The patch titled
Subject: mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
has been added to the -mm tree. Its filename is
mm-damon-dbgfs-fix-missed-use-of-damon_dbgfs_lock.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-damon-dbgfs-fix-missed-use-of-damon_dbgfs_lock.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-damon-dbgfs-fix-missed-use-of-damon_dbgfs_lock.patch
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: SeongJae Park <sj@xxxxxxxxxx>
Subject: mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
DAMON debugfs is supposed to protect dbgfs_ctxs, dbgfs_nr_ctxs, and
dbgfs_dirs using damon_dbgfs_lock. However, some of the code is accessing
the variables without the protection. This commit fixes it by protecting
all such accesses.
Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@xxxxxxxxxx
Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/dbgfs.c | 12 +++++++++---
1 file changed, 9 insertions(+), 3 deletions(-)
--- a/mm/damon/dbgfs.c~mm-damon-dbgfs-fix-missed-use-of-damon_dbgfs_lock
+++ a/mm/damon/dbgfs.c
@@ -877,12 +877,14 @@ static ssize_t dbgfs_monitor_on_write(st
return -EINVAL;
}
+ mutex_lock(&damon_dbgfs_lock);
if (!strncmp(kbuf, "on", count)) {
int i;
for (i = 0; i < dbgfs_nr_ctxs; i++) {
if (damon_targets_empty(dbgfs_ctxs[i])) {
kfree(kbuf);
+ mutex_unlock(&damon_dbgfs_lock);
return -EINVAL;
}
}
@@ -892,6 +894,7 @@ static ssize_t dbgfs_monitor_on_write(st
} else {
ret = -EINVAL;
}
+ mutex_unlock(&damon_dbgfs_lock);
if (!ret)
ret = count;
@@ -944,15 +947,16 @@ static int __init __damon_dbgfs_init(voi
static int __init damon_dbgfs_init(void)
{
- int rc;
+ int rc = -ENOMEM;
+ mutex_lock(&damon_dbgfs_lock);
dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL);
if (!dbgfs_ctxs)
- return -ENOMEM;
+ goto out;
dbgfs_ctxs[0] = dbgfs_new_ctx();
if (!dbgfs_ctxs[0]) {
kfree(dbgfs_ctxs);
- return -ENOMEM;
+ goto out;
}
dbgfs_nr_ctxs = 1;
@@ -963,6 +967,8 @@ static int __init damon_dbgfs_init(void)
pr_err("%s: dbgfs init failed\n", __func__);
}
+out:
+ mutex_unlock(&damon_dbgfs_lock);
return rc;
}
_
Patches currently in -mm which might be from sj@xxxxxxxxxx are
mm-damon-dbgfs-use-__gfp_nowarn-for-user-specified-size-buffer-allocation.patch
mm-damon-dbgfs-fix-missed-use-of-damon_dbgfs_lock.patch
