Messages in this thread Patch in this message | | | From | SeongJae Park <> | Subject | [PATCH for-5.15.x 1/2] mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation | Date | Sun, 21 Nov 2021 11:02:10 +0000 |
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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; -- 2.17.1
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