07-23 at 15:24 -0400, Jörn Engel wrote:
> On Mon, 23 July 2012 23:45:55 +0400, James Bottomley wrote:
> > On Mon, 2012-07-23 at 13:32 -0400, Jörn Engel wrote:
> > > At least two slightly different paths can lead to a NULL pointer
> > > dereference in scsi_prep_state_check and have been hit in practice.
> >
> > Have you checked this with the patches in scsi-misc? There's a series
> > of patches in there that alters the way sdev handling is done.
>
> I would have liked to, but the tree referenced in MAINTAINERS does not
> appear to exist:
>
> git clone git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
> Cloning into 'scsi-misc-2.6'...
> fatal: The remote end hung up unexpectedly
git clone git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git
use the misc branch
James
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd
2012-07-24 5:01 ` James Bottomley
@ 2012-07-25 19:13 ` Jörn Engel
0 siblings, 0 replies; 5+ messages in thread
From: Jörn Engel @ 2012-07-25 19:13 UTC (permalink / raw)
To: James Bottomley; +Cc: linux-scsi
On Tue, 24 July 2012 09:01:41 +0400, James Bottomley wrote:
> On Mon, 2012-07-23 at 15:24 -0400, Jörn Engel wrote:
> > On Mon, 23 July 2012 23:45:55 +0400, James Bottomley wrote:
> > >
> > > Have you checked this with the patches in scsi-misc? There's a series
> > > of patches in there that alters the way sdev handling is done.
> >
> > I would have liked to, but the tree referenced in MAINTAINERS does not
> > appear to exist:
> >
> > git clone git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi-misc-2.6.git
> > Cloning into 'scsi-misc-2.6'...
> > fatal: The remote end hung up unexpectedly
>
> git clone git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git
>
> use the misc branch
joern@Sligo:/usr/src/kernel$ git clone --reference git/ git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi.git
Cloning into 'scsi'...
remote: Counting objects: 869, done.
remote: Compressing objects: 100% (420/420), done.
remote: Total 668 (delta 562), reused 274 (delta 248)
Receiving objects: 100% (668/668), 112.59 KiB, done.
Resolving deltas: 100% (562/562), completed with 110 local objects.
Checking out files: 100% (39127/39127), done.
joern@Sligo:/usr/src/kernel$ cd scsi/
joern@Sligo:/usr/src/kernel/scsi$ git branch
* master
Normally I never use branches, so there is a chance that I'm just
clueless. But to my untrained eye, this looks as if there is no misc
branch.
Jörn
--
To my face you have the audacity to advise me to become a thief - the worst
kind of thief that is conceivable, a thief of spiritual things, a thief of
ideas! It is insufferable, intolerable!
-- M. Binet in Scarabouche
--
To unsubscribe from this list: send the line "unsubscribe linux-scsi" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2012-07-25 20:27 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2012-07-23 17:32 [PATCH] scsi_lib: add NULL check to scsi_setup_blk_pc_cmnd Jörn Engel
2012-07-23 19:45 ` James Bottomley
2012-07-23 19:24 ` Jörn Engel
2012-07-24 5:01 ` James Bottomley
2012-07-25 19:13 ` Jörn Engel
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).