From: Matthew Wilcox <willy@infradead.org>
To: Yu Zhao <yuzhao@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
dev@der-flo.net, Linux-MM <linux-mm@kvack.org>,
Uladzislau Rezki <urezki@gmail.com>,
bugzilla-daemon@kernel.org, Kees Cook <keescook@chromium.org>
Subject: Re: [Bug 216489] New: Machine freezes due to memory lock
Date: Fri, 16 Sep 2022 09:38:33 +0100 [thread overview]
Message-ID: <YyQ2CSdIJdvQPSPO@casper.infradead.org> (raw)
In-Reply-To: <CAOUHufZMpiuzWH7EqqDkr07iP+f80w99fQVRgiuZfc6jtsUJzA@mail.gmail.com>
On Thu, Sep 15, 2022 at 05:59:56PM -0600, Yu Zhao wrote:
> I think this is a manifest of the lockdep warning I reported a couple
> of weeks ago:
> https://lore.kernel.org/r/CAOUHufaPshtKrTWOz7T7QFYUNVGFm0JBjvM700Nhf9qEL9b3EQ@mail.gmail.com/
That would certainly match the symptoms.
Turning vmap_lock into an NMI-safe lock would be bad. I don't even know
if we have primitives for that (it's not like you can disable an NMI
...)
I don't quite have time to write a patch right now. Perhaps something
like:
struct vmap_area *find_vmap_area_nmi(unsigned long addr)
{
struct vmap_area *va;
if (spin_trylock(&vmap_area_lock))
return NULL;
va = __find_vmap_area(addr, &vmap_area_root);
spin_unlock(&vmap_area_lock);
return va;
}
and then call find_vmap_area_nmi() in check_heap_object(). I may have
the polarity of the return value of spin_trylock() incorrect.
next prev parent reply other threads:[~2022-09-16 8:38 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <bug-216489-27@https.bugzilla.kernel.org/>
2022-09-15 20:39 ` [Bug 216489] New: Machine freezes due to memory lock Andrew Morton
2022-09-15 22:42 ` Matthew Wilcox
2022-09-15 23:59 ` Yu Zhao
2022-09-16 8:38 ` Matthew Wilcox [this message]
2022-09-16 9:46 ` Kees Cook
2022-09-16 12:28 ` Uladzislau Rezki
2022-09-16 12:32 ` Uladzislau Rezki
2022-09-16 14:15 ` Matthew Wilcox
2022-09-16 14:42 ` Kees Cook
2022-09-16 18:47 ` Uladzislau Rezki
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