From: "Jianpeng Ma" <majianpeng@gmail.com>
To: Neil Brown <neilb@suse.de>
Cc: linux-raid <linux-raid@vger.kernel.org>
Subject: Re: Re: [PATCH] raid5: fix possible oops in add_stripe_bio when enable pr_debug
Date: Thu, 20 Sep 2012 15:17:54 +0800 [thread overview]
Message-ID: <2012092015175190687821@gmail.com> (raw)
In-Reply-To: 20120920164744.1aab090c@notabene.brown
On 2012-09-20 14:47 NeilBrown <neilb@suse.de> Wrote:
>On Thu, 20 Sep 2012 14:34:00 +0800 "Jianpeng Ma" <majianpeng@gmail.com> 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@gmail.com>
>> ---
>> 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.
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?
Thanks!
next prev parent reply other threads:[~2012-09-20 7:17 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-20 6:34 [PATCH] raid5: fix possible oops in add_stripe_bio when enable pr_debug Jianpeng Ma
2012-09-20 6:47 ` NeilBrown
2012-09-20 7:17 ` Jianpeng Ma [this message]
2012-09-25 6:45 ` NeilBrown
2012-09-25 6:50 ` Jianpeng Ma
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