WARNING in __snd_pcm_lib_xfer

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit:    fff75eb2a08c Merge tag 'errseq-v4.17' of  
git://git.kernel.o...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?id=6530078334779392
kernel config:   
https://syzkaller.appspot.com/x/.config?id=6493557782959164711
dashboard link: https://syzkaller.appspot.com/bug?extid=1dac3a4f6bc9c1c675d4
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)
userspace arch: i386
syzkaller  
repro:https://syzkaller.appspot.com/x/repro.syz?id=5691583680741376

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+1dac3a4f6bc9c1c675d4@xxxxxxxxxxxxxxxxxxxxxxxxx

random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
random: sshd: uninitialized urandom read (32 bytes read)
IPVS: ftp: loaded support on port[0] = 21
WARNING: CPU: 1 PID: 4520 at sound/core/pcm_lib.c:2057 pcm_sanity_check  
sound/core/pcm_lib.c:2057 [inline]
WARNING: CPU: 1 PID: 4520 at sound/core/pcm_lib.c:2057  
__snd_pcm_lib_xfer+0x7c3/0x1d10 sound/core/pcm_lib.c:2122
Kernel panic - not syncing: panic_on_warn set ...

CPU: 1 PID: 4520 Comm: syz-executor0 Not tainted 4.17.0-rc3+ #52
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS  
Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 panic+0x22f/0x4de kernel/panic.c:184
 __warn.cold.8+0x163/0x1b3 kernel/panic.c:536
 report_bug+0x252/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x1de/0x490 arch/x86/kernel/traps.c:296
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:992
RIP: 0010:pcm_sanity_check sound/core/pcm_lib.c:2057 [inline]
RIP: 0010:__snd_pcm_lib_xfer+0x7c3/0x1d10 sound/core/pcm_lib.c:2122
RSP: 0018:ffff8801d97b7898 EFLAGS: 00010293
RAX: ffff8801ad00e0c0 RBX: ffff8801d965e100 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff85c3d333 RDI: ffff8801d965e418
RBP: ffff8801d97b7b38 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000003 R11: 0000000000000000 R12: ffffffff884945c0
R13: 0000000000000000 R14: ffff8801d965e100 R15: ffff8801cdd2c940
 snd_pcm_lib_readv include/sound/pcm.h:1113 [inline]
 snd_pcm_ioctl_xfern_compat+0x266/0x330 sound/core/pcm_compat.c:448
 snd_pcm_ioctl_compat+0xc96/0x1c90 sound/core/pcm_compat.c:716
 __do_compat_sys_ioctl fs/compat_ioctl.c:1461 [inline]
 __se_compat_sys_ioctl fs/compat_ioctl.c:1407 [inline]
 __ia32_compat_sys_ioctl+0x221/0x640 fs/compat_ioctl.c:1407
 do_syscall_32_irqs_on arch/x86/entry/common.c:323 [inline]
 do_fast_syscall_32+0x345/0xf9b arch/x86/entry/common.c:394
 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139
RIP: 0023:0xf7f51cb9
RSP: 002b:00000000ffafd6ac EFLAGS: 00000282 ORIG_RAX: 0000000000000036
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000800c4153
RDX: 0000000020000040 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000292 R12: 0000000000000000
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..


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