Re: [PATCH v4] media: verisilicon: Fix kernel panic due to __initconst misuse

[Francesco Dolcini <francesco@dolcini.it>]

On Mon, Mar 16, 2026 at 04:56:09PM +0100, Thorsten Leemhuis wrote:
> On 3/16/26 16:25, Nicolas Dufresne wrote:
> > Le jeudi 12 mars 2026 à 18:34 +0100, Francesco Dolcini a écrit :
> >> On Fri, Mar 06, 2026 at 11:10:57AM +0800, ming.qian@oss.nxp.com wrote:
> >>> From: Ming Qian <ming.qian@oss.nxp.com>
> >>>
> >>> Fix a kernel panic when probing the driver as a module:
> >>>
> >>>   Unable to handle kernel paging request at virtual address
> >>>   ffffd9c18eb05000
> >>>   of_find_matching_node_and_match+0x5c/0x1a0
> >>>   hantro_probe+0x2f4/0x7d0 [hantro_vpu]
> >>>
> >>> The imx8mq_vpu_shared_resources array is referenced by variant
> >>> structures through their shared_devices field. When built as a
> >>> module, __initconst causes this data to be freed after module
> >>> init, but it's later accessed during probe, causing a page fault.
> >>>
> >>> The imx8mq_vpu_shared_resources is referenced from non-init code,
> >>> so keeping __initconst or __initconst_or_module here is wrong.
> >>>
> >>> Drop the __initconst annotation and let it live in the normal .rodata
> >>> section.
> >>>
> >>> A bug of __initconst called from regular non-init probe code
> >>> leading to bugs during probe deferrals or during unbind-bind cycles.
> >>>
> >>> Reported-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> >>> Closes: https://lore.kernel.org/all/68ef934f-baa0-4bf6-93d8-834bbc441e66@kernel.org/
> >>> Reported-by: Franz Schnyder <franz.schnyder@toradex.com>
> >>> Closes: https://lore.kernel.org/all/n3qmcb62tepxltoskpf7ws6yiirc2so62ia23b42rj3wlmpl67@rvkbuirx7kkp/
> >>> Fixes: e0203ddf9af7 ("media: verisilicon: Avoid G2 bus error while decoding H.264 and HEVC")
> >>> Suggested-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>
> >>> Suggested-by: Marco Felsch <m.felsch@pengutronix.de>
> >>> Reviewed-by: Marco Felsch <m.felsch@pengutronix.de>
> >>> Signed-off-by: Ming Qian <ming.qian@oss.nxp.com>
> >>
> >> What's the plan to merge this? It fixes a quite severe regression,
> >> a boot failure.
> > 
> > To be decided this week. The commit message does not say if it was released, or
> > came in RCs (and I didn't check myself yet). I'd say, if its the first one, it
> > will go through next and backports, otherwise its is really tight to get that
> > into the RC series, but serious enough. Please fill the gap if you have time,
> > and I'll handle it later, probably tomorrow.
> 
> Well, FYI: the culprit according to the fixes tag quoted above is
> e0203ddf9af7c8 ("media: verisilicon: Avoid G2 bus error while decoding
> H.264 and HEVC") [v7.0-rc1, v6.19.6 (286d629d10640b)]. Given that this was
> * reported 11 days ago
> * reported at least two times
> * made it into a stable series
> it is something that Linus would like to see fixed by now in mainline
> afaics, as ""the rule of thumb should generally be "within a week",
> preferably before the next rc."":
> https://www.kernel.org/doc/html/next/process/handling-regressions.html#on-how-quickly-regressions-should-be-fixed
> 
> If that fix is too dangerous a revert is of course an option, too.
> 
> BTW, given that the culprit made it to a stable series, it would be a
> wise to add a stable tag to ensure it's backported (it otherweise might
> be silent dropped and/or applying might be deferred).

Absolutely ... the tag here should help b4

Cc: stable@vger.kernel.org

Francesco