From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A37C3C4338F for ; Thu, 29 Jul 2021 11:44:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8B922604D7 for ; Thu, 29 Jul 2021 11:44:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234746AbhG2LoS convert rfc822-to-8bit (ORCPT ); Thu, 29 Jul 2021 07:44:18 -0400 Received: from coyote.holtmann.net ([212.227.132.17]:48578 "EHLO mail.holtmann.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232149AbhG2LoS (ORCPT ); Thu, 29 Jul 2021 07:44:18 -0400 Received: from smtpclient.apple (p5b3d23f8.dip0.t-ipconnect.de [91.61.35.248]) by mail.holtmann.org (Postfix) with ESMTPSA id 2D341CED19; Thu, 29 Jul 2021 13:44:14 +0200 (CEST) Content-Type: text/plain; charset=utf-8 Mime-Version: 1.0 (Mac OS X Mail 14.0 \(3654.100.0.2.22\)) Subject: Re: memory leak in h4_recv_buf From: Marcel Holtmann In-Reply-To: Date: Thu, 29 Jul 2021 13:44:13 +0200 Cc: syzkaller-bugs , Johan Hedberg , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8BIT Message-Id: References: <0000000000006b1779058c0cbdda@google.com> To: Phi Nguyen X-Mailer: Apple Mail (2.3654.100.0.2.22) Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi Phi, >> Hello, >> syzbot found the following crash on: >> HEAD commit: abf02e29 Merge tag 'pm-5.2-rc6' of >> git://git.kernel.org/pu .. >> git tree: upstream >> console output: >> https://syzkaller.appspot.com/x/log.txt?x=1054e6b2a00000 >> >> kernel config: >> https://syzkaller.appspot.com/x/.config?x=56f1da14935c3cce >> >> dashboard link: >> https://syzkaller.appspot.com/bug?extid=97388eb9d31b997fe1d0 >> >> compiler: gcc (GCC) 9.0.0 20181231 (experimental) >> syz repro: >> https://syzkaller.appspot.com/x/repro.syz?x=1073d8aaa00000 >> >> C reproducer: >> https://syzkaller.appspot.com/x/repro.c?x=17b36fbea00000 >> >> IMPORTANT: if you fix the bug, please add the following tag to the >> commit: >> Reported-by: syzbot+97388e...@syzkaller.appspotmail.com >> program >> BUG: memory leak >> unreferenced object 0xffff88810991fa00 (size 224): >> comm "syz-executor739", pid 7080, jiffies 4294949854 (age 18.640s) >> hex dump (first 32 bytes): >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> backtrace: >> [<00000000da42c09f>] kmemleak_alloc_recursive >> include/linux/kmemleak.h:43 [inline] >> [<00000000da42c09f>] slab_post_alloc_hook mm/slab.h:439 [inline] >> [<00000000da42c09f>] slab_alloc_node mm/slab.c:3269 [inline] >> [<00000000da42c09f>] kmem_cache_alloc_node+0x153/0x2a0 mm/slab.c:3579 >> [<00000000f6fbcf84>] __alloc_skb+0x6e/0x210 net/core/skbuff.c:194 >> [<00000000ea93fc4c>] alloc_skb include/linux/skbuff.h:1054 [inline] >> [<00000000ea93fc4c>] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 >> [inline] >> [<00000000ea93fc4c>] h4_recv_buf+0x26d/0x450 >> drivers/bluetooth/hci_h4.c:182 >> [<00000000e0312475>] h4_recv+0x51/0xb0 drivers/bluetooth/hci_h4.c:116 >> [<00000000ebf11fab>] hci_uart_tty_receive+0xba/0x200 >> drivers/bluetooth/hci_ldisc.c:592 >> [<0000000095e1216e>] tiocsti drivers/tty/tty_io.c:2195 [inline] >> [<0000000095e1216e>] tty_ioctl+0x81c/0xa30 drivers/tty/tty_io.c:2571 >> [<000000009fa523f0>] vfs_ioctl fs/ioctl.c:46 [inline] >> [<000000009fa523f0>] file_ioctl fs/ioctl.c:509 [inline] >> [<000000009fa523f0>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696 >> [<000000000cebb5d9>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713 >> [<000000001630008a>] __do_sys_ioctl fs/ioctl.c:720 [inline] >> [<000000001630008a>] __se_sys_ioctl fs/ioctl.c:718 [inline] >> [<000000001630008a>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718 >> [<00000000c62091e3>] do_syscall_64+0x76/0x1a0 >> arch/x86/entry/common.c:301 >> [<000000005c213625>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> BUG: memory leak >> unreferenced object 0xffff8881204f4400 (size 1024): >> comm "syz-executor739", pid 7080, jiffies 4294949854 (age 18.640s) >> hex dump (first 32 bytes): >> 6c 69 62 75 64 65 76 00 fe ed ca fe 28 00 00 00 libudev.....(... >> 28 00 00 00 a0 00 00 00 52 ca da 77 00 00 00 00 (.......R..w.... >> backtrace: >> [<0000000034504843>] kmemleak_alloc_recursive >> include/linux/kmemleak.h:43 [inline] >> [<0000000034504843>] slab_post_alloc_hook mm/slab.h:439 [inline] >> [<0000000034504843>] slab_alloc_node mm/slab.c:3269 [inline] >> [<0000000034504843>] kmem_cache_alloc_node_trace+0x15b/0x2a0 >> mm/slab.c:3597 >> [<0000000056d30eb5>] __do_kmalloc_node mm/slab.c:3619 [inline] >> [<0000000056d30eb5>] __kmalloc_node_track_caller+0x38/0x50 >> mm/slab.c:3634 >> [<00000000df40176c>] __kmalloc_reserve.isra.0+0x40/0xb0 >> net/core/skbuff.c:138 >> [<0000000035340e64>] __alloc_skb+0xa0/0x210 net/core/skbuff.c:206 >> [<00000000ea93fc4c>] alloc_skb include/linux/skbuff.h:1054 [inline] >> [<00000000ea93fc4c>] bt_skb_alloc include/net/bluetooth/bluetooth.h:339 >> [inline] >> [<00000000ea93fc4c>] h4_recv_buf+0x26d/0x450 >> drivers/bluetooth/hci_h4.c:182 >> [<00000000e0312475>] h4_recv+0x51/0xb0 drivers/bluetooth/hci_h4.c:116 >> [<00000000ebf11fab>] hci_uart_tty_receive+0xba/0x200 >> drivers/bluetooth/hci_ldisc.c:592 >> [<0000000095e1216e>] tiocsti drivers/tty/tty_io.c:2195 [inline] >> [<0000000095e1216e>] tty_ioctl+0x81c/0xa30 drivers/tty/tty_io.c:2571 >> [<000000009fa523f0>] vfs_ioctl fs/ioctl.c:46 [inline] >> [<000000009fa523f0>] file_ioctl fs/ioctl.c:509 [inline] >> [<000000009fa523f0>] do_vfs_ioctl+0x62a/0x810 fs/ioctl.c:696 >> [<000000000cebb5d9>] ksys_ioctl+0x86/0xb0 fs/ioctl.c:713 >> [<000000001630008a>] __do_sys_ioctl fs/ioctl.c:720 [inline] >> [<000000001630008a>] __se_sys_ioctl fs/ioctl.c:718 [inline] >> [<000000001630008a>] __x64_sys_ioctl+0x1e/0x30 fs/ioctl.c:718 >> [<00000000c62091e3>] do_syscall_64+0x76/0x1a0 >> arch/x86/entry/common.c:301 >> [<000000005c213625>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 >> --- >> This bug 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 syzk...@googlegroups.com. >> syzbot will keep track of this bug report. See: >> https://goo.gl/tpsmEJ#status for how >> to communicate with syzbot. >> syzbot can test patches for this bug, for details see: >> https://goo.gl/tpsmEJ#testing-patches >> >> -- >> You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. >> To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@googlegroups.com . >> To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/d71a274f-fdeb-4da1-898e-06f6944e04dan%40googlegroups.com . > > The reason of this memory leak is tty_ldisc_receive_buf() and tiocsti() > can access the h4->rx_skb concurrently by calling > hci_uart_tty_receive(), so the rx_skb be overwritten without > deallocating. There used to be an spin_lock in hci_uart_tty_receive(), > but it was removed by commit 7649ffaff1cfe(Bluetooth: Remove useless > rx_lock spinlock). I don’t have that commit in my Linus’ tree. Where is it? > The commit message claims that hci_uart_tty_receive() was only called by > flush_to_ldisc(), but it seems incorrect. That seems to be a larger problem in the TTY layer if its contract with its users have changed. Regards Marcel