==================================================================
BUG: KASAN: null-ptr-deref in memcpy include/linux/string.h:344 [inline]
BUG: KASAN: null-ptr-deref in do_convert sound/core/oss/linear.c:52 [inline]
BUG: KASAN: null-ptr-deref in convert sound/core/oss/linear.c:81 [inline]
BUG: KASAN: null-ptr-deref in linear_transfer+0x64a/0x900 sound/core/oss/linear.c:110
Write of size 2 at addr           (null) by task syzkaller090840/26082

CPU: 0 PID: 26082 Comm: syzkaller090840 Not tainted 4.15.0-rc6-next-20180102+ #86
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x137/0x198 lib/dump_stack.c:53
 kasan_report_error mm/kasan/report.c:353 [inline]
 kasan_report+0x13f/0x360 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 memcpy include/linux/string.h:344 [inline]
 do_convert sound/core/oss/linear.c:52 [inline]
 convert sound/core/oss/linear.c:81 [inline]
 linear_transfer+0x64a/0x900 sound/core/oss/linear.c:110
 snd_pcm_plug_write_transfer+0x20b/0x390 sound/core/oss/pcm_plugin.c:611
 snd_pcm_oss_write2+0x22e/0x3c0 sound/core/oss/pcm_oss.c:1311
 snd_pcm_oss_sync1+0x158/0x4b0 sound/core/oss/pcm_oss.c:1530
 snd_pcm_oss_sync+0x4f2/0x710 sound/core/oss/pcm_oss.c:1604
 snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431
 __fput+0x291/0x6e0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x122/0x1a0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x7f4/0x2da0 kernel/exit.c:869
 do_group_exit+0x108/0x320 kernel/exit.c:972
 get_signal+0x5e9/0x1460 kernel/signal.c:2337
 do_signal+0x7f/0x1980 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x1aa/0x210 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x383/0x430 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x98/0x9a
RIP: 0033:0x44ac19
RSP: 002b:00007f1debbb3da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006dcc3c RCX: 000000000044ac19
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dcc3c
RBP: 00000000006dcc38 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 6fd5446e47d1c1dd
R13: 04a85bf0c3063392 R14: 0f17db8f3ad16a87 R15: 000000000000000d
==================================================================
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 26082 Comm: syzkaller090840 Tainted: G    B            4.15.0-rc6-next-20180102+ #86
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x137/0x198 lib/dump_stack.c:53
 panic+0x1e4/0x41c kernel/panic.c:183
 kasan_end_report+0x50/0x50 mm/kasan/report.c:180
 kasan_report_error mm/kasan/report.c:360 [inline]
 kasan_report+0x148/0x360 mm/kasan/report.c:413
 check_memory_region_inline mm/kasan/kasan.c:260 [inline]
 check_memory_region+0x137/0x190 mm/kasan/kasan.c:267
 memcpy+0x37/0x50 mm/kasan/kasan.c:303
 memcpy include/linux/string.h:344 [inline]
 do_convert sound/core/oss/linear.c:52 [inline]
 convert sound/core/oss/linear.c:81 [inline]
 linear_transfer+0x64a/0x900 sound/core/oss/linear.c:110
 snd_pcm_plug_write_transfer+0x20b/0x390 sound/core/oss/pcm_plugin.c:611
 snd_pcm_oss_write2+0x22e/0x3c0 sound/core/oss/pcm_oss.c:1311
 snd_pcm_oss_sync1+0x158/0x4b0 sound/core/oss/pcm_oss.c:1530
 snd_pcm_oss_sync+0x4f2/0x710 sound/core/oss/pcm_oss.c:1604
 snd_pcm_oss_release+0x20b/0x280 sound/core/oss/pcm_oss.c:2431
 __fput+0x291/0x6e0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x122/0x1a0 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x7f4/0x2da0 kernel/exit.c:869
 do_group_exit+0x108/0x320 kernel/exit.c:972
 get_signal+0x5e9/0x1460 kernel/signal.c:2337
 do_signal+0x7f/0x1980 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x1aa/0x210 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x383/0x430 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x98/0x9a
RIP: 0033:0x44ac19
RSP: 002b:00007f1debbb3da8 EFLAGS: 00000246 ORIG_RAX: 00000000000000ca
RAX: fffffffffffffe00 RBX: 00000000006dcc3c RCX: 000000000044ac19
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000006dcc3c
RBP: 00000000006dcc38 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 6fd5446e47d1c1dd
R13: 04a85bf0c3063392 R14: 0f17db8f3ad16a87 R15: 000000000000000d
Dumping ftrace buffer:
   (ftrace buffer empty)
Kernel Offset: disabled
Rebooting in 86400 seconds..