Filesystems broken due to "KKASSERT(count & TOK_COUNTMASK);"
Added by tkusumi about 2 years ago.
Updated about 2 years ago.
Many fs including HAMMER2 are broken due to this assert failure.
Confirmed the panic with HAMMER2 and ext2.
It didn't happen a few months ago.
433 static __inline
435 _lwkt_reltokref(lwkt_tokref_t ref, thread_t td)
455 * We are a shared holder
457 count = atomic_fetchadd_long(&tok->t_count,
TOK_INCR); count prior */ <----------
458 KKASSERT; /
Looks like this happens with kernel module filesystems.
I'm going to comment out this KASSERT since it works fine without it.
This assert may be correct, but then the real bug needs to be fixed.
Negative, that assertion cannot be removed. It asserts that there is a token to release. If there isn't one that means there is a get/rel mismatch somewhere that needs to be tracked down and located.
What is needed is a kernel core to determine which call stack is misbehaving. It is possible that the mismatch is incured at a deeper level that has already returned back up the stack, so it can sometimes be difficult to locate. But any sort of mismatch is critical and needs to be found and fixed.
I'll bisect it when I have time.
Shouldn't be super difficult if a commit within the past few months changed behavior.
If you can find a way to easily reproduce the panic I can go looking too. I have not hit this panic at all yet. It really should have caught whatever the issue was with some of the earlier assertions in those code paths. Every token is 100% tracked in a per-thread array so its a bit worrying that a bug could make it that deep into the token release code.
There have been some notable changes in some of those paths. The rename code paths being the most notable (ad1212685b9caac64c086a), some changes to the exec code, and some optimizations in the GETATTR path.
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