Once a key's reference count has been reduced to 0, the garbage collector thread may destroy it at any time and so key_put() is not allowed to touch the key after that point. The most key_put() is normally allowed to do is to touch key_gc_work as that's a static global variable. However, in an effort to speed up the reclamation of quota, this is now done in key_put() once the key's usage is reduced to 0 - but now the code is looking at the key after the deadline, which is forbidden. Fix this by using a flag to indicate that a key can be gc'd now rather than looking at the key's refcount in the garbage collector.
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| @@ -236,6 +236,7 @@ struct key { · 235 unmodified lines | ||
| 236 | 236 | #define KEY_FLAG_ROOT_CAN_INVAL 7 /* set if key can be invalidated by root without permission */ |
| 237 | 237 | #define KEY_FLAG_KEEP 8 /* set if key should not be removed */ |
| 238 | 238 | #define KEY_FLAG_UID_KEYRING 9 /* set if key is a user or user session keyring */ |
| 239 | +#define KEY_FLAG_FINAL_PUT 10 /* set if final put has happened on key */ | |
| 239 | 240 | |
| 240 | 241 | /* the key type and key description string |
| 241 | 242 | * - the desc is used to match a key against search criteria |