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authorSeongJae Park <sj@kernel.org>2021-12-25 08:12:54 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-12-25 23:20:56 +0300
commit34796417964b8d0aef45a99cf6c2d20cebe33733 (patch)
tree580b499bc32555b25e5f8f011409d7a8fe925667 /mm/damon/dbgfs.c
parent595ec1973c276f6c0c1de8aca5eef8dfd81f9b49 (diff)
downloadlinux-34796417964b8d0aef45a99cf6c2d20cebe33733.tar.xz
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/20211221094447.2241-1-sj@kernel.org Reported-by: Sangwoo Bae <sangwoob@amazon.com> Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface") Signed-off-by: SeongJae Park <sj@kernel.org> Cc: <stable@vger.kernel.org> [5.15.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/damon/dbgfs.c')
-rw-r--r--mm/damon/dbgfs.c2
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)