+ mm-madvise-implement-lightweight-guard-page-mechanism-fix.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm: yield on fatal signal/cond_sched() in vector_madvise()
has been added to the -mm mm-unstable branch.  Its filename is
     mm-madvise-implement-lightweight-guard-page-mechanism-fix.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-madvise-implement-lightweight-guard-page-mechanism-fix.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Subject: mm: yield on fatal signal/cond_sched() in vector_madvise()
Date: Fri, 25 Oct 2024 18:05:48 +0100

While we have to treat -ERESTARTNOINTR specially here as we are looping
through a vector of operations and can't simply restart the entire
operation, we mustn't hold up fatal signals or RT kernels.

Link: https://lkml.kernel.org/r/f09086cd-c49c-4eea-adff-d626c16083de@lucifer.local
Signed-off-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Arnd Bergmann <arnd@kernel.org>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Hildenbrand <david@redhat.com>
Cc: Helge Deller <deller@gmx.de>
Cc: James E.J. Bottomley <James.Bottomley@HansenPartnership.com>
Cc: Jann Horn <jannh@google.com>
Cc: Jeff Xu <jeffxu@chromium.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam R. Howlett <Liam.Howlett@Oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Shuah Khan <skhan@linuxfoundation.org>
Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/madvise.c |    8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

--- a/mm/madvise.c~mm-madvise-implement-lightweight-guard-page-mechanism-fix
+++ a/mm/madvise.c
@@ -1713,8 +1713,14 @@ static ssize_t vector_madvise(struct mm_
 		 * we have already rescinded locks, it should be no problem to
 		 * simply try again.
 		 */
-		if (ret == -ERESTARTNOINTR)
+		if (ret == -ERESTARTNOINTR) {
+			if (fatal_signal_pending(current)) {
+				ret = -EINTR;
+				break;
+			}
+			cond_resched();
 			continue;
+		}
 		if (ret < 0)
 			break;
 		iov_iter_advance(iter, iter_iov_len(iter));
_

Patches currently in -mm which might be from lorenzo.stoakes@oracle.com are

mm-avoid-unsafe-vma-hook-invocation-when-error-arises-on-mmap-hook.patch
mm-unconditionally-close-vmas-on-error.patch
mm-refactor-map_deny_write_exec.patch
mm-resolve-faulty-mmap_region-error-path-behaviour.patch
selftests-mm-add-pkey_sighandler_xx-hugetlb_dio-to-gitignore.patch
mm-refactor-mm_access-to-not-return-null.patch
mm-refactor-mm_access-to-not-return-null-fix.patch
mm-madvise-unrestrict-process_madvise-for-current-process.patch
maple_tree-do-not-hash-pointers-on-dump-in-debug-mode.patch
tools-testing-fix-phys_addr_t-size-on-64-bit-systems.patch
tools-testing-fix-phys_addr_t-size-on-64-bit-systems-fix.patch
tools-testing-add-additional-vma_internalh-stubs.patch
mm-isolate-mmap-internal-logic-to-mm-vmac.patch
mm-refactor-__mmap_region.patch
mm-defer-second-attempt-at-merge-on-mmap.patch
mm-pagewalk-add-the-ability-to-install-ptes.patch
mm-add-pte_marker_guard-pte-marker.patch
mm-madvise-implement-lightweight-guard-page-mechanism.patch
mm-madvise-implement-lightweight-guard-page-mechanism-fix.patch
tools-testing-update-tools-uapi-header-for-mman-commonh.patch
selftests-mm-add-self-tests-for-guard-page-feature.patch