| Message ID | 20231007200432.3110-1-sj@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [1/1] mm/damon/sysfs: check DAMOS regions update progress from before_terminate() | expand |
Hello, On Sat, 7 Oct 2023 20:04:32 +0000 SeongJae Park <sj@kernel.org> wrote: > 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@vger.kernel.org> # 6.2.x And this will not cleanly applied to 6.5.y, since this is based on latest mm-unstable tree. I will send a backport once this is merged into the mainline. Thanks, SJ [...]
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;
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@vger.kernel.org> # 6.2.x Signed-off-by: SeongJae Park <sj@kernel.org> --- mm/damon/sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)