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>
+static bool damon_sysfs_schemes_regions_updating;
+
static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
static void damon_sysfs_before_terminate(struct damon_ctx *ctx)
{
struct damon_target *t, *next;
cmd = damon_sysfs_cmd_request.cmd;
if (kdamond && ctx == kdamond->damon_ctx &&
(cmd == DAMON_SYSFS_CMD_UPDATE_SCHEMES_TRIED_REGIONS ||
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_update_regions_stop(ctx);
+ damon_sysfs_schemes_regions_updating = false;
mutex_unlock(&damon_sysfs_lock);
}
mutex_unlock(&damon_sysfs_lock);
}
static int damon_sysfs_cmd_request_callback(struct damon_ctx *c)
{
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;
bool total_bytes_only = false;
int err = 0;