================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read include/linux/instrumented.h:68 [inline] BUG: KASAN: null-ptr-deref in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] BUG: KASAN: null-ptr-deref in page_ref_count include/linux/page_ref.h:67 [inline] BUG: KASAN: null-ptr-deref in put_page_testzero include/linux/mm.h:996 [inline] BUG: KASAN: null-ptr-deref in folio_put_testzero include/linux/mm.h:1002 [inline] BUG: KASAN: null-ptr-deref in folio_put include/linux/mm.h:1429 [inline] BUG: KASAN: null-ptr-deref in filemap_fault+0x544/0x24a0 mm/filemap.c:3382 Read of size 4 at addr 0000000000000032 by task syz-executor.1/16690 CPU: 0 PID: 16690 Comm: syz-executor.1 Not tainted 6.3.0-syzkaller-11025-g89d77f71f493 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 print_report mm/kasan/report.c:465 [inline] kasan_report+0xec/0x130 mm/kasan/report.c:572 check_region_inline mm/kasan/generic.c:181 [inline] kasan_check_range+0x141/0x190 mm/kasan/generic.c:187 instrument_atomic_read include/linux/instrumented.h:68 [inline] atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline] page_ref_count include/linux/page_ref.h:67 [inline] put_page_testzero include/linux/mm.h:996 [inline] folio_put_testzero include/linux/mm.h:1002 [inline] folio_put include/linux/mm.h:1429 [inline] filemap_fault+0x544/0x24a0 mm/filemap.c:3382 __do_fault+0x107/0x600 mm/memory.c:4176 do_read_fault mm/memory.c:4530 [inline] do_fault mm/memory.c:4659 [inline] do_pte_missing mm/memory.c:3647 [inline] handle_pte_fault mm/memory.c:4947 [inline] __handle_mm_fault+0x28bc/0x41c0 mm/memory.c:5089 handle_mm_fault+0x2af/0x9f0 mm/memory.c:5243 do_user_addr_fault+0x51a/0x1210 arch/x86/mm/fault.c:1440 handle_page_fault arch/x86/mm/fault.c:1534 [inline] exc_page_fault+0x98/0x170 arch/x86/mm/fault.c:1590 asm_exc_page_fault+0x26/0x30 arch/x86/include/asm/idtentry.h:570 RIP: 0010:rep_movs_alternative+0x50/0xb0 arch/x86/lib/copy_user_64.S:70 Code: 0f 1f 84 00 00 00 00 00 66 90 48 8b 06 48 89 07 48 83 c6 08 48 83 c7 08 83 e9 08 74 df 83 f9 08 73 e8 eb c9 66 0f 1f 44 00 00 <4c> 8b 06 4c 8b 4e 08 4c 8b 56 10 4c 8b 5e 18 4c 89 07 4c 89 4f 08 RSP: 0018:ffffc9000610fb30 EFLAGS: 00050206 RAX: 0000000000000001 RBX: 0000000000001000 RCX: 0000000000001000 RDX: 0000000000000000 RSI: 0000000020151000 RDI: ffff888029d3e000 RBP: 00007fffffffe000 R08: 0000000000000001 R09: ffff888029d3efff R10: ffffed10053a7dff R11: 0000000000000000 R12: 0000000020151000 R13: ffff888029d3e000 R14: 0000000020151000 R15: 0000000020151000 copy_user_generic arch/x86/include/asm/uaccess_64.h:31 [inline] raw_copy_from_user arch/x86/include/asm/uaccess_64.h:46 [inline] _copy_from_user+0x15b/0x190 lib/usercopy.c:23 copy_from_user include/linux/uaccess.h:183 [inline] snd_rawmidi_kernel_write1+0x355/0x850 sound/core/rawmidi.c:1547 snd_rawmidi_write+0x277/0xbb0 sound/core/rawmidi.c:1616 vfs_write+0x30d/0xe40 fs/read_write.c:582 ksys_write+0x1ec/0x250 fs/read_write.c:637 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline] __do_fast_syscall_32+0x65/0xf0 arch/x86/entry/common.c:178 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203 entry_SYSENTER_compat_after_hwframe+0x70/0x82 RIP: 0023:0xf7f80579 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 8d b4 26 00 00 00 00 8d b4 26 00 00 00 00 RSP: 002b:00000000f7f5a5cc EFLAGS: 00000296 ORIG_RAX: 0000000000000004 RAX: ffffffffffffffda RBX: 0000000000000009 RCX: 0000000020000000 RDX: 00000000fffffd2c RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000296 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 ================================================================== ---------------- Code disassembly (best guess): 0: 0f 1f 84 00 00 00 00 nopl 0x0(%rax,%rax,1) 7: 00 8: 66 90 xchg %ax,%ax a: 48 8b 06 mov (%rsi),%rax d: 48 89 07 mov %rax,(%rdi) 10: 48 83 c6 08 add $0x8,%rsi 14: 48 83 c7 08 add $0x8,%rdi 18: 83 e9 08 sub $0x8,%ecx 1b: 74 df je 0xfffffffc 1d: 83 f9 08 cmp $0x8,%ecx 20: 73 e8 jae 0xa 22: eb c9 jmp 0xffffffed 24: 66 0f 1f 44 00 00 nopw 0x0(%rax,%rax,1) * 2a: 4c 8b 06 mov (%rsi),%r8 <-- trapping instruction 2d: 4c 8b 4e 08 mov 0x8(%rsi),%r9 31: 4c 8b 56 10 mov 0x10(%rsi),%r10 35: 4c 8b 5e 18 mov 0x18(%rsi),%r11 39: 4c 89 07 mov %r8,(%rdi) 3c: 4c 89 4f 08 mov %r9,0x8(%rdi)