Commit a88e03cf authored by Dan Carpenter's avatar Dan Carpenter Committed by Linus Torvalds

zram: off by one in read_block_state()

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: c0265342 ("zram: introduce zram memory tracking")
Signed-off-by: default avatarDan Carpenter <dan.carpenter@oracle.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 4aabdc14
...@@ -910,7 +910,7 @@ static ssize_t read_block_state(struct file *file, char __user *buf, ...@@ -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_HUGE) ? 'h' : '.',
zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.'); zram_test_flag(zram, index, ZRAM_IDLE) ? 'i' : '.');
if (count < copied) { if (count <= copied) {
zram_slot_unlock(zram, index); zram_slot_unlock(zram, index);
break; break;
} }
......
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