================================================================== BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x1316/0x13e0 fs/ext4/namei.c:1221 Read of size 1 at addr ffff88811731ca67 by task syz-executor/485 CPU: 0 PID: 485 Comm: syz-executor Not tainted 5.10.234-syzkaller-1006808-ge0b88ee5f09c #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack_lvl+0x1e2/0x24b lib/dump_stack.c:118 print_address_description+0x81/0x3b0 mm/kasan/report.c:248 __kasan_report mm/kasan/report.c:435 [inline] kasan_report+0x179/0x1c0 mm/kasan/report.c:452 __asan_report_load1_noabort+0x14/0x20 mm/kasan/report_generic.c:306 ext4_htree_fill_tree+0x1316/0x13e0 fs/ext4/namei.c:1221 ext4_dx_readdir fs/ext4/dir.c:598 [inline] ext4_readdir+0x2dde/0x37c0 fs/ext4/dir.c:142 iterate_dir+0x265/0x580 fs/readdir.c:-1 __do_sys_getdents64 fs/readdir.c:369 [inline] __se_sys_getdents64+0x1c1/0x460 fs/readdir.c:354 __x64_sys_getdents64+0x7b/0x90 fs/readdir.c:354 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:-1 entry_SYSCALL_64_after_hwframe+0x61/0xcb RIP: 0033:0x7fdef75d5bf3 Code: c1 66 0f 1f 44 00 00 48 83 c4 08 48 89 ef 5b 5d e9 f2 44 f8 ff 66 90 b8 ff ff ff 7f 48 39 c2 48 0f 47 d0 b8 d9 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 05 c3 0f 1f 40 00 48 c7 c2 a8 ff ff ff f7 d8 RSP: 002b:00007ffd5d6de9b8 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9 RAX: ffffffffffffffda RBX: 0000555555d2e4e0 RCX: 00007fdef75d5bf3 RDX: 0000000000008000 RSI: 0000555555d2e4e0 RDI: 0000000000000005 RBP: 0000555555d2e4b4 R08: 0000000000028b61 R09: 0000000000000000 R10: 00007fdef7702ca0 R11: 0000000000000293 R12: ffffffffffffffa8 R13: 0000000000000010 R14: 0000555555d2e4b0 R15: 000000000000c92e Allocated by task 95: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track mm/kasan/common.c:45 [inline] set_alloc_info mm/kasan/common.c:430 [inline] ____kasan_kmalloc+0xdb/0x110 mm/kasan/common.c:509 __kasan_kmalloc+0x9/0x10 mm/kasan/common.c:518 kasan_kmalloc include/linux/kasan.h:254 [inline] kmem_cache_alloc_trace+0x18a/0x2e0 mm/slub.c:2974 kmalloc include/linux/slab.h:552 [inline] kzalloc include/linux/slab.h:664 [inline] kernfs_iop_get_link+0x65/0x5f0 fs/kernfs/symlink.c:136 vfs_readlink+0x16a/0x400 fs/namei.c:4720 do_readlinkat+0x27f/0x3a0 fs/stat.c:426 __do_sys_readlink fs/stat.c:447 [inline] __se_sys_readlink fs/stat.c:444 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:444 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:-1 entry_SYSCALL_64_after_hwframe+0x61/0xcb Freed by task 95: kasan_save_stack mm/kasan/common.c:38 [inline] kasan_set_track+0x4b/0x70 mm/kasan/common.c:45 kasan_set_free_info+0x23/0x40 mm/kasan/generic.c:370 ____kasan_slab_free+0x121/0x160 mm/kasan/common.c:362 __kasan_slab_free+0x11/0x20 mm/kasan/common.c:370 kasan_slab_free include/linux/kasan.h:220 [inline] slab_free_hook mm/slub.c:1595 [inline] slab_free_freelist_hook+0xc0/0x190 mm/slub.c:1621 slab_free mm/slub.c:3203 [inline] kfree+0xc3/0x270 mm/slub.c:4191 kfree_link+0x15/0x20 fs/libfs.c:1220 do_delayed_call include/linux/delayed_call.h:28 [inline] vfs_readlink+0x23e/0x400 fs/namei.c:4725 do_readlinkat+0x27f/0x3a0 fs/stat.c:426 __do_sys_readlink fs/stat.c:447 [inline] __se_sys_readlink fs/stat.c:444 [inline] __x64_sys_readlink+0x7f/0x90 fs/stat.c:444 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:-1 entry_SYSCALL_64_after_hwframe+0x61/0xcb The buggy address belongs to the object at ffff88811731c000 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 2663 bytes inside of 4096-byte region [ffff88811731c000, ffff88811731d000) The buggy address belongs to the page: page:ffffea00045cc600 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117318 head:ffffea00045cc600 order:3 compound_mapcount:0 compound_pincount:0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100042c00 raw: 0000000000000000 0000000000040004 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 3, migratetype Unmovable, gfp_mask 0xd20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 105, ts 5954168469, free_ts 0 set_page_owner include/linux/page_owner.h:35 [inline] post_alloc_hook mm/page_alloc.c:2456 [inline] prep_new_page+0x166/0x180 mm/page_alloc.c:2462 get_page_from_freelist+0x2d8c/0x2f30 mm/page_alloc.c:4254 __alloc_pages_nodemask+0x435/0xaf0 mm/page_alloc.c:5348 alloc_slab_page mm/slub.c:-1 [inline] allocate_slab mm/slub.c:1808 [inline] new_slab+0x80/0x400 mm/slub.c:1869 new_slab_objects mm/slub.c:2627 [inline] ___slab_alloc+0x302/0x4b0 mm/slub.c:2791 __slab_alloc+0x63/0xa0 mm/slub.c:2831 slab_alloc_node mm/slub.c:2913 [inline] slab_alloc mm/slub.c:2955 [inline] __kmalloc+0x204/0x330 mm/slub.c:4029 __kmalloc_node include/linux/slab.h:418 [inline] kmalloc_node include/linux/slab.h:575 [inline] kvmalloc_node+0x82/0x130 mm/util.c:612 kvmalloc include/linux/mm.h:822 [inline] seq_buf_alloc fs/seq_file.c:38 [inline] seq_read_iter+0x1ff/0xd00 fs/seq_file.c:210 kernfs_fop_read_iter+0x145/0x470 fs/kernfs/file.c:241 call_read_iter include/linux/fs.h:2052 [inline] new_sync_read fs/read_write.c:415 [inline] vfs_read+0x990/0xba0 fs/read_write.c:496 ksys_read+0x199/0x2c0 fs/read_write.c:634 __do_sys_read fs/read_write.c:644 [inline] __se_sys_read fs/read_write.c:642 [inline] __x64_sys_read+0x7b/0x90 fs/read_write.c:642 do_syscall_64+0x34/0x70 arch/x86/entry/common.c:-1 entry_SYSCALL_64_after_hwframe+0x61/0xcb page_owner free stack trace missing Memory state around the buggy address: ffff88811731c900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811731c980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88811731ca00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88811731ca80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88811731cb00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================