From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.163 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794411665; b=D4C9i1/0a0nDlG6UmLsHkO7rEqwSLqETYG9jAp8qr9e1q71Jk8hI6h3Vc66GOcsbsWfM PCx85Rao4oEeexFArcmb+UfEUZ+cmSP59WA2FSZXg37qPxwPcEg+qZQPrShfsGKZb9uJn UAA62MJJ89KgSMDl+jDsmvjSu8Nsn0EloPiwKZcbTt5N4qCuOjbxA7+q6WBHyKSV2MN+J PZOLFxKRLqrQV908elo507erb5k/6ocrIv/K4DwAUzokiCTCc5uGFcO21dzmAju9CE+Y/ 9hjQFqPLebI7kJgbS2v3NY34IOsEzYeBPerxXuvrfhunaVUbQTBK8r67ZEOzHabbMrA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794411665; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Date:From:To:CC:Subject:In-Reply-To: References:Message-ID:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=V2RK/PzuSKL2WWoPvMWzGQDcrRR0IyUh0nU/ByMaJ4Q=; b=qtu8WoWNTeovavKEiHigHcvgn9Aicx+6lZww98EsV6QvCKhKwR7bnR595uqnuOxCQNbn fJnQkGQ5rruVAqwoC38QB+mKSpVc3GmD7VzaxlWUdy/4Noy+sijU5xIpWdy4liqkGzdZf do+qULB+MblVF0gvJI7AzEgVSaXUWRPINDCMPfRXgqRpkYBRi/h7ONQ1fZ1y9i5wxzzyL 3qxl7y1/tg0MvQLhnq4s2N37P/WQVbwYjhhhGpHNZO2lz1XmRUp8//dZQfrun19Tdgky5 wHEgIh7qlcKDfx8MEeOv89u+6aR0U+DjeFNA//+UN/zDvIh8JTAmr6ri73smr8+9dww== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=O4WjbTiC; arc=none smtp.remote-ip=95.215.58.163 Received: from mta1.migadu.com (out-163.mta1.migadu.com [95.215.58.163]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 81676606A324 for ; Wed, 11 Nov 2026 15:41:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 81676606A324 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=O4WjbTiC X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=Eu89BSEwRX3HTJBZoUqF/4O/mFGX7rsk8i5L0YqInwg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1794411661; v=1; x=1795016461; b=O4WjbTiCDcDDTMdSJmO9z6O9LneyWgZ7wTbeHGWbKKuIKNOs6rfmNleYSG+vuW3v8RyTnEak O6YENCmg/1/bgm7J7ogOmbEriJR6qGxGoQff97MRQxlRFymbc/LfsIl3ZGEEnU7zE5ekGAIspQ3 mpWeT4TkDnsfoYbA/tmJTA1o= X-Envelope-To: linux-kernel@vger.kernel.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: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit 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!