diff options
| author | SeongJae Park <[email protected]> | 2021-12-24 21:12:54 -0800 |
|---|---|---|
| committer | Linus Torvalds <[email protected]> | 2021-12-25 12:20:56 -0800 |
| commit | 34796417964b8d0aef45a99cf6c2d20cebe33733 (patch) | |
| tree | 580b499bc32555b25e5f8f011409d7a8fe925667 | |
| parent | 595ec1973c276f6c0c1de8aca5eef8dfd81f9b49 (diff) | |
mm/damon/dbgfs: protect targets destructions with kdamond_lock
DAMON debugfs interface iterates current monitoring targets in
'dbgfs_target_ids_read()' while holding the corresponding
'kdamond_lock'. However, it also destructs the monitoring targets in
'dbgfs_before_terminate()' without holding the lock. This can result in
a use_after_free bug. This commit avoids the race by protecting the
destruction with the corresponding 'kdamond_lock'.
Link: https://lkml.kernel.org/r/[email protected]
Reported-by: Sangwoo Bae <[email protected]>
Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <[email protected]>
Cc: <[email protected]> [5.15.x]
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
| -rw-r--r-- | mm/damon/dbgfs.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 1efac0022e9a..4fbd729edc9e 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -650,10 +650,12 @@ static void dbgfs_before_terminate(struct damon_ctx *ctx) if (!targetid_is_pid(ctx)) return; + mutex_lock(&ctx->kdamond_lock); damon_for_each_target_safe(t, next, ctx) { put_pid((struct pid *)t->id); damon_destroy_target(t); } + mutex_unlock(&ctx->kdamond_lock); } static struct damon_ctx *dbgfs_new_ctx(void) |