Hello, syzbot found the following issue on: HEAD commit: 23e11d031852 Add linux-next specific files for 20240205 git tree: linux-next console output: https://syzkaller.appspot.com/x/log.txt?x=11933ca8180000 kernel config: https://syzkaller.appspot.com/x/.config?x=6f1d38572a4a0540 dashboard link: https://syzkaller.appspot.com/bug?extid=2e64084fa0c65e8706c9 compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 Unfortunately, I don't have any reproducer for this issue yet. Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/b4e82c0f5cca/disk-23e11d03.raw.xz vmlinux: https://storage.googleapis.com/syzbot-assets/018dac30c4d4/vmlinux-23e11d03.xz kernel image: https://storage.googleapis.com/syzbot-assets/ee21a2f37a73/bzImage-23e11d03.xz IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+2e64084fa0c65e8706c9@xxxxxxxxxxxxxxxxxxxxxxxxx ================================================================== BUG: KASAN: use-after-free in sysv_new_inode+0xfdd/0x1170 fs/sysv/ialloc.c:153 Read of size 2 at addr ffff88803b1f61ce by task syz-executor.4/7277 CPU: 1 PID: 7277 Comm: syz-executor.4 Not tainted 6.8.0-rc3-next-20240205-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/25/2024 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e7/0x2e0 lib/dump_stack.c:106 print_address_description mm/kasan/report.c:377 [inline] print_report+0x169/0x550 mm/kasan/report.c:488 kasan_report+0x143/0x180 mm/kasan/report.c:601 sysv_new_inode+0xfdd/0x1170 fs/sysv/ialloc.c:153 sysv_mknod+0x4e/0xe0 fs/sysv/namei.c:53 lookup_open fs/namei.c:3494 [inline] open_last_lookups fs/namei.c:3563 [inline] path_openat+0x1425/0x3240 fs/namei.c:3793 do_filp_open+0x235/0x490 fs/namei.c:3823 do_sys_openat2+0x13e/0x1d0 fs/open.c:1404 do_sys_open fs/open.c:1419 [inline] __do_sys_openat fs/open.c:1435 [inline] __se_sys_openat fs/open.c:1430 [inline] __x64_sys_openat+0x247/0x2a0 fs/open.c:1430 do_syscall_64+0xfb/0x240 entry_SYSCALL_64_after_hwframe+0x6d/0x75 RIP: 0033:0x7f86a7c7dda9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 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 b0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f86a8a900c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f86a7dabf80 RCX: 00007f86a7c7dda9 RDX: 000000000000275a RSI: 0000000020000040 RDI: ffffffffffffff9c RBP: 00007f86a7cca47a R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 000000000000000b R14: 00007f86a7dabf80 R15: 00007fff47892ea8 </TASK> The buggy address belongs to the physical page: page:ffffea0000ec7d80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x3b1f6 flags: 0xfff80000000000(node=0|zone=1|lastcpupid=0xfff) page_type: 0xffffffff() raw: 00fff80000000000 dead000000000100 dead000000000122 0000000000000000 raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as freed page last allocated via order 0, migratetype Movable, gfp_mask 0x141cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP|__GFP_WRITE), pid 16881, tgid 16881 (syz-executor.3), ts 1415422682739, free_ts 1421164748730 set_page_owner include/linux/page_owner.h:31 [inline] post_alloc_hook+0x1ea/0x210 mm/page_alloc.c:1539 prep_new_page mm/page_alloc.c:1546 [inline] get_page_from_freelist+0x34eb/0x3680 mm/page_alloc.c:3353 __alloc_pages+0x256/0x680 mm/page_alloc.c:4609 alloc_pages_mpol+0x3e8/0x680 mm/mempolicy.c:2263 alloc_pages mm/mempolicy.c:2334 [inline] folio_alloc+0x12b/0x330 mm/mempolicy.c:2341 filemap_alloc_folio+0xdf/0x500 mm/filemap.c:975 __filemap_get_folio+0x431/0xbc0 mm/filemap.c:1919 ext4_da_write_begin+0x5b9/0xa50 fs/ext4/inode.c:2885 generic_perform_write+0x322/0x640 mm/filemap.c:3921 ext4_buffered_write_iter+0xc6/0x350 fs/ext4/file.c:299 ext4_file_write_iter+0x1de/0x1a10 __kernel_write_iter+0x435/0x8c0 fs/read_write.c:523 dump_emit_page fs/coredump.c:888 [inline] dump_user_range+0x46d/0x910 fs/coredump.c:915 elf_core_dump+0x3d5e/0x4630 fs/binfmt_elf.c:2077 do_coredump+0x1bab/0x2b50 fs/coredump.c:764 get_signal+0x146b/0x1850 kernel/signal.c:2882 page last free pid 16881 tgid 16881 stack trace: reset_page_owner include/linux/page_owner.h:24 [inline] free_pages_prepare mm/page_alloc.c:1140 [inline] free_unref_page_prepare+0x968/0xa90 mm/page_alloc.c:2388 free_unref_page_list+0x5a3/0x850 mm/page_alloc.c:2574 release_pages+0x2744/0x2a80 mm/swap.c:1042 __folio_batch_release+0x84/0x100 mm/swap.c:1062 folio_batch_release include/linux/pagevec.h:83 [inline] truncate_inode_pages_range+0x457/0xf70 mm/truncate.c:362 ext4_evict_inode+0x21c/0xf30 fs/ext4/inode.c:193 evict+0x2a8/0x630 fs/inode.c:666 __dentry_kill+0x20d/0x630 fs/dcache.c:603 dput+0x19f/0x2b0 fs/dcache.c:845 __fput+0x678/0x8a0 fs/file_table.c:384 task_work_run+0x24f/0x310 kernel/task_work.c:180 exit_task_work include/linux/task_work.h:38 [inline] do_exit+0xa1b/0x27e0 kernel/exit.c:878 do_group_exit+0x207/0x2c0 kernel/exit.c:1027 get_signal+0x176e/0x1850 kernel/signal.c:2896 arch_do_signal_or_restart+0x96/0x860 arch/x86/kernel/signal.c:310 exit_to_user_mode_loop kernel/entry/common.c:105 [inline] exit_to_user_mode_prepare include/linux/entry-common.h:328 [inline] irqentry_exit_to_user_mode+0x79/0x280 kernel/entry/common.c:225 Memory state around the buggy address: ffff88803b1f6080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88803b1f6100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff >ffff88803b1f6180: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ^ ffff88803b1f6200: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ffff88803b1f6280: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ================================================================== --- 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 report is already addressed, let syzbot know by replying with: #syz fix: exact-commit-title If you want to overwrite report's subsystems, reply with: #syz set subsystems: new-subsystem (See the list of subsystem names on the web dashboard) If the report is a duplicate of another one, reply with: #syz dup: exact-subject-of-another-report If you want to undo deduplication, reply with: #syz undup
