On Thu, 20 Sep 2012 15:17:54 +0800 "Jianpeng Ma" <majianpeng@xxxxxxxxx> wrote:
> On 2012-09-20 14:47 NeilBrown <neilb@xxxxxxx> Wrote:
> >On Thu, 20 Sep 2012 14:34:00 +0800 "Jianpeng Ma" <majianpeng@xxxxxxxxx> wrote:
> >
> >> In func add_stripe_bio:
> >> >> .....
> >> >> bip = &sh->dev[dd_idx].toread;
> >> >> ......
> >> >>spin_unlock_irq(&sh->stripe_lock);
> >>
> >> >> pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
> >> >> (unsigned long long)(*bip)->bi_sector,
> >> >> (unsigned long long)sh->sector, dd_idx);
> >> After spin_unlock_irq, this thread scheded and toread may become null.
> >> So it will be oops.
> >>
> >> Signed-off-by: Jianpeng Ma <majianpeng@xxxxxxxxx>
> >> ---
> >> drivers/md/raid5.c | 3 ++-
> >> 1 file changed, 2 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c
> >> index adda94d..f172b1e 100644
> >> --- a/drivers/md/raid5.c
> >> +++ b/drivers/md/raid5.c
> >> @@ -2356,6 +2356,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
> >> struct bio **bip;
> >> struct r5conf *conf = sh->raid_conf;
> >> int firstwrite=0;
> >> + sector_t sector = bi->bi_sector;
> >>
> >> pr_debug("adding bi b#%llu to stripe s#%llu\n",
> >> (unsigned long long)bi->bi_sector,
> >> @@ -2406,7 +2407,7 @@ static int add_stripe_bio(struct stripe_head *sh, struct bio *bi, int dd_idx, in
> >> spin_unlock_irq(&sh->stripe_lock);
> >>
> >> pr_debug("added bi b#%llu to stripe s#%llu, disk %d.\n",
> >> - (unsigned long long)(*bip)->bi_sector,
> >> + (unsigned long long)sector,
> >> (unsigned long long)sh->sector, dd_idx);
> >>
> >> if (conf->mddev->bitmap && firstwrite) {
> >
> >
> >how about we just move the spin_unlock_irq after the pr_debug??
> >
> ah! Why are you think ? my method only add a parameter.
Yes.
> BTW, in func handle_failed_stripe:
> >>if (!test_bit(R5_Wantfill, &sh->dev[i].flags) &&
> >> (!test_bit(R5_Insync, &sh->dev[i].flags) ||
> >> test_bit(R5_ReadError, &sh->dev[i].flags))) {
> >> bi = sh->dev[i].toread;
> >> sh->dev[i].toread = NULL;
> >> if (test_and_clear_bit(R5_Overlap, &sh->dev[i].flags))
> >> wake_up(&conf->wait_for_overlap);
> Why use stripe_lock to protect toread?
I assume you mean that we should be holding the lock to protect toread, but
we aren't.
I've queued a patch to fix that.
Thanks.
NeilBrown
>
> Thanks!
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