Re: [PATCH resend] bsg: Fix sense buffer bug in SG_IO

[Jens Axboe]

On Tue, Feb 03 2009, Boaz Harrosh wrote:
> 
> When submitting requests via SG_IO, which does a sync io, a
> bsg_command is not allocated. So an in-Kernel sense_buffer was not
> set. However when calling blk_execute_rq() with no sense buffer
> one is provided from the stack. Now bsg at blk_complete_sgv4_hdr_rq()
> would check if rq->sense_len and a sense was requested by sg_io_v4
> the rq->sense was copy_user() back, but by now it is already mangled
> stack memory.
> 
> I have fixed that by forcing a sense_buffer when calling bsg_map_hdr().
> The bsg_command->sense is provided in the write/read path like before,
> and on-the-stack buffer is provided when doing SG_IO.
> 
> I have also fixed a dprintk message to print rq->errors in hex because
> of the scsi bit-field use of this member. For other block devices it
> does not matter anyway.

Thanks for the resend Boaz, I'll make sure it gets upstream for 2.6.29.

-- 
Jens Axboe

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