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| author | Longlong Xia <xialonglong@kylinos.cn> | 2026-08-04 14:59:19 +0800 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2026-08-20 18:24:28 -0700 |
| commit | e580088a2d62fb737ce42abe3f443f3d578915a4 (patch) | |
| tree | 723daa781023061c194950000d03595e29580517 /drivers | |
| parent | 7d7f07dc6d8fa7409f0070d9b6b2a69c1cec1a8b (diff) | |
| download | linux-next-e580088a2d62fb737ce42abe3f443f3d578915a4.tar.gz linux-next-e580088a2d62fb737ce42abe3f443f3d578915a4.zip | |
zram: fix out-of-bounds access in read_block_state()
read_block_state() calculates nr_pages before taking dev_lock. If the
device is reset and reinitialized with a smaller disksize before lock
acquisition, nr_pages still describes the old table. The subsequent loop
can then call slot_lock() past the end of the newly allocated table.
Read disksize after acquiring dev_lock and checking that the device is
initialized. The read lock then keeps the table and its bound stable for
the duration of the scan.
Link: https://lore.kernel.org/20260804065919.3970386-3-xialonglong2025@163.com
Fixes: c0265342bff4 ("zram: introduce zram memory tracking")
Assisted-by: Codex:gpt-5.6-sol
Signed-off-by: Longlong Xia <xialonglong@kylinos.cn>
Reviewed-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Minchan Kim <minchan@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/block/zram/zram_drv.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 2be5c20e3f14..82b78e6e55b2 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1543,7 +1543,7 @@ static ssize_t read_block_state(struct file *file, char __user *buf, char *kbuf; ssize_t index, written = 0; struct zram *zram = file->private_data; - unsigned long nr_pages = zram->disksize >> PAGE_SHIFT; + unsigned long nr_pages; kbuf = kvmalloc(count, GFP_KERNEL); if (!kbuf) @@ -1555,6 +1555,8 @@ static ssize_t read_block_state(struct file *file, char __user *buf, return -EINVAL; } + nr_pages = zram->disksize >> PAGE_SHIFT; + for (index = *ppos; index < nr_pages; index++) { int copied; |