From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-wr1-f43.google.com (mail-wr1-f43.google.com [209.85.221.43]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8E370408626 for ; Tue, 30 Jun 2026 11:59:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.221.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782820779; cv=none; b=Oyzol1meee6ruCTQ3gnrQ093xbGSTcAwKXWp00LugQjBvkSOrvAMjt7XYkiAJVLzi+fMGP1IksmwjT+WoJMdIvHf4RB0IJhVxZ0C4oMuXQd4f5GqHRzmZW1g2wqQyvIw36vxXIoCfkdb4LYRw9tGPxhvX61jFbQsSVFiV11tgNE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1782820779; c=relaxed/simple; bh=fvWUtTUUvTpQkCVxc6+vBkhTH2MPEvAFwFLKcBihbxk=; h=From:Date:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=BsgUkLJWChr3FzY4Ku/QT0fhGnkvh5iZye/OuMuQjBVASYxi83ukrWuRI4qI7AxXnleEoWQc9XBFCMp6xczO2gwTLp2xeRUnEQv199BNVxQ6c2DqFrD4A8hxDPpNRjKPgNWEqI12zRTlFtk68JBWV7KXz80W/Ex2qnmmLRhfASw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b=p/26EK3Y; arc=none smtp.client-ip=209.85.221.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="p/26EK3Y" Received: by mail-wr1-f43.google.com with SMTP id ffacd0b85a97d-475881b9a4bso877615f8f.3 for ; Tue, 30 Jun 2026 04:59:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1782820777; x=1783425577; darn=vger.kernel.org; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:date:from:from:to:cc:subject :date:message-id:reply-to:content-type; bh=Wtjkuyq+MLHO8ZADzDM8QMisoUEPsdDW4dYskthH/dw=; b=p/26EK3YMD/92YGR0nKIUmKpHyW6E1LGeop/iWRq2eP7fKHjjiDPBWCxcHIuQatlwa AnE4Q70SbL47IKIg7ptayW467j2NX1uSMKL2sjTMxZJrFLsQ3NADMZ2PA55mQLeYmUDO 9BlGMXn00nbKjb/KIi9b2wDuj7g2d7QVZSFNC/eDdu3UaIQ/qD1sJgUZnuq91056qlD7 SSq7Ek1Z2mzWZmsSq6SdKfXHy4G7dG5MF2l3Ch88vFcV23nmjl0FvZkr0gwi7P9919M2 EN8p0ynxD9xW+um0E3GrmpzYo3xCNPcBvhg4eHtZjV19ft+IZ0AesKfJwrTYm3LKIZR2 Lb0A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782820777; x=1783425577; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:date:from:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Wtjkuyq+MLHO8ZADzDM8QMisoUEPsdDW4dYskthH/dw=; b=QUSjOFjPMsQsQNtbfWWASfeLcPlNSlRTMXmrdVknViOyjYYa9EkI5sqwOtqOvQQQ8r 5jVKpE92UntArkiOnpc7nsOMr+tInALUjmEJK8M248MSpjye64/XEoShOiKHhr/+kbhE u9X4i4zh+v5yZln2UHU0ZhtC9acTmyfy7xWo2LJBZKVQUebwCMZw2ydcZhUI+S/r3aqD Uj80n/YVAalY20OfM2pjPPKfA7TR37fQdLxdGedq4UQH8XooXGghUlxuf1iVkZtRp3sv xO6vX7hXaYBZlw5FUbaenzjNGUSfltDVyatPbO1yqT2pdQCouy9fbqNdlV9lbtHvDkKs xvOg== X-Forwarded-Encrypted: i=1; AHgh+RrLuFIs6k8cGekNnJGe/G+nh89d26lOVCqRg/wAVtEno3JE35rZC1o+9t0gwpLWFEp0CUKK1aJXmK1QH8zSJ9c=@vger.kernel.org X-Gm-Message-State: AOJu0Yx9USGxanswErX3b0772R7t7FR7zK7SC481368ZibSfT/H+3Uw+ /JabIoFMHIRGbehdhkNpwuRR3+OynSiyLvB9TZ2/Nv5Cd/fg+b/LhxsL X-Gm-Gg: AfdE7cnCFlqSOOEY3mfNEVAQ+U+V7V56fSYfp+9FH3WCmBpJnEYgxznN/b1A4DWwHx3 vNVDu25IzyaI7n9BSeY2uIrLuM5aotxsiMVx9v1V8mK2G1piD0F0rUawinPDVXD04xgewdWllIo SKubrQF5EktbV7ANZvCetDtr2JX26N3xR7ZdwhhdqS689hXmFQOMZiOM/vJAO50Dsj71up0vBjd eBRfEZtmf+ne4A/RZUXDl6JxzwzKGaizY59jj0/xeFN3joXXZ3mJqmoleeEgxvB0jKBJe5wmrsX 2Aq1kU9alywbt2gQcqdyTaHdUA+doTIEPKX+a7m7h96XjxH1jcWfXMEtuRyluud0C4vbiUoDNK1 mcBsiUsf5Kx4+FDveaw7cd6kMc1+4xWN81CddIYO8hJDtJXxtjWcWQSU4KYphRnwdkF8nFhcNKq +wpGOZvyWvp7TKns3q5jcUJxiu X-Received: by 2002:a05:6000:4381:b0:475:f100:35fa with SMTP id ffacd0b85a97d-475f1003789mr2289639f8f.55.1782820776839; Tue, 30 Jun 2026 04:59:36 -0700 (PDT) Received: from krava (37-188-177-177.red.o2.cz. [37.188.177.177]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-475671d02f5sm7790027f8f.28.2026.06.30.04.59.33 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 30 Jun 2026 04:59:36 -0700 (PDT) From: Jiri Olsa X-Google-Original-From: Jiri Olsa Date: Tue, 30 Jun 2026 13:59:29 +0200 To: David Windsor Cc: mhiramat@kernel.org, oleg@redhat.com, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, shuah@kernel.org, rick.p.edgecombe@intel.com, linux-trace-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/2] x86/uprobes: Keep shadow stack in sync for emulated CALLs Message-ID: References: <8b5b1c7407b98f31664ad7b6a6faf20d2d4a6cad.1782777969.git.dwindsor@gmail.com> Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8b5b1c7407b98f31664ad7b6a6faf20d2d4a6cad.1782777969.git.dwindsor@gmail.com> On Mon, Jun 29, 2026 at 08:13:33PM -0400, David Windsor wrote: > Uprobe CALL emulation updates the normal user stack, but not the CET user > shadow stack. The subsequent RET then sees a stale shadow stack entry and > raises #CP. > > Update the relative CALL emulation and XOL CALL fixup paths to keep the > shadow stack in sync. > > Fixes: 488af8ea7131 ("x86/shstk: Wire in shadow stack interface") > Signed-off-by: David Windsor hi, lgtm Tested-by: Jiri Olsa Acked-by: Jiri Olsa jirka > --- > > v2: > - propagate error from shshk_update_last_frame() rather than returning > -ERESTART in default_post_xol_op(). (Oleg) > > v1: https://lore.kernel.org/all/20260622183109.1137245-1-dwindsor@gmail.com/ > > arch/x86/kernel/uprobes.c | 12 +++++++++++- > 1 file changed, 11 insertions(+), 1 deletion(-) > > diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c > index ebb1baf1eb1d..d74bb54543b6 100644 > --- a/arch/x86/kernel/uprobes.c > +++ b/arch/x86/kernel/uprobes.c > @@ -1246,9 +1246,15 @@ static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs > long correction = utask->vaddr - utask->xol_vaddr; > regs->ip += correction; > } else if (auprobe->defparam.fixups & UPROBE_FIX_CALL) { > + unsigned long retaddr = utask->vaddr + auprobe->defparam.ilen; > + int err; > + > regs->sp += sizeof_long(regs); /* Pop incorrect return address */ > - if (emulate_push_stack(regs, utask->vaddr + auprobe->defparam.ilen)) > + if (emulate_push_stack(regs, retaddr)) > return -ERESTART; > + err = shstk_update_last_frame(retaddr); > + if (err) > + return err; > } > /* popf; tell the caller to not touch TF */ > if (auprobe->defparam.fixups & UPROBE_FIX_SETF) > @@ -1338,6 +1344,10 @@ static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs) > */ > if (emulate_push_stack(regs, new_ip)) > return false; > + if (shstk_push(new_ip) == -EFAULT) { > + regs->sp += sizeof_long(regs); > + return false; > + } > } else if (!check_jmp_cond(auprobe, regs)) { > offs = 0; > } > -- > 2.53.0 >