Messages in this thread |  | | Date | Fri, 10 Apr 2015 00:32:50 +0200 (CEST) | From | Jan Engelhardt <> | Subject | Re: NULL deref around blkmq in v4.0-rc1–rc7 |
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On Thursday 2015-04-09 23:42, Jens Axboe wrote: > >> So I don't actually expect my patch to really make any difference, >> although I do think that code should be looked at. > > Jan, is it always clearing in a page size? That seems odd, especially if we're > considering random gunk in memory.
The particular memset in scsi_init_cmd_errh would only clear SCSI_SENSE_BUFFERSIZE. The problem really was that cmd->sense_buffer was nonsensical (I did a hexdump) and read 0x1000. In one instance, it even read 0x10000 because I used that value in an if clause preceding a printk statement I added. Together with __GFP_ZERO apparently fixing the issue for today, the noninitialized memory theory looks like the most applicable one to me currently.
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