From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DDC783793AA for ; Fri, 27 Mar 2026 17:22:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774632162; cv=none; b=HP12jgUFRUT7um/hPgJLf8Y6tPVMCpn3s3Vt30RFBFaxfY+auKVfY4wZSwpKl0UkN/TpEFKwc8gAxV7P/EJD1/qUOKT+TG0lc1nmR3DHNR6OTkBUVPPxGP3kC2TCck+HNjJW6DvV5w2E873XfMvnGl2wgzsY/fSZMQo2WzHd1j0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774632162; c=relaxed/simple; bh=YcbPvOq/yeRMxervP6BdeE7ACHJPBhkrpCpKz04b7U8=; h=Date:To:From:Subject:Message-Id; b=Ym2hrHZiSRz+iHtlFEEg/gGZ82141SaBqKbIvkFIBP8wBCqPqQyCTcAoACU2T+F+UjmVgZbCOwSGzl5hrJUxl8V8+yg9kuxvw5cfA9uXivGJ5epVx7cTrV8CvpxA65N6YX6jSLDpCvLCFT/26RNl2pysCfrH0oJwYFlRvK58fUA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=0ccFlD31; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="0ccFlD31" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 867EAC19423; Fri, 27 Mar 2026 17:22:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1774632162; bh=YcbPvOq/yeRMxervP6BdeE7ACHJPBhkrpCpKz04b7U8=; h=Date:To:From:Subject:From; b=0ccFlD31JZLaJmJOj6ILzElocbQ4IpIXb/F8rumn9KtGScOdlXDBcYj/t+9LZU4Y7 G2D2K+Unoo9ckJtST/5TDmVcibC1Uypi+qQxBr6BalpD9nRpKZ1gjZJ2Ris5JULuAX t9T/agBziZHyZltY9zhNRFBDzf7eefzNUwIm1Ht8= Date: Fri, 27 Mar 2026 10:22:42 -0700 To: mm-commits@vger.kernel.org,pasha.tatashin@soleen.com,akpm@linux-foundation.org From: Andrew Morton Subject: + liveupdate-defer-flb-module-refcounting-to-active-sessions.patch added to mm-new branch Message-Id: <20260327172242.867EAC19423@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: liveupdate: defer FLB module refcounting to active sessions has been added to the -mm mm-new branch. Its filename is liveupdate-defer-flb-module-refcounting-to-active-sessions.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/liveupdate-defer-flb-module-refcounting-to-active-sessions.patch This patch will later appear in the mm-new branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Note, mm-new is a provisional staging ground for work-in-progress patches, and acceptance into mm-new is a notification for others take notice and to finish up reviews. Please do not hesitate to respond to review feedback and post updated versions to replace or incrementally fixup patches in mm-new. The mm-new branch of mm.git is not included in linux-next If a few days of testing in mm-new is successful, the patch will me moved into mm.git's mm-unstable branch, which is included in linux-next Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via various branches at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there most days ------------------------------------------------------ From: Pasha Tatashin Subject: liveupdate: defer FLB module refcounting to active sessions Date: Fri, 27 Mar 2026 03:33:29 +0000 Stop pinning modules indefinitely upon FLB registration. Instead, dynamically take a module reference when the FLB is actively used in a session (e.g., during preserve and retrieve) and release it when the session concludes. This allows modules providing FLB operations to be cleanly unloaded when not in active use by the live update orchestrator. Link: https://lkml.kernel.org/r/20260327033335.696621-6-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin Cc: David Matlack Cc: Mike Rapoport Cc: Pratyush Yadav Cc: Samiullah Khawaja Signed-off-by: Andrew Morton --- kernel/liveupdate/luo_flb.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) --- a/kernel/liveupdate/luo_flb.c~liveupdate-defer-flb-module-refcounting-to-active-sessions +++ a/kernel/liveupdate/luo_flb.c @@ -115,10 +115,15 @@ static int luo_flb_file_preserve_one(str struct liveupdate_flb_op_args args = {0}; int err; + if (!try_module_get(flb->ops->owner)) + return -ENODEV; + args.flb = flb; err = flb->ops->preserve(&args); - if (err) + if (err) { + module_put(flb->ops->owner); return err; + } private->outgoing.data = args.data; private->outgoing.obj = args.obj; } @@ -146,6 +151,7 @@ static void luo_flb_file_unpreserve_one( private->outgoing.data = 0; private->outgoing.obj = NULL; + module_put(flb->ops->owner); } } } @@ -181,12 +187,17 @@ static int luo_flb_retrieve_one(struct l if (!found) return -ENOENT; + if (!try_module_get(flb->ops->owner)) + return -ENODEV; + args.flb = flb; args.data = private->incoming.data; err = flb->ops->retrieve(&args); - if (err) + if (err) { + module_put(flb->ops->owner); return err; + } private->incoming.obj = args.obj; private->incoming.retrieved = true; @@ -237,6 +248,7 @@ static void luo_flb_file_finish_one(stru private->incoming.data = 0; private->incoming.obj = NULL; private->incoming.finished = true; + module_put(flb->ops->owner); } } } @@ -412,11 +424,6 @@ int liveupdate_register_flb(struct liveu goto err_resume; } - if (!try_module_get(flb->ops->owner)) { - err = -EAGAIN; - goto err_resume; - } - list_add_tail(&private->list, &luo_flb_global.list); luo_flb_global.count++; } @@ -493,12 +500,11 @@ int liveupdate_unregister_flb(struct liv private->users--; /* * If this is the last file-handler with which we are registred, remove - * from the global list, and relese module reference. + * from the global list. */ if (!private->users) { list_del_init(&private->list); luo_flb_global.count--; - module_put(flb->ops->owner); } up_write(&luo_register_rwlock); @@ -527,7 +533,8 @@ err_resume: * * Return: 0 on success, or a negative errno on failure. -ENODATA means no * incoming FLB data, -ENOENT means specific flb not found in the incoming - * data, and -EOPNOTSUPP when live update is disabled or not configured. + * data, -ENODEV if the FLB's module is unloading, and -EOPNOTSUPP when + * live update is disabled or not configured. */ int liveupdate_flb_get_incoming(struct liveupdate_flb *flb, void **objp) { _ Patches currently in -mm which might be from pasha.tatashin@soleen.com are liveupdate-prevent-double-management-of-files.patch memfd-implement-get_id-for-memfd_luo.patch selftests-liveupdate-add-test-for-double-preservation.patch liveupdate-safely-print-untrusted-strings.patch liveupdate-synchronize-lazy-initialization-of-flb-private-state.patch liveupdate-protect-file-handler-list-with-rwsem.patch liveupdate-protect-flb-lists-with-luo_register_rwlock.patch liveupdate-defer-flb-module-refcounting-to-active-sessions.patch liveupdate-remove-luo_session_quiesce.patch liveupdate-auto-unregister-flbs-on-file-handler-unregistration.patch liveupdate-remove-liveupdate_test_unregister.patch liveupdate-make-unregister-functions-return-void.patch liveupdate-defer-file-handler-module-refcounting-to-active-sessions.patch