On 8/10/18 9:45 AM, Coly Li wrote:
> Commit ea8c5356d390 ("bcache: set max writeback rate when I/O request
> is idle") changes struct bch_ratelimit member rate from uint32_t to
> atomic_long_t and uses atomic_long_set() in drivers/md/bcache/sysfs.c
> to set new writeback rate, after the input is converted from memory
> buf to long int by sysfs_strtoul_clamp().
>
> The above change has a problem because there is an implicit return
> inside sysfs_strtoul_clamp() so the following atomic_long_set()
> won't be called. This error is detected by 0day system with following
> snipped smatch warnings:
>
> drivers/md/bcache/sysfs.c:271 __cached_dev_store() error: uninitialized
> symbol 'v'.
> 270 sysfs_strtoul_clamp(writeback_rate, v, 1, INT_MAX);
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> @271 atomic_long_set(&dc->writeback_rate.rate, v);
>
> This patch fixes the above error by using strtoul_safe_clamp() to
> convert the input buffer into a long int type result.
>
> Fixes: Commit ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle")
> Signed-off-by: Coly Li <colyli@xxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx #4.16+
> Cc: Kai Krakow <kai@xxxxxxxxxxx>
> Cc: Stefan Priebe <s.priebe@xxxxxxxxxxxx>
You don't need to CC stable for this, the commit isn't in a released kernel
yet. In fact, it's not even in Linus's tree, it's just queued up for 4.19.
Also, the fixes line should be:
Fixes: ea8c5356d390 ("bcache: set max writeback rate when I/O request is idle")
(no Commit). I missed that on some of your earlier commits.
Applied with those edits, and some wording changes.
--
Jens Axboe
