From: SeongJae Park <sj@xxxxxxxxxx>
Subject: mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation
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@xxxxxxxxxx
Link: https://lkml.kernel.org/r/20211110145758.16558-2-sj@xxxxxxxxxx
Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/damon/dbgfs.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/mm/damon/dbgfs.c~mm-damon-dbgfs-use-__gfp_nowarn-for-user-specified-size-buffer-allocation
+++ a/mm/damon/dbgfs.c
@@ -32,7 +32,7 @@ static char *user_input_str(const char _
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);
@@ -133,7 +133,7 @@ static ssize_t dbgfs_schemes_read(struct
char *kbuf;
ssize_t len;
- kbuf = kmalloc(count, GFP_KERNEL);
+ kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
@@ -452,7 +452,7 @@ static ssize_t dbgfs_init_regions_read(s
char *kbuf;
ssize_t len;
- kbuf = kmalloc(count, GFP_KERNEL);
+ kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
@@ -578,7 +578,7 @@ static ssize_t dbgfs_kdamond_pid_read(st
char *kbuf;
ssize_t len;
- kbuf = kmalloc(count, GFP_KERNEL);
+ kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;
_
