diff options
| author | Yuntao Wang <yuntao.wang@linux.dev> | 2024-05-30 00:06:56 +0800 |
|---|---|---|
| committer | Christian Brauner <brauner@kernel.org> | 2024-05-30 09:11:47 +0200 |
| commit | ed8c7fbdfe117abbef81f65428ba263118ef298a (patch) | |
| tree | cd0a4971a4bba159285a7a1a3e0a612bc2750037 /fs/file.c | |
| parent | a82c13d29985a4d99dacd700b497f0c062fe3625 (diff) | |
fs/file: fix the check in find_next_fd()
The maximum possible return value of find_next_zero_bit(fdt->full_fds_bits,
maxbit, bitbit) is maxbit. This return value, multiplied by BITS_PER_LONG,
gives the value of bitbit, which can never be greater than maxfd, it can
only be equal to maxfd at most, so the following check 'if (bitbit > maxfd)'
will never be true.
Moreover, when bitbit equals maxfd, it indicates that there are no unused
fds, and the function can directly return.
Fix this check.
Signed-off-by: Yuntao Wang <yuntao.wang@linux.dev>
Link: https://lore.kernel.org/r/20240529160656.209352-1-yuntao.wang@linux.dev
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Diffstat (limited to 'fs/file.c')
| -rw-r--r-- | fs/file.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/fs/file.c b/fs/file.c index 8076aef9c210..a3b72aa64f11 100644 --- a/fs/file.c +++ b/fs/file.c @@ -486,12 +486,12 @@ struct files_struct init_files = { static unsigned int find_next_fd(struct fdtable *fdt, unsigned int start) { - unsigned int maxfd = fdt->max_fds; + unsigned int maxfd = fdt->max_fds; /* always multiple of BITS_PER_LONG */ unsigned int maxbit = maxfd / BITS_PER_LONG; unsigned int bitbit = start / BITS_PER_LONG; bitbit = find_next_zero_bit(fdt->full_fds_bits, maxbit, bitbit) * BITS_PER_LONG; - if (bitbit > maxfd) + if (bitbit >= maxfd) return maxfd; if (bitbit > start) start = bitbit; |