From bb05b298af8b2330db2b39971bf0029798e7ad59 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Tue, 23 Mar 2021 15:31:19 +0100 Subject: [PATCH] btrfs: zoned: bail out in btrfs_alloc_chunk for bad input MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit gcc complains that the ctl->max_chunk_size member might be used uninitialized when none of the three conditions for initializing it in init_alloc_chunk_ctl_policy_zoned() are true: In function ‘init_alloc_chunk_ctl_policy_zoned’, inlined from ‘init_alloc_chunk_ctl’ at fs/btrfs/volumes.c:5023:3, inlined from ‘btrfs_alloc_chunk’ at fs/btrfs/volumes.c:5340:2: include/linux/compiler-gcc.h:48:45: error: ‘ctl.max_chunk_size’ may be used uninitialized [-Werror=maybe-uninitialized] 4998 | ctl->max_chunk_size = min(limit, ctl->max_chunk_size); | ^~~ fs/btrfs/volumes.c: In function ‘btrfs_alloc_chunk’: fs/btrfs/volumes.c:5316:32: note: ‘ctl’ declared here 5316 | struct alloc_chunk_ctl ctl; | ^~~ If we ever get into this condition, something is seriously wrong, as validity is checked in the callers btrfs_alloc_chunk init_alloc_chunk_ctl init_alloc_chunk_ctl_policy_zoned so the same logic as in init_alloc_chunk_ctl_policy_regular() and a few other places should be applied. This avoids both further data corruption, and the compile-time warning. Fixes: 1cd6121f2a38 ("btrfs: zoned: implement zoned chunk allocator") Signed-off-by: Arnd Bergmann Reviewed-by: David Sterba Signed-off-by: David Sterba --- fs/btrfs/volumes.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c index d4ca721c1d91..6d9b2369f17a 100644 --- a/fs/btrfs/volumes.c +++ b/fs/btrfs/volumes.c @@ -4989,6 +4989,8 @@ static void init_alloc_chunk_ctl_policy_zoned( ctl->max_chunk_size = 2 * ctl->max_stripe_size; ctl->devs_max = min_t(int, ctl->devs_max, BTRFS_MAX_DEVS_SYS_CHUNK); + } else { + BUG(); } /* We don't want a chunk larger than 10% of writable space */ -- 2.34.1