syzbot

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BUG: KCSAN: data-race in snd_pcm_lib_malloc_pages / snd_pcm_lib_malloc_pages

write to 0xffff88821a192850 of 8 bytes by task 10186 on cpu 1:
 do_alloc_pages sound/core/pcm_memory.c:46 [inline]
 snd_pcm_lib_malloc_pages+0x2a1/0x3e0 sound/core/pcm_memory.c:409
 snd_pcm_hw_params+0x3a5/0xce0 sound/core/pcm_native.c:705
 snd_pcm_kernel_ioctl+0xd6/0xc20 sound/core/pcm_native.c:3325
 snd_pcm_oss_change_params_locked+0x1cc4/0x2730 sound/core/oss/pcm_oss.c:941
 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1084 [inline]
 snd_pcm_oss_make_ready+0xdd/0x1f0 sound/core/oss/pcm_oss.c:1143
 snd_pcm_oss_sync+0x207/0x680 sound/core/oss/pcm_oss.c:1642
 snd_pcm_oss_release+0xa0/0x190 sound/core/oss/pcm_oss.c:2546
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:190
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:265
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

read to 0xffff88821a192850 of 8 bytes by task 10184 on cpu 0:
 do_alloc_pages sound/core/pcm_memory.c:40 [inline]
 snd_pcm_lib_malloc_pages+0x1d1/0x3e0 sound/core/pcm_memory.c:409
 snd_pcm_hw_params+0x3a5/0xce0 sound/core/pcm_native.c:705
 snd_pcm_kernel_ioctl+0xd6/0xc20 sound/core/pcm_native.c:3325
 snd_pcm_oss_change_params_locked+0x1cc4/0x2730 sound/core/oss/pcm_oss.c:941
 snd_pcm_oss_change_params sound/core/oss/pcm_oss.c:1084 [inline]
 snd_pcm_oss_make_ready+0xdd/0x1f0 sound/core/oss/pcm_oss.c:1143
 snd_pcm_oss_sync+0x207/0x680 sound/core/oss/pcm_oss.c:1642
 snd_pcm_oss_release+0xa0/0x190 sound/core/oss/pcm_oss.c:2546
 __fput+0x246/0x4d0 fs/file_table.c:281
 ____fput+0x11/0x20 fs/file_table.c:314
 task_work_run+0x8e/0x110 kernel/task_work.c:141
 tracehook_notify_resume include/linux/tracehook.h:188 [inline]
 exit_to_user_mode_loop kernel/entry/common.c:163 [inline]
 exit_to_user_mode_prepare+0x1b2/0x210 kernel/entry/common.c:190
 syscall_exit_to_user_mode+0x16/0x30 kernel/entry/common.c:265
 do_syscall_64+0x45/0x80 arch/x86/entry/common.c:56
 entry_SYSCALL_64_after_hwframe+0x44/0xa9

Reported by Kernel Concurrency Sanitizer on:
CPU: 0 PID: 10184 Comm: syz-executor.2 Not tainted 5.9.0-rc5-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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