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KASAN: use-after-free Read in bkey_packed_valid

Status: upstream: reported C repro on 2024/12/16 09:45
Subsystems: bcachefs
[Documentation on labels]
Reported-by: syzbot+5970f72a85a751ab7556@syzkaller.appspotmail.com
First crash: 160d, last: 73d
Cause bisection: introduced by (bisect log) :
commit 03ef80b469d5d83530ce1ce15be78a40e5300f9b
Author: Kent Overstreet <kent.overstreet@linux.dev>
Date: Sat Sep 23 22:41:51 2023 +0000

  bcachefs: Ignore unknown mount options

Crash: invalid opcode in bch2_dump_bset (log)
Repro: C syz .config
  
Fix bisection: the issue occurs on the latest tested release (bisect log)
  
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
[syzbot] [bcachefs?] KASAN: use-after-free Read in bkey_packed_valid 0 (3) 2024/12/19 09:45
▶ ▼ Last patch testing requests (10)
Created Duration User Patch Repo Result
2025/04/28 03:15 1h19m retest repro upstream OK log
2025/03/28 08:55 14m retest repro upstream report log
2025/03/22 20:28 19m retest repro upstream OK log
2025/03/22 20:28 22m retest repro upstream OK log
2025/03/22 20:28 21m retest repro upstream OK log
2025/03/22 13:00 21m retest repro upstream OK log
2025/03/22 13:00 21m retest repro upstream OK log
2025/03/22 13:00 21m retest repro upstream OK log
2025/01/17 05:04 16m retest repro upstream report log
2025/01/17 05:04 13m retest repro upstream report log

Sample crash report:
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 7589ab5e0c11cc7a written 1040 min_key POS_MIN durability: 1 ptr: 0:38:0 gen 0  
  node offset 16/1040 bset u64s 65529 bset byte offset 792: keys out of order: u64s 18 type inode_v3 1536:536870913:U32_MAX len 0 ver 0 > u64s 18 type inode_v3 0:536870914:U32_MAX len 0 ver 0, fixing
bcachefs (loop3): error validating btree node at btree inodes level 0/0
  u64s 11 type btree_ptr_v2 SPOS_MAX len 0 ver 0: seq 7589ab5e0c11cc7a written 1040 min_key POS_MIN durability: 1 ptr: 0:38:0 gen 0  
  node offset 16/1040 bset u64s 65518 bset byte offset 792: bad k->u64s 0 (min 3 max 253), fixing
==================================================================
BUG: KASAN: slab-out-of-bounds in bkey_packed_valid+0x3a8/0x4b0 fs/bcachefs/btree_io.c:847
Read of size 1 at addr ffff88805a0c1000 by task kworker/0:1H/43

CPU: 0 UID: 0 PID: 43 Comm: kworker/0:1H Not tainted 6.13.0-rc3-syzkaller-00301-gbcde95ce32b6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Workqueue: bcachefs_btree_read_complete btree_node_read_work
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:94 [inline]
 dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
 print_address_description mm/kasan/report.c:378 [inline]
 print_report+0x169/0x550 mm/kasan/report.c:489
 kasan_report+0x143/0x180 mm/kasan/report.c:602
 bkey_packed_valid+0x3a8/0x4b0 fs/bcachefs/btree_io.c:847
 validate_bset_keys+0x98d/0x1610 fs/bcachefs/btree_io.c:955
 bch2_btree_node_read_done+0x2402/0x5e90 fs/bcachefs/btree_io.c:1130
 btree_node_read_work+0x68b/0x1260 fs/bcachefs/btree_io.c:1323
 process_one_work kernel/workqueue.c:3229 [inline]
 process_scheduled_works+0xa66/0x1840 kernel/workqueue.c:3310
 worker_thread+0x870/0xd30 kernel/workqueue.c:3391
 kthread+0x2f0/0x390 kernel/kthread.c:389
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244
 </TASK>

The buggy address belongs to the object at ffff88805a0c0000
 which belongs to the cache kmalloc-rcl-4k of size 4096
The buggy address is located 0 bytes to the right of
 allocated 4096-byte region [ffff88805a0c0000, ffff88805a0c1000)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x5a0c0
head: order:3 mapcount:0 entire_mapcount:0 nr_pages_mapped:0 pincount:0
memcg:ffff888064c76201
flags: 0xfff00000000040(head|node=0|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 00fff00000000040 ffff88801ac4c280 dead000000000122 0000000000000000
raw: 0000000000000000 0000000000040004 00000001f5000000 ffff888064c76201
head: 00fff00000000040 ffff88801ac4c280 dead000000000122 0000000000000000
head: 0000000000000000 0000000000040004 00000001f5000000 ffff888064c76201
head: 00fff00000000003 ffffea0001683001 ffffffffffffffff 0000000000000000
head: 0000000000000008 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 3, migratetype Reclaimable, gfp_mask 0xd20d0(__GFP_IO|__GFP_FS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC|__GFP_RECLAIMABLE), pid 6065, tgid 6064 (syz.3.19), ts 80089948634, free_ts 16189106356
 set_page_owner include/linux/page_owner.h:32 [inline]
 post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1558
 prep_new_page mm/page_alloc.c:1566 [inline]
 get_page_from_freelist+0x3651/0x37a0 mm/page_alloc.c:3476
 __alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4753
 alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2269
 alloc_slab_page+0x6a/0x110 mm/slub.c:2423
 allocate_slab+0x5a/0x2b0 mm/slub.c:2589
 new_slab mm/slub.c:2642 [inline]
 ___slab_alloc+0xc27/0x14a0 mm/slub.c:3830
 __slab_alloc+0x58/0xa0 mm/slub.c:3920
 __slab_alloc_node mm/slub.c:3995 [inline]
 slab_alloc_node mm/slub.c:4156 [inline]
 __do_kmalloc_node mm/slub.c:4297 [inline]
 __kmalloc_node_noprof+0x2ee/0x4d0 mm/slub.c:4304
 __kvmalloc_node_noprof+0x72/0x190 mm/util.c:650
 btree_node_data_alloc+0x15a/0x260 fs/bcachefs/btree_cache.c:157
 __bch2_btree_node_mem_alloc+0x1d8/0x3e0 fs/bcachefs/btree_cache.c:198
 bch2_fs_btree_cache_init+0x26f/0x630 fs/bcachefs/btree_cache.c:653
 bch2_fs_alloc fs/bcachefs/super.c:917 [inline]
 bch2_fs_open+0x2aa4/0x2f80 fs/bcachefs/super.c:2065
 bch2_fs_get_tree+0x738/0x1710 fs/bcachefs/fs.c:2157
 vfs_get_tree+0x90/0x2b0 fs/super.c:1814
page last free pid 1 tgid 1 stack trace:
 reset_page_owner include/linux/page_owner.h:25 [inline]
 free_pages_prepare mm/page_alloc.c:1127 [inline]
 free_unref_page+0xd2c/0x1000 mm/page_alloc.c:2659
 free_contig_range+0x14c/0x430 mm/page_alloc.c:6632
 destroy_args+0x92/0x910 mm/debug_vm_pgtable.c:1017
 debug_vm_pgtable+0x4be/0x550 mm/debug_vm_pgtable.c:1397
 do_one_initcall+0x248/0x870 init/main.c:1266
 do_initcall_level+0x157/0x210 init/main.c:1328
 do_initcalls+0x3f/0x80 init/main.c:1344
 kernel_init_freeable+0x435/0x5d0 init/main.c:1577
 kernel_init+0x1d/0x2b0 init/main.c:1466
 ret_from_fork+0x4b/0x80 arch/x86/kernel/process.c:147
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:244

Memory state around the buggy address:
 ffff88805a0c0f00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88805a0c0f80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88805a0c1000: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
                   ^
 ffff88805a0c1080: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff88805a0c1100: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
==================================================================

Crashes (38):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2024/12/22 20:09 upstream bcde95ce32b6 b4fbdbd4 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/08 12:32 upstream 21e4543a2e2f 7e3bd60d .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/03/05 05:55 upstream 48a5eed9ad58 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/03/03 21:29 upstream 7eb172143d55 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/03/03 18:22 upstream 7eb172143d55 c3901742 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/03/03 17:53 upstream 7eb172143d55 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/03/03 13:47 upstream 7eb172143d55 c3901742 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/01/03 04:11 upstream 0bc21e701a6f d3ccff63 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2024/12/24 15:49 upstream f07044dd0df0 444551c4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2024/12/16 04:45 upstream dccbe2047a5b 7cbfbb3a .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2024/12/11 09:12 upstream f92f4749861b cfc402b4 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: use-after-free Read in bkey_packed_valid
2025/03/05 23:51 upstream bb2281fb05e5 831e3629 .config console log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: slab-use-after-free Read in bkey_packed_valid
2025/03/02 22:37 upstream b91872c56940 c3901742 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 22:03 upstream b91872c56940 c3901742 .config console log report syz / log [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: slab-use-after-free Read in bkey_packed_valid
2024/12/18 16:33 upstream aef25be35d23 a0626d3a .config strace log report syz / log C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-upstream-fs KASAN: slab-use-after-free Read in bkey_packed_valid
2025/03/05 18:16 upstream cfced12f5100 60f5d8d9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/05 15:46 upstream 48a5eed9ad58 60f5d8d9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/05 11:55 upstream 48a5eed9ad58 60f5d8d9 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/05 06:36 upstream 48a5eed9ad58 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/05 06:20 upstream 48a5eed9ad58 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/04 16:19 upstream 99fa936e8e4f c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/04 13:59 upstream 99fa936e8e4f c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/04 13:56 upstream 99fa936e8e4f c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/04 09:04 upstream 99fa936e8e4f c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/04 02:13 upstream 99fa936e8e4f c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bkey_packed_valid
2025/03/03 18:24 upstream 7eb172143d55 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/03 16:20 upstream 7eb172143d55 c3901742 .config console log report syz / log C [disk image (non-bootable)] [vmlinux] [kernel image] [mounted in repro #1] [mounted in repro #2] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/03 12:18 upstream 7eb172143d55 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/03 10:58 upstream 7eb172143d55 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bkey_packed_valid
2025/03/03 07:40 upstream 1973160c90d7 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/03 04:18 upstream 1973160c90d7 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/03 03:09 upstream 1973160c90d7 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 23:31 upstream 1973160c90d7 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 22:18 upstream 1973160c90d7 c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 17:51 upstream ece144f151ac c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 15:39 upstream ece144f151ac c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 15:37 upstream ece144f151ac c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-out-of-bounds Read in bkey_packed_valid
2025/03/02 15:36 upstream ece144f151ac c3901742 .config console log report [disk image (non-bootable)] [vmlinux] [kernel image] ci-snapshot-upstream-root KASAN: slab-use-after-free Read in bkey_packed_valid
* Struck through repros no longer work on HEAD.