KASAN: use-after-free Read in f2fs_destroy_extent_tree

Status: upstream: reported C repro on 2024/09/30 06:40
Bug presence: origin:lts-only
[Documentation on labels]
Reported-by: syzbot+8aedc9aed9921d711a8e@syzkaller.appspotmail.com
First crash: 699d, last: 57d
▶ ▼ Bug presence (2)
Date Name Commit Repro Result
2024/09/30 linux-5.15.y (ToT) 3a5928702e71 C [report] KASAN: use-after-free Read in f2fs_destroy_extent_tree
2024/09/30 upstream (ToT) 9852d85ec9d4 C Didn't crash
▶ ▼ Last patch testing requests (9)
Created Duration User Patch Repo Result
2026/07/04 06:17 15m retest repro linux-5.15.y report log
2026/04/20 13:51 2h25m retest repro linux-5.15.y report log
2026/02/09 09:17 55m retest repro linux-5.15.y report log
2025/12/01 06:50 11m retest repro linux-5.15.y report log
2025/09/19 06:08 21m retest repro linux-5.15.y report log
2025/07/11 02:01 17m retest repro linux-5.15.y report log
2025/04/30 23:23 10m retest repro linux-5.15.y report log
2025/02/18 11:52 10m retest repro linux-5.15.y report log
2024/12/10 10:42 9m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (2)
Created Duration User Patch Repo Result
2024/12/15 19:49 2h37m fix candidate upstream OK (0) job log
2024/10/15 02:08 0m fix candidate upstream error job log

Sample crash report:
F2FS-fs (loop1): sanity_check_inode: inode (ino=8) has corrupted i_xattr_nid: 218103808, run fsck to fix.
==================================================================
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:71 [inline]
BUG: KASAN: use-after-free in atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
BUG: KASAN: use-after-free in f2fs_destroy_extent_node fs/f2fs/extent_cache.c:789 [inline]
BUG: KASAN: use-after-free in f2fs_destroy_extent_tree+0x151/0x670 fs/f2fs/extent_cache.c:839
Read of size 4 at addr ffff88806e5ef080 by task syz-executor738/3604

CPU: 1 PID: 3604 Comm: syz-executor738 Not tainted 5.15.167-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+0x1e3/0x2d0 lib/dump_stack.c:106
 print_address_description+0x63/0x3b0 mm/kasan/report.c:248
 __kasan_report mm/kasan/report.c:434 [inline]
 kasan_report+0x16b/0x1c0 mm/kasan/report.c:451
 kasan_check_range+0x27e/0x290 mm/kasan/generic.c:189
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 atomic_read include/linux/atomic/atomic-instrumented.h:27 [inline]
 f2fs_destroy_extent_node fs/f2fs/extent_cache.c:789 [inline]
 f2fs_destroy_extent_tree+0x151/0x670 fs/f2fs/extent_cache.c:839
 f2fs_evict_inode+0x3b1/0x1510 fs/f2fs/inode.c:767
 evict+0x529/0x930 fs/inode.c:622
 f2fs_iget+0x1ca5/0x4b90 fs/f2fs/inode.c:566
 f2fs_nfs_get_inode+0x70/0x100 fs/f2fs/super.c:3089
 generic_fh_to_dentry+0x94/0xe0 fs/libfs.c:1044
 exportfs_decode_fh_raw+0x140/0x590 fs/exportfs/expfs.c:436
 exportfs_decode_fh+0x38/0x70 fs/exportfs/expfs.c:576
 do_handle_to_path fs/fhandle.c:152 [inline]
 handle_to_path fs/fhandle.c:207 [inline]
 do_handle_open+0x44c/0x960 fs/fhandle.c:223
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc2e8d66a39
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 81 18 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:00007fc2e8d02168 EFLAGS: 00000246 ORIG_RAX: 0000000000000130
RAX: ffffffffffffffda RBX: 00007fc2e8df2618 RCX: 00007fc2e8d66a39
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000004
RBP: 00007fc2e8df2610 R08: 00007ffc73ab54b7 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007fc2e8df261c
R13: 000000000000006e R14: 00007ffc73ab53d0 R15: 00007ffc73ab54b8
 </TASK>

Allocated by task 3576:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track mm/kasan/common.c:46 [inline]
 set_alloc_info mm/kasan/common.c:434 [inline]
 __kasan_slab_alloc+0x8e/0xc0 mm/kasan/common.c:467
 kasan_slab_alloc include/linux/kasan.h:254 [inline]
 slab_post_alloc_hook+0x53/0x380 mm/slab.h:519
 slab_alloc_node mm/slub.c:3220 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0xf3/0x280 mm/slub.c:3233
 f2fs_kmem_cache_alloc_nofail fs/f2fs/f2fs.h:2623 [inline]
 f2fs_kmem_cache_alloc fs/f2fs/f2fs.h:2633 [inline]
 __grab_extent_tree fs/f2fs/extent_cache.c:295 [inline]
 __f2fs_init_extent_tree fs/f2fs/extent_cache.c:381 [inline]
 f2fs_init_extent_tree+0x58d/0xc50 fs/f2fs/extent_cache.c:404
 do_read_inode fs/f2fs/inode.c:392 [inline]
 f2fs_iget+0xfb0/0x4b90 fs/f2fs/inode.c:514
 f2fs_nfs_get_inode+0x70/0x100 fs/f2fs/super.c:3089
 generic_fh_to_dentry+0x94/0xe0 fs/libfs.c:1044
 exportfs_decode_fh_raw+0x140/0x590 fs/exportfs/expfs.c:436
 exportfs_decode_fh+0x38/0x70 fs/exportfs/expfs.c:576
 do_handle_to_path fs/fhandle.c:152 [inline]
 handle_to_path fs/fhandle.c:207 [inline]
 do_handle_open+0x44c/0x960 fs/fhandle.c:223
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

Freed by task 3576:
 kasan_save_stack mm/kasan/common.c:38 [inline]
 kasan_set_track+0x4b/0x80 mm/kasan/common.c:46
 kasan_set_free_info+0x1f/0x40 mm/kasan/generic.c:360
 ____kasan_slab_free+0xd8/0x120 mm/kasan/common.c:366
 kasan_slab_free include/linux/kasan.h:230 [inline]
 slab_free_hook mm/slub.c:1705 [inline]
 slab_free_freelist_hook+0xdd/0x160 mm/slub.c:1731
 slab_free mm/slub.c:3499 [inline]
 kmem_cache_free+0x91/0x1f0 mm/slub.c:3515
 f2fs_destroy_extent_tree+0x382/0x670 fs/f2fs/extent_cache.c:845
 f2fs_evict_inode+0x3b1/0x1510 fs/f2fs/inode.c:767
 evict+0x529/0x930 fs/inode.c:622
 f2fs_iget+0x1ca5/0x4b90 fs/f2fs/inode.c:566
 f2fs_nfs_get_inode+0x70/0x100 fs/f2fs/super.c:3089
 generic_fh_to_dentry+0x94/0xe0 fs/libfs.c:1044
 exportfs_decode_fh_raw+0x140/0x590 fs/exportfs/expfs.c:436
 exportfs_decode_fh+0x38/0x70 fs/exportfs/expfs.c:576
 do_handle_to_path fs/fhandle.c:152 [inline]
 handle_to_path fs/fhandle.c:207 [inline]
 do_handle_open+0x44c/0x960 fs/fhandle.c:223
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0

The buggy address belongs to the object at ffff88806e5ef000
 which belongs to the cache f2fs_extent_tree of size 136
The buggy address is located 128 bytes inside of
 136-byte region [ffff88806e5ef000, ffff88806e5ef088)
The buggy address belongs to the page:
page:ffffea0001b97bc0 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x6e5ef
flags: 0xfff00000000200(slab|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000000200 0000000000000000 dead000000000122 ffff88801e7963c0
raw: 0000000000000000 0000000080140014 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Reclaimable, gfp_mask 0x12c50(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_RECLAIMABLE), pid 3576, ts 55965798973, free_ts 15761265160
 prep_new_page mm/page_alloc.c:2426 [inline]
 get_page_from_freelist+0x322a/0x33c0 mm/page_alloc.c:4159
 __alloc_pages+0x272/0x700 mm/page_alloc.c:5423
 alloc_slab_page mm/slub.c:1775 [inline]
 allocate_slab mm/slub.c:1912 [inline]
 new_slab+0xbb/0x4b0 mm/slub.c:1975
 ___slab_alloc+0x6f6/0xe10 mm/slub.c:3008
 __slab_alloc mm/slub.c:3095 [inline]
 slab_alloc_node mm/slub.c:3186 [inline]
 slab_alloc mm/slub.c:3228 [inline]
 kmem_cache_alloc+0x18e/0x280 mm/slub.c:3233
 f2fs_kmem_cache_alloc_nofail fs/f2fs/f2fs.h:2623 [inline]
 f2fs_kmem_cache_alloc fs/f2fs/f2fs.h:2633 [inline]
 __grab_extent_tree fs/f2fs/extent_cache.c:295 [inline]
 __f2fs_init_extent_tree fs/f2fs/extent_cache.c:381 [inline]
 f2fs_init_extent_tree+0x58d/0xc50 fs/f2fs/extent_cache.c:404
 do_read_inode fs/f2fs/inode.c:392 [inline]
 f2fs_iget+0xfb0/0x4b90 fs/f2fs/inode.c:514
 f2fs_nfs_get_inode+0x70/0x100 fs/f2fs/super.c:3089
 generic_fh_to_dentry+0x94/0xe0 fs/libfs.c:1044
 exportfs_decode_fh_raw+0x140/0x590 fs/exportfs/expfs.c:436
 exportfs_decode_fh+0x38/0x70 fs/exportfs/expfs.c:576
 do_handle_to_path fs/fhandle.c:152 [inline]
 handle_to_path fs/fhandle.c:207 [inline]
 do_handle_open+0x44c/0x960 fs/fhandle.c:223
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
page last free stack trace:
 reset_page_owner include/linux/page_owner.h:24 [inline]
 free_pages_prepare mm/page_alloc.c:1340 [inline]
 free_pcp_prepare mm/page_alloc.c:1391 [inline]
 free_unref_page_prepare+0xc34/0xcf0 mm/page_alloc.c:3317
 free_unref_page+0x95/0x2d0 mm/page_alloc.c:3396
 free_contig_range+0x95/0xf0 mm/page_alloc.c:9342
 destroy_args+0xfe/0x980 mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x40d/0x470 mm/debug_vm_pgtable.c:1331
 do_one_initcall+0x22b/0x7a0 init/main.c:1302
 do_initcall_level+0x157/0x210 init/main.c:1375
 do_initcalls+0x49/0x90 init/main.c:1391
 kernel_init_freeable+0x425/0x5c0 init/main.c:1615
 kernel_init+0x19/0x290 init/main.c:1506
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287

Memory state around the buggy address:
 ffff88806e5eef80: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88806e5ef000: fa fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff88806e5ef080: fb fc fc fc fc fc fc fc fc fa fb fb fb fb fb fb
                   ^
 ffff88806e5ef100: fb fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc
 ffff88806e5ef180: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/09/30 07:43 linux-5.15.y 3a5928702e71 ba29ff75 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: use-after-free Read in f2fs_destroy_extent_tree
2024/09/30 06:40 linux-5.15.y 3a5928702e71 ba29ff75 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan KASAN: use-after-free Read in f2fs_destroy_extent_tree
* Struck through repros no longer work on HEAD.