From: Rainer Weikusat Date: Thu, 18 Jun 2009 15:04:00 +0000 (+0200) Subject: ide-cd: prevent null pointer deref via cdrom_newpc_intr X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Fbart%2Fide-2.6.git;a=commitdiff_plain;h=39c58f37a10198054c656c28202fb1e6d22fd505 ide-cd: prevent null pointer deref via cdrom_newpc_intr 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. This fixes http://bugzilla.kernel.org/show_bug.cgi?id=13399. Signed-off-by: Rainer Weikusat Signed-off-by: Borislav Petkov Signed-off-by: Bartlomiej Zolnierkiewicz --- diff --git a/drivers/ide/ide-cd.c b/drivers/ide/ide-cd.c index 0b7645b..4a19686 100644 --- a/drivers/ide/ide-cd.c +++ b/drivers/ide/ide-cd.c @@ -667,7 +667,7 @@ 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 */