Messages in this thread | | | Date | Sun, 04 Nov 2001 20:58:16 -0500 | From | Douglas Gilbert <> | Subject | Re: Linux 2.4.13-ac7 |
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Alan, I getting repeatable lockups on my SMP box (dual Celeron Abit hack) after sg does direct IO in this new version.
This sequence using sg_rbuf from my sg3_utils package (www.torque.net/sg) locks at the end of the transfer just before returning: $ echo 1 > /proc/scsi/sg/allow_dio $ sg_rbuf -d -b=512 /dev/sg0 # /dev/sg0 is a fast disk. # this executes multiple READ BUFFER commands each 512 KB
The box is still usable but the "sg_rbuf" process is unkillable and ps locks just before it would have listed the damaged process. Alt-SysRq-T shows that the sg_rbuf task in "D" state. The stack backtrace is: write_chan rwsem_down_write_failed ???? ret_from_fork
This is with sg version 3.2.21 utilising alloc_kiovec_sz() and friend. I didn't see this "feature" when I tested it against ac4 before submitting it to you. Changing the "nbhs" value from 0 to 256 doesn't make any difference. I have just retested with ac4+sg3.1.21 and it works.
When normal double buffering is used (i.e. no "-d" switch to the above sg_rbuf) there is no lockup.
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