Red Hat Bugzilla – Bug 433481
sg: cap reserved_size values to max_sectors
Last modified: 2010-10-22 18:37:39 EDT
Description of problem: The sg driver does not cap the reserved_size values at max_sectors for the SG_GET_RESERVED_SIZE and SG_SET_RESERVED_SIZE sg ioctls. This prevents tools like cdrecord and sg_dd from obtaining a legal value for the maximum transfer length and causing problems such as failed burns and I/O errors. See kernel bugzill #7026: http://bugzilla.kernel.org/show_bug.cgi?id=7026 Version-Release number of selected component (if applicable): 2.6.18-53.el5, 2.6.18-81.el5 How reproducible: 100% Steps to Reproduce: With sg_dd: 1. sg_dd if=/dev/sg1 of=/dev/null bpt=128 bs=2048 count=128 Using cdrecord you can hit the same underlying problem (see steps in kbz#7026). Actual results: # sg_dd if=/dev/sg1 of=/dev/null bpt=128 bs=2048 count=128 reading: SCSI status: Check Condition Descriptor format, current; Sense key: Aborted Command Additional sense: No additional sense information Descriptor type: Information 0x0000000000000000 plus...: Driver_status=0x08 [DRIVER_SENSE, SUGGEST_OK] sg_read failed, at or after lba=0 [0x0] Some error occurred, remaining block count=128 0+0 records in 0+0 records out 1 unrecovered read error(s) Expected results: sg_dd exits with success. Additional info: Fixed upstream: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=44ec95425c1d9dce6e4638c29e4362cfb44814e7
commit 44ec95425c1d9dce6e4638c29e4362cfb44814e7 Author: Alan Stern <stern@rowland.harvard.edu> Date: Tue Feb 20 11:01:57 2007 -0500 [SCSI] sg: cap reserved_size values at max_sectors Alan Stern [Tue, 20 Feb 2007 16:01:57 +0000 (11:01 -0500)] This patch (as857) modifies the SG_GET_RESERVED_SIZE and SG_SET_RESERVED_SIZE ioctls in the sg driver, capping the values at the device's request_queue's max_sectors value. This will permit cdrecord to obtain a legal value for the maximum transfer length, fixing Bugzilla #7026. The patch also caps the initial reserved_size value. There's no reason to have a reserved buffer larger than max_sectors, since it would be impossible to use the extra space. The corresponding ioctls in the block layer are modified similarly, and the initial value for the reserved_size is set as large as possible. This will effectively make it default to max_sectors. Note that the actual value is meaningless anyway, since block devices don't have a reserved buffer. Finally, the BLKSECTGET ioctl is added to sg, so that there will be a uniform way for users to determine the actual max_sectors value for any raw SCSI transport. Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Acked-by: Jens Axboe <jens.axboe@oracle.com> Acked-by: Douglas Gilbert <dougg@torque.net> Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
This bugzilla has Keywords: Regression. Since no regressions are allowed between releases, it is also being proposed as a blocker for this release. Please resolve ASAP.
This request was evaluated by Red Hat Product Management for inclusion in a Red Hat Enterprise Linux maintenance release. Product Management has requested further review of this request by Red Hat Engineering, for potential inclusion in a Red Hat Enterprise Linux Update release for currently deployed products. This request is not yet committed for inclusion in an Update release.
in kernel-2.6.18-87.el5 You can download this test kernel from http://people.redhat.com/dzickus/el5
An advisory has been issued which should help the problem described in this bug report. This report is therefore being closed with a resolution of ERRATA. For more information on the solution and/or where to find the updated files, please follow the link below. You may reopen this bug report if the solution does not work for you. http://rhn.redhat.com/errata/RHBA-2008-0314.html