block: blk-timeout.c possible mishandling of jiffies wrap?

From: Richard Kennedy
Date: Sun Mar 07 2010 - 12:48:07 EST

Hi Jens,

In blk_rq_timed_out_timer() in blk-timeout.c the comment at line 129
says that the request deadline can never be zero as that gets fixed in

However commit 7838c15b8dd18e78a523513749e5b54bda07b0cb
removed the line that bumped deadline if zero.

So now AFAICT there's nothing to prevent deadline being zero, and
blk_rq_timed_out_timer may not always do the right thing when jiffies is
about to wrap.

There was a next_set flag in blk_rq_timed_out_timer but that's been
removed too.

Do you have any preferred fix? A next_set flag or a deadline bump or
something else?


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