This patchset is a backport of DAMON fixes that merged in the mainline, for v5.15.x stable series.
SeongJae Park (2): mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
mm/damon/dbgfs.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)
commit db7a347b26fe05d2e8c115bb24dfd908d0252bc3 upstream.
Patch series "DAMON fixes".
This patch (of 2):
DAMON users can trigger below warning in '__alloc_pages()' by invoking write() to some DAMON debugfs files with arbitrarily high count argument, because DAMON debugfs interface allocates some buffers based on the user-specified 'count'.
if (unlikely(order >= MAX_ORDER)) { WARN_ON_ONCE(!(gfp & __GFP_NOWARN)); return NULL; }
Because the DAMON debugfs interface code checks failure of the 'kmalloc()', this commit simply suppresses the warnings by adding '__GFP_NOWARN' flag.
Link: https://lkml.kernel.org/r/20211110145758.16558-1-sj@kernel.org Link: https://lkml.kernel.org/r/20211110145758.16558-2-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.x Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org --- mm/damon/dbgfs.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index faee070977d8..2741ff79e8e8 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -32,7 +32,7 @@ static char *user_input_str(const char __user *buf, size_t count, loff_t *ppos) if (*ppos) return ERR_PTR(-EINVAL);
- kbuf = kmalloc(count + 1, GFP_KERNEL); + kbuf = kmalloc(count + 1, GFP_KERNEL | __GFP_NOWARN); if (!kbuf) return ERR_PTR(-ENOMEM);
@@ -247,7 +247,7 @@ static ssize_t dbgfs_kdamond_pid_read(struct file *file, char *kbuf; ssize_t len;
- kbuf = kmalloc(count, GFP_KERNEL); + kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN); if (!kbuf) return -ENOMEM;
commit d78f3853f831eee46c6dbe726debf3be9e9c0d05 upstream.
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 fixes it by protecting all such accesses.
Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@kernel.org Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts") 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 --- mm/damon/dbgfs.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-)
diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 2741ff79e8e8..f94d19a690df 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -538,12 +538,14 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, return -EINVAL; }
+ mutex_lock(&damon_dbgfs_lock); if (!strncmp(kbuf, "on", count)) err = damon_start(dbgfs_ctxs, dbgfs_nr_ctxs); else if (!strncmp(kbuf, "off", count)) err = damon_stop(dbgfs_ctxs, dbgfs_nr_ctxs); else err = -EINVAL; + mutex_unlock(&damon_dbgfs_lock);
if (err) ret = err; @@ -596,15 +598,16 @@ static int __init __damon_dbgfs_init(void)
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;
@@ -615,6 +618,8 @@ static int __init damon_dbgfs_init(void) pr_err("%s: dbgfs init failed\n", __func__); }
+out: + mutex_unlock(&damon_dbgfs_lock); return rc; }
On Sun, Nov 21, 2021 at 11:02:09AM +0000, SeongJae Park wrote:
This patchset is a backport of DAMON fixes that merged in the mainline, for v5.15.x stable series.
SeongJae Park (2): mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation mm/damon/dbgfs: fix missed use of damon_dbgfs_lock
mm/damon/dbgfs.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-)
-- 2.17.1
Now queued up, thanks for the backports.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
SeongJae Park