On Thu, Feb 10, 2022 at 10:15:52AM +0000, Lee Jones wrote:
On Wed, 09 Feb 2022, Darrick J. Wong wrote:
On Wed, Feb 09, 2022 at 08:52:43AM +0000, Lee Jones wrote:
This reverts commit 60263d5889e6dc5987dc51b801be4955ff2e4aa7.
Reverting since this commit opens a potential avenue for abuse.
What kind of abuse? Did you conclude there's an avenue solely because some combination of userspace rigging produced a BUG warning? Or is this a real problem that someone found?
Genuine question: Is the ability for userspace to crash the kernel not enough to cause concern? I would have thought that we'd want to prevent this.
The kernel doesn't crash. It's a BUG(). That means it kills the task which caused the BUG(). If you've specified that the kernel should crash on seeing a BUG(), well, you made that decision, and you get to live with the consequences.
The link provided doesn't contain any further analysis. Only the reproducer and kernel configuration used, which are both too large to enter into a Git commit.
But not too large to put in an email. Which you should have sent to begin with, not a stupid reversion commit.
OH WAIT, you're running this on the Android 5.10 kernel, aren't you? The BUG report came from page_buffers failing to find any buffer heads attached to the page. https://android.googlesource.com/kernel/common/+/refs/heads/android12-5.10-2...
Yes, the H/W I have to prototype these on is a phone and the report that came in was specifically built against the aforementioned kernel.
Yeah, don't care.
"There is nothing to worry about, as it's intended behaviour"?
No. You've come in like a fucking meteorite full of arrogance and ignorance. Nobody's reacting well to you right now. Start again, write a good bug report in a new thread.