lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [day] [month] [year] [list]
Message-ID: <20240423192221.301095-3-mcgrof@kernel.org>
Date: Tue, 23 Apr 2024 12:22:21 -0700
From: Luis Chamberlain <mcgrof@...nel.org>
To: akpm@...ux-foundation.org,
	willy@...radead.org,
	Liam.Howlett@...cle.com
Cc: linux-fsdevel@...r.kernel.org,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	djwong@...nel.org,
	david@...morbit.com,
	gost.dev@...sung.com,
	p.raghav@...sung.com,
	da.gomez@...sung.com,
	mcgrof@...nel.org
Subject: [PATCH v2 2/2] lib/test_xarray.c: fix error assumptions on check_xa_multi_store_adv_add()

While testing lib/test_xarray in userspace I've noticed we can fail with:

make -C tools/testing/radix-tree
/tools/testing/radix-tree/xarray

BUG at check_xa_multi_store_adv_add:749
xarray: 0x55905fb21a00x head 0x55905fa1d8e0x flags 0 marks 0 0 0
0: 0x55905fa1d8e0x
xarray: ../../../lib/test_xarray.c:749: check_xa_multi_store_adv_add: Assertion `0' failed.
Aborted

We get a failure with a BUG_ON(), and that is because we actually can
fail due to -ENOMEM, the check in xas_nomem() will fix this for us so
it makes no sense to expect no failure inside the loop. So modify the
check and since this is also useful for instructional purposes clarify
the situation.

The check for XA_BUG_ON(xa, xa_load(xa, index) != p) is already done
at the end of the loop so just remove the bogus on inside the loop.

With this we now pass the test in both kernel and userspace:

In userspace:

/tools/testing/radix-tree/xarray
XArray: 149092856 of 149092856 tests passed

In kernel space:

XArray: 148257077 of 148257077 tests passed

Fixes: a60cc288a1a2 ("test_xarray: add tests for advanced multi-index use")
Signed-off-by: Luis Chamberlain <mcgrof@...nel.org>
---
 lib/test_xarray.c | 13 +++++++++----
 1 file changed, 9 insertions(+), 4 deletions(-)

diff --git a/lib/test_xarray.c b/lib/test_xarray.c
index ebe2af2e072d..5ab35190aae3 100644
--- a/lib/test_xarray.c
+++ b/lib/test_xarray.c
@@ -744,15 +744,20 @@ static noinline void check_xa_multi_store_adv_add(struct xarray *xa,
 
 	do {
 		xas_lock_irq(&xas);
-
 		xas_store(&xas, p);
-		XA_BUG_ON(xa, xas_error(&xas));
-		XA_BUG_ON(xa, xa_load(xa, index) != p);
-
 		xas_unlock_irq(&xas);
+		/*
+		 * In our selftest case the only failure we can expect is for
+		 * there not to be enough memory as we're not mimicking the
+		 * entire page cache, so verify that's the only error we can run
+		 * into here. The xas_nomem() which follows will ensure to fix
+		 * that condition for us so to chug on on the loop.
+		 */
+		XA_BUG_ON(xa, xas_error(&xas) && xas_error(&xas) != -ENOMEM);
 	} while (xas_nomem(&xas, GFP_KERNEL));
 
 	XA_BUG_ON(xa, xas_error(&xas));
+	XA_BUG_ON(xa, xa_load(xa, index) != p);
 }
 
 /* mimics page_cache_delete() */
-- 
2.43.0


Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ