On Fri, 27 Jul 2007 16:46:23 +0200 Maik Hampel <[EMAIL PROTECTED]> wrote:

> In case of read errors raid10d tries to print a nice error message,
> unfortunately using data from an already put bio.
> 
> Signed-off-by: Maik Hampel <[EMAIL PROTECTED]>
> 
> diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c
> index f730a14..ea1b3e3 100644
> --- a/drivers/md/raid10.c
> +++ b/drivers/md/raid10.c
> @@ -1557,7 +1557,6 @@ static void raid10d(mddev_t *mddev)
>                       bio = r10_bio->devs[r10_bio->read_slot].bio;
>                       r10_bio->devs[r10_bio->read_slot].bio =
>                               mddev->ro ? IO_BLOCKED : NULL;
> -                     bio_put(bio);
>                       mirror = read_balance(conf, r10_bio);
>                       if (mirror == -1) {
>                               printk(KERN_ALERT "raid10: %s: unrecoverable 
> I/O"
> @@ -1567,6 +1566,7 @@ static void raid10d(mddev_t *mddev)
>                               raid_end_bio_io(r10_bio);
>                       } else {
>                               const int do_sync = 
> bio_sync(r10_bio->master_bio);
> +                             bio_put(bio);
>                               rdev = conf->mirrors[mirror].rdev;
>                               if (printk_ratelimit())
>                                       printk(KERN_ERR "raid10: %s: 
> redirecting sector %llu to"
> 
> 

Surely we just leaked that bio if (mirror == -1)?

better:

--- a/drivers/md/raid10.c~md-raid10-fix-use-after-free-of-bio
+++ a/drivers/md/raid10.c
@@ -1534,7 +1534,6 @@ static void raid10d(mddev_t *mddev)
                        bio = r10_bio->devs[r10_bio->read_slot].bio;
                        r10_bio->devs[r10_bio->read_slot].bio =
                                mddev->ro ? IO_BLOCKED : NULL;
-                       bio_put(bio);
                        mirror = read_balance(conf, r10_bio);
                        if (mirror == -1) {
                                printk(KERN_ALERT "raid10: %s: unrecoverable 
I/O"
@@ -1542,8 +1541,10 @@ static void raid10d(mddev_t *mddev)
                                       bdevname(bio->bi_bdev,b),
                                       (unsigned long long)r10_bio->sector);
                                raid_end_bio_io(r10_bio);
+                               bio_put(bio);
                        } else {
                                const int do_sync = 
bio_sync(r10_bio->master_bio);
+                               bio_put(bio);
                                rdev = conf->mirrors[mirror].rdev;
                                if (printk_ratelimit())
                                        printk(KERN_ERR "raid10: %s: 
redirecting sector %llu to"
_

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