================================================================== 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.1/8122 CPU: 1 PID: 8122 Comm: syz-executor.1 Not tainted 6.3.0-syzkaller-12999-gfa31fc82fb77 #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.14.0-2 04/01/2014 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_shared_fault mm/memory.c:4585 [inline] do_fault mm/memory.c:4663 [inline] do_pte_missing mm/memory.c:3647 [inline] handle_pte_fault mm/memory.c:4947 [inline] __handle_mm_fault+0x24c9/0x41c0 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:__put_user_nocheck_4+0xb/0x20 arch/x86/lib/putuser.S:101 Code: 0f 1e fa 48 89 cb 48 c1 fb 3f 48 09 d9 0f 01 cb 89 01 31 c9 0f 01 ca c3 0f 1f 80 00 00 00 00 f3 0f 1e fa f3 0f 1e fa 0f 01 cb <89> 01 31 c9 0f 01 ca c3 66 66 2e 0f 1f 84 00 00 00 00 00 66 90 f3 RSP: 0018:ffffc90002d6f9b0 EFLAGS: 00050246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 000000002005b178 RDX: 0000000000040000 RSI: ffffffff880464dc RDI: 0000000000000005 RBP: ffffc90002d6fd60 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000080000002 R11: 0000000000000000 R12: 0000000000000000 R13: 000000002005b178 R14: 0000000080000002 R15: 0000000000000000 ____sys_recvmsg+0x2f7/0x5a0 net/socket.c:2735 ___sys_recvmsg+0xf2/0x180 net/socket.c:2764 do_recvmmsg+0x554/0x6e0 net/socket.c:2850 __sys_recvmmsg+0x242/0x250 net/socket.c:2937 __do_compat_sys_recvmmsg_time32 net/compat.c:418 [inline] __se_compat_sys_recvmmsg_time32 net/compat.c:414 [inline] __ia32_compat_sys_recvmmsg_time32+0xc6/0x160 net/compat.c:414 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: 0023:0xf7f2e579 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:00000000f7f295cc EFLAGS: 00000296 ORIG_RAX: 0000000000000151 RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 00000000200000c0 RDX: 0000000000010106 RSI: 0000000000000002 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 1e fa nop %edx 3: 48 89 cb mov %rcx,%rbx 6: 48 c1 fb 3f sar $0x3f,%rbx a: 48 09 d9 or %rbx,%rcx d: 0f 01 cb stac 10: 89 01 mov %eax,(%rcx) 12: 31 c9 xor %ecx,%ecx 14: 0f 01 ca clac 17: c3 retq 18: 0f 1f 80 00 00 00 00 nopl 0x0(%rax) 1f: f3 0f 1e fa endbr64 23: f3 0f 1e fa endbr64 27: 0f 01 cb stac * 2a: 89 01 mov %eax,(%rcx) <-- trapping instruction 2c: 31 c9 xor %ecx,%ecx 2e: 0f 01 ca clac 31: c3 retq 32: 66 66 2e 0f 1f 84 00 data16 nopw %cs:0x0(%rax,%rax,1) 39: 00 00 00 00 3d: 66 90 xchg %ax,%ax 3f: f3 repz