From 22cc37a943832c948808884604ec6f5ff2594c1d Mon Sep 17 00:00:00 2001 From: Lars Ellenberg Date: Tue, 14 Sep 2010 20:40:41 +0200 Subject: drbd: fix unlikely access after free and list corruption Various cleanup paths have been incomplete, for the very unlikely case that we cannot allocate enough bios from process context when submitting on behalf of the peer or resync process. Never observed. Signed-off-by: Philipp Reisner Signed-off-by: Lars Ellenberg --- drivers/block/drbd/drbd_receiver.c | 25 +++++++++++++++++++++++++ drivers/block/drbd/drbd_worker.c | 7 +++++++ 2 files changed, 32 insertions(+) (limited to 'drivers') diff --git a/drivers/block/drbd/drbd_receiver.c b/drivers/block/drbd/drbd_receiver.c index 990fe01afa50..71775a9de21d 100644 --- a/drivers/block/drbd/drbd_receiver.c +++ b/drivers/block/drbd/drbd_receiver.c @@ -1573,6 +1573,13 @@ static int recv_resync_read(struct drbd_conf *mdev, sector_t sector, int data_si if (drbd_submit_ee(mdev, e, WRITE, DRBD_FAULT_RS_WR) == 0) return TRUE; + /* drbd_submit_ee currently fails for one reason only: + * not being able to allocate enough bios. + * Is dropping the connection going to help? */ + spin_lock_irq(&mdev->req_lock); + list_del(&e->w.list); + spin_unlock_irq(&mdev->req_lock); + drbd_free_ee(mdev, e); fail: put_ldev(mdev); @@ -1998,6 +2005,16 @@ static int receive_Data(struct drbd_conf *mdev, enum drbd_packets cmd, unsigned if (drbd_submit_ee(mdev, e, rw, DRBD_FAULT_DT_WR) == 0) return TRUE; + /* drbd_submit_ee currently fails for one reason only: + * not being able to allocate enough bios. + * Is dropping the connection going to help? */ + spin_lock_irq(&mdev->req_lock); + list_del(&e->w.list); + hlist_del_init(&e->colision); + spin_unlock_irq(&mdev->req_lock); + if (e->flags & EE_CALL_AL_COMPLETE_IO) + drbd_al_complete_io(mdev, e->sector); + out_interrupted: /* yes, the epoch_size now is imbalanced. * but we drop the connection anyways, so we don't have a chance to @@ -2202,6 +2219,14 @@ submit: if (drbd_submit_ee(mdev, e, READ, fault_type) == 0) return TRUE; + /* drbd_submit_ee currently fails for one reason only: + * not being able to allocate enough bios. + * Is dropping the connection going to help? */ + spin_lock_irq(&mdev->req_lock); + list_del(&e->w.list); + spin_unlock_irq(&mdev->req_lock); + /* no drbd_rs_complete_io(), we are dropping the connection anyways */ + out_free_e: put_ldev(mdev); drbd_free_ee(mdev, e); diff --git a/drivers/block/drbd/drbd_worker.c b/drivers/block/drbd/drbd_worker.c index 88be45ad84ed..f12822d53867 100644 --- a/drivers/block/drbd/drbd_worker.c +++ b/drivers/block/drbd/drbd_worker.c @@ -387,6 +387,13 @@ static int read_for_csum(struct drbd_conf *mdev, sector_t sector, int size) if (drbd_submit_ee(mdev, e, READ, DRBD_FAULT_RS_RD) == 0) return 0; + /* drbd_submit_ee currently fails for one reason only: + * not being able to allocate enough bios. + * Is dropping the connection going to help? */ + spin_lock_irq(&mdev->req_lock); + list_del(&e->w.list); + spin_unlock_irq(&mdev->req_lock); + drbd_free_ee(mdev, e); defer: put_ldev(mdev); -- cgit v1.2.3-55-g7522