Re: [PATCH v2 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock

[Vladimir Oltean]

On Fri, Mar 31, 2023 at 11:14:13AM -0400, Sean Anderson wrote:
> cgr_lock may be locked with interrupts already disabled by
> smp_call_function_single. As such, we must use a raw spinlock to avoid
> problems on PREEMPT_RT kernels. Although this bug has existed for a
> while, it was not apparent until commit ef2a8d5478b9 ("net: dpaa: Adjust
> queue depth on rate change") which invokes smp_call_function_single via
> qman_update_cgr_safe every time a link goes up or down.
> 
> Fixes: c535e923bb97 ("soc/fsl: Introduce DPAA 1.x QMan device driver")

Same comment about the Fixes tag.

git tag --contains c535e923bb97
v4.9
git tag --contains 96f413f47677
v4.16

Looking at https://www.kernel.org/, I see that kernel 4.14 is still
maintained but should not have this patch backported, do you agree?

> Reported-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>
> Link: https://lore.kernel.org/all/20230323153935.nofnjucqjqnz34ej@skbuf/
> Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxx>
> ---

Anyway,

Tested-by: Vladimir Oltean <vladimir.oltean@xxxxxxx>