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| author | Ming Lei <ming.lei@redhat.com> | 2020-10-09 12:03:56 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2020-10-09 12:32:06 -0600 |
| commit | 7ea6bf2e6c409e245a31b9ac6a4ba24949ad442f (patch) | |
| tree | 709047965688b8a10260522de051e5fe23afbbb9 /lib | |
| parent | f4ac712e4fe009635344b9af5d890fe25fcc8c0d (diff) | |
| download | lwn-7ea6bf2e6c409e245a31b9ac6a4ba24949ad442f.tar.gz lwn-7ea6bf2e6c409e245a31b9ac6a4ba24949ad442f.zip | |
percpu_ref: don't refer to ref->data if it isn't allocated
We can't check ref->data->confirm_switch directly in __percpu_ref_exit(), since
ref->data may not be allocated in one not-initialized refcount.
Fixes: 2b0d3d3e4fcf ("percpu_ref: reduce memory footprint of percpu_ref in fast path")
Reported-by: syzbot+fd15ff734dace9e16437@syzkaller.appspotmail.com
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/percpu-refcount.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c index b6350d13538a..e59eda07305e 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -109,7 +109,7 @@ static void __percpu_ref_exit(struct percpu_ref *ref) if (percpu_count) { /* non-NULL confirm_switch indicates switching in progress */ - WARN_ON_ONCE(ref->data->confirm_switch); + WARN_ON_ONCE(ref->data && ref->data->confirm_switch); free_percpu(percpu_count); ref->percpu_count_ptr = __PERCPU_REF_ATOMIC_DEAD; } |