RE: [PATCH v2 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock
> -Original Message-
> From: Sean Anderson
> Sent: Friday, March 31, 2023 18:14
> To: Leo Li ; linuxppc-dev@lists.ozlabs.org; linux-arm-
> ker...@lists.infradead.org
> Cc: Scott Wood ; Camelia Alexandra Groza
> ; linux-ker...@vger.kernel.org; Roy Pledge
> ; David S . Miller ; Claudiu
> Manoil ; Vladimir Oltean
> ; Sean Anderson
> Subject: [PATCH v2 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock
>
> 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")
> Reported-by: Vladimir Oltean
> Link: https://lore.kernel.org/all/20230323153935.nofnjucqjqnz34ej@skbuf/
> Signed-off-by: Sean Anderson
Reviewed-by: Camelia Groza
Re: [PATCH v2 2/2] soc: fsl: qbman: Use raw spinlock for cgr_lock
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
> Link: https://lore.kernel.org/all/20230323153935.nofnjucqjqnz34ej@skbuf/
> Signed-off-by: Sean Anderson
> ---
Anyway,
Tested-by: Vladimir Oltean
