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Date:   Fri, 23 Sep 2022 15:29:26 +0200
From:   Michal Hocko <mhocko@suse.com>
To:     Florian Westphal <fw@strlen.de>
Cc:     linux-mm@kvack.org, linux-kernel@vger.kernel.org, vbabka@suse.cz,
        akpm@linux-foundation.org, urezki@gmail.com,
        netdev@vger.kernel.org, netfilter-devel@vger.kernel.org,
        Martin Zaharinov <micron10@gmail.com>
Subject: Re: [PATCH mm] mm: fix BUG with kvzalloc+GFP_ATOMIC
Message-ID: <Yy20toVrIktiMSvH@dhcp22.suse.cz>
References: <20220923103858.26729-1-fw@strlen.de>
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On Fri 23-09-22 12:38:58, Florian Westphal wrote:
> Martin Zaharinov reports BUG() in mm land for 5.19.10 kernel:
>  kernel BUG at mm/vmalloc.c:2437!
>  invalid opcode: 0000 [#1] SMP
>  CPU: 28 PID: 0 Comm: swapper/28 Tainted: G        W  O      5.19.9 #1
>  [..]
>  RIP: 0010:__get_vm_area_node+0x120/0x130
>   __vmalloc_node_range+0x96/0x1e0
>   kvmalloc_node+0x92/0xb0
>   bucket_table_alloc.isra.0+0x47/0x140
>   rhashtable_try_insert+0x3a4/0x440
>   rhashtable_insert_slow+0x1b/0x30
>  [..]
> 
> bucket_table_alloc uses kvzallocGPF_ATOMIC).  If kmalloc fails, this now
> falls through to vmalloc and hits code paths that assume GFP_KERNEL.
> 
> Revert the problematic change and stay with slab allocator.

Why don't you simply fix the caller?
-- 
Michal Hocko
SUSE Labs