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authorKefeng Wang <wangkefeng.wang@huawei.com>2021-08-06 16:21:24 +0800
committerDavid S. Miller <davem@davemloft.net>2021-08-08 13:00:20 +0100
commit1027b96ec9d34f9abab69bc1a4dc5b1ad8ab1349 (patch)
treecd0aaca19f2c451ac22683a7bfd1d321b915f25d /lib/once.c
parentd329e41a08f37c478159d5c3379a17b9c07befa3 (diff)
once: Fix panic when module unload
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>
Diffstat (limited to 'lib/once.c')
-rw-r--r--lib/once.c11
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);