Hello,

syzkaller hit the following crash on 30a7acd573899fd8b8ac39236eff6468b195ac7d git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/master compiler: gcc (GCC) 7.1.1 20170620 .config is attached Raw console output is attached. Unfortunately, I don't have any reproducer for this bug yet.

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BUG: unable to handle kernel paging request at ffffc90006002000 IP: memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:65 PGD 1dad2c067 P4D 1dad2c067 PUD 1dad2d067 PMD 192fc9067 PTE 0 Oops: 0002 [#1] SMP KASAN Dumping ftrace buffer: (ftrace buffer empty) Modules linked in: CPU: 1 PID: 13106 Comm: syz-executor6 Not tainted 4.15.0-rc6+ #245 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:65 RSP: 0018:ffff8801bfc57508 EFLAGS: 00010246 RAX: fffff52000c2a800 RBX: ffffc90006000000 RCX: 0000000000152000 RDX: 0000000000154000 RSI: 0000000000000000 RDI: ffffc90006002000 RBP: ffff8801bfc57528 R08: 0000000000000000 R09: ffffc90006000000 R10: 000000000002a800 R11: fffff52000c2a7ff R12: 0000000000154000 R13: 0000000000000000 R14: ffffffff86e6625c R15: 0000000000000010 FS: 00007fa978f9e700(0000) GS:ffff8801db300000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffc90006002000 CR3: 00000001cb3c0006 CR4: 00000000001606e0 DR0: 0000000020000000 DR1: 0000000020000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600 Call Trace: memset include/linux/string.h:329 [inline] snd_pcm_format_set_silence+0x13f/0x4b0 sound/core/pcm_misc.c:414 loopback_prepare+0xcdc/0x1000 sound/drivers/aloop.c:356 snd_pcm_do_prepare+0x58/0x90 sound/core/pcm_native.c:1640 snd_pcm_action_single+0x70/0x110 sound/core/pcm_native.c:1084 snd_pcm_action_nonatomic+0x95/0xa0 sound/core/pcm_native.c:1151 snd_pcm_prepare+0x115/0x1a0 sound/core/pcm_native.c:1687 snd_pcm_kernel_ioctl+0x97/0x240 sound/core/pcm_native.c:2993 snd_pcm_oss_prepare+0x49/0x150 sound/core/oss/pcm_oss.c:1105 snd_pcm_oss_make_ready+0xf9/0x130 sound/core/oss/pcm_oss.c:1133 snd_pcm_oss_set_trigger+0x62d/0x830 sound/core/oss/pcm_oss.c:1944 snd_pcm_oss_poll+0x77c/0xd20 sound/core/oss/pcm_oss.c:2712 do_pollfd fs/select.c:822 [inline] do_poll fs/select.c:872 [inline] do_sys_poll+0x715/0x10b0 fs/select.c:966 SYSC_poll fs/select.c:1024 [inline] SyS_poll+0x10d/0x450 fs/select.c:1012 entry_SYSCALL_64_fastpath+0x23/0x9a RIP: 0033:0x452ac9 RSP: 002b:00007fa978f9dc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000007 RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9 RDX: 0000000000000000 RSI: 0000000000000002 RDI: 0000000020038000 RBP: 000000000000030f R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f2a08 R13: 00000000ffffffff R14: 00007fa978f9e6d4 R15: 0000000000000000 Code: 48 c1 e9 03 40 0f b6 f6 48 b8 01 01 01 01 01 01 01 01 48 0f af c6 f3 48 ab 89 d1 f3 aa 4c 89 c8 c3 90 49 89 f9 40 88 f0 48 89 d1 <f3> aa 4c 89 c8 c3 90 49 89 fa 40 0f b6 ce 48 b8 01 01 01 01 01 RIP: memset_erms+0x9/0x10 arch/x86/lib/memset_64.S:65 RSP: ffff8801bfc57508 CR2: ffffc90006002000 ---[ end trace 64150ed1bb325dd0 ]---

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