On sabato 9 aprile 2022 00:52:26 CEST syzbot wrote:

Hello,

syzbot found the following issue on:

HEAD commit: 312310928417 Linux 5.18-rc1 git tree: upstream console output: https://syzkaller.appspot.com/x/log.txt?x=16f30a90f00000 kernel config: https://syzkaller.appspot.com/x/.config?x=595bcd2109a73f9c dashboard link: https://syzkaller.appspot.com/bug?extid=205eb15961852c2c5974 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=1798df4f700000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12981dbf700000

IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+205eb15961852c2c5974@syzkaller.appspotmail.com

================================================================== BUG: KASAN: null-ptr-deref in snd_pcm_format_set_silence sound/core/pcm_misc.c:441 [inline] BUG: KASAN: null-ptr-deref in snd_pcm_format_set_silence+0x215/0x350 sound/core/pcm_misc.c:424 Write of size 16383 at addr 0000000000000001 by task syz-executor156/3605

CPU: 0 PID: 3605 Comm: syz-executor156 Not tainted 5.18.0-rc1-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace:

<TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106 print_report mm/kasan/report.c:432 [inline] kasan_report.cold+0x61/0x1c6 mm/kasan/report.c:491 check_region_inline mm/kasan/generic.c:183 [inline] kasan_check_range+0x13d/0x180 mm/kasan/generic.c:189 memset+0x20/0x40 mm/kasan/shadow.c:44 snd_pcm_format_set_silence sound/core/pcm_misc.c:441 [inline] snd_pcm_format_set_silence+0x215/0x350 sound/core/pcm_misc.c:424 snd_pcm_oss_sync+0x60e/0x800 sound/core/oss/pcm_oss.c:1690 snd_pcm_oss_ioctl+0x208c/0x3430 sound/core/oss/pcm_oss.c:2634 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+0x193/0x200 fs/ioctl.c:856 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0x80 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0846a59e69 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 c1 18 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:00007f0846c74318 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f0846af0028 RCX: 00007f0846a59e69 RDX: 0000000000000000 RSI: 0000000000005001 RDI: 0000000000000003 RBP: 00007f0846af0020 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 6475612f7665642f R13: 00007f0846bffd8f R14: 00007f0846c74400 R15: 0000000000022000 </TASK> ==================================================================

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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. syzbot can test patches for this issue, for details see: https://goo.gl/tpsmEJ#testing-patches

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Let's try and check if "pat" is valid...

#syz test: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

Fabio M. De Francesco

P.S.: I'm sorry, in my previous email I forgot to Cc all people and lists.