================================================================== 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.1/9163 CPU: 0 PID: 9163 Comm: syz-executor.1 Not tainted 6.3.0-syzkaller-13027-g1a5304fecee5 #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_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:fault_in_readable+0x1df/0x270 mm/gup.c:1856 Code: 00 fc ff df 48 c7 04 01 00 00 00 00 48 83 c4 48 4c 89 e0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 45 31 e4 eb ce e8 53 eb c4 ff 31 db <41> 8a 45 00 31 ff 89 de 88 44 24 28 e8 60 e7 c4 ff 85 db 75 6c e8 RSP: 0018:ffffc90003b47a38 EFLAGS: 00050246 RAX: 0000000000000380 RBX: 0000000000000000 RCX: ffffc900051e4000 RDX: 0000000000040000 RSI: ffffffff81be93ad RDI: 0000000000000007 RBP: 0000000020000040 R08: 0000000000000007 R09: 0000000000000000 R10: 0000000000000040 R11: 0000000000000000 R12: 0000000000001000 R13: 0000000020000040 R14: 0000000000000000 R15: 1ffff92000768f48 fault_in_iov_iter_readable+0x252/0x2c0 lib/iov_iter.c:362 generic_perform_write+0x1ae/0x570 mm/filemap.c:3913 ext4_buffered_write_iter+0x15b/0x460 fs/ext4/file.c:289 ext4_file_write_iter+0xbe0/0x1740 fs/ext4/file.c:710 call_write_iter include/linux/fs.h:1868 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0xa17/0xe40 fs/read_write.c:584 ksys_write+0x12b/0x250 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fb8cb88c169 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007fb8cc5e2168 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007fb8cb9abf80 RCX: 00007fb8cb88c169 RDX: 000000000208e24b RSI: 0000000020000040 RDI: 0000000000000003 RBP: 00007fb8cb8e7ca1 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffe9639fd1f R14: 00007fb8cc5e2300 R15: 0000000000022000 ================================================================== ---------------- Code disassembly (best guess), 3 bytes skipped: 0: df 48 c7 fisttps -0x39(%rax) 3: 04 01 add $0x1,%al 5: 00 00 add %al,(%rax) 7: 00 00 add %al,(%rax) 9: 48 83 c4 48 add $0x48,%rsp d: 4c 89 e0 mov %r12,%rax 10: 5b pop %rbx 11: 5d pop %rbp 12: 41 5c pop %r12 14: 41 5d pop %r13 16: 41 5e pop %r14 18: 41 5f pop %r15 1a: c3 retq 1b: 45 31 e4 xor %r12d,%r12d 1e: eb ce jmp 0xffffffee 20: e8 53 eb c4 ff callq 0xffc4eb78 25: 31 db xor %ebx,%ebx * 27: 41 8a 45 00 mov 0x0(%r13),%al <-- trapping instruction 2b: 31 ff xor %edi,%edi 2d: 89 de mov %ebx,%esi 2f: 88 44 24 28 mov %al,0x28(%rsp) 33: e8 60 e7 c4 ff callq 0xffc4e798 38: 85 db test %ebx,%ebx 3a: 75 6c jne 0xa8 3c: e8 .byte 0xe8