* [PATCH] mm/damon/dbgfs: protect targets destructions with kdamond_lock
@ 2021-12-26 10:26 SeongJae Park
2021-12-27 12:35 ` Greg KH
0 siblings, 1 reply; 3+ messages in thread
From: SeongJae Park @ 2021-12-26 10:26 UTC (permalink / raw)
To: stable, gregkh
Cc: akpm, linux-mm, linux-kernel, SeongJae Park, Linus Torvalds
commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream.
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>
---
This is a backport of a DAMON fix that merged in the mainline, for
v5.15.x stable series.
mm/damon/dbgfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index f94d19a690df..d3bc110430f9 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -309,10 +309,12 @@ static int dbgfs_before_terminate(struct damon_ctx *ctx)
if (!targetid_is_pid(ctx))
return 0;
+ 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);
return 0;
}
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] mm/damon/dbgfs: protect targets destructions with kdamond_lock
2021-12-26 10:26 [PATCH] mm/damon/dbgfs: protect targets destructions with kdamond_lock SeongJae Park
@ 2021-12-27 12:35 ` Greg KH
0 siblings, 0 replies; 3+ messages in thread
From: Greg KH @ 2021-12-27 12:35 UTC (permalink / raw)
To: SeongJae Park; +Cc: stable, akpm, linux-mm, linux-kernel, Linus Torvalds
On Sun, Dec 26, 2021 at 10:26:32AM +0000, SeongJae Park wrote:
> commit 34796417964b8d0aef45a99cf6c2d20cebe33733 upstream.
>
> 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>
> ---
> This is a backport of a DAMON fix that merged in the mainline, for
> v5.15.x stable series.
Now queued up, thanks.
greg k-h
^ permalink raw reply [flat|nested] 3+ messages in thread
* [PATCH] mm/damon/dbgfs: Protect targets destructions with kdamond_lock
@ 2021-12-21 9:44 SeongJae Park
0 siblings, 0 replies; 3+ messages in thread
From: SeongJae Park @ 2021-12-21 9:44 UTC (permalink / raw)
To: akpm; +Cc: linux-mm, linux-kernel, SeongJae Park, stable
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'.
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
---
This cannot cleanly applied on 5.15.y tree. I will post a backport as
soon as this is applied on the mainline.
mm/damon/dbgfs.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c
index 58dbb9692279..489be9c830c4 100644
--- a/mm/damon/dbgfs.c
+++ b/mm/damon/dbgfs.c
@@ -659,10 +659,12 @@ 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)
--
2.17.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2021-12-27 12:35 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-12-26 10:26 [PATCH] mm/damon/dbgfs: protect targets destructions with kdamond_lock SeongJae Park
2021-12-27 12:35 ` Greg KH
-- strict thread matches above, loose matches on Subject: below --
2021-12-21 9:44 [PATCH] mm/damon/dbgfs: Protect " SeongJae Park
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).