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SubjectRe: [PATCH] locks: fix a memory leak bug
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On Mon, 2019-08-19 at 18:47 -0500, Wenwen Wang wrote:
> In __break_lease(), the file lock 'new_fl' is allocated in lease_alloc().
> However, it is not deallocated in the following execution if
> smp_load_acquire() fails, leading to a memory leak bug. To fix this issue,
> free 'new_fl' before returning the error.
>
> Signed-off-by: Wenwen Wang <wenwen@cs.uga.edu>
> ---
> fs/locks.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index 686eae2..5993b2a 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1592,7 +1592,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
> ctx = smp_load_acquire(&inode->i_flctx);
> if (!ctx) {
> WARN_ON_ONCE(1);
> - return error;
> + goto free_lock;
> }
>
> percpu_down_read(&file_rwsem);
> @@ -1672,6 +1672,7 @@ int __break_lease(struct inode *inode, unsigned int mode, unsigned int type)
> spin_unlock(&ctx->flc_lock);
> percpu_up_read(&file_rwsem);
> locks_dispose_list(&dispose);
> +free_lock:
> locks_free_lock(new_fl);
> return error;
> }

Good catch! Merged for v5.4. Let me know if you think this needs to go
in earlier and/or to stable kernels.

Thanks,
--
Jeff Layton <jlayton@kernel.org>

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