From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 24C691361; Tue, 15 Apr 2025 00:11:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744675869; cv=none; b=L4Sdvac4oxlMx+Qf4ZH8jMYGeQclUTDK0cmH/vzW7enZ/HpTJZkCOQWgvdaOi2BUqi6guufnzeZ2jd/T+8UQwn3dEzOhg3jesrAax1aIxNkwF3OZ5YXWsVX76C6/dvA8APQWGjKovRlPVIWlW/TM1zepZDCBmCqLz/GLlzIF6jc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744675869; c=relaxed/simple; bh=KQUKYquf80Jjc7PCKVNEqJWzgQ+LkrCovnf84LnvUo8=; h=Date:To:From:Subject:Message-Id; b=sJ3escaVOTum3ag6GvQcC9dgO7Gitt6BBNbDUj/zkMY4sCg1JN6ymKk2YaZLvQYcVsplvj4/kZZ265Zo0Ax/HOM1kNjXMOCzaVItrrpKz4TtLfvU5MEEuLkL5HAxPInSFmfEbnUiU92vp6MI82OnRGz0I6F+oxIAv+SZscGNGyk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=RDxAbgs5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="RDxAbgs5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 79E0BC4CEE2; Tue, 15 Apr 2025 00:11:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1744675868; bh=KQUKYquf80Jjc7PCKVNEqJWzgQ+LkrCovnf84LnvUo8=; h=Date:To:From:Subject:From; b=RDxAbgs5HuVDvjyjUvfEjWl0aWHc/ibfgASWIRtuvBVRw7/JdNAc03rEgzyTbhGYp F12WZZTlzJLio8oztHwH8WqGVSM8t0P0wcrqTNYxBub1MS4omL5kNxDZrMzEw68B4M cX5KCcTdqEoqJ6m26Ylj2VjA6cqVw/DZ2IsQ+wvY= Date: Mon, 14 Apr 2025 17:11:07 -0700 To: mm-commits@vger.kernel.org,stable@vger.kernel.org,ryabinin.a.a@gmail.com,kees@kernel.org,elver@google.com,andreyknvl@gmail.com,smostafa@google.com,akpm@linux-foundation.org From: Andrew Morton Subject: + lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch added to mm-hotfixes-unstable branch Message-Id: <20250415001108.79E0BC4CEE2@smtp.kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The patch titled Subject: lib/test_ubsan.c: fix panic from test_ubsan_out_of_bounds has been added to the -mm mm-hotfixes-unstable branch. Its filename is lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch This patch will later appear in the mm-hotfixes-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Mostafa Saleh Subject: lib/test_ubsan.c: fix panic from test_ubsan_out_of_bounds Date: Mon, 14 Apr 2025 21:36:48 +0000 Running lib_ubsan.ko on arm64 (without CONFIG_UBSAN_TRAP) panics the kernel [ 31.616546] Kernel panic - not syncing: stack-protector: Kernel stack is corrupted in: test_ubsan_out_of_bounds+0x158/0x158 [test_ubsan] [ 31.646817] CPU: 3 UID: 0 PID: 179 Comm: insmod Not tainted 6.15.0-rc2 #1 PREEMPT [ 31.648153] Hardware name: linux,dummy-virt (DT) [ 31.648970] Call trace: [ 31.649345] show_stack+0x18/0x24 (C) [ 31.650960] dump_stack_lvl+0x40/0x84 [ 31.651559] dump_stack+0x18/0x24 [ 31.652264] panic+0x138/0x3b4 [ 31.652812] __ktime_get_real_seconds+0x0/0x10 [ 31.653540] test_ubsan_load_invalid_value+0x0/0xa8 [test_ubsan] [ 31.654388] init_module+0x24/0xff4 [test_ubsan] [ 31.655077] do_one_initcall+0xd4/0x280 [ 31.655680] do_init_module+0x58/0x2b4 That happens because the test corrupts other data in the stack: 400: d5384108 mrs x8, sp_el0 404: f9426d08 ldr x8, [x8, #1240] 408: f85f83a9 ldur x9, [x29, #-8] 40c: eb09011f cmp x8, x9 410: 54000301 b.ne 470 // b.any As there is no guarantee the compiler will order the local variables as declared in the module: volatile char above[4] = { }; /* Protect surrounding memory. */ volatile int arr[4]; volatile char below[4] = { }; /* Protect surrounding memory. */ So, instead of writing out-of-bound, we can read out-of-bound which still triggers UBSAN but doesn't corrupt the stack. Link: https://lkml.kernel.org/r/20250414213648.2660150-1-smostafa@google.com Fixes: 4a26f49b7b3d ubsan: ("expand tests and reporting") Signed-off-by: Mostafa Saleh Cc: Andrey Konovalov Cc: Andrey Ryabinin Cc: Macro Elver Cc: Kees Cook Cc: Signed-off-by: Andrew Morton --- lib/test_ubsan.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-) --- a/lib/test_ubsan.c~lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds +++ a/lib/test_ubsan.c @@ -77,18 +77,15 @@ static void test_ubsan_shift_out_of_boun static void test_ubsan_out_of_bounds(void) { - volatile int i = 4, j = 5, k = -1; - volatile char above[4] = { }; /* Protect surrounding memory. */ + volatile int j = 5, k = -1; + volatile int scratch[4] = { }; volatile int arr[4]; - volatile char below[4] = { }; /* Protect surrounding memory. */ - - above[0] = below[0]; UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "above"); - arr[j] = i; + scratch[1] = arr[j]; UBSAN_TEST(CONFIG_UBSAN_BOUNDS, "below"); - arr[k] = i; + scratch[2] = arr[k]; } enum ubsan_test_enum { _ Patches currently in -mm which might be from smostafa@google.com are lib-test_ubsanc-fix-panic-from-test_ubsan_out_of_bounds.patch