From: Peter Xu <peterx@redhat.com>
To: Joe Komlodi <komlodi@google.com>
Cc: qemu-devel@nongnu.org, pbonzini@redhat.com, david@redhat.com,
philmd@linaro.org, venture@google.com, pefoley@google.com
Subject: Re: [PATCH] system/physmem: Fix UBSan finding in address_space_write_rom_internal
Date: Tue, 6 May 2025 09:16:23 -0400 [thread overview]
Message-ID: <aBoLp9kw7-SHAGRa@x1.local> (raw)
In-Reply-To: <20250505222236.1616628-1-komlodi@google.com>
On Mon, May 05, 2025 at 10:22:36PM +0000, Joe Komlodi wrote:
> address_space_write_rom_internal can take in a NULL pointer for ptr if
> it's only doing cache flushes instead of populating the ROM.
>
> However, if building with --enable-ubsan, incrementing buf causes ubsan
> to go off when doing cache flushes, since it will trigger on pointer
> arithmetic on a NULL pointer, even if that NULL pointer doesn't get
> dereferenced.
>
> To fix this, we can move the buf incrementing to only be done when
> writing data to ROM, since that's the only point where it gets
> dereferenced and should be non-NULL.
>
> Found by running:
> qemu-system-aarch64 \
> -machine virt \
> -accel kvm
>
> When built with --enable-ubsan.
>
> Signed-off-by: Joe Komlodi <komlodi@google.com>
queued, thanks.
--
Peter Xu
next prev parent reply other threads:[~2025-05-06 13:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-05 22:22 [PATCH] system/physmem: Fix UBSan finding in address_space_write_rom_internal Joe Komlodi
2025-05-06 13:16 ` Peter Xu [this message]
2025-05-06 13:21 ` Peter Maydell
2025-05-09 15:22 ` Peter Xu
2025-05-14 20:57 ` Peter Xu
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