From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from toronto-edge.smtp.mymangomail.com (toronto-edge.smtp.mymangomail.com [209.38.81.170]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9DD9E18E025 for ; Sat, 21 Mar 2026 14:39:46 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.38.81.170 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774103989; cv=none; b=D5nb4Cm7DHAjRec70dJZd/Gx+Hj9STsxcuJ2/FdaM9CiVdHB+7ZT07P94lWuogOvk0HTR8+JHI8RacBs6oSc0c0u9Mms80Lag/S8N29NnXk2Sac8veHkCsIlYlx9hdee4PC7dQ/hXzt4qy/+gv9Rq/Uk376ls2Qbw9lrMbLtw3U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774103989; c=relaxed/simple; bh=jz9Jb4ua+BZoDIIioX5BJmmKHIi5gc9v+wumLKcLorw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=alCiAxu7BKYbc5a4mBrfSb0hNz8zLXvuI++TVaTj6T7c+P4zPAFqM/LhCu+afM1+BdoZ8JzKb+RCmbZbQiwHN9Nu2cK9yzMWEFKdaJ8Ic1t+4WbGjWsPXc6uH69023DGowkbAGEwcie9JkcT7h/3Yyvt3rR/j6qR+Sxnn1rxltk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gerlicz.space; spf=pass smtp.mailfrom=gerlicz.space; dkim=pass (1024-bit key) header.d=gerlicz.space header.i=@gerlicz.space header.b=JVqdmvMK; arc=none smtp.client-ip=209.38.81.170 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=gerlicz.space Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gerlicz.space Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=gerlicz.space header.i=@gerlicz.space header.b="JVqdmvMK" Received: from smtp.mymangomail.com (localhost [127.0.0.1]) by smtp.mymangomail.com (Mango Mail) with ESMTP id 38265408C6; Sat, 21 Mar 2026 10:39:37 -0400 (EDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=gerlicz.space; s=mango-1; t=1774103977; bh=jz9Jb4ua+BZoDIIioX5BJmmKHIi5gc9v+wumLKcLorw=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=JVqdmvMKUvq7LkIocLlE+laSboKDD8eUR7gtgbTJNfrEUqkWY7oww1mbKyjxe15ZH +B46IAuq0t89QKyh2cxDSV/TKkLdndJ0H2bh7Y4CajAdagVA5N9j1wwXjFrbgDafcT jExo16mpKfZI0hj7IJrVuaBXiN3EI6DRSKsOOehY= X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 X-Mango-Origin: 1 Received: from authenticated-user (smtp.mymangomail.com [205.185.121.143]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by smtp.mymangomail.com (Mango Mail) with ESMTPSA id 2255641648; Sat, 21 Mar 2026 10:38:15 -0400 (EDT) From: Oskar Gerlicz Kowalczuk To: Pasha Tatashin , Mike Rapoport , Baoquan He Cc: Pratyush Yadav , Andrew Morton , linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, Oskar Gerlicz Kowalczuk Subject: [PATCH v3 2/5] kexec: abort liveupdate handover on kernel_kexec() unwind Date: Sat, 21 Mar 2026 15:36:39 +0100 Message-ID: <20260321143642.166313-2-oskar@gerlicz.space> In-Reply-To: <20260321143642.166313-1-oskar@gerlicz.space> References: <20260321143642.166313-1-oskar@gerlicz.space> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit liveupdate_reboot() can freeze outgoing session state before the kexec transition completes. v2 only unwound that state when kernel_kexec() returned a non-zero error, which misses the preserve_context path where machine_kexec() can return to the old kernel with error == 0. If that return path skips the abort, outgoing sessions remain stuck in the reboot state and later user space operations cannot make progress. Treat every return to the original kernel after a prepared liveupdate handover as an unwind point and call liveupdate_reboot_abort() there as well. Fixes: 8b32d3ced269 ("kexec: abort liveupdate handover on kernel_kexec() unwind") Signed-off-by: Oskar Gerlicz Kowalczuk --- include/linux/liveupdate.h | 5 +++++ kernel/kexec_core.c | 6 +++++- kernel/liveupdate/luo_core.c | 11 ++++++++++- kernel/liveupdate/luo_internal.h | 1 + kernel/liveupdate/luo_session.c | 23 +++++++++++++++++++++++ 5 files changed, 44 insertions(+), 2 deletions(-) diff --git a/include/linux/liveupdate.h b/include/linux/liveupdate.h index dd11fdc76a5f..d93b043a0421 100644 --- a/include/linux/liveupdate.h +++ b/include/linux/liveupdate.h @@ -226,6 +226,7 @@ bool liveupdate_enabled(void); /* Called during kexec to tell LUO that entered into reboot */ int liveupdate_reboot(void); +void liveupdate_reboot_abort(void); int liveupdate_register_file_handler(struct liveupdate_file_handler *fh); int liveupdate_unregister_file_handler(struct liveupdate_file_handler *fh); @@ -250,6 +251,10 @@ static inline int liveupdate_reboot(void) return 0; } +static inline void liveupdate_reboot_abort(void) +{ +} + static inline int liveupdate_register_file_handler(struct liveupdate_file_handler *fh) { return -EOPNOTSUPP; diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index 2fea396d29b9..95710a7d5e56 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1139,6 +1139,7 @@ bool kexec_load_permitted(int kexec_image_type) int kernel_kexec(void) { int error = 0; + bool liveupdate_prepared = false; if (!kexec_trylock()) return -EBUSY; @@ -1147,6 +1148,7 @@ int kernel_kexec(void) goto Unlock; } + liveupdate_prepared = true; error = liveupdate_reboot(); if (error) goto Unlock; @@ -1230,7 +1232,9 @@ int kernel_kexec(void) } #endif - Unlock: +Unlock: + if (liveupdate_prepared) + liveupdate_reboot_abort(); kexec_unlock(); return error; } diff --git a/kernel/liveupdate/luo_core.c b/kernel/liveupdate/luo_core.c index dda7bb57d421..95a0b81ce60d 100644 --- a/kernel/liveupdate/luo_core.c +++ b/kernel/liveupdate/luo_core.c @@ -233,8 +233,9 @@ int liveupdate_reboot(void) err = kho_finalize(); if (err) { pr_err("kho_finalize failed %d\n", err); + liveupdate_reboot_abort(); /* - * kho_finalize() may return libfdt errors, to aboid passing to + * kho_finalize() may return libfdt errors, to avoid passing to * userspace unknown errors, change this to EAGAIN. */ err = -EAGAIN; @@ -243,6 +244,14 @@ int liveupdate_reboot(void) return err; } +void liveupdate_reboot_abort(void) +{ + if (!liveupdate_enabled()) + return; + + luo_session_abort_reboot(); +} + /** * liveupdate_enabled - Check if the live update feature is enabled. * diff --git a/kernel/liveupdate/luo_internal.h b/kernel/liveupdate/luo_internal.h index 0cfc0269d746..8a6b1f6c9b4f 100644 --- a/kernel/liveupdate/luo_internal.h +++ b/kernel/liveupdate/luo_internal.h @@ -88,6 +88,7 @@ int luo_session_retrieve(const char *name, struct file **filep); int __init luo_session_setup_outgoing(void *fdt); int __init luo_session_setup_incoming(void *fdt); int luo_session_serialize(void); +void luo_session_abort_reboot(void); int luo_session_deserialize(void); bool luo_session_quiesce(void); void luo_session_resume(void); diff --git a/kernel/liveupdate/luo_session.c b/kernel/liveupdate/luo_session.c index d97ec91e1118..200dd3b8229c 100644 --- a/kernel/liveupdate/luo_session.c +++ b/kernel/liveupdate/luo_session.c @@ -788,6 +788,29 @@ int luo_session_serialize(void) return err; } +void luo_session_abort_reboot(void) +{ + struct luo_session_header *sh = &luo_session_global.outgoing; + struct luo_session *session; + int i = 0; + + guard(rwsem_write)(&sh->rwsem); + if (!READ_ONCE(sh->rebooting)) + return; + + list_for_each_entry(session, &sh->list, list) { + if (i >= sh->header_ser->count) + break; + + luo_session_unfreeze_one(session, &sh->ser[i]); + memset(&sh->ser[i], 0, sizeof(sh->ser[i])); + i++; + } + + sh->header_ser->count = 0; + luo_session_reboot_done(sh); +} + /** * luo_session_quiesce - Ensure no active sessions exist and lock session lists. * -- 2.53.0