From nobody Mon Jun 8 16:44:28 2026 X-Original-To: dev-commits-src-all@mlmmj.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mlmmj.nyi.freebsd.org (Postfix) with ESMTP id 4gYyYn2QwGz6gM98 for ; Mon, 08 Jun 2026 16:44:29 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from mxrelay.nyi.freebsd.org (mxrelay.nyi.freebsd.org [IPv6:2610:1c1:1:606c::19:3]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "mxrelay.nyi.freebsd.org", Issuer "R13" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 4gYyYm6jy5z3Dcn for ; Mon, 08 Jun 2026 16:44:28 +0000 (UTC) (envelope-from git@FreeBSD.org) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1780937069; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=RuANojvttz/jDCcMkFTQA+AfoSfRIZK9HncSNplK//k=; b=VdVA9sUPeZ+a2BE/kMvKrEwEc5XVUo12HWZ6MZ1UUo9sAxSsN4JtMNds5k3pyyVF8bh9PE OflUBL1iQZhCUVSUyOqQURWZz0x/Axx4GpArVfIa+f1hno/mRXMsHXSLMNJtEWO/2TB/gT 8Z11FXiIpHaA+1rSgdIlh14tAM5iuTnkIVj+2u8NCadP+LeGjltNFY+dy1nJ0QF5fi8Z6K 0TOLlKqajeqT0dSKnsLGiEg/QTM/xsrad7gZ4ua846jTM/Oru04x4SqT2RMzuchyBmW18g gKvYzeynWoDa5OzKub3e3H3+rdtpJ2K5ItVo/d1hJ+f/g5Eq16EsvUqOcRDyGA== ARC-Seal: i=1; s=dkim; d=freebsd.org; t=1780937069; a=rsa-sha256; cv=none; b=yezxp8j+ZBMIMf6AFzyFTaLh5yltKhqnoS17tvK7PNZS0zPO650fIqf9aOEI6FK8fKCsrf QNc4HzWuCZ9ZFDsOJ/iUa2rkGAgz1+M6E4D4KnE2Cd2OPbSUeNYFoh4568cYaXXNT90/UE mDpmFRAK7/v7WfXh6OdpBPJMD2aLKMHDzxq9K+mRuGckgtCVi+wTIV6pehP1OOUV6aPI3F +QVZwKGqSVNmJiFmjTmsz1F/g3292rjs2AfzTeagmwjWWmlXdtwbYYeUuwOK14RUlPIdrY lbNb/BqjSibpU1aehejjIekXYOnSo4deGbmtiXIoN4Ze4tp8i6G6LaF3HQOH6A== ARC-Authentication-Results: i=1; mx1.freebsd.org; none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=freebsd.org; s=dkim; t=1780937069; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=RuANojvttz/jDCcMkFTQA+AfoSfRIZK9HncSNplK//k=; b=M2dQ8ezSwXcm105+QabMYo6pvDIunFEkZThSNS0Hp1ewAuDeo8PuxQGAX4VCLqlhTe7D3h +x2W90Zu94fBSwDrd+U6K17zs5HQrQvN0diw07iGRd2bqb3wQ05XLPPhbhQZPTuuIv4xSw m8LFoWaH7Ez3Fgvb/InsOgdKyqe5cmhgRy8eXP26XYlt3290JknsyfcLxUkuRsMnGqqVXe KMNWlk2TxohtK5YHu3UG851lVg+QBqmkv+rK9RDugapjhAKWWzqdPNjkaPjMJVg8cAfru3 L/KEzc/VoECP2jKma3gBji8PQv1XVGMVH5PIQ3LG4PTNuhEGyGOPDOk3U1eXug== Received: from gitrepo.freebsd.org (gitrepo.freebsd.org [IPv6:2610:1c1:1:6068::e6a:5]) by mxrelay.nyi.freebsd.org (Postfix) with ESMTP id 4gYyYm5jmHzwyW for ; Mon, 08 Jun 2026 16:44:28 +0000 (UTC) (envelope-from git@FreeBSD.org) Received: from git (uid 1279) (envelope-from git@FreeBSD.org) id 25786 by gitrepo.freebsd.org (DragonFly Mail Agent v0.13+ on gitrepo.freebsd.org); Mon, 08 Jun 2026 16:44:28 +0000 To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-branches@FreeBSD.org From: Warner Losh Subject: git: 8dca7fccfa65 - stable/14 - loader.efi: Fix when staging moves late List-Id: Commit messages for all branches of the src repository List-Archive: https://lists.freebsd.org/archives/dev-commits-src-all List-Help: List-Post: List-Subscribe: List-Unsubscribe: X-BeenThere: dev-commits-src-all@freebsd.org Sender: owner-dev-commits-src-all@FreeBSD.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 X-Git-Committer: imp X-Git-Repository: src X-Git-Refname: refs/heads/stable/14 X-Git-Reftype: branch X-Git-Commit: 8dca7fccfa6514b0a48a290683572fadbb4e2a68 Auto-Submitted: auto-generated Date: Mon, 08 Jun 2026 16:44:28 +0000 Message-Id: <6a26f16c.25786.51544913@gitrepo.freebsd.org> The branch stable/14 has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=8dca7fccfa6514b0a48a290683572fadbb4e2a68 commit 8dca7fccfa6514b0a48a290683572fadbb4e2a68 Author: Warner Losh AuthorDate: 2026-06-05 05:18:40 +0000 Commit: Warner Losh CommitDate: 2026-06-08 16:34:58 +0000 loader.efi: Fix when staging moves late Prior to this commit, we'd compute the page tables and have the last entries point to the staging area. We'd then add some more metadata to the image and boot. This assumed the staging area didn't need to move for this last bit of data. However, if we go over the staging limit, when we copyin new data, we grow the staging area, usually be moving it to a lower address. This overage usually happens when we're loading modules and so things work out nicely. Sometimes we're close to the limit, and we need to do this growing inside bi_load, after we've computed the page table, making the page table wrong, and the code we jump to random rather than the btext routine we normally start at. To fix this, move computation of the table (but not its allocation) to after bi_load, but before we call the trampoline. This problem was most observed when loading microcode for many peole, but Gleb reproduced the error with a set of modules that didn't include ucode. This bug hunt was greatly assisted by Claude who looked at the crash from the EFI boot loader and surmised that we weren't jumping to the code we thought we were jumping to. After inspecting the code, I asked claude how corruption could happen (I thought overwriting the page table), but claude notice the possibility that staging might change after we computed the page table, and this fix is the result. Claude didn't suggest a diff, but did provide many helpful clues that lead me to this fix. PR: 294630 Reviewed by: kib (prior version) Sponsored by: Netflix MFC After: insta per re@ request Differential Revision: https://reviews.freebsd.org/D57462 (cherry picked from commit 3915ffb1c3e04b26d1506bf35d3f665b2e25a915) --- stand/efi/loader/arch/amd64/elf64_freebsd.c | 47 ++++++++++++++++++----------- stand/efi/loader/bootinfo.c | 19 +++++++++++- 2 files changed, 48 insertions(+), 18 deletions(-) diff --git a/stand/efi/loader/arch/amd64/elf64_freebsd.c b/stand/efi/loader/arch/amd64/elf64_freebsd.c index 91dd979a677e..72c8d558d8a6 100644 --- a/stand/efi/loader/arch/amd64/elf64_freebsd.c +++ b/stand/efi/loader/arch/amd64/elf64_freebsd.c @@ -94,7 +94,7 @@ elf64_exec(struct preloaded_file *fp) Elf_Ehdr *ehdr; vm_offset_t modulep, kernend, trampcode, trampstack; int err, i; - bool copy_auto; + bool copy_auto, needs_pt4; copy_auto = copy_staging == COPY_STAGING_AUTO; if (copy_auto) @@ -162,6 +162,7 @@ elf64_exec(struct preloaded_file *fp) PT2[i] = (pd_entry_t)i * (2 * 1024 * 1024); PT2[i] |= PG_V | PG_RW | PG_PS; } + needs_pt4 = false; } else { PT4 = (pml4_entry_t *)0x0000000100000000; /* 4G */ err = BS->AllocatePages(AllocateMaxAddress, EfiLoaderData, 9, @@ -173,7 +174,35 @@ elf64_exec(struct preloaded_file *fp) copy_staging = COPY_STAGING_AUTO; return (ENOMEM); } + needs_pt4 = true; + } + + printf("%scopying staging tramp %p PT4 %p\n", + copy_staging == COPY_STAGING_ENABLE ? "" : "not ", + trampoline, PT4); + printf("Start @ 0x%lx ...\n", ehdr->e_entry); + + /* + * we have to cleanup here because net_cleanup() doesn't work after + * we call ExitBootServices + */ + dev_cleanup(); + + efi_time_fini(); + err = bi_load(fp->f_args, &modulep, &kernend, true); + if (err != 0) { + efi_time_init(); + if (copy_auto) + copy_staging = COPY_STAGING_AUTO; + return (err); + } + /* + * staging might move in bi_load because we automatiaclly move when we + * copy data in. At this point, staging can't move anymore, so create + * PT4 with the correct value. + */ + if (needs_pt4) { bzero(PT4, 9 * EFI_PAGE_SIZE); PT3_l = &PT4[NPML4EPG * 1]; @@ -210,22 +239,6 @@ elf64_exec(struct preloaded_file *fp) } } - printf("staging %#lx (%scopying) tramp %p PT4 %p\n", - staging, copy_staging == COPY_STAGING_ENABLE ? "" : "not ", - trampoline, PT4); - printf("Start @ 0x%lx ...\n", ehdr->e_entry); - - efi_time_fini(); - err = bi_load(fp->f_args, &modulep, &kernend, true); - if (err != 0) { - efi_time_init(); - if (copy_auto) - copy_staging = COPY_STAGING_AUTO; - return (err); - } - - dev_cleanup(); - trampoline(trampstack, copy_staging == COPY_STAGING_ENABLE ? efi_copy_finish : efi_copy_finish_nop, kernend, modulep, PT4, ehdr->e_entry); diff --git a/stand/efi/loader/bootinfo.c b/stand/efi/loader/bootinfo.c index 2961b8b97fb7..e56cd90ed7b8 100644 --- a/stand/efi/loader/bootinfo.c +++ b/stand/efi/loader/bootinfo.c @@ -213,6 +213,17 @@ bi_load_efi_data(struct preloaded_file *kfp, bool exit_bs) } #endif +#if defined(__amd64__) || defined(__i386__) + extern uint64_t staging; + /* + * Staging can't move after this point, so report the final value before + * we try to exit boot services below. The metadata added is added to + * the malloced arena that we setup when we started and doesn't interact + * with boot services. + */ + printf("staging %#jx\n", (uintmax_t)staging); +#endif + do_vmap = true; efi_novmap = getenv("efi_disable_vmap"); if (efi_novmap != NULL) @@ -302,14 +313,20 @@ bi_load_efi_data(struct preloaded_file *kfp, bool exit_bs) * loader.conf(5). By default we will setup the virtual * map entries. */ - if (do_vmap) efi_do_vmap(mm, sz, dsz, mmver); + + /* + * Add the memory map to the metadata. addmetadata copies the data into + * the malloc arena, so we can safely free the memory map pages after. + * Or could if boot services was still running. + */ efihdr->memory_size = sz; efihdr->descriptor_size = dsz; efihdr->descriptor_version = mmver; file_addmetadata(kfp, MODINFOMD_EFI_MAP, efisz + sz, efihdr); + /* BS->FreePages(addr, pages); */ return (0); }