diff options
author | Christoph Hellwig <hch@lst.de> | 2020-09-07 10:27:00 +0200 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-09-07 10:46:35 +0200 |
commit | ab04de8ec235ab03573e7ef33b21c357ba248b5f (patch) | |
tree | b6e2bfa2e0bd3d867228412ce203c7f589f7245f /drivers/char/mem.c | |
parent | 947bece14b741ed339eda14db42cf3c357183501 (diff) | |
download | linux-stable-ab04de8ec235ab03573e7ef33b21c357ba248b5f.tar.gz linux-stable-ab04de8ec235ab03573e7ef33b21c357ba248b5f.tar.bz2 linux-stable-ab04de8ec235ab03573e7ef33b21c357ba248b5f.zip |
/dev/zero: fixups for ->read
Reported the cleared bytes in case of a partial clear_user instead
of -EFAULT, and remove a pointless conditional, as cleared must be
non-zero by the time we hit the signal_pending check.
Reported-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200907082700.2057137-1-hch@lst.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r-- | drivers/char/mem.c | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c index 1dc99ab15845..94c2b556cf97 100644 --- a/drivers/char/mem.c +++ b/drivers/char/mem.c @@ -733,14 +733,20 @@ static ssize_t read_zero(struct file *file, char __user *buf, while (count) { size_t chunk = min_t(size_t, count, PAGE_SIZE); + size_t left; - if (clear_user(buf + cleared, chunk)) - return cleared ? cleared : -EFAULT; + left = clear_user(buf + cleared, chunk); + if (unlikely(left)) { + cleared += (chunk - left); + if (!cleared) + return -EFAULT; + break; + } cleared += chunk; count -= chunk; if (signal_pending(current)) - return cleared ? cleared : -ERESTARTSYS; + break; cond_resched(); } |