Re: KASAN: slab-use-after-free Read in ext4_find_extent

[Theodore Ts'o]

On Thu, Mar 14, 2024 at 02:58:04PM +0800, cheung wall wrote:
> Hello,
> 
> when using Healer to fuzz the latest Linux Kernel, the following crash
> 
> was triggered on:
> 

> HEAD commit: e8f897f4afef0031fe618a8e94127a0934896aba  (tag: v6.8)
> 
> git tree: upstream
> 
> console output: https://pastebin.com/raw/YBKrQHxW
> 
> kernel config: https://pastebin.com/raw/SJFReJfc
> 
> C reproducer: https://pastebin.com/raw/GUVzwEmx
> 
> Syzlang reproducer: https://pastebin.com/raw/9KqQRP2e
> 
> If you fix this issue, please add the following tag to the commit:
> 
> Reported-by: Qiang Zhang <zzqq0103.hey@xxxxxxxxx>

This is not reproducible using the above-specified kernel version,
kernel config, and C reproducer using kvm-xfstests.

In any case, looking at the C reproducer, it looks like the reproducer
involves forcibly deactivating the loop device, which requires root
privileges, and so this is not a terribly intereseting bug report.

	    	   	       - Ted