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Mon, 17 Jul 2023 06:27:49 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id n3axCGXftGT2awAAMHmgww (envelope-from ); Mon, 17 Jul 2023 06:27:49 +0000 Date: Mon, 17 Jul 2023 08:27:48 +0200 Message-ID: <87y1jfjbmj.wl-tiwai@suse.de> From: Takashi Iwai To: Geraldo Nascimento Cc: syzbot , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, perex@perex.cz, syzkaller-bugs@googlegroups.com, tiwai@suse.com Subject: Re: [syzbot] [alsa?] memory leak in snd_seq_create_port In-Reply-To: References: <00000000000098ed3a0600965f89@google.com> <87v8ekattg.wl-tiwai@suse.de> User-Agent: Wanderlust/2.15.9 (Almost Unreal) Emacs/27.2 Mule/6.0 MIME-Version: 1.0 (generated by SEMI-EPG 1.14.7 - "Harue") Content-Type: text/plain; charset=US-ASCII Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, 16 Jul 2023 21:06:52 +0200, Geraldo Nascimento wrote: > > On Sun, Jul 16, 2023 at 03:07:23PM +0200, Takashi Iwai wrote: > > On Sun, 16 Jul 2023 10:21:49 +0200, > > syzbot wrote: > > > > > > Hello, > > > > > > syzbot found the following issue on: > > > > > > HEAD commit: 3f01e9fed845 Merge tag 'linux-watchdog-6.5-rc2' of git://w.. > > > git tree: upstream > > > console output: https://syzkaller.appspot.com/x/log.txt?x=14b07344a80000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=75da4f0a455bdbd3 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=cf8e7fa4eeec59b3d485 > > > compiler: gcc (Debian 10.2.1-6) 10.2.1 20210110, GNU ld (GNU Binutils for Debian) 2.35.2 > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=15877dc2a80000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12905004a80000 > > > > > > Downloadable assets: > > > disk image: https://storage.googleapis.com/syzbot-assets/441fb7ea58b8/disk-3f01e9fe.raw.xz > > > vmlinux: https://storage.googleapis.com/syzbot-assets/8fa7790ba0c3/vmlinux-3f01e9fe.xz > > > kernel image: https://storage.googleapis.com/syzbot-assets/5e7a6471dadf/bzImage-3f01e9fe.xz > > > > > > IMPORTANT: if you fix the issue, please add the following tag to the commit: > > > Reported-by: syzbot+cf8e7fa4eeec59b3d485@syzkaller.appspotmail.com > > > > > > Warning: Permanently added '10.128.1.1' (ED25519) to the list of known hosts. > > > executing program > > > executing program > > > BUG: memory leak > > > unreferenced object 0xffff888100877000 (size 512): > > > comm "syz-executor257", pid 5012, jiffies 4294941742 (age 12.790s) > > > hex dump (first 32 bytes): > > > 80 ff 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: > > > [] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076 > > > [] kmalloc include/linux/slab.h:582 [inline] > > > [] kzalloc include/linux/slab.h:703 [inline] > > > [] snd_seq_create_port+0x78/0x300 sound/core/seq/seq_ports.c:135 > > > [] snd_seq_ioctl_create_port+0xe1/0x2a0 sound/core/seq/seq_clientmgr.c:1324 > > > [] snd_seq_ioctl+0x13e/0x290 sound/core/seq/seq_clientmgr.c:2327 > > > [] vfs_ioctl fs/ioctl.c:51 [inline] > > > [] __do_sys_ioctl fs/ioctl.c:870 [inline] > > > [] __se_sys_ioctl fs/ioctl.c:856 [inline] > > > [] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856 > > > [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > > [] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > > [] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > > > > > BUG: memory leak > > > unreferenced object 0xffff888106742c00 (size 512): > > > comm "syz-executor257", pid 5013, jiffies 4294942276 (age 7.450s) > > > hex dump (first 32 bytes): > > > 80 ff 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: > > > [] kmalloc_trace+0x24/0x90 mm/slab_common.c:1076 > > > [] kmalloc include/linux/slab.h:582 [inline] > > > [] kzalloc include/linux/slab.h:703 [inline] > > > [] snd_seq_create_port+0x78/0x300 sound/core/seq/seq_ports.c:135 > > > [] snd_seq_ioctl_create_port+0xe1/0x2a0 sound/core/seq/seq_clientmgr.c:1324 > > > [] snd_seq_ioctl+0x13e/0x290 sound/core/seq/seq_clientmgr.c:2327 > > > [] vfs_ioctl fs/ioctl.c:51 [inline] > > > [] __do_sys_ioctl fs/ioctl.c:870 [inline] > > > [] __se_sys_ioctl fs/ioctl.c:856 [inline] > > > [] __x64_sys_ioctl+0x103/0x140 fs/ioctl.c:856 > > > [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] > > > [] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 > > > [] entry_SYSCALL_64_after_hwframe+0x63/0xcd > > > > Likely a forgotten kfree() at the error path. > > The patch below should fix it. > > > > > > Takashi > > > > -- 8< -- > > From: Takashi Iwai > > Subject: [PATCH] ALSA: seq: Fix memory leak at error path in > > snd_seq_create_port() > > > > We forgot to release a newly allocated item at the error path in > > snd_seq_create_port(). This patch fixes it. > > Thanks for the clarification and quick proposed resolution Takashi. As > an ALSA novice these bots always stunt me, personally. I understand how > helpful they are however, even if cryptic. > > But shouldn't this be reported to security? It's always prone to bad > stuff when we forget a kfree() It's a bug that happened only on 6.5-rc1, so no need to bother too much with security issue fiasco for distros. Takashi