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| author | Xiyu Yang <xiyuyang19@fudan.edu.cn> | 2021-07-19 07:59:45 +0200 |
|---|---|---|
| committer | Sam Ravnborg <sam@ravnborg.org> | 2021-07-19 22:16:35 +0200 |
| commit | 0189cb57b96ff92f75e3680b3710a46dacd6509f (patch) | |
| tree | bb892fadc63bdafc3f10444a2faa97b9b40a354e | |
| parent | video: fbdev: kyro: fix a DoS bug by restricting user input (diff) | |
| download | linux-0189cb57b96ff92f75e3680b3710a46dacd6509f.tar.xz linux-0189cb57b96ff92f75e3680b3710a46dacd6509f.zip | |
fbmem: Convert from atomic_t to refcount_t on fb_info->count
refcount_t type and corresponding API can protect refcounters from
accidental underflow and overflow and further use-after-free situations.
Signed-off-by: Xiyu Yang <xiyuyang19@fudan.edu.cn>
Signed-off-by: Xin Tan <tanxin.ctf@gmail.com>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1626674392-55857-1-git-send-email-xiyuyang19@fudan.edu.cn
| -rw-r--r-- | drivers/video/fbdev/core/fbmem.c | 6 | ||||
| -rw-r--r-- | include/linux/fb.h | 3 |
2 files changed, 5 insertions, 4 deletions
diff --git a/drivers/video/fbdev/core/fbmem.c b/drivers/video/fbdev/core/fbmem.c index 072780b0e570..1598736e3bcf 100644 --- a/drivers/video/fbdev/core/fbmem.c +++ b/drivers/video/fbdev/core/fbmem.c @@ -67,7 +67,7 @@ static struct fb_info *get_fb_info(unsigned int idx) mutex_lock(®istration_lock); fb_info = registered_fb[idx]; if (fb_info) - atomic_inc(&fb_info->count); + refcount_inc(&fb_info->count); mutex_unlock(®istration_lock); return fb_info; @@ -75,7 +75,7 @@ static struct fb_info *get_fb_info(unsigned int idx) static void put_fb_info(struct fb_info *fb_info) { - if (!atomic_dec_and_test(&fb_info->count)) + if (!refcount_dec_and_test(&fb_info->count)) return; if (fb_info->fbops->fb_destroy) fb_info->fbops->fb_destroy(fb_info); @@ -1590,7 +1590,7 @@ static int do_register_framebuffer(struct fb_info *fb_info) if (!registered_fb[i]) break; fb_info->node = i; - atomic_set(&fb_info->count, 1); + refcount_set(&fb_info->count, 1); mutex_init(&fb_info->lock); mutex_init(&fb_info->mm_lock); diff --git a/include/linux/fb.h b/include/linux/fb.h index a8dccd23c249..9023739e9a42 100644 --- a/include/linux/fb.h +++ b/include/linux/fb.h @@ -2,6 +2,7 @@ #ifndef _LINUX_FB_H #define _LINUX_FB_H +#include <linux/refcount.h> #include <linux/kgdb.h> #include <uapi/linux/fb.h> @@ -435,7 +436,7 @@ struct fb_tile_ops { struct fb_info { - atomic_t count; + refcount_t count; int node; int flags; /* |