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Tue, 13 Oct 2026 07:07:29 +0000 (GMT) Received: from tuxmaker.linux.ibm.com (unknown [9.87.85.9]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTPS; Tue, 13 Oct 2026 07:07:29 +0000 (GMT) From: Sven Schnelle To: Heiko Carstens Cc: Alexander Gordeev , Vasily Gorbik , Christian Borntraeger , linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: Re: [PATCH] s390/signal: Fix incorrect return address in signal frame In-Reply-To: <20261012153355.1529314-1-hca@linux.ibm.com> (Heiko Carstens's message of "Mon, 12 Oct 2026 17:33:55 +0200") References: <20261012153355.1529314-1-hca@linux.ibm.com> Date: Tue, 13 Oct 2026 09:07:29 +0200 Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDEzMDAyNiBTYWx0ZWRfX/kwoxLBmXHrY kZYRbpAICyKGPNfDPYhiqQxV4AxNtAWOz2e00h4zPThmEbju9EXpO32UVdJ+7POcG17zz+ASXMX DwQNwYyenKwpaIvug7J4h7iqwji+dvpC4hb6urvYV/IpWAf4pctlZOkLMN8fidD1yuOnzpovOX1 BOcvmLH8HTn92AHG4/fNRtCuizCmXCF0lXmphEe03/Q+p2yb9Y/Fp/dB65UY7F+a8pfwiOyG3XG 0UOFFgkoFuOIzJ1bo8EevX8KLUuwA/UD5GcLTOZitZ42o/gCqhs2/wrZYmRLPzdGuFrJadqwrxh ncCRzB8gezBt0BTOmCZ8JF5DZMqL2IF7e01/4a7DQsKksjUCHNzM4gbIIKVNevTGjaATsIU51NB X8AZKvoB4uTUI7O8WgKq3HixNB1tHwB3Fmp2apfd74xdDG0//rs83KA6F2T6yGOIlwmPjKz8P2C 40qOXecGTdfBAiHHvIg== X-Proofpoint-Spam-Info: AW1haW4tMjYxMDEzMDAyNiBTYWx0ZWRfX+PrC2LQoOTHT wdPWobqBisd4+hzterCNcfOi9asqD1nUAzp1EQNYdXXQ70HCxT+EEIPAXaDBaPeoXBJWGhmR4Q5 /nFIr630A9zSsrXkma0U6YhyKmTYJRM= X-Proofpoint-ORIG-GUID: A0ZOZxIUQL0nWyGZnbmLzRBZMtE8UuzP X-Authority-Analysis: v=2.4 cv=a6KlZkSF c=1 sm=1 tr=0 ts=6acdd8b6 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=YxXDSYN5aMXGUAyqVTYA:9 X-Proofpoint-GUID: A0ZOZxIUQL0nWyGZnbmLzRBZMtE8UuzP X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-10-13_01,2026-10-09_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 malwarescore=0 spamscore=0 suspectscore=0 clxscore=1015 phishscore=0 priorityscore=1501 lowpriorityscore=0 impostorscore=0 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610080000 definitions=main-2610130026 Heiko Carstens writes: > exit_to_user_mode_loop() can call arch_do_signal_or_restart() multiple > times when signals are pending. > > If the first call set up a vDSO system call restart by saving the real > user return address and adjusting psw.addr so it points to the vDSO stub, > a second call builds the signal frame with the wrong return address. > > Restore psw.addr from arch_data before building the signal frame. > > Fixes: df29a7440c4b ("s390/signal: switch to using vdso for sigreturn and syscall restart") > Cc: stable@vger.kernel.org > Signed-off-by: Heiko Carstens > --- > arch/s390/kernel/signal.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/arch/s390/kernel/signal.c b/arch/s390/kernel/signal.c > index 4874de5edea0..25781d4a0ad0 100644 > --- a/arch/s390/kernel/signal.c > +++ b/arch/s390/kernel/signal.c > @@ -475,7 +475,10 @@ void arch_do_signal_or_restart(struct pt_regs *regs) > } > /* No longer in a system call */ > clear_pt_regs_flag(regs, PIF_SYSCALL); > - > + if (!(current->restart_block.arch_data & 1)) { > + regs->psw.addr = current->restart_block.arch_data; > + current->restart_block.arch_data = 1; > + } > rseq_signal_deliver(&ksig, regs); > handle_signal(&ksig, oldset, regs); > return; Reviewed-by: Sven Schnelle