Messages in this thread | | | Date | Mon, 3 Jan 2022 18:17:58 +0100 | Subject | Re: [PATCH v2] ipc/sem: do not sleep with a spin lock held | From | Manfred Spraul <> |
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Hi Jiri,
On 1/3/22 10:27, Jiri Slaby wrote: > On 23. 12. 21, 4:12, cgel.zte@gmail.com wrote: >> From: Minghao Chi <chi.minghao@zte.com.cn> >> >> We can't call kvfree() with a spin lock held, so defer it. > > Sorry, defer what? > First drop the spinlock, then call kvfree().
> There are attempts to fix kvfree instead, not sure which of these > approaches (fix kvfree or its callers) won in the end? > Exactly. We have three options - but noone volunteered yet to decide:
- change ipc/sem.c [minimal change]
- change kvfree() to use vfree_atomic() [would also fix other changes that did s/kfree/kvfree/]
- Modify the vma handling so that it becomes safe to call vfree() while holding a spinlock. [perfect approach, but I'm concerned about side effects]
--
Manfred
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