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Thu, 17 Sep 2026 06:58:24 +0000 (GMT) Received: from tuxmaker.lnxne.boe (unknown [9.87.85.9]) by smtpav07.fra02v.mail.ibm.com (Postfix) with ESMTP; Thu, 17 Sep 2026 06:58:24 +0000 (GMT) From: Alexander Egorenkov To: oberpar@linux.ibm.com Cc: gor@linux.ibm.com, hca@linux.ibm.com, agordeev@linux.ibm.com, borntraeger@linux.ibm.com, linux390-list@tuxmaker.boeblingen.de.ibm.com, linux-s390@vger.kernel.org Subject: [PATCH v5 0/4] s390/sclp: Misc fixes Date: Thu, 17 Sep 2026 08:58:20 +0200 Message-ID: <20260917065824.2858737-1-egorenar@linux.ibm.com> X-Mailer: git-send-email 2.53.0 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTE3MDA4NiBTYWx0ZWRfXycXD49V5rEXz 6Et4RonSjvelgJx3/gQw5AuxrUtshOoKTDWbbQIJLksxLaQxhRKuLR71pJzTbrNs+oT4h83akKA xiMsRcHfEQdbIiSk6uBcM/bBJ8tYvh3AsCVVB7UoPMz54EH6GySReLRE09k+TO83LFtxsZH+CVV DYUlbLXoyPmqfeisUQOxvaiC2nVlgLXqqSji0X+o6HK1AuF5rkyTtTHjmMlYY1kq+MbA14aXB63 PHNtwg+1FmmPKXhBVyJuCrmDqZQd9i5yO4UuaJ7mZl13InpChRNLyq0KxI0pSW65TYZzDj26XKg rnchb7JMNH6qpsimGj8pw16wNm8o9JD9fLm/ahWdyJIYIcxWs+SaxpEen4TOK/F+fFOgvZDudut TxYVZfQq6vcgjsHeCf0XFeFkPkwjT+8NX164v6q/RVBLVqWypurdneTaOa/tBXHvG/1FXiDgFUe 68rPrauhPhVvp4rKWzg== X-Proofpoint-ORIG-GUID: AEJyjr59GI1-6rxfBjf33GbQwah-NPkG X-Proofpoint-GUID: AEJyjr59GI1-6rxfBjf33GbQwah-NPkG X-Proofpoint-Spam-Info: AW1haW4tMjYwOTE3MDA4NiBTYWx0ZWRfX8W0DfBzslPFH gPwAHeBWsxjAiR2GtQAVM52+MokDav8HLwsc6Vd1ss7DPSi654Y6eJKeH3LZ/hvHQhi+2S2n00v Lbdy3ViX+G6qd+A8pUAAkalKa6yyUQQ= X-Authority-Analysis: v=2.4 cv=cY9HPXDM c=1 sm=1 tr=0 ts=6aab8f97 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=VdqzKS8jKosA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=97JCGAZeZryCTmDfBgsA:9 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=2026-09-17_01,2026-09-16_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 spamscore=0 bulkscore=0 clxscore=1015 suspectscore=0 impostorscore=0 malwarescore=0 phishscore=0 adultscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609170086 This series consists of several fixes for the s390 SCLP driver. * The first patch introduces the macro sclp_gds_for_each() to safely iterate over GDS {sub}vectors and serves to improve error handling in sclp_find_gds_{sub}vector() to prevent out-of-range memory read and potential infinite loops when a malformed event buffer is received from SCLP. * The second patch reuses the macro sclp_gds_for_each() in SCLP TTY introduced in the first patch to replace manual and error-prone iteration over entries of a GDS {sub}vector to fix the same issues addressed in the first patch. * The third patch fixes 2 potential illegal memory accesses when reading the value from a GDS subvector in SCLP event buffers sent by OCF. * The fourth patch fixes race situations with in-flight callbacks and sclp_unregister() calls. Changes since v4 ---------------- - Drop patch "s390/sclp: Drop volatile type class from SCLP state variables" - There are several doubts to it being correct in all situations - Introduce the macro sclp_gds_for_each() - Reusable and safe iteration over GDS {sub}vectors - Make use of sclp_gds_for_each() in SCLP TTY - Rework the patch "s390/sclp: Ensure no callback gets called after sclp_{un}register() returns" - Remove waiting for SCLP mask and reading states to become idle from sclp_register() on sclp_init_mask() failure - First, it is incorrect to sleep in sclp_register() which is called from atomic context - sclp_console_init() -> sclp_rw_init() -> sclp_register() - sclp_vt220_con_init() -> __sclp_vt220_init() -> sclp_register() - Second, it is redundant because no race situation can occur if sclp_init_mask() fails because in that case no events can be received from SCLP due to SCLP receive event mask update performed in sclp_init_mask() having failed - Add might_sleep() to sclp_unregister() to indicate that the function could potentially sleep - Adjust coding style of function sclp_unregister() - Add "Fixes" tag where necessary Changes since v3 ---------------- - Rework the patch "s390/sclp: Ensure no callback gets called after sclp_{un}register() returns" - Shorten and reword the commit description - Replace wake_up_all_locked() with wake_up_all() - Replace sclp_init_state with sclp_mask_state in wait queue condition - Call wake_up_all() unconditionally - Add call to wake_up_call() in sclp_init_mask() after updating sclp_mask_state Changes since v2 ---------------- - Add 2 new patches: - s390/sclp: Drop volatile type class from SCLP state variables - s390/sclp: Improve robustness of sclp_find_gds_{sub}vector() - Rework the patch "s390/sclp: Ensure no callback gets called after sclp_unregister() returns" to implement Peter Oberparleiter's suggestion with a global wait queue and checking the state variables as its condition. It turns out the implementation with a single completion per struct sclp_register is inadequate because theoretically the callback state_change_fn() and receive_fn() could get invoked in parallel, however unlikely. Furthermore, the same race situation might happen with sclp_register() too. Changes since v1 ---------------- - Drop redundant empty lines in sclp.c - Make commit message more verbose for the fix in sclp.c Alexander Egorenkov (4): s390/sclp: Introduce macro sclp_gds_for_each() s390/sclp_tty: Make use of sclp_gds_for_each() s390/sclp_ocf: Fix computation of length of GDS values s390/sclp: Ensure no callback gets called after sclp_unregister() returns drivers/s390/char/sclp.c | 24 ++++++++++++++++++------ drivers/s390/char/sclp.h | 24 ++++++++++++++++-------- drivers/s390/char/sclp_ocf.c | 4 ++-- drivers/s390/char/sclp_tty.c | 30 +++++++++++++++--------------- 4 files changed, 51 insertions(+), 31 deletions(-) -- 2.53.0