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| author | Elena Reshetova <elena.reshetova@intel.com> | 2017-03-03 11:04:04 +0200 |
|---|---|---|
| committer | Miklos Szeredi <mszeredi@redhat.com> | 2017-04-18 16:58:37 +0200 |
| commit | ec99f6d31f2590a4c0ff2dae8fb1fa27f0647a42 (patch) | |
| tree | 21d44ad6c09ba6799248e53fe85596a3a6d2596e /fs | |
| parent | 4e8c2eb54327a6f8b0ef6d6afb28ab24b721dbe0 (diff) | |
| download | lwn-ec99f6d31f2590a4c0ff2dae8fb1fa27f0647a42.tar.gz lwn-ec99f6d31f2590a4c0ff2dae8fb1fa27f0647a42.zip | |
fuse: convert fuse_req.count from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/fuse/dev.c | 9 | ||||
| -rw-r--r-- | fs/fuse/fuse_i.h | 2 |
2 files changed, 5 insertions, 6 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c index b681b43c766e..5e815072be1b 100644 --- a/fs/fuse/dev.c +++ b/fs/fuse/dev.c @@ -45,7 +45,7 @@ static void fuse_request_init(struct fuse_req *req, struct page **pages, INIT_LIST_HEAD(&req->list); INIT_LIST_HEAD(&req->intr_entry); init_waitqueue_head(&req->waitq); - atomic_set(&req->count, 1); + refcount_set(&req->count, 1); req->pages = pages; req->page_descs = page_descs; req->max_pages = npages; @@ -102,14 +102,13 @@ void fuse_request_free(struct fuse_req *req) void __fuse_get_request(struct fuse_req *req) { - atomic_inc(&req->count); + refcount_inc(&req->count); } /* Must be called with > 1 refcount */ static void __fuse_put_request(struct fuse_req *req) { - BUG_ON(atomic_read(&req->count) < 2); - atomic_dec(&req->count); + refcount_dec(&req->count); } static void fuse_req_init_context(struct fuse_req *req) @@ -264,7 +263,7 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc, void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req) { - if (atomic_dec_and_test(&req->count)) { + if (refcount_dec_and_test(&req->count)) { if (test_bit(FR_BACKGROUND, &req->flags)) { /* * We get here in the unlikely case that a background diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h index 1d6d67e64f49..9d4374032290 100644 --- a/fs/fuse/fuse_i.h +++ b/fs/fuse/fuse_i.h @@ -307,7 +307,7 @@ struct fuse_req { struct list_head intr_entry; /** refcount */ - atomic_t count; + refcount_t count; /** Unique ID for the interrupt request */ u64 intr_unique; |