syz-executor5 (12006) used greatest stack depth: 22248 bytes left ================================================================== binder: 12085:12089 ioctl c018620b 0 returned -14 BUG: KASAN: null-ptr-deref in copy_to_user arch/x86/include/asm/uaccess.h:731 [inline] BUG: KASAN: null-ptr-deref in snd_timer_user_read+0x594/0x710 sound/core/timer.c:2006 Read of size 32 at addr (null) by task syz-executor3/12075 CPU: 1 PID: 12075 Comm: syz-executor3 Not tainted 4.9.141+ #23 ffff8801adc4f958 ffffffff81b42e79 0000000000000000 0000000000000020 0000000000000000[ 210.950780] binder: BINDER_SET_CONTEXT_MGR already set binder: 12085:12092 ioctl 40046207 0 returned -16 binder: 12085:12092 ioctl 400454de 20000080 returned -22 binder: 12085:12092 Release 1 refcount change on invalid ref 1 ret -22 binder: 12085:12092 unknown command -1073488791 binder: 12085:12092 ioctl c0306201 20000380 returned -22 ffff8801adc4fb28 ffff8801d757db80 ffff8801adc4f9a0 ffffffff81500bed ffffffff8224e014 0000000000000282 f74087f607d29846 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] kasan_report_error mm/kasan/report.c:353 [inline] [] kasan_report.cold.6+0x6d/0x2fe mm/kasan/report.c:412 [] check_memory_region_inline mm/kasan/kasan.c:318 [inline] [] check_memory_region+0x14d/0x1b0 mm/kasan/kasan.c:325 [] kasan_check_read+0x11/0x20 mm/kasan/kasan.c:330 [] copy_to_user arch/x86/include/asm/uaccess.h:731 [inline] [] snd_timer_user_read+0x594/0x710 sound/core/timer.c:2006 [] do_loop_readv_writev.part.1+0xd5/0x280 fs/read_write.c:718 [] do_loop_readv_writev fs/read_write.c:707 [inline] [] compat_do_readv_writev+0x570/0x7b0 fs/read_write.c:1091 [] compat_readv+0xe2/0x150 fs/read_write.c:1120 [] do_compat_readv+0xf2/0x1d0 fs/read_write.c:1140 [] C_SYSC_readv fs/read_write.c:1152 [inline] [] compat_SyS_readv+0x26/0x30 fs/read_write.c:1148 [] do_syscall_32_irqs_on arch/x86/entry/common.c:328 [inline] [] do_fast_syscall_32+0x2f1/0xa10 arch/x86/entry/common.c:390 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 ==================================================================