+ alloc_tag-prevent-enabling-memory-profiling-if-it-was-shut-down.patch added to mm-new branch

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

The patch titled
     Subject: alloc_tag: prevent enabling memory profiling if it was shut down
has been added to the -mm mm-new branch.  Its filename is
     alloc_tag-prevent-enabling-memory-profiling-if-it-was-shut-down.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/alloc_tag-prevent-enabling-memory-profiling-if-it-was-shut-down.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
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fixup patches in mm-new.

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------------------------------------------------------
From: Suren Baghdasaryan <surenb@google.com>
Subject: alloc_tag: prevent enabling memory profiling if it was shut down
Date: Tue, 9 Sep 2025 16:34:08 -0700

Memory profiling can be shut down due to reasons like a failure during
initialization.  When this happens, the user should not be able to
re-enable it.  Current sysctrl interface does not handle this properly and
will allow re-enabling memory profiling.  Fix this by checking for this
condition during sysctrl write operation.

Link: https://lkml.kernel.org/r/20250909233409.1013367-3-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: David Wang <00107082@163.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Pasha Tatashin <pasha.tatashin@soleen.com>
Cc: Shakeel Butt <shakeel.butt@linux.dev>
Cc: Sourav Panda <souravpanda@google.com>
Cc: Usama Arif <usamaarif642@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 lib/alloc_tag.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

--- a/lib/alloc_tag.c~alloc_tag-prevent-enabling-memory-profiling-if-it-was-shut-down
+++ a/lib/alloc_tag.c
@@ -767,6 +767,16 @@ struct page_ext_operations page_alloc_ta
 EXPORT_SYMBOL(page_alloc_tagging_ops);
 
 #ifdef CONFIG_SYSCTL
+static int proc_mem_profiling_handler(const struct ctl_table *table, int write,
+				      void *buffer, size_t *lenp, loff_t *ppos)
+{
+	if (!mem_profiling_support && write)
+		return -EINVAL;
+
+	return proc_do_static_key(table, write, buffer, lenp, ppos);
+}
+
+
 static struct ctl_table memory_allocation_profiling_sysctls[] = {
 	{
 		.procname	= "mem_profiling",
@@ -776,7 +786,7 @@ static struct ctl_table memory_allocatio
 #else
 		.mode		= 0644,
 #endif
-		.proc_handler	= proc_do_static_key,
+		.proc_handler	= proc_mem_profiling_handler,
 	},
 };
 
_

Patches currently in -mm which might be from surenb@google.com are

mm-limit-the-scope-of-vma_start_read.patch
mm-change-vma_start_read-to-drop-rcu-lock-on-failure.patch
selftests-proc-test-procmap_query-ioctl-while-vma-is-concurrently-modified.patch
fs-proc-task_mmu-factor-out-proc_maps_private-fields-used-by-procmap_query.patch
fs-proc-task_mmu-execute-procmap_query-ioctl-under-per-vma-locks.patch
alloc_tag-use-release_pages-in-the-cleanup-path.patch
alloc_tag-prevent-enabling-memory-profiling-if-it-was-shut-down.patch
alloc_tag-avoid-warnings-when-freeing-non-compound-tail-pages.patch