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Tue, 27 Oct 2026 14:30:31 +0000 (GMT) Received: from tuxmaker.lnxne.boe (unknown [9.87.85.9]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Tue, 27 Oct 2026 14:30:31 +0000 (GMT) From: Heiko Carstens To: Alexander Gordeev , Sven Schnelle , Vasily Gorbik , Christian Borntraeger , Ilya Leoshkevich Cc: linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org Subject: [PATCH v2 02/10] s390/ftrace: Serialize text patching with text_mutex Date: Tue, 27 Oct 2026 15:30:22 +0100 Message-ID: <20261027143030.3154657-3-hca@linux.ibm.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261027143030.3154657-1-hca@linux.ibm.com> References: <20261027143030.3154657-1-hca@linux.ibm.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYxMDI3MDA1NiBTYWx0ZWRfX8oCqLCfapnS2 xBgJv87Xx2UoZ8CerVmcbR9EUcZ81Y2ZqKpQDV9lwJ78C5Zo3PVbFvylujiDY9QIzmhkTfUV/jX PQYfhNSEnMaSWNuWedxK5aT62RFO6tE= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYxMDI3MDA1NiBTYWx0ZWRfX1j48Bm5hZaQb 3qYVmROQjapvjl/BM1JZNbeZEvcpGZ1sWfE+LKOgX8OEoebfRMsdNWl79MOquUOZ/u0vX+QKdlV CqNYWcQP8qbI6EZjYQ6YKCcfvOKLVJqN3dlNA6mpE9tx0ro2V3hTqiYMQv5vBsTAflutxXv9//f d5oekne1p6q4xm77/afiCWP+goWUkLl0RyAdeUFN40FT19nZLaFW2CcHwzVJmnqD9yA4Miml56+ T/FHT2wlBJV1ppfCMddEzS3T61bSe3H68VdimiUoeHVTo+X9jcUM2+Y6ifxOxoYJFdCHhMG8n99 ycbkFRltf3mbKcjRwSMH1mqMQIWgH53q3KTTTVIMdO1MFUTD1RJnFx9j5XrEpYYHjq2IZQEfP7B IhREz4nP/OTsgIBhzQsVqAOcDoXlRUwEQZ9dSNHAho7bCkV+9wUqx3YEuR/UVpUyjTOAt8cvWdo 66Mff8BDD9M9XOVsvzA== X-Proofpoint-ORIG-GUID: fpJExi3LiK7X5v1QVoSuUr3CUfRnGyOJ X-Authority-Analysis: v=2.4 cv=Uu32pOwB c=1 sm=1 tr=0 ts=6ae0b58c cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=660iZSQnnn4A:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=TQKjL49O_MRvjM01t5MA:9 X-Proofpoint-GUID: fpJExi3LiK7X5v1QVoSuUr3CUfRnGyOJ X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.138,FMLib:17.12.100.49 definitions=2026-10-27_03,2026-10-21_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 priorityscore=1501 spamscore=0 adultscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2610190000 definitions=main-2610270056 Add ftrace_arch_code_modify_prepare() and extend ftrace_arch_code_modify_post_process() to acquire and release text_mutex when ftrace code is modified. Also add locking to ftrace_init_nop(). This way s390 uses text_mutex like e.g. x86 and riscv. This is part of larger series where at the end s390_kernel_write() requires that callers hold text_mutex for serialization. Signed-off-by: Heiko Carstens --- arch/s390/kernel/ftrace.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/arch/s390/kernel/ftrace.c b/arch/s390/kernel/ftrace.c index e94bb98f5231..2f0c4ef1b2d6 100644 --- a/arch/s390/kernel/ftrace.c +++ b/arch/s390/kernel/ftrace.c @@ -8,6 +8,7 @@ */ #include +#include #include #include #include @@ -90,6 +91,8 @@ int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec) BUILD_BUG_ON(sizeof(struct ftrace_hotpatch_trampoline) != SIZEOF_FTRACE_HOTPATCH_TRAMPOLINE); + guard(mutex)(&text_mutex); + next_trampoline = &next_vmlinux_trampoline; trampolines_end = __ftrace_hotpatch_trampolines_end; shared = ftrace_shared_hotpatch_trampoline(NULL); @@ -247,13 +250,21 @@ int ftrace_update_ftrace_func(ftrace_func_t func) return 0; } +void ftrace_arch_code_modify_prepare(void) + __acquires(&text_mutex) +{ + mutex_lock(&text_mutex); +} + void arch_ftrace_update_code(int command) { ftrace_modify_all_code(command); } void ftrace_arch_code_modify_post_process(void) + __releases(&text_mutex) { + mutex_unlock(&text_mutex); /* * Flush any pre-fetched instructions on all * CPUs to make the new code visible. -- 2.53.0