Re: [PATCH 1/8] pwm: tegra: Prevent 32-bit period truncation and division by zero

[Uwe Kleine-König]

Hello Lee,

On Thu, Nov 05, 2026 at 02:38:03PM +0000, Lee Jones wrote:
> tegra_pwm_apply() passes the 64-bit state->duty_cycle and state->period
> values into tegra_pwm_config(), which accepts signed 32-bit int
> parameters and performs DIV_ROUND_CLOSEST_ULL(c, period_ns) before
> validating period_ns against pc->min_period_ns.  If a consumer requests
> a period that is a non-zero multiple of 2^32 nanoseconds, period_ns
> truncates to zero and triggers a divide-by-zero panic.
> 
> Widen duty_ns and period_ns to u64 and validate that period_ns lies
> within [pc->min_period_ns, U32_MAX] prior to dividing by period_ns.
> 
> Fixes: 1d7796bdb63a ("pwm: tegra: Support dynamic clock frequency configuration")
> Fixes: fd3ddd4355c0 ("pwm: tegra: Implement .apply() callback")
> Closes: https://sashiko.dev/#/bug/linux-5c5b97d6-4da6-4d06-9dc7-957419dcd832
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Lee Jones <lee@xxxxxxxxxx>

This is already addressed in
9ad5602d4943 ("pwm: tegra: Fix value discarding for duty and period")
which is next-20261102 and later.

Best regards
Uwe

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