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smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com; spf=pass smtp.mailfrom=huawei.com; arc=none smtp.client-ip=45.249.212.187 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=huawei.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=huawei.com Received: from mail.maildlp.com (unknown [172.19.163.174]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4WCT4l6qcTzZh5Y; Mon, 1 Jul 2024 22:31:35 +0800 (CST) Received: from dggpeml100021.china.huawei.com (unknown [7.185.36.148]) by mail.maildlp.com (Postfix) with ESMTPS id 095A4140121; Mon, 1 Jul 2024 22:36:07 +0800 (CST) Received: from [10.174.177.174] (10.174.177.174) by dggpeml100021.china.huawei.com (7.185.36.148) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.1.2507.39; Mon, 1 Jul 2024 22:36:06 +0800 Message-ID: Date: Mon, 1 Jul 2024 22:36:06 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [ext4?] BUG: unable to handle kernel paging request in do_split To: syzbot , , , , , References: <00000000000075a135061c0480d0@google.com> Content-Language: en-US From: Baokun Li In-Reply-To: <00000000000075a135061c0480d0@google.com> Content-Type: text/plain; charset="UTF-8"; format=flowed Content-Transfer-Encoding: 8bit X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml100021.china.huawei.com (7.185.36.148) On 2024/6/29 18:05, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 55027e689933 Merge tag 'input-for-v6.10-rc5' of git://git... > git tree: upstream > console+strace: https://syzkaller.appspot.com/x/log.txt?x=100ec271980000 > kernel config: https://syzkaller.appspot.com/x/.config?x=67463c0717b8d4ca > dashboard link: https://syzkaller.appspot.com/bug?extid=ae688d469e36fb5138d0 > compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=14296bb6980000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=10a53e3e980000 > > Downloadable assets: > disk image: https://storage.googleapis.com/syzbot-assets/5a4561e75890/disk-55027e68.raw.xz > vmlinux: https://storage.googleapis.com/syzbot-assets/40e478722974/vmlinux-55027e68.xz > kernel image: https://storage.googleapis.com/syzbot-assets/d3bbbd2462f2/bzImage-55027e68.xz > mounted in repro: https://storage.googleapis.com/syzbot-assets/451986899a3c/mount_0.gz > > Bisection is inconclusive: the first bad commit could be any of: > > 3b51788a2d5f IB/hfi1: use new function dev_fetch_sw_netstats > 44fa32f008ab net: add function dev_fetch_sw_netstats for fetching pcpu_sw_netstats > 3618ad2a7c0e virtio-net: ethtool configurable RXCSUM > 9d0151673e70 net: macsec: use new function dev_fetch_sw_netstats > c9bf52a173c7 net/af_unix: Remove unused old_pid variable > ec173778e96e net: usb: qmi_wwan: use new function dev_fetch_sw_netstats > 0403a2b53c29 net/tls: use semicolons rather than commas to separate statements > ab2b3ff21b9f net: usbnet: use new function dev_fetch_sw_netstats > 1f68b2096f65 qtnfmac: use new function dev_fetch_sw_netstats > 6159e9633f17 net/ipv6: use semicolons rather than commas to separate statements > 44797589c20e tcp: use semicolons rather than commas to separate statements > f3f04f0f3ab9 net: bridge: use new function dev_fetch_sw_netstats > 7e38b03f0fe7 net: mscc: ocelot: remove duplicate ocelot_port_dev_check > a0d269810185 net: dsa: use new function dev_fetch_sw_netstats > c93c5482c7d4 Merge branch 'macb-support-the-2-deep-Tx-queue-on-at91' > cf89f18fa407 iptunnel: use new function dev_fetch_sw_netstats > 0a4e9ce17ba7 macb: support the two tx descriptors on at91rm9200 > 6401297e7610 mac80211: use new function dev_fetch_sw_netstats > 3569939a811e net: openvswitch: use new function dev_fetch_sw_netstats > 73d742281383 macb: prepare at91 to use a 2-frame TX queue > 5fc3594d36d1 xfrm: use new function dev_fetch_sw_netstats > fa6031df12fc macb: add RM9200's interrupt flag TBRE > a003ec1f47bc Merge branch 'net-add-and-use-function-dev_fetch_sw_netstats-for-fetching-pcpu_sw_netstats' > ccdf7fae3afa Merge git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next > 30cf856a691f i40e: Allow changing FEC settings on X722 if supported by FW > a308283fdbf7 Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next > 793d5d612426 netfilter: flowtable: reduce calls to pskb_may_pull() > f2bf814a27c5 e1000: remove unused and incorrect code > d3519cb89f6d netfilter: nf_tables: add inet ingress support > d5e6f064ac66 Merge branch '40GbE-Intel-Wired-LAN-Driver-Updates-2020-10-12' > 50172733d01c Merge tag 'mlx5-updates-2020-10-12' of git://git.kernel.org/pub/scm/linux/kernel/git/saeed/linux > 60a3815da702 netfilter: add inet ingress support > d25e2e9388ed netfilter: restore NF_INET_NUMHOOKS > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=14154fda980000 > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > Reported-by: syzbot+ae688d469e36fb5138d0@syzkaller.appspotmail.com > > EXT4-fs error (device loop0): ext4_orphan_get:1399: comm syz-executor306: couldn't read orphan inode 15 (err -117) > EXT4-fs (loop0): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none. > BUG: unable to handle page fault for address: ffffed11022e24fe > #PF: supervisor read access in kernel mode > #PF: error_code(0x0000) - not-present page > PGD 23ffee067 P4D 23ffee067 PUD 0 > Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI > CPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-syzkaller-00018-g55027e689933 #0 > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024 > RIP: 0010:do_split+0x150b/0x2490 fs/ext4/namei.c:2046 > Code: 89 f8 48 c1 e8 03 0f b6 04 10 84 c0 48 89 74 24 18 0f 85 f5 0c 00 00 46 8b 3c f6 41 8d 46 ff 48 8d 1c c6 48 89 d8 48 c1 e8 03 <0f> b6 04 10 84 c0 4c 8b a4 24 98 00 00 00 0f 85 f7 0c 00 00 8b 1b > RSP: 0018:ffffc9000327f060 EFLAGS: 00010a02 > RAX: 1ffff111022e24fe RBX: ffff8888117127f0 RCX: ffff8880237e1e00 > RDX: dffffc0000000000 RSI: ffff8880117127f8 RDI: ffff8880117127f8 > RBP: ffffc9000327f250 R08: ffffffff825fc2ad R09: ffffffff82541cf8 > R10: 0000000000000007 R11: ffffffff825435f0 R12: 0000000000000000 > R13: 0000000000000400 R14: 0000000000000000 R15: 000000002b74e18c > FS: 00005555787b4380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffed11022e24fe CR3: 0000000043598000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > Call Trace: > > make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341 > ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451 > ext4_rename fs/ext4/namei.c:3936 [inline] > ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214 > vfs_rename+0xbdb/0xf00 fs/namei.c:4887 > do_renameat2+0xd94/0x13f0 fs/namei.c:5044 > __do_sys_rename fs/namei.c:5091 [inline] > __se_sys_rename fs/namei.c:5089 [inline] > __x64_sys_rename+0x86/0xa0 fs/namei.c:5089 > do_syscall_x64 arch/x86/entry/common.c:52 [inline] > do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 > entry_SYSCALL_64_after_hwframe+0x77/0x7f > RIP: 0033:0x7fe5c7dcdb59 > Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 17 00 00 90 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 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 > RSP: 002b:00007ffcd201c228 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 > RAX: ffffffffffffffda RBX: 00007fe5c7e16568 RCX: 00007fe5c7dcdb59 > RDX: 0000000000000000 RSI: 0000000020000f40 RDI: 00000000200003c0 > RBP: 00007fe5c7e16668 R08: 00005555787b54c0 R09: 00005555787b54c0 > R10: 00005555787b54c0 R11: 0000000000000246 R12: 00007ffcd201c250 > R13: 00007ffcd201c478 R14: 431bde82d7b634db R15: 00007fe5c7e1603b > > Modules linked in: > CR2: ffffed11022e24fe > ---[ end trace 0000000000000000 ]--- > RIP: 0010:do_split+0x150b/0x2490 fs/ext4/namei.c:2046 > Code: 89 f8 48 c1 e8 03 0f b6 04 10 84 c0 48 89 74 24 18 0f 85 f5 0c 00 00 46 8b 3c f6 41 8d 46 ff 48 8d 1c c6 48 89 d8 48 c1 e8 03 <0f> b6 04 10 84 c0 4c 8b a4 24 98 00 00 00 0f 85 f7 0c 00 00 8b 1b > RSP: 0018:ffffc9000327f060 EFLAGS: 00010a02 > RAX: 1ffff111022e24fe RBX: ffff8888117127f0 RCX: ffff8880237e1e00 > RDX: dffffc0000000000 RSI: ffff8880117127f8 RDI: ffff8880117127f8 > RBP: ffffc9000327f250 R08: ffffffff825fc2ad R09: ffffffff82541cf8 > R10: 0000000000000007 R11: ffffffff825435f0 R12: 0000000000000000 > R13: 0000000000000400 R14: 0000000000000000 R15: 000000002b74e18c > FS: 00005555787b4380(0000) GS:ffff8880b9400000(0000) knlGS:0000000000000000 > CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 > CR2: ffffed11022e24fe CR3: 0000000043598000 CR4: 00000000003506f0 > DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 > ---------------- > Code disassembly (best guess): > 0: 89 f8 mov %edi,%eax > 2: 48 c1 e8 03 shr $0x3,%rax > 6: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax > a: 84 c0 test %al,%al > c: 48 89 74 24 18 mov %rsi,0x18(%rsp) > 11: 0f 85 f5 0c 00 00 jne 0xd0c > 17: 46 8b 3c f6 mov (%rsi,%r14,8),%r15d > 1b: 41 8d 46 ff lea -0x1(%r14),%eax > 1f: 48 8d 1c c6 lea (%rsi,%rax,8),%rbx > 23: 48 89 d8 mov %rbx,%rax > 26: 48 c1 e8 03 shr $0x3,%rax > * 2a: 0f b6 04 10 movzbl (%rax,%rdx,1),%eax <-- trapping instruction > 2e: 84 c0 test %al,%al > 30: 4c 8b a4 24 98 00 00 mov 0x98(%rsp),%r12 > 37: 00 > 38: 0f 85 f7 0c 00 00 jne 0xd35 > 3e: 8b 1b mov (%rbx),%ebx > > > --- > This report is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this issue. See: > https://goo.gl/tpsmEJ#status for how to communicate with syzbot. > For information about bisection process see: https://goo.gl/tpsmEJ#bisection > > If the report is already addressed, let syzbot know by replying with: > #syz fix: exact-commit-title > > If you want syzbot to run the reproducer, reply with: > #syz test: git://repo/address.git branch-or-commit-hash > If you attach or paste a git patch, syzbot will apply it before testing. > > If you want to overwrite report's subsystems, reply with: > #syz set subsystems: new-subsystem > (See the list of subsystem names on the web dashboard) > > If the report is a duplicate of another one, reply with: > #syz dup: exact-subject-of-another-report > > If you want to undo deduplication, reply with: > #syz undup The immediate cause of this problem is that there is only one valid dentry for the block to be split during do_split, so split==0 results in out-of-bounds accesses to the map triggering the problem.      do_split        unsigned split        dx_make_map         count = 1        split = count/2 = 0;        continued = hash2 == map[split - 1].hash;         ---> map[4294967295] The root cause is that syzbot constructs a directory that is not inline but does not have a dirblock, and we don't check for it when we create files under the folder.     ext4_mknod       ext4_add_entry         // Read block 0         ext4_read_dirblock(dir, block, DIRENT)           bh = ext4_bread(NULL, inode, block, 0)           if (!bh && (type == INDEX || type == DIRENT_HTREE))           // The first directory block is a hole           // But type == DIRENT, so no error is reported. Therefore, reporting error when ext4_read_dirblock() finds the first directory block is a hole to avoid error spreading leading to something bad. Here's the patch in testing, I'll send it out officially after it is tested. Regards, Baokun From: Baokun Li Date: Mon, 1 Jul 2024 20:23:59 +0800 Subject: [PATCH] ext4: make sure the first directory block is not a hole Syzbot reports a issue as follows: ============================================ BUG: unable to handle page fault for address: ffffed11022e24fe PGD 23ffee067 P4D 23ffee067 PUD 0 Oops: Oops: 0000 [#1] PREEMPT SMP KASAN PTI CPU: 0 PID: 5079 Comm: syz-executor306 Not tainted 6.10.0-rc5-g55027e689933 #0 Call Trace:    make_indexed_dir+0xdaf/0x13c0 fs/ext4/namei.c:2341  ext4_add_entry+0x222a/0x25d0 fs/ext4/namei.c:2451  ext4_rename fs/ext4/namei.c:3936 [inline]  ext4_rename2+0x26e5/0x4370 fs/ext4/namei.c:4214 [...] ============================================ The immediate cause of this problem is that there is only one valid dentry for the block to be split during do_split, so split==0 results in out-of-bounds accesses to the map triggering the problem.     do_split       unsigned split       dx_make_map        count = 1       split = count/2 = 0;       continued = hash2 == map[split - 1].hash;        ---> map[4294967295] The root cause is that the syzbot constructs a directory that is not inline but does not have a dirblock, and we don't check for it when we create files under the folder.     ext4_mknod       ext4_add_entry         // Read block 0         ext4_read_dirblock(dir, block, DIRENT)           bh = ext4_bread(NULL, inode, block, 0)           if (!bh && (type == INDEX || type == DIRENT_HTREE))           // The first directory block is a hole           // But type == DIRENT, so no error is reported. Therefore, report that the filesystem is corrupted when ext4_read_dirblock() finds the first directory block to be a hole, to avoid spreading the error to cause something bad. Fixes: 4e19d6b65fb4 ("ext4: allow directory holes") Signed-off-by: Baokun Li ---  fs/ext4/namei.c | 13 ++++---------  1 file changed, 4 insertions(+), 9 deletions(-) diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index a630b27a4cc6..facdf0e97a48 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -151,7 +151,8 @@ static struct buffer_head *__ext4_read_dirblock(struct inode *inode,          return bh;      } -    if (!bh && (type == INDEX || type == DIRENT_HTREE)) { +    /* The first directory block must not be a hole. */ +    if (!bh && (type == INDEX || type == DIRENT_HTREE || block == 0)) {          ext4_error_inode(inode, func, line, block,                   "Directory hole found for htree %s block",                   (type == INDEX) ? "index" : "leaf"); @@ -3083,10 +3084,7 @@ bool ext4_empty_dir(struct inode *inode)          EXT4_ERROR_INODE(inode, "invalid size");          return false;      } -    /* The first directory block must not be a hole, -     * so treat it as DIRENT_HTREE -     */ -    bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); +    bh = ext4_read_dirblock(inode, 0, EITHER)      if (IS_ERR(bh))          return false; @@ -3531,10 +3529,7 @@ static struct buffer_head *ext4_get_first_dir_block(handle_t *handle,          struct ext4_dir_entry_2 *de;          unsigned int offset; -        /* The first directory block must not be a hole, so -         * treat it as DIRENT_HTREE -         */ -        bh = ext4_read_dirblock(inode, 0, DIRENT_HTREE); +        bh = ext4_read_dirblock(inode, 0, EITHER);          if (IS_ERR(bh)) {              *retval = PTR_ERR(bh);              return NULL; -- 2.31.1