On 8/27/13 5:21 PM, Eric Sandeen wrote: > On 8/27/13 4:07 PM, Jeff Mahoney wrote: >> On 8/27/13 4:56 PM, Josef Bacik wrote: >>> On Tue, Aug 27, 2013 at 03:28:24PM -0400, Jeff Mahoney wrote: >>>> On 8/26/13 4:56 PM, Josef Bacik wrote: >>>>> One of the complaints we get a lot is how many BUG_ON()'s we have. So to >>>>> help >>>>> with this I'm introducing a kconfig option to enable/disable a new >>>>> ASSERT() >>>>> mechanism much like what XFS does. This will allow us developers to >>>>> still get >>>>> our nice panics but allow users/distros to compile them out. With this >>>>> we can >>>>> go through and convert any BUG_ON()'s that we have to catch actual >>>>> programming >>>>> mistakes to the new ASSERT() and then fix everybody else to return >>>>> errors. This >>>>> will also allow developers to leave sanity checks in their new code to >>>>> make sure >>>>> we don't trip over problems while testing stuff and vetting new features. >>>>> Thanks, >>>> >>>> I don't think the complaint is so much about the number of BUG_ONs, but >>>> that there's no distinction between something that is supposed to be >>>> impossible and something that is improbable. The BUG_ONs to keep code >>>> correctness are good and are littered all over the kernel with positive >>>> results. The BUG_ONs that are there in place of real error handling >>>> served their purpose and need to be replaced. >>>> >>>> So, I don't know if it's a net win to compile the "good" BUG_ONs out of >>>> the code. Especially if a user runs into something strange yet familiar >>>> and the first response is "oh, huh, can you rebuild with asserts enabled?" >>>> >>> >>> Either I provide an option for it or distros do it themselves, this cuts >>> out the >>> middle man. I'd really rather they just be on all the time since they >>> aren't >>> things we should hit anyway, but at least this way people have a choice. > >> Ok. With my distro hat on, I can tell you I'll be leaving them on. :) > >> -Jeff > > XFS also has XFS_WARN as a config option, which keeps all the assertions > in place, but printk's & backtraces w/o the icky BUG(). That might be > good to add as well, and perhaps best for a shipping distro (vs. a developer > debugging who might want to drop a core file when the assert trips).
Isn't that the distinction between BUG_ON and WARN_ON? If it's worth a BUG_ON, things should be bad enough (or could result in being bad enough) that we want to bail out. -Jeff -- Jeff Mahoney SUSE Labs
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