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Donenfeld" , Mark Brown , Florian Fainelli , Dominik Brodowski , Herbert Xu , kernelci-results@groups.io, bot@kernelci.org, gtucker@collabora.com, linux-arm-kernel@lists.infradead.org, linux-rpi-kernel@lists.infradead.org, bcm-kernel-feedback-list@broadcom.com, linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org References: <20221010150607.720600-1-Jason@zx2c4.com> From: Florian Fainelli In-Reply-To: <20221010150607.720600-1-Jason@zx2c4.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/10/22 08:06, 'Jason A. Donenfeld' via BCM-KERNEL-FEEDBACK-LIST,PDL wrote: > Rather than busy looping, yield back to the scheduler and sleep for a > bit in the event that there's no data. This should hopefully prevent the > stalls that Mark reported: > > <6>[ 3.362859] Freeing initrd memory: 16196K > <3>[ 23.160131] rcu: INFO: rcu_sched self-detected stall on CPU > <3>[ 23.166057] rcu: 0-....: (2099 ticks this GP) idle=03b4/1/0x40000002 softirq=28/28 fqs=1050 > <4>[ 23.174895] (t=2101 jiffies g=-1147 q=2353 ncpus=4) > <4>[ 23.180203] CPU: 0 PID: 49 Comm: hwrng Not tainted 6.0.0 #1 > <4>[ 23.186125] Hardware name: BCM2835 > <4>[ 23.189837] PC is at bcm2835_rng_read+0x30/0x6c > <4>[ 23.194709] LR is at hwrng_fillfn+0x71/0xf4 > <4>[ 23.199218] pc : [] lr : [] psr: 40000033 > <4>[ 23.205840] sp : f093df70 ip : 00000000 fp : 00000000 > <4>[ 23.211404] r10: c3c7e800 r9 : 00000000 r8 : c17e6b20 > <4>[ 23.216968] r7 : c17e6b64 r6 : c18b0a74 r5 : c07ccd99 r4 : c3f171c0 > <4>[ 23.223855] r3 : 000fffff r2 : 00000040 r1 : c3c7e800 r0 : c3f171c0 > <4>[ 23.230743] Flags: nZcv IRQs on FIQs on Mode SVC_32 ISA Thumb Segment none > <4>[ 23.238426] Control: 50c5387d Table: 0020406a DAC: 00000051 > <4>[ 23.244519] CPU: 0 PID: 49 Comm: hwrng Not tainted 6.0.0 #1 > > Link: https://lore.kernel.org/all/Y0QJLauamRnCDUef@sirena.org.uk/ > Signed-off-by: Jason A. Donenfeld Acked-by: Florian Fainelli -- Florian