From: SeongJae Park sj@kernel.org 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@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 Signed-off-by: Andrew Morton akpm@linux-foundation.org ---
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;
_