| Message ID | 20220728113919.7985-1-Wentao_Liang_g@163.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Song Liu |
| Headers | show |
| Series | drivers:md:fix a potential use-after-free bug | expand |
On Wed, Jul 27, 2022 at 8:40 PM Wentao_Liang <Wentao_Liang_g@163.com> wrote: > > In line 2884, "raid5_release_stripe(sh);" drops the reference to sh and > may cause sh to be released. However, sh is subsequently used in lines > 2886 "if (sh->batch_head && sh != sh->batch_head)". This may result in an > use-after-free bug. > > It can be fixed by moving "raid5_release_stripe(sh);" to the bottom of > the function. > > The bug has been confirmed by Song on 2021-08-14. Now, I resend this > patch with my real name. I hope the patch can be updated in a near > future. I removed this paragraph while applying the patch, as it doesn't belong to the commit log. In the future you can put it after a "---", so it will be dropped automatically by git-am. In other words, use something like: ======================================== ... Signed-off-by: Wentao_Liang <Wentao_Liang_g@163.com> --- The bug has been confirmed by Song on 2021-08-14. Now, I resend this patch with my real name. I hope the patch can be updated in a near future. (This will be dropped.) --- drivers/md/raid5.c | 2 +- ... ====================================== > > Signed-off-by: Wentao_Liang <Wentao_Liang_g@163.com> Applied to md-next. Thanks for the fix. > --- > drivers/md/raid5.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c > index 5d09256d7f81..93fcbeac5096 100644 > --- a/drivers/md/raid5.c > +++ b/drivers/md/raid5.c > @@ -2881,10 +2881,10 @@ static void raid5_end_write_request(struct bio *bi) > if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags)) > clear_bit(R5_LOCKED, &sh->dev[i].flags); > set_bit(STRIPE_HANDLE, &sh->state); > - raid5_release_stripe(sh); > > if (sh->batch_head && sh != sh->batch_head) > raid5_release_stripe(sh->batch_head); > + raid5_release_stripe(sh); > } > > static void raid5_error(struct mddev *mddev, struct md_rdev *rdev) > -- > 2.25.1 >
diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 5d09256d7f81..93fcbeac5096 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -2881,10 +2881,10 @@ static void raid5_end_write_request(struct bio *bi) if (!test_and_clear_bit(R5_DOUBLE_LOCKED, &sh->dev[i].flags)) clear_bit(R5_LOCKED, &sh->dev[i].flags); set_bit(STRIPE_HANDLE, &sh->state); - raid5_release_stripe(sh); if (sh->batch_head && sh != sh->batch_head) raid5_release_stripe(sh->batch_head); + raid5_release_stripe(sh); } static void raid5_error(struct mddev *mddev, struct md_rdev *rdev)
In line 2884, "raid5_release_stripe(sh);" drops the reference to sh and may cause sh to be released. However, sh is subsequently used in lines 2886 "if (sh->batch_head && sh != sh->batch_head)". This may result in an use-after-free bug. It can be fixed by moving "raid5_release_stripe(sh);" to the bottom of the function. The bug has been confirmed by Song on 2021-08-14. Now, I resend this patch with my real name. I hope the patch can be updated in a near future. Signed-off-by: Wentao_Liang <Wentao_Liang_g@163.com> --- drivers/md/raid5.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)