From cda10b34ecfb27935f4a4dad0d0cb1f6405747b4 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 19 Nov 2021 16:43:49 -0800 Subject: [PATCH] mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- 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;