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| author | SeongJae Park <sj@kernel.org> | 2021-12-31 07:12:34 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-01-05 14:42:39 +0300 |
| commit | ffe4a1ba1a82c416a6b3a09d46594f6a885ae141 (patch) | |
| tree | e5aeb0d52599508e6d4b61d84e7aae5220efeb7e /mm/damon | |
| parent | 466267ced87dd514fc0f64e477c3ef5bb881d4f3 (diff) | |
| download | linux-ffe4a1ba1a82c416a6b3a09d46594f6a885ae141.tar.xz | |
mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'
commit ebb3f994dd92f8fb4d70c7541091216c1e10cb71 upstream.
DAMON debugfs interface increases the reference counts of 'struct pid's
for targets from the 'target_ids' file write callback
('dbgfs_target_ids_write()'), but decreases the counts only in DAMON
monitoring termination callback ('dbgfs_before_terminate()').
Therefore, when 'target_ids' file is repeatedly written without DAMON
monitoring start/termination, the reference count is not decreased and
therefore memory for the 'struct pid' cannot be freed. This commit
fixes this issue by decreasing the reference counts when 'target_ids' is
written.
Link: https://lkml.kernel.org/r/20211229124029.23348-1-sj@kernel.org
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+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm/damon')
| -rw-r--r-- | mm/damon/dbgfs.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index d3bc110430f9..36624990b577 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -185,6 +185,7 @@ static ssize_t dbgfs_target_ids_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) { struct damon_ctx *ctx = file->private_data; + struct damon_target *t, *next_t; char *kbuf, *nrs; unsigned long *targets; ssize_t nr_targets; @@ -224,6 +225,13 @@ static ssize_t dbgfs_target_ids_write(struct file *file, goto unlock_out; } + /* remove previously set targets */ + damon_for_each_target_safe(t, next_t, ctx) { + if (targetid_is_pid(ctx)) + put_pid((struct pid *)t->id); + damon_destroy_target(t); + } + err = damon_set_targets(ctx, targets, nr_targets); if (err) { if (targetid_is_pid(ctx)) |