From db7a347b26fe05d2e8c115bb24dfd908d0252bc3 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 19 Nov 2021 16:43:49 -0800 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/damon/dbgfs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'mm/damon/dbgfs.c') diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index eccc14b34901..8ce1311ac533 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); @@ -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; -- cgit v1.2.3 From d78f3853f831eee46c6dbe726debf3be9e9c0d05 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Fri, 19 Nov 2021 16:43:52 -0800 Subject: mm/damon/dbgfs: fix missed use of damon_dbgfs_lock DAMON debugfs is supposed to protect dbgfs_ctxs, dbgfs_nr_ctxs, and dbgfs_dirs using damon_dbgfs_lock. However, some of the code is accessing the variables without the protection. This fixes it by protecting all such accesses. Link: https://lkml.kernel.org/r/20211110145758.16558-3-sj@kernel.org Fixes: 75c1c2b53c78 ("mm/damon/dbgfs: support multiple contexts") Signed-off-by: SeongJae Park Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/damon/dbgfs.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'mm/damon/dbgfs.c') diff --git a/mm/damon/dbgfs.c b/mm/damon/dbgfs.c index 8ce1311ac533..9b520bb4a3e7 100644 --- a/mm/damon/dbgfs.c +++ b/mm/damon/dbgfs.c @@ -877,12 +877,14 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, return -EINVAL; } + mutex_lock(&damon_dbgfs_lock); if (!strncmp(kbuf, "on", count)) { int i; for (i = 0; i < dbgfs_nr_ctxs; i++) { if (damon_targets_empty(dbgfs_ctxs[i])) { kfree(kbuf); + mutex_unlock(&damon_dbgfs_lock); return -EINVAL; } } @@ -892,6 +894,7 @@ static ssize_t dbgfs_monitor_on_write(struct file *file, } else { ret = -EINVAL; } + mutex_unlock(&damon_dbgfs_lock); if (!ret) ret = count; @@ -944,15 +947,16 @@ static int __init __damon_dbgfs_init(void) static int __init damon_dbgfs_init(void) { - int rc; + int rc = -ENOMEM; + mutex_lock(&damon_dbgfs_lock); dbgfs_ctxs = kmalloc(sizeof(*dbgfs_ctxs), GFP_KERNEL); if (!dbgfs_ctxs) - return -ENOMEM; + goto out; dbgfs_ctxs[0] = dbgfs_new_ctx(); if (!dbgfs_ctxs[0]) { kfree(dbgfs_ctxs); - return -ENOMEM; + goto out; } dbgfs_nr_ctxs = 1; @@ -963,6 +967,8 @@ static int __init damon_dbgfs_init(void) pr_err("%s: dbgfs init failed\n", __func__); } +out: + mutex_unlock(&damon_dbgfs_lock); return rc; } -- cgit v1.2.3