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mm/damon/dbgfs: use '__GFP_NOWARN' for user-specified size buffer allocation

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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/[email protected]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 4bc05954d0 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
This commit is contained in:
SeongJae Park authored and Linus Torvalds committed 2021-11-20 10:35:54 -08:00
1 parent cab71f7495
commit db7a347b26
1 file changed
+4 -4
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mm/damon/dbgfs.c
+4 -4
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@@ -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);
@@ -133,7 +133,7 @@ static ssize_t dbgfs_schemes_read(struct file *file, char __user *buf,
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(struct file *file, char __user *buf,
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(struct file *file,
char *kbuf;
ssize_t len;
kbuf = kmalloc(count, GFP_KERNEL);
kbuf = kmalloc(count, GFP_KERNEL | __GFP_NOWARN);
if (!kbuf)
return -ENOMEM;