Re: Kernel bug: "general protection fault in bch2_btree_path_traverse_one"

[Kent Overstreet]

On Fri, Dec 20, 2024 at 01:53:25PM +0000, Matthew Wilcox wrote:
> On Fri, Dec 20, 2024 at 07:43:44PM +0800, Haichi Wang wrote:
> > Dear Linux maintainers and reviewers:
> > We are reporting a Linux kernel bug titled **general protection fault in bch2_btree_path_traverse_one**, discovered using a modified version of Syzkaller.
> 
> No, you aren't.  This is a terrible bug report, and you seem to have
> sent several with the same defects.  First, read:
> 
> https://blog.regehr.org/archives/2037
> 
> Then, specifically to reporting a kernel bug *LOOK AT HOW OTHER PEOPLE
> DO IT*.  Your email includes lots of stuff that is of no help and
> doesn't include the most important thing -- the kernel logs from around
> the time of the failure.
> 
> > ### Affected Files
> > The affected files, as obtained from the VM log, are listed below. The corresponding maintainers were identified using `./scripts/get_maintainer.pl`:
> > fs/bcachefs/btree_update_interior.c
> > fs/bcachefs/alloc_foreground.c
> > fs/bcachefs/btree_iter.c
> > fs/bcachefs/btree_trans_commit.c
> > fs/namespace.c
> > arch/x86/entry/common.c
> > fs/bcachefs/recovery.c
> > fs/bcachefs/recovery_passes.c
> > fs/bcachefs/super.c
> > fs/bcachefs/fs.c
> > fs/super.c
> 
> This is useless.
> 
> > ### Kernel Versions
> > - **Kernel Version Tested:** v6.12-rc6:59b723cd2adbac2a34fc8e12c74ae26ae45bf230
> > - **Latest Kernel Version Reproduced On:** f44d154d6e3d633d4c49a5d6a8aed0e4684ae25e
> 
> Useful
> 
> > ### Environment Details
> > - **QEMU Version:** QEMU emulator version 4.2.1 (Debian 1:4.2-3ubuntu6.29)  
> > - **GCC Version:** gcc (Ubuntu 11.4.0-2ubuntu1~20.04) 11.4.0  
> > - **Syzkaller Version:** 2b3ef1577cde5da4fd1f7ece079731e140351177
> 
> Useful
> 
> > ### Attached Files
> > We have attached the following files to assist in reproducing and diagnosing the bug:
> > - **Bug Title:** `bugtitle`  
> > - **Bug Report:** `report`  
> > - **Machine Information:** `machineInfo`  
> > - **Kernel Config:** `config`  
> > - **Compiled Kernel Image:** `vmlinux`  
> 
> You didn't attach these things, but please don't.
> 
> We want the stacktrace.  Preferably passed through
> scripts/decode_stacktrace.sh so we get nice symbols.

I'm not at all clear on why we need a syzbot copycat project - why not
just work with those guys and contribute whatever improvements you have
there?

I've been doing some work with the syzbot folks on ktest integration so
I can reproduce syzbot bugs in a single command - I'm not going to redo
that work for a second backend.