This is a note to let you know that I've just added the patch titled
zram: off by one in read_block_state()
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
zram-off-by-one-in-read_block_state.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit ea47306901ac58edecb8031ae6f2076f6986c035
Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Fri Nov 5 13:45:12 2021 -0700
zram: off by one in read_block_state()
[ 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@xxxxxxxxxx>
Cc: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sergey Senozhatsky <senozhatsky@xxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 104206a795015..5e05bfcecd7b7 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -699,7 +699,7 @@ static ssize_t read_block_state(struct file *file, char __user *buf,
zram_test_flag(zram, index, ZRAM_WB) ? 'w' : '.',
zram_test_flag(zram, index, ZRAM_HUGE) ? 'h' : '.');
- if (count < copied) {
+ if (count <= copied) {
zram_slot_unlock(zram, index);
break;
}
