| Message ID | 20231028213936.45621-1-sj@kernel.org (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [RESEND,6.5.y] mm/damon/sysfs: check DAMOS regions update progress from before_terminate() | expand |
On Sat, Oct 28, 2023 at 09:39:36PM +0000, SeongJae Park 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. > > Link: https://lkml.kernel.org/r/20231007200432.3110-1-sj@kernel.org > Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command") > Signed-off-by: SeongJae Park <sj@kernel.org> > Cc: <stable@vger.kernel.org> [6.2.x] > Signed-off-by: Andrew Morton <akpm@linux-foundation.org> > (cherry picked from commit 76b7069bcc89dec33f03eb08abee165d0306b754) > --- > > I sent this patch yesterday, but seems not archived in lore.kernel.org. > Sending again Cc-ing more mailing lists, to ensure it is sent and others can > find it, to avoid any duplicated works. Now queued up, thanks. greg k-h
diff --git a/mm/damon/sysfs.c b/mm/damon/sysfs.c index 33e1d5c9cb54..df165820c605 100644 --- a/mm/damon/sysfs.c +++ b/mm/damon/sysfs.c @@ -1202,6 +1202,8 @@ 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; @@ -1209,10 +1211,12 @@ static void damon_sysfs_before_terminate(struct damon_ctx *ctx) /* damon_sysfs_schemes_update_regions_stop() might not yet called */ kdamond = damon_sysfs_cmd_request.kdamond; - if (kdamond && damon_sysfs_cmd_request.cmd == + if (kdamond && (damon_sysfs_cmd_request.cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS && + damon_sysfs_schemes_regions_updating) && ctx == kdamond->damon_ctx) { damon_sysfs_schemes_update_regions_stop(ctx); + damon_sysfs_schemes_regions_updating = false; mutex_unlock(&damon_sysfs_lock); } @@ -1331,7 +1335,6 @@ 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; int err = 0; /* avoid deadlock due to concurrent state_store('off') */
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. Link: https://lkml.kernel.org/r/20231007200432.3110-1-sj@kernel.org Fixes: f1d13cacabe1 ("mm/damon/sysfs: implement DAMOS tried regions update command") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: <stable@vger.kernel.org> [6.2.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> (cherry picked from commit 76b7069bcc89dec33f03eb08abee165d0306b754) --- I sent this patch yesterday, but seems not archived in lore.kernel.org. Sending again Cc-ing more mailing lists, to ensure it is sent and others can find it, to avoid any duplicated works. mm/damon/sysfs.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-)