From patchwork Mon Sep 11 15:37:32 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 13379960 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6999ACA0EC2 for ; Mon, 11 Sep 2023 21:29:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345535AbjIKVVL (ORCPT ); Mon, 11 Sep 2023 17:21:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59696 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242464AbjIKPhj (ORCPT ); Mon, 11 Sep 2023 11:37:39 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DF902E9 for ; Mon, 11 Sep 2023 08:37:33 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 51D02C433C9; Mon, 11 Sep 2023 15:37:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1694446653; bh=QW4pb4R6Ccpb8384BjgXZniEg+jxpzOwMWDVqj1BEFw=; h=Date:From:To:Cc:Subject:From; b=EAr9mFNZdQ4DFI4b0vdExjwb44nggD677WpCMr8p30gqPMGPWLQ3CZOYrcnG6g7gv 10igkOyWRD3TLtFLoWZO0IGEgRWBeNBZ6V8kxdTNorUb4dfaz2ZXl66tapZ3Vq/ISY JfPc1Emb0tkdYFaZYFmd1ssegUf+SqyJUz9jkfHGeJfDzpFm460KETfPgfo+02Wgor /wl1N6Oj2DfpZicnup2lqj3i3Twigix3WX1QoqXk76I2vd8Xby5YfFqrNOYeihcB+q SLdEAwY3//juMgigowHLnQ72lnQxNpNO89nGZ2CYT0z7bn4/Ld32zzatPVDl4RpN9v ujibFNqa87TJg== Date: Mon, 11 Sep 2023 08:37:32 -0700 From: "Darrick J. Wong" To: Chandan Babu R Cc: Dave Chinner , xfs , harshit.m.mogalapalli@oracle.com Subject: [PATCH] xfs: only call xchk_stats_merge after validating scrub inputs Message-ID: <20230911153732.GZ28186@frogsfrogsfrogs> MIME-Version: 1.0 Content-Disposition: inline Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org From: Darrick J. Wong Harshit Mogalapalli slogged through several reports from our internal syzbot instance and observed that they all had a common stack trace: BUG: KASAN: user-memory-access in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: user-memory-access in atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1294 [inline] BUG: KASAN: user-memory-access in queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] BUG: KASAN: user-memory-access in do_raw_spin_lock include/linux/spinlock.h:187 [inline] BUG: KASAN: user-memory-access in __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline] BUG: KASAN: user-memory-access in _raw_spin_lock+0x76/0xe0 kernel/locking/spinlock.c:154 Write of size 4 at addr 0000001dd87ee280 by task syz-executor365/1543 CPU: 2 PID: 1543 Comm: syz-executor365 Not tainted 6.5.0-syzk #1 Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29 04/01/2014 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x83/0xb0 lib/dump_stack.c:106 print_report+0x3f8/0x620 mm/kasan/report.c:478 kasan_report+0xb0/0xe0 mm/kasan/report.c:588 check_region_inline mm/kasan/generic.c:181 [inline] kasan_check_range+0x139/0x1e0 mm/kasan/generic.c:187 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] atomic_try_cmpxchg_acquire include/linux/atomic/atomic-instrumented.h:1294 [inline] queued_spin_lock include/asm-generic/qspinlock.h:111 [inline] do_raw_spin_lock include/linux/spinlock.h:187 [inline] __raw_spin_lock include/linux/spinlock_api_smp.h:134 [inline] _raw_spin_lock+0x76/0xe0 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] xchk_stats_merge_one.isra.1+0x39/0x650 fs/xfs/scrub/stats.c:191 xchk_stats_merge+0x5f/0xe0 fs/xfs/scrub/stats.c:225 xfs_scrub_metadata+0x252/0x14e0 fs/xfs/scrub/scrub.c:599 xfs_ioc_scrub_metadata+0xc8/0x160 fs/xfs/xfs_ioctl.c:1646 xfs_file_ioctl+0x3fd/0x1870 fs/xfs/xfs_ioctl.c:1955 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:871 [inline] __se_sys_ioctl fs/ioctl.c:857 [inline] __x64_sys_ioctl+0x199/0x220 fs/ioctl.c:857 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3e/0x90 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x6e/0xd8 RIP: 0033:0x7ff155af753d Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48 RSP: 002b:00007ffc006e2568 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff155af753d RDX: 00000000200000c0 RSI: 00000000c040583c RDI: 0000000000000003 RBP: 00000000ffffffff R08: 00000000004010c0 R09: 00000000004010c0 R10: 00000000004010c0 R11: 0000000000000246 R12: 0000000000400cb0 R13: 00007ffc006e2670 R14: 0000000000000000 R15: 0000000000000000 The root cause here is that xchk_stats_merge_one walks off the end of the xchk_scrub_stats.cs_stats array because it has been fed a garbage value in sm->sm_type. That occurs because I put the xchk_stats_merge in the wrong place -- it should have been after the last xchk_teardown call on our way out of xfs_scrub_metadata because we only call the teardown function if we called the setup function, and we don't call the setup functions if the inputs are obviously garbage. Thanks to Harshit for triaging the bug reports and bringing this to my attention. This is a helluva better way to handle syzbot reports than spraying sploits on the public list like Googlers do. Fixes: d7a74cad8f45 ("xfs: track usage statistics of online fsck") Reported-by: Harshit Mogalapalli Signed-off-by: Darrick J. Wong Reviewed-by: Dave Chinner --- fs/xfs/scrub/scrub.c | 4 ++-- fs/xfs/scrub/stats.c | 5 ++++- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c index 7d3aa14d81b5..4849efcaa33a 100644 --- a/fs/xfs/scrub/scrub.c +++ b/fs/xfs/scrub/scrub.c @@ -588,6 +588,8 @@ xfs_scrub_metadata( out_teardown: error = xchk_teardown(sc, error); out_sc: + if (error != -ENOENT) + xchk_stats_merge(mp, sm, &run); kfree(sc); out: trace_xchk_done(XFS_I(file_inode(file)), sm, error); @@ -595,8 +597,6 @@ xfs_scrub_metadata( sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT; error = 0; } - if (error != -ENOENT) - xchk_stats_merge(mp, sm, &run); return error; need_drain: error = xchk_teardown(sc, 0); diff --git a/fs/xfs/scrub/stats.c b/fs/xfs/scrub/stats.c index aeb92624176b..cd91db4a5548 100644 --- a/fs/xfs/scrub/stats.c +++ b/fs/xfs/scrub/stats.c @@ -185,7 +185,10 @@ xchk_stats_merge_one( { struct xchk_scrub_stats *css; - ASSERT(sm->sm_type < XFS_SCRUB_TYPE_NR); + if (sm->sm_type >= XFS_SCRUB_TYPE_NR) { + ASSERT(sm->sm_type < XFS_SCRUB_TYPE_NR); + return; + } css = &cs->cs_stats[sm->sm_type]; spin_lock(&css->css_lock);