| Message ID | 20211226102632.836-1-sj@kernel.org |
|---|---|
| State | Accepted |
| Commit | 34796417964b8d0aef45a99cf6c2d20cebe33733 |
| Headers | show |
| Series | mm/damon/dbgfs: protect targets destructions with kdamond_lock | expand |
On Sun, Dec 26, 2021 at 10:26:32AM +0000, SeongJae Park wrote: > commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream. > > DAMON debugfs interface iterates current monitoring targets in > 'dbgfs_target_ids_read()' while holding the corresponding > 'kdamond_lock'. However, it also destructs the monitoring targets in > 'dbgfs_before_terminate()' without holding the lock. This can result in > a use_after_free bug. This commit avoids the race by protecting the > destruction with the corresponding 'kdamond_lock'. > > Link: https://lkml.kernel.org/r/20211221094447.2241-1-sj@kernel.org > Reported-by: Sangwoo Bae <sangwoob@amazon.com> > Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface") > Signed-off-by: SeongJae Park <sj@kernel.org> > Cc: <stable@vger.kernel.org> # 5.15.x > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> > --- > This is a backport of a DAMON fix that merged in the mainline, for > v5.15.x stable series. Now queued up, thanks. greg k-h
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index f94d19a690df..d3bc110430f9 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -309,10 +309,12 @@ static int dbgfs_before_terminate(struct damon_ctx *ctx) if (!targetid_is_pid(ctx)) return 0; + mutex_lock(&ctx->kdamond_lock); damon_for_each_target_safe(t, next, ctx) { put_pid((struct pid *)t->id); damon_destroy_target(t); } + mutex_unlock(&ctx->kdamond_lock); return 0; }
commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream. DAMON debugfs interface iterates current monitoring targets in 'dbgfs_target_ids_read()' while holding the corresponding 'kdamond_lock'. However, it also destructs the monitoring targets in 'dbgfs_before_terminate()' without holding the lock. This can result in a use_after_free bug. This commit avoids the race by protecting the destruction with the corresponding 'kdamond_lock'. Link: https://lkml.kernel.org/r/20211221094447.2241-1-sj@kernel.org Reported-by: Sangwoo Bae <sangwoob@amazon.com> Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: <stable@vger.kernel.org> # 5.15.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> --- This is a backport of a DAMON fix that merged in the mainline, for v5.15.x stable series. mm/damon/dbgfs.c | 2 ++ 1 file changed, 2 insertions(+)