syzbot

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BUG: KASAN: use-after-free in __ocfs2_find_path+0x1ff/0x7e0 fs/ocfs2/alloc.c:1817
Read of size 4 at addr ffff888069f3a000 by task syz.2.14/4402

CPU: 1 PID: 4402 Comm: syz.2.14 Not tainted 6.1.116-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106
 print_address_description mm/kasan/report.c:284 [inline]
 print_report+0x15f/0x4f0 mm/kasan/report.c:395
 kasan_report+0x136/0x160 mm/kasan/report.c:495
 __ocfs2_find_path+0x1ff/0x7e0 fs/ocfs2/alloc.c:1817
 ocfs2_find_leaf+0xcb/0x220 fs/ocfs2/alloc.c:1931
 ocfs2_get_clusters_nocache+0x1a9/0xbe0 fs/ocfs2/extent_map.c:418
 ocfs2_get_clusters+0x5b5/0xbc0 fs/ocfs2/extent_map.c:621
 ocfs2_extent_map_get_blocks+0x248/0x7d0 fs/ocfs2/extent_map.c:668
 ocfs2_read_virt_blocks+0x313/0xab0 fs/ocfs2/extent_map.c:977
 ocfs2_read_dir_block fs/ocfs2/dir.c:508 [inline]
 ocfs2_find_entry_el fs/ocfs2/dir.c:715 [inline]
 ocfs2_find_entry+0x436/0x28c0 fs/ocfs2/dir.c:1080
 ocfs2_find_files_on_disk+0x10d/0x3a0 fs/ocfs2/dir.c:1982
 ocfs2_lookup_ino_from_name+0xad/0x1e0 fs/ocfs2/dir.c:2004
 _ocfs2_get_system_file_inode fs/ocfs2/sysfile.c:136 [inline]
 ocfs2_get_system_file_inode+0x314/0x7b0 fs/ocfs2/sysfile.c:112
 ocfs2_init_global_system_inodes+0x328/0x720 fs/ocfs2/super.c:457
 ocfs2_initialize_super fs/ocfs2/super.c:2250 [inline]
 ocfs2_fill_super+0x2f82/0x5730 fs/ocfs2/super.c:994
 mount_bdev+0x2c9/0x3f0 fs/super.c:1443
 legacy_get_tree+0xeb/0x180 fs/fs_context.c:632
 vfs_get_tree+0x88/0x270 fs/super.c:1573
 do_new_mount+0x2ba/0xb40 fs/namespace.c:3056
 do_mount fs/namespace.c:3399 [inline]
 __do_sys_mount fs/namespace.c:3607 [inline]
 __se_sys_mount+0x2d5/0x3c0 fs/namespace.c:3584
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7fddd597feba
Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb a6 e8 de 1a 00 00 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fddd66dce68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fddd66dcef0 RCX: 00007fddd597feba
RDX: 0000000020004440 RSI: 0000000020000780 RDI: 00007fddd66dceb0
RBP: 0000000020004440 R08: 00007fddd66dcef0 R09: 0000000001000000
R10: 0000000001000000 R11: 0000000000000246 R12: 0000000020000780
R13: 00007fddd66dceb0 R14: 000000000000444a R15: 00000000200005c0
 </TASK>

The buggy address belongs to the physical page:
page:ffffea0001a7ce80 refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x69f3a
flags: 0xfff00000000000(node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000000 ffffea0001a7cec8 ffff8880b8f411e0 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 0x140cca(GFP_HIGHUSER_MOVABLE|__GFP_COMP), pid 4326, tgid 4325 (syz.0.1), ts 63580534674, free_ts 65477335293
 set_page_owner include/linux/page_owner.h:31 [inline]
 post_alloc_hook+0x18d/0x1b0 mm/page_alloc.c:2517
 prep_new_page mm/page_alloc.c:2524 [inline]
 get_page_from_freelist+0x3731/0x38d0 mm/page_alloc.c:4313
 __alloc_pages+0x28d/0x770 mm/page_alloc.c:5589
 __folio_alloc+0xf/0x30 mm/page_alloc.c:5621
 vma_alloc_folio+0x486/0x990 mm/mempolicy.c:2243
 shmem_alloc_folio mm/shmem.c:1591 [inline]
 shmem_alloc_and_acct_folio+0x5a8/0xd50 mm/shmem.c:1615
 shmem_get_folio_gfp+0x13f0/0x3470 mm/shmem.c:1943
 shmem_get_folio mm/shmem.c:2074 [inline]
 shmem_write_begin+0x16e/0x4e0 mm/shmem.c:2561
 generic_perform_write+0x2fc/0x5e0 mm/filemap.c:3845
 __generic_file_write_iter+0x176/0x400 mm/filemap.c:3973
 generic_file_write_iter+0xab/0x310 mm/filemap.c:4005
 call_write_iter include/linux/fs.h:2265 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x857/0xbc0 fs/read_write.c:584
 ksys_write+0x19c/0x2c0 fs/read_write.c:637
 do_syscall_x64 arch/x86/entry/common.c:51 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1444 [inline]
 free_pcp_prepare mm/page_alloc.c:1494 [inline]
 free_unref_page_prepare+0xf63/0x1120 mm/page_alloc.c:3369
 free_unref_page_list+0x663/0x900 mm/page_alloc.c:3510
 release_pages+0x2836/0x2b40 mm/swap.c:1055
 __pagevec_release+0x80/0xf0 mm/swap.c:1075
 pagevec_release include/linux/pagevec.h:71 [inline]
 folio_batch_release include/linux/pagevec.h:135 [inline]
 shmem_undo_range+0x865/0x2390 mm/shmem.c:946
 shmem_truncate_range mm/shmem.c:1062 [inline]
 shmem_evict_inode+0x265/0xa60 mm/shmem.c:1173
 evict+0x529/0x930 fs/inode.c:701
 __dentry_kill+0x436/0x650 fs/dcache.c:611
 dentry_kill+0xbb/0x290
 dput+0xfb/0x1d0 fs/dcache.c:918
 __fput+0x62e/0x8d0 fs/file_table.c:328
 task_work_run+0x246/0x300 kernel/task_work.c:203
 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline]
 exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177
 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210
 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline]
 syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303
 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87

Memory state around the buggy address:
 ffff888069f39f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff888069f39f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff888069f3a000: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                   ^
 ffff888069f3a080: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff888069f3a100: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
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