fbdev: fix fb_compat_ioctl() deadlocks
commit3e680aae4e
("fb: convert lock/unlock_kernel() into local fb mutex") introduced several deadlocks in the fb_compat_ioctl() path, as mutex_lock() doesn't allow recursion, unlike lock_kernel(). This broke frame buffer applications on 64-bit systems with a 32-bit userland. commit120a37470c
("framebuffer compat_ioctl deadlock") fixed one of the deadlocks. This patch fixes the remaining deadlocks: - Revert commit120a37470c
, - Extract the core logic of fb_ioctl() into a new function do_fb_ioctl(), - Change all callsites of fb_ioctl() where info->lock is already held to call do_fb_ioctl() instead, - Add sparse annotations to all routines that take info->lock. Signed-off-by: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com> Cc: Mikulas Patocka <mpatocka@redhat.com> Cc: Krzysztof Helt <krzysztof.h1@wp.pl> Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
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a70dcb969f
commit
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@ -1002,13 +1002,9 @@ fb_blank(struct fb_info *info, int blank)
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return ret;
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}
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static long
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fb_ioctl(struct file *file, unsigned int cmd,
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static long do_fb_ioctl(struct fb_info *info, unsigned int cmd,
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unsigned long arg)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int fbidx = iminor(inode);
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struct fb_info *info;
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struct fb_ops *fb;
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struct fb_var_screeninfo var;
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struct fb_fix_screeninfo fix;
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@ -1018,14 +1014,10 @@ fb_ioctl(struct file *file, unsigned int cmd,
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void __user *argp = (void __user *)arg;
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long ret = 0;
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info = registered_fb[fbidx];
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mutex_lock(&info->lock);
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fb = info->fbops;
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if (!fb) {
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mutex_unlock(&info->lock);
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if (!fb)
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return -ENODEV;
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}
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switch (cmd) {
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case FBIOGET_VSCREENINFO:
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ret = copy_to_user(argp, &info->var,
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@ -1126,6 +1118,21 @@ fb_ioctl(struct file *file, unsigned int cmd,
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else
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ret = fb->fb_ioctl(info, cmd, arg);
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}
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return ret;
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}
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static long fb_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int fbidx = iminor(inode);
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struct fb_info *info;
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long ret;
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info = registered_fb[fbidx];
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mutex_lock(&info->lock);
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ret = do_fb_ioctl(info, cmd, arg);
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mutex_unlock(&info->lock);
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return ret;
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}
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@ -1157,8 +1164,8 @@ struct fb_cmap32 {
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compat_caddr_t transp;
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};
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static int fb_getput_cmap(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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static int fb_getput_cmap(struct fb_info *info, unsigned int cmd,
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unsigned long arg)
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{
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struct fb_cmap_user __user *cmap;
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struct fb_cmap32 __user *cmap32;
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@ -1181,7 +1188,7 @@ static int fb_getput_cmap(struct inode *inode, struct file *file,
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put_user(compat_ptr(data), &cmap->transp))
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return -EFAULT;
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err = fb_ioctl(file, cmd, (unsigned long) cmap);
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err = do_fb_ioctl(info, cmd, (unsigned long) cmap);
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if (!err) {
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if (copy_in_user(&cmap32->start,
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@ -1223,8 +1230,8 @@ static int do_fscreeninfo_to_user(struct fb_fix_screeninfo *fix,
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return err;
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}
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static int fb_get_fscreeninfo(struct inode *inode, struct file *file,
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unsigned int cmd, unsigned long arg)
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static int fb_get_fscreeninfo(struct fb_info *info, unsigned int cmd,
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unsigned long arg)
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{
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mm_segment_t old_fs;
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struct fb_fix_screeninfo fix;
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@ -1235,7 +1242,7 @@ static int fb_get_fscreeninfo(struct inode *inode, struct file *file,
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old_fs = get_fs();
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set_fs(KERNEL_DS);
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err = fb_ioctl(file, cmd, (unsigned long) &fix);
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err = do_fb_ioctl(info, cmd, (unsigned long) &fix);
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set_fs(old_fs);
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if (!err)
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@ -1244,8 +1251,10 @@ static int fb_get_fscreeninfo(struct inode *inode, struct file *file,
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return err;
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}
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static long
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fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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static long fb_compat_ioctl(struct file *file, unsigned int cmd,
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unsigned long arg)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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struct inode *inode = file->f_path.dentry->d_inode;
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int fbidx = iminor(inode);
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@ -1262,16 +1271,16 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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case FBIOPUT_CON2FBMAP:
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arg = (unsigned long) compat_ptr(arg);
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case FBIOBLANK:
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mutex_unlock(&info->lock);
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return fb_ioctl(file, cmd, arg);
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ret = do_fb_ioctl(info, cmd, arg);
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break;
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case FBIOGET_FSCREENINFO:
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ret = fb_get_fscreeninfo(inode, file, cmd, arg);
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ret = fb_get_fscreeninfo(info, cmd, arg);
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break;
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case FBIOGETCMAP:
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case FBIOPUTCMAP:
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ret = fb_getput_cmap(inode, file, cmd, arg);
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ret = fb_getput_cmap(info, cmd, arg);
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break;
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default:
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@ -1286,6 +1295,8 @@ fb_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
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static int
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fb_mmap(struct file *file, struct vm_area_struct * vma)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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int fbidx = iminor(file->f_path.dentry->d_inode);
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struct fb_info *info = registered_fb[fbidx];
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@ -1339,6 +1350,8 @@ fb_mmap(struct file *file, struct vm_area_struct * vma)
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static int
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fb_open(struct inode *inode, struct file *file)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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int fbidx = iminor(inode);
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struct fb_info *info;
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@ -1374,6 +1387,8 @@ out:
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static int
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fb_release(struct inode *inode, struct file *file)
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__acquires(&info->lock)
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__releases(&info->lock)
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{
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struct fb_info * const info = file->private_data;
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