From: Dan Carpenter dan.carpenter@oracle.com
[ Upstream commit a88e03cf3d190cf46bc4063a9b7efe87590de5f4 ]
snprintf() returns the number of bytes it would have printed if there were space. But it does not count the NUL terminator. So that means that if "count == copied" then this has already overflowed by one character.
This bug likely isn't super harmful in real life.
Link: https://lkml.kernel.org/r/20210916130404.GA25094@kili Fixes: c0265342bff4 ("zram: introduce zram memory tracking") Signed-off-by: Dan Carpenter dan.carpenter@oracle.com Cc: Minchan Kim minchan@kernel.org Cc: Sergey Senozhatsky senozhatsky@chromium.org Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/block/zram/zram_drv.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index fcaf2750f68f7..6383c81ac5b37 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -910,7 +910,7 @@ static ssize_t read_block_state(struct file *file, char __user *buf, zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.', zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.');
- if (count < copied) { + if (count <= copied) { zram_slot_unlock(zram, index); break; }