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s=key1; t=1794411661; v=1; x=1795016461; b=O4WjbTiCDcDDTMdSJmO9z6O9LneyWgZ7wTbeHGWbKKuIKNOs6rfmNleYSG+vuW3v8RyTnEak O6YENCmg/1/bgm7J7ogOmbEriJR6qGxGoQff97MRQxlRFymbc/LfsIl3ZGEEnU7zE5ekGAIspQ3 mpWeT4TkDnsfoYbA/tmJTA1o= X-Envelope-To: linuxppc-dev@lists.ozlabs.org Received: by smtp.migadu.com with ESMTPS id c6d4ac561fa4402f; Wed, 11 Nov 2026 15:41:01 +0000 X-Mizu-Trace-ID: c6d4ac561fa4402f X-Migadu-Flow: FLOW_OUT Date: Wed, 11 Nov 2026 15:40:57 +0000 From: Bradley Morgan To: Madhavan Srinivasan , ritesh.list@gmail.com CC: brads@mainlining.org, chleroy@kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mpe@ellerman.id.au, npiggin@gmail.com, sshegde@linux.ibm.com Subject: =?US-ASCII?Q?Re=3A_=5BPATCH=5D_powerpc32/modules=3A_Reser?= =?US-ASCII?Q?ve_a_PLT_entry_for_ftrace=5Fregs=5Fcaller?= In-Reply-To: <371108c3-0314-4015-9ca4-d96a11f1e597@linux.ibm.com> References: <80D9FEB3-9FB3-4878-BC66-74C13761CC9A@linux.dev> <371108c3-0314-4015-9ca4-d96a11f1e597@linux.ibm.com> Message-ID: <23E9A6DC-579A-4B62-B35C-578A8E3389BD@linux.dev> X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , Precedence: list X-Archived-By: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_PASS, SPF_PASS autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 On 11 November 2026 11:58:28 GMT, Madhavan Srinivasan wrote: > >On 11/11/26 12:58 PM, Bradley Morgan wrote: >> On 11 November 2026 03:48:41 GMT, Ritesh Harjani >> wrote: >>> Bradley Morgan writes: >>> >>>> Commit 7dfbfb87c243 ("powerpc/ftrace: Activate >>>> HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") made count_relocs() >>>> undercount the PLT entries the loader >>>> consumes: module_finalize_ftrace() now creates two trampolines >>>> (mod->arch.tramp for ftrace_caller() and mod->arch.tramp_regs for >>>> ftrace_regs_caller()), while count_relocs() reserves only one entry >>>> for ftrace. >>>> >>>> So the core .plt ends up one ppc_plt_entry (16 bytes) short. The >>>> walk in do_plt_call() scans for a free slot with >>>> "while (entry->jump[0])" and has no bound check, so once the last >>>> reserved slot is used up, the walk steps past the end of the section >>>> and patch_instruction() writes the 4-instruction trampoline into >>>> whatever module memory follows the .plt. >>>> >>>> Count the second entry, mirroring what module_64.c does for the same >>>> pair of stubs. >>>> >>>> Signed-off-by: Bradley Morgan >>>> --- >>>> arch/powerpc/kernel/module_32.c | 3 +++ >>>> 1 file changed, 3 insertions(+) >>>> >>> Do we also need fixes and stable tag here? >>> >>> Fixes: 7dfbfb87c243 ("powerpc/ftrace: Activate >HAVE_DYNAMIC_FTRACE_WITH_REGS on PPC32") >>> Cc: stable@vger.kernel.org >> Hmm.. could the merger add that? If anyone merges.. :( >planned to be part of my fixes PR and will add it. >Thanks for the fix. No worries, mind changing sob to this email? > >Maddy >>> >>> -ritesh >>> >> --- Thanks! > --- Thanks!