+ selftests-proc-test-procmap_query-ioctl-while-vma-is-concurrently-modified.patch added to mm-unstable branch

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

The patch titled
     Subject: selftests/proc: test PROCMAP_QUERY ioctl while vma is concurrently modified
has been added to the -mm mm-unstable branch.  Its filename is
     selftests-proc-test-procmap_query-ioctl-while-vma-is-concurrently-modified.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-proc-test-procmap_query-ioctl-while-vma-is-concurrently-modified.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: Suren Baghdasaryan <surenb@google.com>
Subject: selftests/proc: test PROCMAP_QUERY ioctl while vma is concurrently modified
Date: Fri, 8 Aug 2025 08:28:47 -0700

Extend /proc/pid/maps tearing tests to verify PROCMAP_QUERY ioctl operation
correctness while the vma is being concurrently modified.

Link: https://lkml.kernel.org/r/20250808152850.2580887-2-surenb@google.com
Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Tested-by: SeongJae Park <sj@kernel.org>
Acked-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 tools/testing/selftests/proc/proc-maps-race.c |   65 ++++++++++++++++
 1 file changed, 65 insertions(+)

--- a/tools/testing/selftests/proc/proc-maps-race.c~selftests-proc-test-procmap_query-ioctl-while-vma-is-concurrently-modified
+++ a/tools/testing/selftests/proc/proc-maps-race.c
@@ -32,6 +32,8 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <linux/fs.h>
+#include <sys/ioctl.h>
 #include <sys/mman.h>
 #include <sys/stat.h>
 #include <sys/types.h>
@@ -317,6 +319,25 @@ static bool capture_mod_pattern(FIXTURE_
 	       strcmp(restored_first_line->text, self->first_line.text) == 0;
 }
 
+static bool query_addr_at(int maps_fd, void *addr,
+			  unsigned long *vma_start, unsigned long *vma_end)
+{
+	struct procmap_query q;
+
+	memset(&q, 0, sizeof(q));
+	q.size = sizeof(q);
+	/* Find the VMA at the split address */
+	q.query_addr = (unsigned long long)addr;
+	q.query_flags = 0;
+	if (ioctl(maps_fd, PROCMAP_QUERY, &q))
+		return false;
+
+	*vma_start = q.vma_start;
+	*vma_end = q.vma_end;
+
+	return true;
+}
+
 static inline bool split_vma(FIXTURE_DATA(proc_maps_race) *self)
 {
 	return mmap(self->mod_info->addr, self->page_size, self->mod_info->prot | PROT_EXEC,
@@ -559,6 +580,8 @@ TEST_F(proc_maps_race, test_maps_tearing
 	do {
 		bool last_line_changed;
 		bool first_line_changed;
+		unsigned long vma_start;
+		unsigned long vma_end;
 
 		ASSERT_TRUE(read_boundary_lines(self, &new_last_line, &new_first_line));
 
@@ -595,6 +618,19 @@ TEST_F(proc_maps_race, test_maps_tearing
 		first_line_changed = strcmp(new_first_line.text, self->first_line.text) != 0;
 		ASSERT_EQ(last_line_changed, first_line_changed);
 
+		/* Check if PROCMAP_QUERY ioclt() finds the right VMA */
+		ASSERT_TRUE(query_addr_at(self->maps_fd, mod_info->addr + self->page_size,
+					  &vma_start, &vma_end));
+		/*
+		 * The vma at the split address can be either the same as
+		 * original one (if read before the split) or the same as the
+		 * first line in the second page (if read after the split).
+		 */
+		ASSERT_TRUE((vma_start == self->last_line.start_addr &&
+			     vma_end == self->last_line.end_addr) ||
+			    (vma_start == split_first_line.start_addr &&
+			     vma_end == split_first_line.end_addr));
+
 		clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts);
 		end_test_iteration(&end_ts, self->verbose);
 	} while (end_ts.tv_sec - start_ts.tv_sec < self->duration_sec);
@@ -636,6 +672,9 @@ TEST_F(proc_maps_race, test_maps_tearing
 	clock_gettime(CLOCK_MONOTONIC_COARSE, &start_ts);
 	start_test_loop(&start_ts, self->verbose);
 	do {
+		unsigned long vma_start;
+		unsigned long vma_end;
+
 		ASSERT_TRUE(read_boundary_lines(self, &new_last_line, &new_first_line));
 
 		/* Check if we read vmas after shrinking it */
@@ -662,6 +701,16 @@ TEST_F(proc_maps_race, test_maps_tearing
 					"Expand result invalid", self));
 		}
 
+		/* Check if PROCMAP_QUERY ioclt() finds the right VMA */
+		ASSERT_TRUE(query_addr_at(self->maps_fd, mod_info->addr, &vma_start, &vma_end));
+		/*
+		 * The vma should stay at the same address and have either the
+		 * original size of 3 pages or 1 page if read after shrinking.
+		 */
+		ASSERT_TRUE(vma_start == self->last_line.start_addr &&
+			    (vma_end - vma_start == self->page_size * 3 ||
+			     vma_end - vma_start == self->page_size));
+
 		clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts);
 		end_test_iteration(&end_ts, self->verbose);
 	} while (end_ts.tv_sec - start_ts.tv_sec < self->duration_sec);
@@ -703,6 +752,9 @@ TEST_F(proc_maps_race, test_maps_tearing
 	clock_gettime(CLOCK_MONOTONIC_COARSE, &start_ts);
 	start_test_loop(&start_ts, self->verbose);
 	do {
+		unsigned long vma_start;
+		unsigned long vma_end;
+
 		ASSERT_TRUE(read_boundary_lines(self, &new_last_line, &new_first_line));
 
 		/* Check if we read vmas after remapping it */
@@ -729,6 +781,19 @@ TEST_F(proc_maps_race, test_maps_tearing
 					"Remap restore result invalid", self));
 		}
 
+		/* Check if PROCMAP_QUERY ioclt() finds the right VMA */
+		ASSERT_TRUE(query_addr_at(self->maps_fd, mod_info->addr + self->page_size,
+					  &vma_start, &vma_end));
+		/*
+		 * The vma should either stay at the same address and have the
+		 * original size of 3 pages or we should find the remapped vma
+		 * at the remap destination address with size of 1 page.
+		 */
+		ASSERT_TRUE((vma_start == self->last_line.start_addr &&
+			     vma_end - vma_start == self->page_size * 3) ||
+			    (vma_start == self->last_line.start_addr + self->page_size &&
+			     vma_end - vma_start == self->page_size));
+
 		clock_gettime(CLOCK_MONOTONIC_COARSE, &end_ts);
 		end_test_iteration(&end_ts, self->verbose);
 	} while (end_ts.tv_sec - start_ts.tv_sec < self->duration_sec);
_

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

userfaultfd-fix-a-crash-in-uffdio_move-when-pmd-is-a-migration-entry.patch
userfaultfd-fix-a-crash-in-uffdio_move-when-pmd-is-a-migration-entry-fix.patch
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