diff options
| author | Kefeng Wang <wangkefeng.wang@huawei.com> | 2021-08-06 16:21:24 +0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2021-09-03 10:08:12 +0200 |
| commit | 57bd5b59f1ce8052e916b0b8cd97daa8e763e2e0 (patch) | |
| tree | 8201d642d6efa682abe90cdea308f5f3e9baa8ce /lib | |
| parent | 5892f910f401c1facfc410e0b042108f2827a77b (diff) | |
once: Fix panic when module unload
[ Upstream commit 1027b96ec9d34f9abab69bc1a4dc5b1ad8ab1349 ]
DO_ONCE
DEFINE_STATIC_KEY_TRUE(___once_key);
__do_once_done
once_disable_jump(once_key);
INIT_WORK(&w->work, once_deferred);
struct once_work *w;
w->key = key;
schedule_work(&w->work); module unload
//*the key is
destroy*
process_one_work
once_deferred
BUG_ON(!static_key_enabled(work->key));
static_key_count((struct static_key *)x) //*access key, crash*
When module uses DO_ONCE mechanism, it could crash due to the above
concurrency problem, we could reproduce it with link[1].
Fix it by add/put module refcount in the once work process.
[1] https://lore.kernel.org/netdev/eaa6c371-465e-57eb-6be9-f4b16b9d7cbf@huawei.com/
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: David S. Miller <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Reported-by: Minmin chen <chenmingmin@huawei.com>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/once.c | 11 |
1 files changed, 8 insertions, 3 deletions
diff --git a/lib/once.c b/lib/once.c index 8b7d6235217e..59149bf3bfb4 100644 --- a/lib/once.c +++ b/lib/once.c @@ -3,10 +3,12 @@ #include <linux/spinlock.h> #include <linux/once.h> #include <linux/random.h> +#include <linux/module.h> struct once_work { struct work_struct work; struct static_key_true *key; + struct module *module; }; static void once_deferred(struct work_struct *w) @@ -16,10 +18,11 @@ static void once_deferred(struct work_struct *w) work = container_of(w, struct once_work, work); BUG_ON(!static_key_enabled(work->key)); static_branch_disable(work->key); + module_put(work->module); kfree(work); } -static void once_disable_jump(struct static_key_true *key) +static void once_disable_jump(struct static_key_true *key, struct module *mod) { struct once_work *w; @@ -29,6 +32,8 @@ static void once_disable_jump(struct static_key_true *key) INIT_WORK(&w->work, once_deferred); w->key = key; + w->module = mod; + __module_get(mod); schedule_work(&w->work); } @@ -53,11 +58,11 @@ bool __do_once_start(bool *done, unsigned long *flags) EXPORT_SYMBOL(__do_once_start); void __do_once_done(bool *done, struct static_key_true *once_key, - unsigned long *flags) + unsigned long *flags, struct module *mod) __releases(once_lock) { *done = true; spin_unlock_irqrestore(&once_lock, *flags); - once_disable_jump(once_key); + once_disable_jump(once_key, mod); } EXPORT_SYMBOL(__do_once_done); |