KASAN: out-of-bounds Read in leaf_insert_into_buf

Status: upstream: reported C repro on 2023/08/21 01:29
Bug presence: origin:upstream
Labels: missing-backport
[Documentation on labels]
Reported-by: syzbot+d2e9ff892c5b482d6bf8@syzkaller.appspotmail.com
First crash: 1085d, last: 519d
Fix commit to backport (bisect log) :
tree: upstream
commit fb6f20ecb121cef4d7946f834a6ee867c4e21b4a
Author: Jan Kara <jack@suse.cz>
Date: Thu Oct 17 10:28:23 2024 +0000

  reiserfs: The last commit

  
Fix bisection: the issue occurs on the latest tested release (bisect log)
Crash: KASAN: out-of-bounds Read in leaf_paste_in_buffer (log)
Repro: C syz .config
  
▶ ▼ Bug presence (3)
Date Name Commit Repro Result
2024/12/26 linux-5.15.y (ToT) 91786f140358 C [report] KASAN: out-of-bounds Read in leaf_paste_in_buffer
2023/08/21 upstream (ToT) 706a74159504 C [report] UBSAN: array-index-out-of-bounds in direntry_create_vi
2024/12/26 upstream (ToT) 9b2ffa6148b1 C Didn't crash
▶ ▼ Similar bugs (3)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: out-of-bounds Read in leaf_insert_into_buf origin:upstream missing-backport 19 syz, C error 4 14d 1072d 0/3 upstream: reported C repro on 2023/09/02 13:42
upstream KASAN: use-after-free Read in leaf_insert_into_buf fs 19 1 1301d 1297d 0/29 auto-obsoleted due to no activity on 2023/04/17 00:48
upstream KASAN: use-after-free Read in leaf_insert_into_buf (2) fs 19 4 1138d 1168d 0/29 auto-obsoleted due to no activity on 2023/10/07 08:10
▶ ▼ Last patch testing requests (8)
Created Duration User Patch Repo Result
2026/08/09 17:55 36m retest repro linux-5.15.y report log
2026/05/17 11:28 19m retest repro linux-5.15.y report log
2026/03/05 17:50 52m retest repro linux-5.15.y report log
2025/12/25 14:29 12m retest repro linux-5.15.y report log
2025/10/15 16:21 1h35m retest repro linux-5.15.y report log
2025/07/31 00:44 9m retest repro linux-5.15.y report log
2025/05/17 11:55 11m retest repro linux-5.15.y report log
2025/03/06 22:09 9m retest repro linux-5.15.y report log
▶ ▼ Fix bisection attempts (14)
Created Duration User Patch Repo Result
2024/12/30 10:23 6h26m fix candidate upstream OK (1) job log
2024/12/08 01:47 3h33m bisect fix linux-5.15.y OK (0) job log log
2024/10/24 17:56 1h36m bisect fix linux-5.15.y OK (0) job log log
2024/09/22 03:55 1h09m bisect fix linux-5.15.y OK (0) job log log
2024/08/18 20:47 3h14m bisect fix linux-5.15.y OK (0) job log log
2024/07/07 03:43 1h02m bisect fix linux-5.15.y OK (0) job log log
2024/05/28 08:51 1h06m bisect fix linux-5.15.y OK (0) job log log
2024/04/24 03:09 2h09m bisect fix linux-5.15.y OK (0) job log log
2024/03/24 05:06 1h05m bisect fix linux-5.15.y OK (0) job log log
2024/02/23 00:12 1h02m bisect fix linux-5.15.y OK (0) job log log
2024/01/14 01:22 1h15m bisect fix linux-5.15.y OK (0) job log log
2023/12/12 20:03 1h10m bisect fix linux-5.15.y OK (0) job log log
2023/11/12 12:22 1h06m bisect fix linux-5.15.y OK (0) job log log
2023/10/10 21:53 2h30m bisect fix linux-5.15.y OK (0) job log log

Sample crash report:
REISERFS (device loop0): using 3.5.x disk format
REISERFS (device loop0): Created .reiserfs_priv - reserved for xattr storage.
==================================================================
BUG: KASAN: out-of-bounds in leaf_insert_into_buf+0x327/0x9a0 fs/reiserfs/lbalance.c:942
Read of size 372 at addr ffff88804a07ce8c by task syz-executor406/3486

CPU: 1 PID: 3486 Comm: syz-executor406 Not tainted 5.15.127-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/26/2023
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2cb 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
 memmove+0x25/0x60 mm/kasan/shadow.c:54
 leaf_insert_into_buf+0x327/0x9a0 fs/reiserfs/lbalance.c:942
 leaf_item_bottle fs/reiserfs/lbalance.c:508 [inline]
 leaf_copy_items fs/reiserfs/lbalance.c:617 [inline]
 leaf_move_items+0x1bc1/0x28a0 fs/reiserfs/lbalance.c:726
 balance_leaf_new_nodes_paste_whole fs/reiserfs/do_balan.c:1162 [inline]
 balance_leaf_new_nodes_paste fs/reiserfs/do_balan.c:1215 [inline]
 balance_leaf_new_nodes fs/reiserfs/do_balan.c:1246 [inline]
 balance_leaf+0x6515/0x12510 fs/reiserfs/do_balan.c:1450
 do_balance+0x309/0x8f0 fs/reiserfs/do_balan.c:1888
 reiserfs_paste_into_item+0x73b/0x880 fs/reiserfs/stree.c:2159
 reiserfs_get_block+0x226a/0x5390 fs/reiserfs/inode.c:1077
 __block_write_begin_int+0x60b/0x1650 fs/buffer.c:2012
 reiserfs_write_begin+0x346/0x810 fs/reiserfs/inode.c:2790
 generic_cont_expand_simple+0x144/0x230 fs/buffer.c:2362
 reiserfs_setattr+0x3ff/0xf90 fs/reiserfs/inode.c:3319
 notify_change+0xd4d/0x1000 fs/attr.c:488
 do_truncate+0x21c/0x300 fs/open.c:65
 do_sys_ftruncate+0x2eb/0x390 fs/open.c:193
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x61/0xcb
RIP: 0033:0x7efea1f57679
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 61 17 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fff2e29a408 EFLAGS: 00000246 ORIG_RAX: 000000000000004d
RAX: ffffffffffffffda RBX: 00007fff2e29a5d8 RCX: 00007efea1f57679
RDX: 00007efea1f57679 RSI: 0000000002007ffb RDI: 0000000000000005
RBP: 00007efea1fcb610 R08: 00007fff2e29a5d8 R09: 00007fff2e29a5d8
R10: 00007fff2e29a5d8 R11: 0000000000000246 R12: 0000000000000001
R13: 00007fff2e29a5c8 R14: 0000000000000001 R15: 0000000000000001
 </TASK>

The buggy address belongs to the page:
page:ffffea0001281f00 refcount:1 mapcount:1 mapping:0000000000000000 index:0x7fffffffd pfn:0x4a07c
memcg:ffff888011e34000
anon flags: 0xfff00000080014(uptodate|lru|swapbacked|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff00000080014 ffffea000129fc08 ffffea0001281ec8 ffff8880196bd001
raw: 00000007fffffffd 0000000000000000 0000000100000000 ffff888011e34000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Movable, gfp_mask 0x1100cca(GFP_HIGHUSER_MOVABLE), pid 2949, ts 53274993701, free_ts 12298732275
 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:5421
 alloc_pages_vma+0x39a/0x800 mm/mempolicy.c:2146
 wp_page_copy+0x24e/0x2070 mm/memory.c:3026
 handle_pte_fault mm/memory.c:4639 [inline]
 __handle_mm_fault mm/memory.c:4756 [inline]
 handle_mm_fault+0x2a3d/0x5950 mm/memory.c:4854
 do_user_addr_fault arch/x86/mm/fault.c:1397 [inline]
 handle_page_fault arch/x86/mm/fault.c:1485 [inline]
 exc_page_fault+0x271/0x740 arch/x86/mm/fault.c:1541
 asm_exc_page_fault+0x22/0x30 arch/x86/include/asm/idtentry.h:568
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:9340
 destroy_args+0xfe/0x97f mm/debug_vm_pgtable.c:1018
 debug_vm_pgtable+0x40d/0x462 mm/debug_vm_pgtable.c:1331
 do_one_initcall+0x22b/0x7a0 init/main.c:1295
 do_initcall_level+0x157/0x207 init/main.c:1368
 do_initcalls+0x49/0x86 init/main.c:1384
 kernel_init_freeable+0x43c/0x5c5 init/main.c:1608
 kernel_init+0x19/0x290 init/main.c:1499
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:298

Memory state around the buggy address:
 ffff88804a07cd80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804a07ce00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff88804a07ce80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
                      ^
 ffff88804a07cf00: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff88804a07cf80: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
==================================================================

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2023/08/21 01:29 linux-5.15.y f6f7927ac664 d216d8a0 .config console log report syz C [disk image] [vmlinux] [kernel image] [mounted in repro] ci2-linux-5-15-kasan KASAN: out-of-bounds Read in leaf_insert_into_buf
2025/03/08 15:12 linux-5.15.y c16c81c81336 7e3bd60d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan-arm64 KASAN: use-after-free Read in leaf_insert_into_buf
* Struck through repros no longer work on HEAD.