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| author | Coly Li <colyli@suse.de> | 2019-02-09 07:53:06 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-04-05 23:33:17 +0300 |
| commit | e7d26616c92bd96364b45c532b39e455523abb5f (patch) | |
| tree | 4a79cf897b585a272004b565dbbba6a10b86ea1c | |
| parent | 09abe130820ba36ad6bd9d3b9632624a9391b15b (diff) | |
| download | linux-e7d26616c92bd96364b45c532b39e455523abb5f.tar.xz | |
bcache: fix potential div-zero error of writeback_rate_p_term_inverse
[ Upstream commit 5b5fd3c94eef69dcfaa8648198e54c92e5687d6d ]
Current code already uses d_strtoul_nonzero() to convert input string
to an unsigned integer, to make sure writeback_rate_p_term_inverse
won't be zero value. But overflow may happen when converting input
string to an unsigned integer value by d_strtoul_nonzero(), then
dc->writeback_rate_p_term_inverse can still be set to 0 even if the
sysfs file input value is not zero, e.g. 4294967296 (a.k.a UINT_MAX+1).
If dc->writeback_rate_p_term_inverse is set to 0, it might cause a
dev-zero error in following code from __update_writeback_rate(),
int64_t proportional_scaled =
div_s64(error, dc->writeback_rate_p_term_inverse);
This patch replaces d_strtoul_nonzero() by sysfs_strtoul_clamp() and
limit the value range in [1, UINT_MAX]. Then the unsigned integer
overflow and dev-zero error can be avoided.
Signed-off-by: Coly Li <colyli@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -rw-r--r-- | drivers/md/bcache/sysfs.c | 4 |
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/md/bcache/sysfs.c b/drivers/md/bcache/sysfs.c index 503ad954ccc0..d9481640b3e1 100644 --- a/drivers/md/bcache/sysfs.c +++ b/drivers/md/bcache/sysfs.c @@ -286,7 +286,9 @@ STORE(__cached_dev) sysfs_strtoul_clamp(writeback_rate_i_term_inverse, dc->writeback_rate_i_term_inverse, 1, UINT_MAX); - d_strtoul_nonzero(writeback_rate_p_term_inverse); + sysfs_strtoul_clamp(writeback_rate_p_term_inverse, + dc->writeback_rate_p_term_inverse, + 1, UINT_MAX); d_strtoul_nonzero(writeback_rate_minimum); sysfs_strtoul_clamp(io_error_limit, dc->error_limit, 0, INT_MAX); |