On 2012-09-25 14:45 NeilBrown <neilb@xxxxxxx> Wrote:
>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.
>
Hi,
Last Saturday, i sent a patch-set which contained a patch which fix this bug.
You can check your mail!
Thanks!
>Thanks.
>NeilBrown
>
>
>>
>> Thanks!
>
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