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Fri, 6 Mar 2026 11:28:45 +0000 (GMT) Date: Fri, 6 Mar 2026 12:28:43 +0100 From: Vasily Gorbik To: Heiko Carstens Cc: Alexander Gordeev , Sven Schnelle , Christian Borntraeger , Mikhail Zaslonko , Peter Zijlstra , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH] s390: Revert "s390/irq/idle: Remove psw bits early" Message-ID: References: <20260306111919.362559-1-hca@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260306111919.362559-1-hca@linux.ibm.com> X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=M9BA6iws c=1 sm=1 tr=0 ts=69aaba72 cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=Yq5XynenixoA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=JfrnYn6hAAAA:8 a=ppuWM-M1jrCgF4sErI0A:9 a=QEXdDO2ut3YA:10 a=1CNFftbPRP8L7MoqJWF3:22 X-Proofpoint-ORIG-GUID: hXmkvoLWoOeUNbQDGEWJTZnKEzDORs-2 X-Proofpoint-GUID: hXmkvoLWoOeUNbQDGEWJTZnKEzDORs-2 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMzA2MDEwNiBTYWx0ZWRfX7MNMLWEr3gF6 2qyWsrXlnvVI6jbetZUWGzXDbwbscGkduJS4CZ1e3BZAazMZKUfazdRsKXrrcsaktDkSde7CXVi Ic9ugd7+GTU16yX7jiXUTAlA/WHY4Bih7Pp3z8e1PbuVOcI9kPpufnNdATAXuppdyF+pvXOTPvd rFvf65PXujx+gBufzAvmqcw7ZEeQVwCX7FJYWqRyha02FT/RUgD7gRdHcPBfyty33Ce/URI809Y ZwcDG3D+ni9KncyxKjSWbIAIHCf8mjonCHOBydNfA6pMUGe5azIOZpQ2cACwgg40NdoXYFkupdT 8URNju8pSxnyLA+SE5XYuhMYaDv3pqcfvEpDezrXuOOMV6acV4/XxVfHNnF+WNjZhhKOvnup7rT gySoztqpp/VDbjc9N1hrK02iHksnZ1OiewzqXyluXLPuCEjPyMjlVAxYz/Dppf+H26Q7m0MdNTd cyxjNVuhT9gapsBa30w== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-03-06_03,2026-03-04_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1011 priorityscore=1501 spamscore=0 adultscore=0 malwarescore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 phishscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2602130000 definitions=main-2603060106 On Fri, Mar 06, 2026 at 12:19:19PM +0100, Heiko Carstens wrote: > This reverts commit d8b5cf9c63143fae54a734c41e3bb55cf3f365c7. > > Mikhail Zaslonko reported that linux-next doesn't boot anymore [2]. Reason > for this is recent change [2] was supposed to slightly optimize the irq > entry/exit path by removing some psw bits early in case of an idle exit. > > This however is incorrect since irqentry_exit() requires the correct old > psw state at irq entry. Otherwise the embedded regs_irqs_disabled() will > not provide the correct result. > > With linux-next and HRTIMER_REARM_DEFERRED this leads to the observed boot > problems, however the commit is broken in any case. > > Revert the commit which introduced this. > > Thanks to Peter Zijlstra for pointing out that this is a bug in the s390 > entry code. > > Fixes: d8b5cf9c6314 ("s390/irq/idle: Remove psw bits early") [1] > Reported-by: Mikhail Zaslonko > Reported-by: Peter Zijlstra > Closes: https://lore.kernel.org/r/af549a19-db99-4b16-8511-bf315177a13e@linux.ibm.com/ [2] > Signed-off-by: Heiko Carstens > --- > arch/s390/kernel/irq.c | 14 ++++++++------ > 1 file changed, 8 insertions(+), 6 deletions(-) Acked-by: Vasily Gorbik Applied, thank you!