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BUG: KASAN: use-after-free in ext4_htree_fill_tree+0x1316/0x13e0 fs/ext4/namei.c:1221
Read of size 1 at addr ffff888117d4aa67 by task syz-executor/501

CPU: 0 PID: 501 Comm: syz-executor Not tainted 5.10.226-syzkaller-1003431-ge5e5644ea27f #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
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
 __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
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7f3689644bf3
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:00007ffc4a426e88 EFLAGS: 00000293 ORIG_RAX: 00000000000000d9
RAX: ffffffffffffffda RBX: 0000555582beb4e0 RCX: 00007f3689644bf3
RDX: 0000000000008000 RSI: 0000555582beb4e0 RDI: 0000000000000005
RBP: 0000555582beb4b4 R08: 0000000000028b61 R09: 0000000000000000
R10: 00007f3689771ca0 R11: 0000000000000293 R12: ffffffffffffffa8
R13: 0000000000000010 R14: 0000555582beb4b0 R15: 000000000000ca71

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_slab_alloc+0xb1/0xe0 mm/kasan/common.c:463
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x61/0x2f0 mm/slab.h:583
 slab_alloc_node mm/slub.c:2947 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 kmem_cache_alloc+0x168/0x2e0 mm/slub.c:2960
 getname_flags+0xba/0x520 fs/namei.c:141
 getname+0x19/0x20 fs/namei.c:212
 do_sys_openat2+0xd7/0x710 fs/open.c:1211
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_openat fs/open.c:1249 [inline]
 __se_sys_openat fs/open.c:1244 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1244
 do_syscall_64+0x34/0x70
 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]
 kmem_cache_free+0xa9/0x1e0 mm/slub.c:3219
 putname+0xe7/0x140 fs/namei.c:262
 do_sys_openat2+0x1fc/0x710 fs/open.c:1226
 do_sys_open fs/open.c:1233 [inline]
 __do_sys_openat fs/open.c:1249 [inline]
 __se_sys_openat fs/open.c:1244 [inline]
 __x64_sys_openat+0x243/0x290 fs/open.c:1244
 do_syscall_64+0x34/0x70
 entry_SYSCALL_64_after_hwframe+0x61/0xcb

The buggy address belongs to the object at ffff888117d4a200
 which belongs to the cache names_cache of size 4096
The buggy address is located 2151 bytes inside of
 4096-byte region [ffff888117d4a200, ffff888117d4b200)
The buggy address belongs to the page:
page:ffffea00045f5200 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x117d48
head:ffffea00045f5200 order:3 compound_mapcount:0 compound_pincount:0
flags: 0x4000000000010200(slab|head)
raw: 4000000000010200 dead000000000100 dead000000000122 ffff888100192f00
raw: 0000000000000000 0000000000070007 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 0x1d20c0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_HARDWALL), pid 95, ts 51860342740, free_ts 51845905993
 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
 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]
 kmem_cache_alloc+0x1b9/0x2e0 mm/slub.c:2960
 getname_flags+0xba/0x520 fs/namei.c:141
 user_path_at_empty+0x2d/0x50 fs/namei.c:2740
 do_readlinkat+0x114/0x3a0 fs/stat.c:414
 __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
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:28 [inline]
 free_pages_prepare mm/page_alloc.c:1349 [inline]
 __free_pages_ok+0x82c/0x850 mm/page_alloc.c:1629
 free_the_page+0x76/0x370 mm/page_alloc.c:5409
 __free_pages+0x67/0xc0 mm/page_alloc.c:5418
 __free_slab+0xcf/0x190 mm/slub.c:1894
 free_slab mm/slub.c:1909 [inline]
 discard_slab mm/slub.c:1915 [inline]
 unfreeze_partials+0x15e/0x190 mm/slub.c:2410
 put_cpu_partial+0xbf/0x180 mm/slub.c:2446
 __slab_free+0x2c8/0x3a0 mm/slub.c:3095
 do_slab_free mm/slub.c:3191 [inline]
 ___cache_free+0x111/0x130 mm/slub.c:3210
 qlink_free+0x50/0x90 mm/kasan/quarantine.c:157
 qlist_free_all+0x47/0xb0 mm/kasan/quarantine.c:176
 kasan_quarantine_reduce+0x15a/0x170 mm/kasan/quarantine.c:283
 __kasan_slab_alloc+0x2f/0xe0 mm/kasan/common.c:440
 kasan_slab_alloc include/linux/kasan.h:244 [inline]
 slab_post_alloc_hook+0x61/0x2f0 mm/slab.h:583
 slab_alloc_node mm/slub.c:2947 [inline]
 slab_alloc mm/slub.c:2955 [inline]
 __kmalloc+0x183/0x330 mm/slub.c:4029
 kmalloc include/linux/slab.h:557 [inline]
 kernfs_fop_write_iter+0x151/0x410 fs/kernfs/file.c:273
 call_write_iter include/linux/fs.h:2021 [inline]
 new_sync_write fs/read_write.c:518 [inline]
 vfs_write+0xb4c/0xe70 fs/read_write.c:605

Memory state around the buggy address:
 ffff888117d4a900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888117d4a980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff888117d4aa00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                       ^
 ffff888117d4aa80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff888117d4ab00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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