DAMON_SYSFS can receive DAMOS tried regions update request while kdamond
is already out of the main loop and before_terminate callback
(damon_sysfs_before_terminate() in this case) is not yet called. And
damon_sysfs_handle_cmd() can further be finished before the callback is
invoked. Then, damon_sysfs_before_terminate() unlocks damon_sysfs_lock,
which is not locked by anyone. This happens because the callback
function assumes damon_sysfs_cmd_request_callback() should be called
before it. Check if the assumption was true before doing the unlock, to
avoid this problem.
Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command")
Cc: <stable@xxxxxxxxxxxxxxx> # 6.2.x
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
mm/damon/sysfs.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c
index b86ba7b0a921..f60e56150feb 100644
--- a/mm/damon/sysfs.c
+++ b/mm/damon/sysfs.c
@@ -1208,6 +1208,8 @@ static int damon_sysfs_set_targets(struct damon_ctx *ctx,
return 0;
}
+static bool damon_sysfs_schemes_regions_updating;
+
static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
@@ -1219,8 +1221,10 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
cmd = damon_sysfs_cmd_request.cmd;
if (kdamond && ctx == kdamond->damon_ctx &&
(cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS ||
- cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES)) {
+ cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_BYTES) &&
+ damon_sysfs_schemes_regions_updating) {
damon_sysfs_schemes_update_regions_stop(ctx);
+ damon_sysfs_schemes_regions_updating = false;
mutex_unlock(&damon_sysfs_lock);
}
@@ -1340,7 +1344,6 @@ static int damon_sysfs_commit_input(struct damon_sysfs_kdamond *kdamond)
static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
{
struct damon_sysfs_kdamond *kdamond;
- static bool damon_sysfs_schemes_regions_updating;
bool total_bytes_only = false;
int err = 0;
--
2.34.1
