"WARNING in ext4_destroy_inode" in Linux Kernel v6.12-rc4

"WARNING in ext4_destroy_inode" in Linux Kernel v6.12-rc4

[cheung wall]

Hello,

I am writing to report a potential vulnerability identified in the
Linux Kernel version v6.12-rc4. This vulnerability was discovered
while i was testing the kernel.

Linux Kernel Repository Git Commit:
42f7652d3eb527d03665b09edac47f85fb600924 (tag: v6.12-rc4)

Bug Location: 0010:ext4_destroy_inode+0x1d0/0x270 fs/ext4/super.c:1465

Bug report: https://pastebin.com/YKFyLm5P

Entire Log: https://pastebin.com/fE1tFAUS

Thank you for your time and attention.

Best regards

Wall

Re: "WARNING in ext4_destroy_inode" in Linux Kernel v6.12-rc4

[Theodore Ts'o]

On Wed, Jan 15, 2025 at 10:34:24AM +0800, cheung wall wrote:
> Hello,
> 
> I am writing to report a potential vulnerability identified in the
> Linux Kernel version v6.12-rc4. This vulnerability was discovered
> while i was testing the kernel.

A WARN_ON is not something I generally consider a "security
vulnerability".  This is especially if (as I suspect) triggering
failure requires mounting a maliciously fuzzed file system image,
which is something I don't consider an interesting threat mode.

And without a reliable reproducer, I'm not likely to waste a lot of
time on this.  So if you're a researcher trying to mess with Syzkaller
in some weird proprietary way without runninga proper syzbot
interface, sorry, this is a super-terrible way to try to demonstrate
real-world impact.

Feel free to do more of your own analysis, and when you have a
reliable reproucer, please let me know.

> 
> Linux Kernel Repository Git Commit:
> 42f7652d3eb527d03665b09edac47f85fb600924 (tag: v6.12-rc4)
> 
> Bug Location: 0010:ext4_destroy_inode+0x1d0/0x270 fs/ext4/super.c:1465
> 
> Bug report: https://pastebin.com/YKFyLm5P
> 
> Entire Log: https://pastebin.com/fE1tFAUS

For the record, this URL is not accessible; possibly because you
failed to make it be public.

> Thank you for your time and attention.

Sorry, but you've wasted my time.

					- Ted