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| author | Al Viro <viro@zeniv.linux.org.uk> | 2022-05-18 02:13:40 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-06-06 08:42:40 +0200 |
| commit | d007f49ab789bee8ed76021830b49745d5feaf61 (patch) | |
| tree | 3e9c6f45c562b02772a75f3a16afac9a6d624fbe /lib | |
| parent | 75e35951d6ec28a3a1802ffd76fabe788aa8bb02 (diff) | |
percpu_ref_init(): clean ->percpu_count_ref on failure
[ Upstream commit a91714312eb16f9ecd1f7f8b3efe1380075f28d4 ]
That way percpu_ref_exit() is safe after failing percpu_ref_init().
At least one user (cgroup_create()) had a double-free that way;
there might be other similar bugs. Easier to fix in percpu_ref_init(),
rather than playing whack-a-mole in sloppy users...
Usual symptoms look like a messed refcounting in one of subsystems
that use percpu allocations (might be percpu-refcount, might be
something else). Having refcounts for two different objects share
memory is Not Nice(tm)...
Reported-by: syzbot+5b1e53987f858500ec00@syzkaller.appspotmail.com
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/percpu-refcount.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/lib/percpu-refcount.c b/lib/percpu-refcount.c index e59eda07305e..493093b97093 100644 --- a/lib/percpu-refcount.c +++ b/lib/percpu-refcount.c @@ -75,6 +75,7 @@ int percpu_ref_init(struct percpu_ref *ref, percpu_ref_func_t *release, data = kzalloc(sizeof(*ref->data), gfp); if (!data) { free_percpu((void __percpu *)ref->percpu_count_ptr); + ref->percpu_count_ptr = 0; return -ENOMEM; } |