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authorSeongJae Park <sj@kernel.org>2023-12-08 17:50:18 +0000
committerAndrew Morton <akpm@linux-foundation.org>2023-12-12 17:20:17 -0800
commit6376a824595607e99d032a39ba3394988b4fce96 (patch)
tree7176ac63c877da843207b5799f76b4c0cf51a743 /include
parenta6fcd57cf2df409d35e9225b8dbad6f937b28df0 (diff)
mm/damon/core: make damon_start() waits until kdamond_fn() starts
The cleanup tasks of kdamond threads including reset of corresponding DAMON context's ->kdamond field and decrease of global nr_running_ctxs counter is supposed to be executed by kdamond_fn(). However, commit 0f91d13366a4 ("mm/damon: simplify stop mechanism") made neither damon_start() nor damon_stop() ensure the corresponding kdamond has started the execution of kdamond_fn(). As a result, the cleanup can be skipped if damon_stop() is called fast enough after the previous damon_start(). Especially the skipped reset of ->kdamond could cause a use-after-free. Fix it by waiting for start of kdamond_fn() execution from damon_start(). Link: https://lkml.kernel.org/r/20231208175018.63880-1-sj@kernel.org Fixes: 0f91d13366a4 ("mm/damon: simplify stop mechanism") Signed-off-by: SeongJae Park <sj@kernel.org> Reported-by: Jakub Acs <acsjakub@amazon.de> Cc: Changbin Du <changbin.du@intel.com> Cc: Jakub Acs <acsjakub@amazon.de> Cc: <stable@vger.kernel.org> # 5.15.x Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r--include/linux/damon.h2
1 files changed, 2 insertions, 0 deletions
diff --git a/include/linux/damon.h b/include/linux/damon.h
index ab2f17d9926b..e00ddf1ed39c 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -559,6 +559,8 @@ struct damon_ctx {
* update
*/
unsigned long next_ops_update_sis;
+ /* for waiting until the execution of the kdamond_fn is started */
+ struct completion kdamond_started;
/* public: */
struct task_struct *kdamond;