Re: [PATCH] mm/vmalloc: Remove WARN_ON_ONCE related to adjust_va_to_fit_type

[Uladzislau Rezki <urezki@gmail.com>]

On Fri, Sep 22, 2023 at 03:27:04PM +0900, Jaeseon Sim wrote:
> There's panic issue as follows when do alloc_vmap_area:
> 
> Kernel panic - not syncing: kernel: panic_on_warn set ...
> 
> page allocation failure: order:0, mode:0x800(GFP_NOWAIT)
> Call Trace:
> warn_alloc+0xf4/0x190
> __alloc_pages_slowpath+0xe0c/0xffc
> __alloc_pages+0x250/0x2d0
> new_slab+0x17c/0x4e0
> ___slab_alloc+0x4e4/0x8a8
> __slab_alloc+0x34/0x6c
> kmem_cache_alloc+0x20c/0x2f0
> adjust_va_to_fit_type
> __alloc_vmap_area
> alloc_vmap_area+0x298/0x7fc
> __get_vm_area_node+0x10c/0x1b4
> __vmalloc_node_range+0x19c/0x7c0
> 
> Commit 1b23ff80b399 ("mm/vmalloc: invoke classify_va_fit_type() in
> adjust_va_to_fit_type()") moved classify_va_fit_type() into
> adjust_va_to_fit_type() and used WARN_ON_ONCE() to handle return
> value of adjust_va_to_fit_type(), just as classify_va_fit_type()
> was handled.
> 
> There is another path in adjust_va_to_fit_type() which could
> return failure and will be handled in alloc_vmap_area().
> Remove WARN_ON_ONCE() for this case.
> 
> Fixes: 45c62fc2897d ("mm/vmalloc: Remove WARN_ON_ONCE related to adjust_va_to_fit_type")
>
This is i do not follow. The stack shows the warning in the __alloc_pages() path.

What does this patch fix?

--
Uladzislau Rezki