linux-kernel - Re: [PATCH 1/2] [xarry]:Fixed an issue with memory allocated using the GFP

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20201104023608.GK27442@casper.infradead.org>
Date:   Wed, 4 Nov 2020 02:36:08 +0000
From:   Matthew Wilcox <willy@...radead.org>
To:     "xiaofeng.yan" <xiaofeng.yan2012@...il.com>
Cc:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        dledford@...hat.com, jgg@...pe.ca, oulijun@...wei.com,
        yanxiaofeng7@...com
Subject: Re: [PATCH 1/2] [xarry]:Fixed an issue with memory allocated using
 the GFP_KERNEL flag in spinlocks

On Wed, Nov 04, 2020 at 10:32:12AM +0800, xiaofeng.yan wrote:
>  	xa_lock_irq(xa);
> -	curr = __xa_store(xa, index, entry, gfp);
> +	curr = __xa_store(xa, index, entry, GFP_ATOMIC);
>  	xa_unlock_irq(xa);

You haven't actually seen a bug, have you?  You just read the code
wrongly.

void *__xa_store(struct xarray *xa, unsigned long index, void *entry, gfp_t gfp)
...
        } while (__xas_nomem(&xas, gfp));
...
        if (gfpflags_allow_blocking(gfp)) {
                xas_unlock_type(xas, lock_type);
                xas->xa_alloc = kmem_cache_alloc(radix_tree_node_cachep, gfp);
                xas_lock_type(xas, lock_type);