Re: [PATCH 12/11 TESTSUITE] audit_testsuite: Add stress test for tree watches

[Paul Moore <paul@paul-moore.com>]

On Tue, Sep 4, 2018 at 12:06 PM Jan Kara <jack@suse.cz> wrote:
> Add stress test for stressing audit tree watches by adding and deleting
> rules while events are generated and watched filesystems are mounted and
> unmounted in parallel.
>
> Signed-off-by: Jan Kara <jack@suse.cz>
> ---
>  tests/stress_tree/Makefile |   8 +++
>  tests/stress_tree/test     | 171 +++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 179 insertions(+)
>  create mode 100644 tests/stress_tree/Makefile
>  create mode 100755 tests/stress_tree/test

No commentary on the test itself, other than perhaps it should live
under test_manual/, but in running the tests in a loop today I am
reliably able to panic my test kernel after ~30m or so.

I'm using the kernel linked below which is Fedora Rawhide +
selinux/next + audit/next + audit/working-fsnotify_fixes; a link to
the patches added to the Rawhide kernel can be found in the list
archive linked below.

* https://groups.google.com/forum/#!topic/kernel-secnext/SFv0d-ij3z8
* https://copr.fedorainfracloud.org/coprs/pcmoore/kernel-secnext/build/805949

The initial panic dump is below:

[  139.619065] list_del corruption. prev->next should be
ffff985fa98d4100, but was ffff985fae91e370
[  139.622504] ------------[ cut here ]------------
[  139.623402] kernel BUG at lib/list_debug.c:53!
[  139.624294] invalid opcode: 0000 [#1] SMP PTI
[  139.625439] CPU: 1 PID: 3248 Comm: auditctl Not tainted
4.19.0-0.rc6.git2.1.1.secnext.fc30.x86_64 #1
[  139.630761] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[  139.631812] RIP: 0010:__list_del_entry_valid.cold.1+0x34/0x4c
[  139.632853] Code: ce 34 ac e8 b8 f7 c0 ff 0f 0b 48 c7 c7 a8 cf 34
ac e8 aa f7 c0 ff 0f 0b 48 89 f2 48 89 fe 48 c7 c7 68 cf 34 ac e8 96
f7 c0 ff <0f> 0b 48 89 fe 48 c7 c7 30 cf 34 ac e8 85 f7 c0 ff 0f 0b 90
90 90
[  139.636347] RSP: 0018:ffffb4890293fbb8 EFLAGS: 00010246
[  139.637295] RAX: 0000000000000054 RBX: ffff985fae91e620 RCX: 0000000000000000
[  139.638573] RDX: 0000000000000000 RSI: ffff985fb77d6be8 RDI: ffff985fb77d6be8
[  139.639855] RBP: ffff985fa98d40c0 R08: 00046c1ac1fe8d00 R09: 0000000000000000
[  139.641136] R10: 0000000000000000 R11: 0000000000000000 R12: ffff985fa98d4100
[  139.642416] R13: 0000000000000000 R14: ffff985faf00fe20 R15: 00000000000003f4
[  139.643699] FS:  00007f9898252b80(0000) GS:ffff985fb7600000(0000)
knlGS:0000000000000000
[  139.645199] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  139.646244] CR2: 0000561d333b8218 CR3: 000000023110a000 CR4: 00000000001406e0
[  139.647533] Call Trace:
[  139.647997]  audit_remove_tree_rule+0xad/0x160
[  139.648819]  audit_del_rule+0x90/0x190
[  139.649507]  audit_rule_change+0x98e/0xbf0
[  139.650259]  audit_receive_msg+0x142/0x1160
[  139.651030]  ? netlink_deliver_tap+0x99/0x410
[  139.651832]  audit_receive+0x54/0xb0
[  139.652495]  netlink_unicast+0x181/0x210
[  139.653211]  netlink_sendmsg+0x218/0x3e0
[  139.653936]  sock_sendmsg+0x36/0x40
[  139.654583]  __sys_sendto+0xf1/0x160
[  139.655244]  ? syscall_trace_enter+0x1d3/0x330
[  139.656055]  ? trace_hardirqs_off_thunk+0x1a/0x1c
[  139.656912]  __x64_sys_sendto+0x24/0x30
[  139.657615]  do_syscall_64+0x60/0x1f0
[  139.658285]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
[  139.659192] RIP: 0033:0x7f989835a7fb
[  139.659847] Code: 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 f3
0f 1e fa 48 8d 05 25 6f 0c 00 41 89 ca 8b 00 85 c0 75 14 b8 2c 00 00
00 0f 05 <48> 3d 00 f0 ff ff 77 75 c3 0f 1f 40 00 41 57 4d 89 c7 41 56
41 89
[  139.663170] RSP: 002b:00007ffc95ae6b48 EFLAGS: 00000246 ORIG_RAX:
000000000000002c
[  139.664531] RAX: ffffffffffffffda RBX: 0000000000000460 RCX: 00007f989835a7fb
[  139.665809] RDX: 0000000000000460 RSI: 00007ffc95ae6b80 RDI: 0000000000000003
[  139.667087] RBP: 0000000000000003 R08: 00007ffc95ae6b6c R09: 000000000000000c
[  139.668370] R10: 0000000000000000 R11: 0000000000000246 R12: 00007ffc95ae6b80
[  139.669648] R13: 00007ffc95ae6b6c R14: 0000000000000002 R15: 000000000000044f
[  139.670935] Modules linked in: ib_isert iscsi_target_mod ib_srpt
target_core_mod ib_srp scsi_transport_srp rpcrdma ib_umad rdma_ucm
ib_iser ib_ipoib rdma_cm iw_cm libiscsi scsi_transport_iscsi ib_cm
mlx5_ib ib_uverbs ib_core crct10dif_pclmul crc32_pclmul
ghash_clmulni_intel joydev virtio_balloon i2c_piix4 sunrpc
drm_kms_helper ttm crc32c_intel mlx5_core drm virtio_console mlxfw
serio_raw devlink virtio_blk virtio_net net_failover failover
ata_generic pata_acpi qemu_fw_cfg
[  139.678676] ---[ end trace be98f2acb1e536e4 ]---

> diff --git a/tests/stress_tree/Makefile b/tests/stress_tree/Makefile
> new file mode 100644
> index 000000000000..7ade09aad86f
> --- /dev/null
> +++ b/tests/stress_tree/Makefile
> @@ -0,0 +1,8 @@
> +TARGETS=$(patsubst %.c,%,$(wildcard *.c))
> +
> +LDLIBS += -lpthread
> +
> +all: $(TARGETS)
> +clean:
> +       rm -f $(TARGETS)
> +
> diff --git a/tests/stress_tree/test b/tests/stress_tree/test
> new file mode 100755
> index 000000000000..6215bec810d1
> --- /dev/null
> +++ b/tests/stress_tree/test
> @@ -0,0 +1,171 @@
> +#!/usr/bin/perl
> +
> +use strict;
> +
> +use Test;
> +BEGIN { plan tests => 1 }
> +
> +use File::Temp qw/ tempdir tempfile /;
> +
> +###
> +# functions
> +
> +sub key_gen {
> +       my @chars = ( "A" .. "Z", "a" .. "z" );
> +       my $key = "testsuite-" . time . "-";
> +       $key .= $chars[ rand @chars ] for 1 .. 8;
> +       return $key;
> +}
> +
> +# Run stat on random files in subtrees to generate audit events
> +sub run_stat {
> +       my($dir,$dirs) = @_;
> +       my $path;
> +
> +       while (1) {
> +               $path = "$dir/mnt/mnt".int(rand($dirs))."/subdir".int(rand($dirs));
> +               stat($path);
> +       }
> +}
> +
> +# Generate audit rules for subtrees. Do one rule per subtree. Because watch
> +# recursively iterates child mounts and we mount $dir/leaf$i under various
> +# subtrees, the inode corresponding to $dir/leaf$i gets tagged by different
> +# trees.
> +sub run_mark_audit {
> +       my($dir,$dirs,$key) = @_;
> +
> +       while (1) {
> +               for (my $i=0; $i < $dirs; $i++) {
> +                       system("auditctl -w $dir/mnt/mnt$i -p r -k $key");
> +               }
> +               system("auditctl -D -k $key >& /dev/null");
> +       }
> +}
> +
> +sub umount_all {
> +       my($dir,$dirs,$ignore_fail) = @_;
> +
> +       for (my $i=0; $i < $dirs; $i++) {
> +               while (system("umount $dir/leaf$i >& /dev/null") > 0 &&
> +                      $ignore_fail == 0) {
> +                       # Nothing - loop until umount succeeds
> +               }
> +       }
> +       for (my $i=0; $i < $dirs; $i++) {
> +               for (my $j=0; $j < $dirs; $j++) {
> +                       while (system("umount $dir/mnt/mnt$i/subdir$j >& /dev/null") > 0 &&
> +                              $ignore_fail == 0) {
> +                               # Nothing - loop until umount succeeds
> +                       }
> +               }
> +               while (system("umount $dir/mnt/mnt$i >& /dev/null") > 0 &&
> +                      $ignore_fail == 0) {
> +                       # Nothing - loop until umount succeeds
> +               }
> +       }
> +}
> +
> +# Mount and unmount filesystems. We pick random leaf mount so that sometimes
> +# a leaf mount point root inode will gather more tags from different trees
> +# and sometimes we will be quicker in unmounting all instances of leaf and
> +# thus excercise inode evistion path
> +sub run_mount {
> +       my($dir,$dirs) = @_;
> +
> +       while (1) {
> +               # We use tmpfs here and not just bind mounts of some dir so
> +               # that the root inode gets evicted once all instances are
> +               # unmounted.
> +               for (my $i=0; $i < $dirs; $i++) {
> +                       system("mount -t tmpfs none $dir/leaf$i");
> +               }
> +               for (my $i=0; $i < $dirs; $i++) {
> +                       system("mount --bind $dir/dir$i $dir/mnt/mnt$i");
> +                       for (my $j=0; $j < $dirs; $j++) {
> +                               my $leaf="$dir/leaf".int(rand($dirs));
> +                               system("mount --bind $leaf $dir/mnt/mnt$i/subdir$j");
> +                       }
> +               }
> +               umount_all($dir, $dirs, 0);
> +       }
> +}
> +
> +
> +###
> +# setup
> +
> +# reset audit
> +system("auditctl -D >& /dev/null");
> +
> +# create temp directory
> +my $dir = tempdir( TEMPLATE => '/tmp/audit-testsuite-XXXX', CLEANUP => 1 );
> +
> +# create stdout/stderr sinks
> +( my $fh_out, my $stdout ) = tempfile(
> +       TEMPLATE => '/tmp/audit-testsuite-out-XXXX',
> +       UNLINK   => 1
> +);
> +( my $fh_err, my $stderr ) = tempfile(
> +       TEMPLATE => '/tmp/audit-testsuite-err-XXXX',
> +       UNLINK   => 1
> +);
> +
> +###
> +# tests
> +
> +my $dirs = 4;
> +
> +# setup directory hierarchy
> +for (my $i=0; $i < $dirs; $i++) {
> +       mkdir $dir."/dir".$i;
> +       for (my $j=0; $j < $dirs; $j++) {
> +               mkdir $dir."/dir".$i."/subdir".$j;
> +       }
> +}
> +mkdir "$dir/mnt";
> +for (my $i=0; $i < $dirs; $i++) {
> +       mkdir "$dir/mnt/mnt$i";
> +       mkdir "$dir/leaf$i";
> +}
> +
> +my $stat_pid = fork();
> +
> +if ($stat_pid == 0) {
> +       run_stat($dir, $dirs);
> +       # Never reached
> +       exit;
> +}
> +
> +my $mount_pid = fork();
> +
> +if ($mount_pid == 0) {
> +       run_mount($dir, $dirs);
> +       # Never reached
> +       exit;
> +}
> +
> +my $key = key_gen();
> +
> +my $audit_pid = fork();
> +
> +if ($audit_pid == 0) {
> +       run_mark_audit($dir, $dirs, $key);
> +       # Never reached
> +       exit;
> +}
> +
> +# Sleep for a minute to let stress test run...
> +sleep(60);
> +ok(1);
> +
> +###
> +# cleanup
> +
> +kill('KILL', $stat_pid, $mount_pid, $audit_pid);
> +# Wait for children to terminate
> +waitpid($stat_pid, 0);
> +waitpid($mount_pid, 0);
> +waitpid($audit_pid, 0);
> +system("auditctl -D >& /dev/null");
> +umount_all($dir, $dirs, 1);
> --
> 2.16.4
>


--
paul moore
www.paul-moore.com