Messages in this thread | | | Subject | Re: [PATCH] drivers/net: Use RCU_INIT_POINTER(x, NULL) in tun.c | From | Eric Dumazet <> | Date | Mon, 24 Mar 2014 05:53:58 -0700 |
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On Mon, 2014-03-24 at 08:22 +0200, Michael S. Tsirkin wrote:
> What happens if someone then changes that NULL to something else? > Things will start to break in subtle way, won't they?
Sure. As anything else can break when/if using wrong API or in any change. Particularly in RCU protected code. Even a kzalloc() can be buggy.
Note that smp_wmb() is hardly expensive in all these paths, so thats why I do not care anymore asking guys using RCU_INIT_POINTER(x, NULL) instead of rcu_assign_pointer() as I used to.
When doing tree wide change (like in commit 2cfa5a0471fef43), I usually not do a dumb one, I take the time to read the code and check it for defects.
I do not remember what kind of compiler warnings we had 3 years ago, But I do not want to spend more cycles on this subject...
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