I made a mistake on the fixes line, it should have been
Fixes: 06d57378bcc9 ("cifs: Fix potential deadlock when updating vol in cifs_reconnect()")
- if (!IS_ERR(vi))
- free_vol(vi);
- mutex_unlock(&vol_lock);
+ spin_unlock(&vol_list_lock);
+
+ kref_put(&vi->refcnt, vol_release);
This change is not needed for 5.4 unless the deadlock change is also needed.
Tom
On 1/17/21 6:16 AM, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
> The patch below does not apply to the 5.4-stable tree.
> If someone wants it applied there, or to any other stable or longterm
> tree, then please email the backport, including the original git commit
> id to <stable@xxxxxxxxxxxxxxx>.
>
> thanks,
>
> greg k-h
>
> ------------------ original commit in Linus's tree ------------------
>
> From 77b6ec01c29aade01701aa30bf1469acc7f2be76 Mon Sep 17 00:00:00 2001
> From: Tom Rix <trix@xxxxxxxxxx>
> Date: Tue, 5 Jan 2021 12:21:26 -0800
> Subject: [PATCH] cifs: check pointer before freeing
>
> clang static analysis reports this problem
>
> dfs_cache.c:591:2: warning: Argument to kfree() is a constant address
> (18446744073709551614), which is not memory allocated by malloc()
> kfree(vi);
> ^~~~~~~~~
>
> In dfs_cache_del_vol() the volume info pointer 'vi' being freed
> is the return of a call to find_vol(). The large constant address
> is find_vol() returning an error.
>
> Add an error check to dfs_cache_del_vol() similar to the one done
> in dfs_cache_update_vol().
>
> Fixes: 54be1f6c1c37 ("cifs: Add DFS cache routines")
> Signed-off-by: Tom Rix <trix@xxxxxxxxxx>
> Reviewed-by: Nathan Chancellor <natechancellor@xxxxxxxxx>
> CC: <stable@xxxxxxxxxxxxxxx> # v5.0+
> Signed-off-by: Steve French <stfrench@xxxxxxxxxxxxx>
>
> diff --git a/fs/cifs/dfs_cache.c b/fs/cifs/dfs_cache.c
> index 6ad6ba5f6ebe..0fdb0de7ff86 100644
> --- a/fs/cifs/dfs_cache.c
> +++ b/fs/cifs/dfs_cache.c
> @@ -1260,7 +1260,8 @@ void dfs_cache_del_vol(const char *fullpath)
> vi = find_vol(fullpath);
> spin_unlock(&vol_list_lock);
>
> - kref_put(&vi->refcnt, vol_release);
> + if (!IS_ERR(vi))
> + kref_put(&vi->refcnt, vol_release);
> }
>
> /**
>
