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| author |  Khazhismel Kumykov <khazhy@chromium.org>
| 2022-08-01 08:50:34 -0700 |
|---|---|---|
| committer |  Andrew Morton <akpm@linux-foundation.org>
| 2022-08-28 14:02:43 -0700 |
| commit | f87904c075515f3e1d8f4a7115869d3b914674fd (patch) | |
| tree | 311757d653b1ef1229b68692699e5b63949ba911 /fs/fs-writeback.c | |
| parent | shmem: update folio if shmem_replace_page() updates the page (diff) | |
| download | linux-f87904c075515f3e1d8f4a7115869d3b914674fd.tar.gz linux-f87904c075515f3e1d8f4a7115869d3b914674fd.tar.bz2 linux-f87904c075515f3e1d8f4a7115869d3b914674fd.zip | |
writeback: avoid use-after-free after removing device
When a disk is removed, bdi_unregister gets called to stop further
writeback and wait for associated delayed work to complete. However,
wb_inode_writeback_end() may schedule bandwidth estimation dwork after
this has completed, which can result in the timer attempting to access the
just freed bdi_writeback.
Fix this by checking if the bdi_writeback is alive, similar to when
scheduling writeback work.
Since this requires wb->work_lock, and wb_inode_writeback_end() may get
called from interrupt, switch wb->work_lock to an irqsafe lock.
Link: https://lkml.kernel.org/r/20220801155034.3772543-1-khazhy@google.com
Fixes: 45a2966fd641 ("writeback: fix bandwidth estimate for spiky workload")
Signed-off-by: Khazhismel Kumykov <khazhy@google.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: Michael Stapelberg <stapelberg+linux@google.com>
Cc: Wu Fengguang <fengguang.wu@intel.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'fs/fs-writeback.c')
| -rw-r--r-- | fs/fs-writeback.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c index 05221366a16d..08a1993ab7fd 100644 --- a/fs/fs-writeback.c +++ b/fs/fs-writeback.c @@ -134,10 +134,10 @@ static bool inode_io_list_move_locked(struct inode *inode, static void wb_wakeup(struct bdi_writeback *wb) { - spin_lock_bh(&wb->work_lock); + spin_lock_irq(&wb->work_lock); if (test_bit(WB_registered, &wb->state)) mod_delayed_work(bdi_wq, &wb->dwork, 0); - spin_unlock_bh(&wb->work_lock); + spin_unlock_irq(&wb->work_lock); } static void finish_writeback_work(struct bdi_writeback *wb, @@ -164,7 +164,7 @@ static void wb_queue_work(struct bdi_writeback *wb, if (work->done) atomic_inc(&work->done->cnt); - spin_lock_bh(&wb->work_lock); + spin_lock_irq(&wb->work_lock); if (test_bit(WB_registered, &wb->state)) { list_add_tail(&work->list, &wb->work_list); @@ -172,7 +172,7 @@ static void wb_queue_work(struct bdi_writeback *wb, } else finish_writeback_work(wb, work); - spin_unlock_bh(&wb->work_lock); + spin_unlock_irq(&wb->work_lock); } /** @@ -2082,13 +2082,13 @@ static struct wb_writeback_work *get_next_work_item(struct bdi_writeback *wb) { struct wb_writeback_work *work = NULL; - spin_lock_bh(&wb->work_lock); + spin_lock_irq(&wb->work_lock); if (!list_empty(&wb->work_list)) { work = list_entry(wb->work_list.next, struct wb_writeback_work, list); list_del_init(&work->list); } - spin_unlock_bh(&wb->work_lock); + spin_unlock_irq(&wb->work_lock); return work; } |