Messages in this thread | | | Date | Tue, 22 Mar 2011 11:39:27 -0400 | From | Vivek Goyal <> | Subject | Re: Re: cfq-iosched.c: panic in cfq_dispatch_requests |
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On Tue, Mar 22, 2011 at 11:32:47PM +0800, Lina Lu wrote: > On 2011-03-21 22:08:19, Vivek Goyal wrote: > >On Sun, Mar 20, 2011 at 03:23:23PM +0800, Lina Lu wrote: > >> Hi Vivek, > >> > >> I did some test with blkio weight policy these days. The kernel panic > >> once in a while. > >> > >> From the calltrace, It 's in func cfq_dispatch_requests(+0x058D). > >> And I caught a divide by zero error with system monitor tools. > > > >Hi Lina, > > > >Can you please paste the full backtrace here. > > > >> > >> The panic happens when I first set 100 weight to two IO pids, then > >> change the weight to 200, and begin to perform IO. The kernel panic > >> accurately when the IO begin. > > > >So you notice this only if weights are changed otherwise not? > > Hi Vivek > > Thanks for this patch! I did objdump and find place that divide by zero. > It's in cfq_group_slice function, the st->total_weight is zero in my issue. > As described in the patch, this is because I change the weight when the > group on service tree.
Ok, so this patch did solve the issue you are facing?
Thanks Vivek
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