linux-kernel - [PATCH 1/6] mm/selftests: Fix virtual_address

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Message-ID: <20250616160632.35250-2-aboorvad@linux.ibm.com>
Date: Mon, 16 Jun 2025 21:36:27 +0530
From: Aboorva Devarajan <aboorvad@...ux.ibm.com>
To: akpm@...ux-foundation.org, Liam.Howlett@...cle.com,
        lorenzo.stoakes@...cle.com, shuah@...nel.org, pfalcato@...e.de,
        david@...hat.com, ziy@...dia.com, baolin.wang@...ux.alibaba.com,
        npache@...hat.com, ryan.roberts@....com, dev.jain@....com,
        baohua@...nel.org
Cc: linux-mm@...ck.org, linux-kselftest@...r.kernel.org,
        linux-kernel@...r.kernel.org, donettom@...ux.ibm.com,
        ritesh.list@...il.com, aboorvad@...ux.ibm.com
Subject: [PATCH 1/6] mm/selftests: Fix virtual_address_range test issues.

From: Donet Tom <donettom@...ux.ibm.com>

In this patch, we are fixing three issues in the virtual_address_range
test.

1. validate_addr() checks if the allocated address is within the range.
In the current implementation, if addr is greater than HIGH_ADDR_MARK,
the test fails. However, addr will be greater than HIGH_ADDR_MARK if
high_addr is set. Therefore, if high_addr is set, we should not check
the (addr > HIGH_ADDR_MARK) condition.

2.In main(), the high address is stored in hptr, but for mark_range(),
the address passed is ptr, not hptr. Fixed this by changing ptr[i] to
hptr[i] in mark_range() function call.

3./proc/self/maps may not always have gaps smaller than MAP_CHUNK_SIZE.
The gap between the first high address mapping and the previous mapping
is not smaller than MAP_CHUNK_SIZE.

$cat /proc/3713/maps
10000000-10010000 r-xp 00000000 fd:00 36140094
10010000-10020000 r--p 00000000 fd:00 36140094
10020000-10030000 rw-p 00010000 fd:00 36140094
4ee80000-4eeb0000 rw-p 00000000 00:00 0
578f0000-57c00000 rw-p 00000000 00:00 0
57c00000-7fff97c00000 r--p 00000000 00:00 0
7fff97c00000-7fff97e20000 r-xp 00000000 fd:00 33558923
7fff97e20000-7fff97e30000 r--p 00220000 fd:00 33558923
7fff97e30000-7fff97e40000 rw-p 00230000 fd:00 33558923
7fff97f40000-7fff98020000 r-xp 00000000 fd:00 33558924
7fff98020000-7fff98030000 r--p 000d0000 fd:00 33558924
7fff98030000-7fff98040000 rw-p 000e0000 fd:00 33558924
7fff98050000-7fff98090000 r--p 00000000 00:00 0
7fff98090000-7fff980a0000 r-xp 00000000 00:00 0
7fff980a0000-7fff980f0000 r-xp 00000000 fd:00 2634
7fff980f0000-7fff98100000 r--p 00040000 fd:00 2634
7fff98100000-7fff98110000 rw-p 00050000 fd:00 2634
7fffcf8a0000-7fffcf9b0000 rw-p 00000000 00:00 0
1000000000000-1000040000000 r--p 00000000 00:00 0   --> High Addr
2000000000000-2000040000000 r--p 00000000 00:00 0
4000000000000-4000040000000 r--p 00000000 00:00 0
8000000000000-8000040000000 r--p 00000000 00:00 0
e800098110000-fffff98110000 r--p 00000000 00:00 0
$

In this patch, the condition that checks for gaps smaller than MAP_CHUNK_SIZE has been removed.

Fixes: d1d86ce28d0f ("selftests/mm: virtual_address_range: conform to TAP format output")
Fixes: b2a79f62133a ("selftests/mm: virtual_address_range: unmap chunks after validation")
Fixes: 010409649885 ("selftests/mm: confirm VA exhaustion without reliance on correctness of mmap()")
Signed-off-by: Donet Tom <donettom@...ux.ibm.com>
Signed-off-by: Aboorva Devarajan <aboorvad@...ux.ibm.com>
---
 tools/testing/selftests/mm/virtual_address_range.c | 14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

diff --git a/tools/testing/selftests/mm/virtual_address_range.c b/tools/testing/selftests/mm/virtual_address_range.c
index b380e102b22f..606e601a8984 100644
--- a/tools/testing/selftests/mm/virtual_address_range.c
+++ b/tools/testing/selftests/mm/virtual_address_range.c
@@ -80,7 +80,7 @@ static void validate_addr(char *ptr, int high_addr)
 	if (high_addr && addr < HIGH_ADDR_MARK)
 		ksft_exit_fail_msg("Bad address %lx\n", addr);
 
-	if (addr > HIGH_ADDR_MARK)
+	if (!high_addr && addr > HIGH_ADDR_MARK)
 		ksft_exit_fail_msg("Bad address %lx\n", addr);
 }
 
@@ -117,7 +117,7 @@ static int validate_lower_address_hint(void)
 
 static int validate_complete_va_space(void)
 {
-	unsigned long start_addr, end_addr, prev_end_addr;
+	unsigned long start_addr, end_addr;
 	char line[400];
 	char prot[6];
 	FILE *file;
@@ -134,7 +134,6 @@ static int validate_complete_va_space(void)
 	if (file == NULL)
 		ksft_exit_fail_msg("cannot open /proc/self/maps\n");
 
-	prev_end_addr = 0;
 	while (fgets(line, sizeof(line), file)) {
 		const char *vma_name = NULL;
 		int vma_name_start = 0;
@@ -151,12 +150,6 @@ static int validate_complete_va_space(void)
 		if (start_addr & (1UL << 63))
 			return 0;
 
-		/* /proc/self/maps must have gaps less than MAP_CHUNK_SIZE */
-		if (start_addr - prev_end_addr >= MAP_CHUNK_SIZE)
-			return 1;
-
-		prev_end_addr = end_addr;
-
 		if (prot[0] != 'r')
 			continue;
 
@@ -223,8 +216,7 @@ int main(int argc, char *argv[])
 
 		if (hptr[i] == MAP_FAILED)
 			break;
-
-		mark_range(ptr[i], MAP_CHUNK_SIZE);
+		mark_range(hptr[i], MAP_CHUNK_SIZE);
 		validate_addr(hptr[i], 1);
 	}
 	hchunks = i;
-- 
2.43.5