Messages in this thread Patch in this message | | | Subject | Re: [PATCH] ide-cd: prevent null pointer deref via cdrom_newpc_intr | From | Rainer Weikusat <> | Date | Thu, 18 Jun 2009 17:04:00 +0200 |
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From: Rainer Weikusat <rweikusat@mssgmbh.com>
With 2.6.30, the error handling code in cdrom_newpc_intr was changed to deal with partial request failures by normally completing the 'good' parts of a request and only 'error' the last (and presumably, incompletely transferred) bio associated with a particular request. In order to do this, ide_complete_rq is called over ide_cd_error_cmd() to partially complete the rq. The block layer does partial completion only for requests with bio's and if the rq doesn't have one (eg 'GPCMD_READ_DISC_INFO') the request is completed as a whole and the drive->hwif->rq pointer set to NULL afterwards. When calling ide_complete_rq again to report the error, this null pointer is derefenced, resulting in a kernel crash.
Signed-Off-By: Rainer Weikusat <rweikusat@mssgmbh.com>
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--- drivers/ide/ide-cd.c.orig 2009-06-18 15:10:24.000000000 +0200 +++ drivers/ide/ide-cd.c 2009-06-18 14:10:16.000000000 +0200 @@ -758,7 +758,7 @@ out_end: rq->errors = -EIO; } - if (uptodate == 0) + if (uptodate == 0 && rq->bio) ide_cd_error_cmd(drive, cmd); /* make sure it's fully ended */
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