Re: BUG: KASAN lib/test_kasan.c
From: Jeffrin Jose T
Date: Fri Dec 04 2020 - 15:53:34 EST
On Fri, 2020-12-04 at 21:29 +0100, Marco Elver wrote:
> On Fri, 4 Dec 2020 at 19:56, Jeffrin Jose T
> <jeffrin@xxxxxxxxxxxxxxxxxxx> wrote:
> > hello,
> >
> > detected KASAN BUG
> >
> > [ related information ]
> >
> > -------------------x-------------------x------------------------>
> > [ 43.616259] BUG: KASAN: vmalloc-out-of-bounds in
> > vmalloc_oob+0x146/0x2c0
> >
> > (gdb) l *vmalloc_oob+0x146/0x2c0
> > 0xffffffff81b8b0b0 is in vmalloc_oob (lib/test_kasan.c:764).
>
> This is the KASAN test. It's a feature, not a bug. ;-)
>
> > 759 kfree_sensitive(ptr);
> > 760 KUNIT_EXPECT_KASAN_FAIL(test,
> > kfree_sensitive(ptr));
> > 761 }
> > 762
> > 763 static void vmalloc_oob(struct kunit *test)
> > 764 {
> > 765 void *area;
> > 766
> > 767 if (!IS_ENABLED(CONFIG_KASAN_VMALLOC)) {
> > 768 kunit_info(test, "CONFIG_KASAN_VMALLOC is
> > not
> > enabled.");
> > (gdb) l *vmalloc_oob+0x146
> > 0xffffffff81b8b1f6 is in vmalloc_oob (lib/test_kasan.c:779).
> > 774 * The MMU will catch that and crash us.
> > 775 */
> > 776 area = vmalloc(3000);
> > 777 KUNIT_ASSERT_NOT_ERR_OR_NULL(test, area);
> > 778
> > 779 KUNIT_EXPECT_KASAN_FAIL(test, ((volatile char
> > *)area)[3100]);
> > 780 vfree(area);
> > 781 }
> > 782
> > 783 static struct kunit_case kasan_kunit_test_cases[] = {
> > ----------------x-----------------------------x--------------------
> > >
> >
> > Reported by: Jeffrin Jose T <jeffrin@xxxxxxxxxxxxxxxxxxx>
>
> Which CI system is reporting these?
>
> If you look, this is the KASAN test, and the report is very much
> intended since it's testing KASAN. Please blacklist the KASAN test
> (and any other tests testing debugging tools).
>
> Thanks,
> -- Marco
gdb session was started by me. (gdb ./vmlinux)
portion from dmesg output is as follows
--------------------x------------------------x-------------------------
-->
[ 43.616259] BUG: KASAN: vmalloc-out-of-bounds in
vmalloc_oob+0x146/0x2c0
[ 43.630470] Read of size 1 at addr ffffc9000006ec1c by task
kunit_try_catch/193
[ 43.659055] CPU: 2 PID: 193 Comm: kunit_try_catch Tainted: G B
5.10.0-rc6+ #10
[ 43.659070] Hardware name: ASUSTeK COMPUTER INC. VivoBook 15_ASUS
Laptop X507UAR/X507UAR, BIOS X507UAR.203 05/31/2018
[ 43.659080] Call Trace:
[ 43.659105] dump_stack+0x119/0x179
[ 43.659131] print_address_description.constprop.0+0x1c/0x210
[ 43.659163] ? vmalloc_oob+0x146/0x2c0
[ 43.659185] kasan_report.cold+0x1f/0x37
[ 43.659210] ? vmalloc_oob+0x146/0x2c0
[ 43.659234] vmalloc_oob+0x146/0x2c0
[ 43.659259] ? kasan_global_oob+0x280/0x280
[ 43.659287] ? kunit_fail_assert_format+0xa0/0xa0
[ 43.659313] ? lock_release+0xb2/0x730
[ 43.659334] ? __kthread_parkme+0xa1/0x120
[ 43.659356] ? lock_acquired+0xb4/0x5b0
[ 43.659379] ? lock_downgrade+0x3d0/0x3d0
[ 43.659403] ? lock_contended+0x6e0/0x6e0
[ 43.659423] ? do_raw_spin_lock+0x1b0/0x1b0
[ 43.659447] ? io_schedule_timeout+0xb0/0xb0
[ 43.659467] ? static_obj+0x31/0x80
[ 43.659492] ? lockdep_hardirqs_on_prepare+0xe/0x240
[ 43.659517] ? memcg_accounted_kmem_cache+0x1b0/0x1b0
[ 43.659542] kunit_try_run_case+0xa6/0x150
[ 43.659567] ? kunit_catch_run_case+0x170/0x170
[ 43.659591] ? kunit_try_catch_throw+0x40/0x40
[ 43.659617] kunit_generic_run_threadfn_adapter+0x2e/0x50
[ 43.659637] kthread+0x232/0x260
[ 43.659659] ? __kthread_bind_mask+0x90/0x90
[ 43.659684] ret_from_fork+0x22/0x30
[ 43.686511] Memory state around the buggy address:
[ 43.700445] ffffc9000006eb00: 00 00 00 00 00 00 00 00 00 00 00 00
00 00 00 00
[ 43.714559] ffffc9000006eb80: 00 00 00 00 00 00 00 f8 f8 f8 f8 f8
f8 f8 f8 f8
[ 43.728725] >ffffc9000006ec00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
f8 f8 f8 f8
[ 43.742808] ^
[ 43.757156] ffffc9000006ec80: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
f8 f8 f8 f8
[ 43.771845] ffffc9000006ed00: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
f8 f8 f8 f8
[ 43.785957]
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--
software engineer
rajagiri school of engineering and technology - autonomous