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| author | SeongJae Park <sj@kernel.org> | 2023-12-08 17:50:18 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-01-01 12:42:23 +0000 |
| commit | e93bcaebda90c237b2ce2b4e0ee7897b83b5cbf0 (patch) | |
| tree | 427c7677252f59042ee674e6a6f5bfaa65b28c8d /mm/damon | |
| parent | c708a5e51b43797539d787f27ee947d95986c382 (diff) | |
| download | linux-e93bcaebda90c237b2ce2b4e0ee7897b83b5cbf0.tar.gz linux-e93bcaebda90c237b2ce2b4e0ee7897b83b5cbf0.tar.bz2 linux-e93bcaebda90c237b2ce2b4e0ee7897b83b5cbf0.zip | |
mm/damon/core: make damon_start() waits until kdamond_fn() starts
[ Upstream commit 6376a824595607e99d032a39ba3394988b4fce96 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'mm/damon')
| -rw-r--r-- | mm/damon/core.c | 6 |
1 files changed, 6 insertions, 0 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c index 30c93de59475..aff611b6eafe 100644 --- a/mm/damon/core.c +++ b/mm/damon/core.c @@ -423,6 +423,8 @@ struct damon_ctx *damon_new_ctx(void) if (!ctx) return NULL; + init_completion(&ctx->kdamond_started); + ctx->attrs.sample_interval = 5 * 1000; ctx->attrs.aggr_interval = 100 * 1000; ctx->attrs.ops_update_interval = 60 * 1000 * 1000; @@ -636,11 +638,14 @@ static int __damon_start(struct damon_ctx *ctx) mutex_lock(&ctx->kdamond_lock); if (!ctx->kdamond) { err = 0; + reinit_completion(&ctx->kdamond_started); ctx->kdamond = kthread_run(kdamond_fn, ctx, "kdamond.%d", nr_running_ctxs); if (IS_ERR(ctx->kdamond)) { err = PTR_ERR(ctx->kdamond); ctx->kdamond = NULL; + } else { + wait_for_completion(&ctx->kdamond_started); } } mutex_unlock(&ctx->kdamond_lock); @@ -1347,6 +1352,7 @@ static int kdamond_fn(void *data) pr_debug("kdamond (%d) starts\n", current->pid); + complete(&ctx->kdamond_started); kdamond_init_intervals_sis(ctx); if (ctx->ops.init) |