Hello, syzbot found the following issue on: HEAD commit: 4d6d4c7f541d Merge tag 'linux-kselftest-fixes-6.4-rc3' of .. git tree: upstream console+strace: https://syzkaller.appspot.com/x/log.txt?x=17b34a5a280000 kernel config: https://syzkaller.appspot.com/x/.config?x=94af80bb8ddd23c4 dashboard link: https://syzkaller.appspot.com/bug?extid=aad58150cbc64ba41bdc compiler: Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1615fbe9280000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1282842e280000 Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/dcd8898335fc/disk-4d6d4c7f.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/6a1f7abe57aa/vmlinux-4d6d4c7f.xz kernel image: https://storage.googleapis.com/syzbot-assets/b485f41c18e6/bzImage-4d6d4c7f.xz mounted in repro: https://storage.googleapis.com/syzbot-assets/19be7546cd7d/mount_1.gz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+aad58150cbc64ba41bdc@xxxxxxxxxxxxxxxxxxxxxxxxx memfd_create() without MFD_EXEC nor MFD_NOEXEC_SEAL, pid=4996 'syz-executor412' loop0: detected capacity change from 0 to 128 VFS: Found a Xenix FS (block size = 512) on device loop0 sysv_free_block: trying to free block not in datazone ================================================================== BUG: KASAN: null-ptr-deref in instrument_atomic_read_write include/linux/instrumented.h:96 [inline] BUG: KASAN: null-ptr-deref in test_and_set_bit_lock include/asm-generic/bitops/instrumented-lock.h:57 [inline] BUG: KASAN: null-ptr-deref in trylock_buffer include/linux/buffer_head.h:399 [inline] BUG: KASAN: null-ptr-deref in lock_buffer include/linux/buffer_head.h:405 [inline] BUG: KASAN: null-ptr-deref in alloc_branch fs/sysv/itree.c:148 [inline] BUG: KASAN: null-ptr-deref in get_block+0x567/0x16a0 fs/sysv/itree.c:251 Write of size 8 at addr 0000000000000000 by task syz-executor412/4996 CPU: 1 PID: 4996 Comm: syz-executor412 Not tainted 6.4.0-rc2-syzkaller-00018-g4d6d4c7f541d #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/28/2023 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2d0 lib/dump_stack.c:106 print_report+0xe6/0x540 mm/kasan/report.c:465 kasan_report+0x176/0x1b0 mm/kasan/report.c:572 kasan_check_range+0x283/0x290 mm/kasan/generic.c:187 instrument_atomic_read_write include/linux/instrumented.h:96 [inline] test_and_set_bit_lock include/asm-generic/bitops/instrumented-lock.h:57 [inline] trylock_buffer include/linux/buffer_head.h:399 [inline] lock_buffer include/linux/buffer_head.h:405 [inline] alloc_branch fs/sysv/itree.c:148 [inline] get_block+0x567/0x16a0 fs/sysv/itree.c:251 __block_write_begin_int+0x548/0x1a50 fs/buffer.c:2064 __block_write_begin fs/buffer.c:2114 [inline] block_write_begin+0x9c/0x1f0 fs/buffer.c:2175 sysv_write_begin+0x31/0x70 fs/sysv/itree.c:485 generic_perform_write+0x300/0x5e0 mm/filemap.c:3923 __generic_file_write_iter+0x17a/0x400 mm/filemap.c:4051 generic_file_write_iter+0xaf/0x310 mm/filemap.c:4083 do_iter_write+0x7b1/0xcb0 fs/read_write.c:860 vfs_writev fs/read_write.c:933 [inline] do_pwritev+0x21a/0x360 fs/read_write.c:1030 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f3233222b19 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 14 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffecf15f268 EFLAGS: 00000246 ORIG_RAX: 0000000000000128 RAX: ffffffffffffffda RBX: 0031656c69662f2e RCX: 00007f3233222b19 RDX: 0000000000000005 RSI: 0000000020000480 RDI: 0000000000000004 RBP: 00007f32331e2150 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000007fff R11: 0000000000000246 R12: 00007f32331e21e0 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 </TASK> ================================================================== --- This report is generated by a bot. It may contain errors. See https://goo.gl/tpsmEJ for more information about syzbot. syzbot engineers can be reached at syzkaller@xxxxxxxxxxxxxxxx. syzbot will keep track of this issue. See: https://goo.gl/tpsmEJ#status for how to communicate with syzbot. If the bug is already fixed, let syzbot know by replying with: #syz fix: exact-commit-title If you want syzbot to run the reproducer, reply with: #syz test: git://repo/address.git branch-or-commit-hash If you attach or paste a git patch, syzbot will apply it before testing. If you want to change bug's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the bug is a duplicate of another bug, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
