Messages in this thread | | | Date | Fri, 10 Jan 2020 16:14:38 -0500 | From | Joel Fernandes <> | Subject | Re: [PATCH -tip V2 0/2] kprobes: Fix RCU warning and cleanup |
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On Tue, Jan 07, 2020 at 09:15:35PM +0900, Masami Hiramatsu wrote: > Hello, > > Anyone have any comment on this series? > Without this series, I still see the suspicious RCU warning for kprobe on -tip tree.
+Paul since RCU.
Hi Masami,
I believe I had commented before that I don't agree with this patch: https://lore.kernel.org/lkml/157535318870.16485.6366477974356032624.stgit@devnote2/
The rationale you used is to replace RCU-api with non-RCU api just to avoid warnings. I think a better approach is to use RCU api and pass the optional expression to silence the false-positive warnings by informing the RCU API about the fact that locks are held (similar to what we do for rcu_dereference_protected()). The RCU API will do additional checking (such as making sure preemption is disabled for safe RCU usage etc) as well.
Could you repost the latest versions?
thanks,
- Joel
> > Thank you, > > On Sat, 21 Dec 2019 03:55:41 +0900 > Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > Hi Ingo, > > > > Could you pick this series to fix the false-positive RCU-list warnings? > > > > Thank you, > > > > On Tue, 3 Dec 2019 15:06:06 +0900 > > Masami Hiramatsu <mhiramat@kernel.org> wrote: > > > > > Hi, > > > > > > Here is a couple of patches which fix suspicious RCU > > > usage warnings in kprobes. > > > > > > Anders reported the first warning in kprobe smoke test > > > with CONFIG_PROVE_RCU_LIST=y. While fixing this issue, > > > I found similar issues and cleanups in kprobes. > > > > > > Thank you, > > > > > > --- > > > > > > Masami Hiramatsu (2): > > > kprobes: Suppress the suspicious RCU warning on kprobes > > > kprobes: Use non RCU traversal APIs on kprobe_tables if possible > > > > > > > > > kernel/kprobes.c | 32 ++++++++++++++++++++++---------- > > > 1 file changed, 22 insertions(+), 10 deletions(-) > > > > > > -- > > > Masami Hiramatsu (Linaro) <mhiramat@kernel.org> > > > > > > -- > > Masami Hiramatsu <mhiramat@kernel.org> > > > -- > Masami Hiramatsu <mhiramat@kernel.org>
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