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 3EA1B175A9E for ; Fri, 27 Mar 2026 17:22:40 +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=1774632160; cv=none; b=lbWnY/gfehafPM0MZzGniOjpE9mD3JC/uVR6BS7e1H37qS1Megc5hinTCt/ZwYJgEJ9IiR26xoxNasPWvFmicSs3cwTGOojXoL+Br1RFy1ocTZRnVcdik05bwDwJvDjikTZjiFM7dZlmcIQay2YcHmkUyDdj3h29IPhCUuKH5W0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774632160; c=relaxed/simple; bh=UXGgsJMZTVehH+gKFgPJu1dVZ0Er1fqScTI1iAqJkho=; h=Date:To:From:Subject:Message-Id; b=RmS733Y5GzCmXf3aVz36My3oRLQqvXq+Cto+/sclAVJ68MYtvnOIFh8IPlsnowo4gHZQB7+oa7g+jVK8jHr/EgiFhAK3DAiFTaQTXp4qb4L2fzIHcur6Y/gXXa5uwBpMjshiBpm0Z4B5OEtIK3561Y0jyjLlSNeUtZCdVRwj50E= 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=FPB0bGDS; 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="FPB0bGDS" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F59BC19423; Fri, 27 Mar 2026 17:22:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1774632160; bh=UXGgsJMZTVehH+gKFgPJu1dVZ0Er1fqScTI1iAqJkho=; h=Date:To:From:Subject:From; b=FPB0bGDS76SnJoxAjxk5qwgtmxi5/y92IHLPYkM+K1xQ9+Rs/PD9ccvhWX+U6spV8 SziBha4HOzgPglsFqatsGcZLEVvjnbTNGlIN4ZCcTBZ2Yk6yBS642z3fsgGUjyxNjs sqWpiWL800brDpQPz+0zJYMT2m4uTICFozLmYBtU= Date: Fri, 27 Mar 2026 10:22:39 -0700 To: mm-commits@vger.kernel.org,pasha.tatashin@soleen.com,akpm@linux-foundation.org From: Andrew Morton Subject: + liveupdate-protect-flb-lists-with-luo_register_rwlock.patch added to mm-new branch Message-Id: <20260327172240.0F59BC19423@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: liveupdate: protect FLB lists with luo_register_rwlock has been added to the -mm mm-new branch. Its filename is liveupdate-protect-flb-lists-with-luo_register_rwlock.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/liveupdate-protect-flb-lists-with-luo_register_rwlock.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: protect FLB lists with luo_register_rwlock Date: Fri, 27 Mar 2026 03:33:28 +0000 Because liveupdate FLB objects will soon drop their persistent module references when registered, list traversals must be protected against concurrent module unloading. To provide this protection, utilize the global luo_register_rwlock. It protects the global registry of FLBs and the handler's specific list of FLB dependencies. Read locks are used during concurrent list traversals (e.g., during preservation and serialization). Write locks are taken during registration and unregistration. Link: https://lkml.kernel.org/r/20260327033335.696621-5-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 --- include/linux/liveupdate.h | 1 + kernel/liveupdate/luo_flb.c | 14 ++++++++++++++ 2 files changed, 15 insertions(+) --- a/include/linux/liveupdate.h~liveupdate-protect-flb-lists-with-luo_register_rwlock +++ a/include/linux/liveupdate.h @@ -12,6 +12,7 @@ #include #include #include +#include #include #include --- a/kernel/liveupdate/luo_flb.c~liveupdate-protect-flb-lists-with-luo_register_rwlock +++ a/kernel/liveupdate/luo_flb.c @@ -262,17 +262,20 @@ int luo_flb_file_preserve(struct liveupd struct luo_flb_link *iter; int err = 0; + down_read(&luo_register_rwlock); list_for_each_entry(iter, flb_list, list) { err = luo_flb_file_preserve_one(iter->flb); if (err) goto exit_err; } + up_read(&luo_register_rwlock); return 0; exit_err: list_for_each_entry_continue_reverse(iter, flb_list, list) luo_flb_file_unpreserve_one(iter->flb); + up_read(&luo_register_rwlock); return err; } @@ -294,6 +297,7 @@ void luo_flb_file_unpreserve(struct live struct list_head *flb_list = &ACCESS_PRIVATE(fh, flb_list); struct luo_flb_link *iter; + guard(rwsem_read)(&luo_register_rwlock); list_for_each_entry_reverse(iter, flb_list, list) luo_flb_file_unpreserve_one(iter->flb); } @@ -314,6 +318,7 @@ void luo_flb_file_finish(struct liveupda struct list_head *flb_list = &ACCESS_PRIVATE(fh, flb_list); struct luo_flb_link *iter; + guard(rwsem_read)(&luo_register_rwlock); list_for_each_entry_reverse(iter, flb_list, list) luo_flb_file_finish_one(iter->flb); } @@ -377,6 +382,8 @@ int liveupdate_register_flb(struct liveu if (!luo_session_quiesce()) return -EBUSY; + down_write(&luo_register_rwlock); + /* Check that this FLB is not already linked to this file handler */ err = -EEXIST; list_for_each_entry(iter, flb_list, list) { @@ -418,11 +425,13 @@ int liveupdate_register_flb(struct liveu private->users++; link->flb = flb; list_add_tail(&no_free_ptr(link)->list, flb_list); + up_write(&luo_register_rwlock); luo_session_resume(); return 0; err_resume: + up_write(&luo_register_rwlock); luo_session_resume(); return err; } @@ -466,6 +475,8 @@ int liveupdate_unregister_flb(struct liv if (!luo_session_quiesce()) return -EBUSY; + down_write(&luo_register_rwlock); + /* Find and remove the link from the file handler's list */ list_for_each_entry(iter, flb_list, list) { if (iter->flb == flb) { @@ -490,11 +501,13 @@ int liveupdate_unregister_flb(struct liv module_put(flb->ops->owner); } + up_write(&luo_register_rwlock); luo_session_resume(); return 0; err_resume: + up_write(&luo_register_rwlock); luo_session_resume(); return err; } @@ -660,6 +673,7 @@ void luo_flb_serialize(void) struct liveupdate_flb *gflb; int i = 0; + guard(rwsem_read)(&luo_register_rwlock); list_private_for_each_entry(gflb, &luo_flb_global.list, private.list) { struct luo_flb_private *private = luo_flb_get_private(gflb); _ 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