On Thu, 19 Dec 2024, Janne Grunau wrote:
This reduces the amount the horizontal filters read beyond the filter
width to a consistent 1 pixel. The data is not used so this is usually
not noticeable. It becomes a problem when the application allocates
frame buffers only for the aligned picture size and the end of it is at
a page boundary. This happens for picture sizes which are a multiple of
the page size like 1280x640. The frame buffer allocation is based on
its most likely done via mmap + MAP_ANONYMOUS so start and end of the
buffer are page aligned and the previous and next page are not
necessarily mapped.
Under these conditions like seen by Firefox a read beyond the end of the
buffer results in a segfault.
After the over-read is reduced to a single pixel it's reasonable to use
VP9's emulated edge motion compensation for this.
Fixes: https://bugzilla.mozilla.org/show_bug.cgi?id=1881185
Signed-off-by: Janne Grunau <janne-ffm...@jannau.net>
---
libavcodec/aarch64/vp9mc_neon.S | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)
Thanks; the assembly changes here and in 2/3 are ok with me; I have no
opinion on how 3/3 is one though. Do you still have push access (once 3/3
is sorted out with Ronald), or do you need someone to push the patches for
you at that point?
I guess these fixes should be backported to all maintained releases too,
once we've settled on the final form of the fix.
// Martin
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