[syzbot] [btrfs?] KASAN: slab-use-after-free Read in free_block_entry

From: syzbot
Date: Fri Nov 15 2024 - 05:35:39 EST

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Hello,

syzbot found the following issue on:

HEAD commit: 2d5404caa8c7 Linux 6.12-rc7
git tree: upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=141534e8580000
kernel config: https://syzkaller.appspot.com/x/.config?x=d2aeec8c0b2e420c
dashboard link: https://syzkaller.appspot.com/bug?extid=7325f164162e200000c1
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40

Unfortunately, I don't have any reproducer for this issue yet.

Downloadable assets:
disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/7feb34a89c2a/non_bootable_disk-2d5404ca.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/c68277f7b0f1/vmlinux-2d5404ca.xz
kernel image: https://storage.googleapis.com/syzbot-assets/161b075483b1/bzImage-2d5404ca.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+7325f164162e200000c1@xxxxxxxxxxxxxxxxxxxxxxxxx

BTRFS error (device loop0 state EA): Ref action 2, root 5, ref_root 0, parent 8564736, owner 0, offset 0, num_refs 18446744073709551615
__btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523
update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512
btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594
btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116
btrfs_insert_empty_items+0x9c/0x1a0 fs/btrfs/ctree.c:4314
btrfs_insert_empty_item fs/btrfs/ctree.h:669 [inline]
btrfs_insert_orphan_item+0x1f1/0x320 fs/btrfs/orphan.c:23
btrfs_orphan_add+0x6d/0x1a0 fs/btrfs/inode.c:3482
btrfs_unlink+0x267/0x350 fs/btrfs/inode.c:4293
vfs_unlink+0x365/0x650 fs/namei.c:4469
do_unlinkat+0x4ae/0x830 fs/namei.c:4533
__do_sys_unlinkat fs/namei.c:4576 [inline]
__se_sys_unlinkat fs/namei.c:4569 [inline]
__x64_sys_unlinkat+0xcc/0xf0 fs/namei.c:4569
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
BTRFS error (device loop0 state EA): Ref action 1, root 5, ref_root 5, parent 0, owner 260, offset 0, num_refs 1
__btrfs_mod_ref+0x76b/0xac0 fs/btrfs/extent-tree.c:2521
update_ref_for_cow+0x96a/0x11f0
btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594
btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411
__btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030
btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline]
__btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137
__btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171
btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313
prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586
relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611
btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377
__btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161
btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538
BTRFS error (device loop0 state EA): Ref action 2, root 5, ref_root 0, parent 8564736, owner 0, offset 0, num_refs 18446744073709551615
__btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523
update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512
btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594
btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411
__btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030
btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline]
__btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137
__btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171
btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313
prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586
relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611
btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377
__btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161
btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538
==================================================================
BUG: KASAN: slab-use-after-free in rb_first+0x69/0x70 lib/rbtree.c:473
Read of size 8 at addr ffff888042d1af38 by task syz.0.0/5329

CPU: 0 UID: 0 PID: 5329 Comm: syz.0.0 Not tainted 6.12.0-rc7-syzkaller #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
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:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
rb_first+0x69/0x70 lib/rbtree.c:473
free_block_entry+0x78/0x230 fs/btrfs/ref-verify.c:248
btrfs_free_ref_cache+0xa3/0x100 fs/btrfs/ref-verify.c:917
btrfs_ref_tree_mod+0x139f/0x15e0 fs/btrfs/ref-verify.c:898
btrfs_free_extent+0x33c/0x380 fs/btrfs/extent-tree.c:3544
__btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523
update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512
btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594
btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411
__btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030
btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline]
__btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137
__btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171
btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313
prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586
relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611
btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377
__btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161
btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538
btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f996df7e719
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f996ede7038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f996e135f80 RCX: 00007f996df7e719
RDX: 0000000020000180 RSI: 00000000c4009420 RDI: 0000000000000004
RBP: 00007f996dff139e R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f996e135f80 R15: 00007fff79f32e68
</TASK>

Allocated by task 5329:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
poison_kmalloc_redzone mm/kasan/common.c:377 [inline]
__kasan_kmalloc+0x98/0xb0 mm/kasan/common.c:394
kasan_kmalloc include/linux/kasan.h:257 [inline]
__kmalloc_cache_noprof+0x19c/0x2c0 mm/slub.c:4295
kmalloc_noprof include/linux/slab.h:878 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
btrfs_ref_tree_mod+0x264/0x15e0 fs/btrfs/ref-verify.c:701
btrfs_free_extent+0x33c/0x380 fs/btrfs/extent-tree.c:3544
__btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523
update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512
btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594
btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411
__btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030
btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline]
__btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137
__btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171
btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313
prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586
relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611
btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377
__btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161
btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538
btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 5329:
kasan_save_stack mm/kasan/common.c:47 [inline]
kasan_save_track+0x3f/0x80 mm/kasan/common.c:68
kasan_save_free_info+0x40/0x50 mm/kasan/generic.c:579
poison_slab_object mm/kasan/common.c:247 [inline]
__kasan_slab_free+0x59/0x70 mm/kasan/common.c:264
kasan_slab_free include/linux/kasan.h:230 [inline]
slab_free_hook mm/slub.c:2342 [inline]
slab_free mm/slub.c:4579 [inline]
kfree+0x1a0/0x440 mm/slub.c:4727
btrfs_ref_tree_mod+0x136c/0x15e0
btrfs_free_extent+0x33c/0x380 fs/btrfs/extent-tree.c:3544
__btrfs_mod_ref+0x7dd/0xac0 fs/btrfs/extent-tree.c:2523
update_ref_for_cow+0x9cd/0x11f0 fs/btrfs/ctree.c:512
btrfs_force_cow_block+0x9f6/0x1da0 fs/btrfs/ctree.c:594
btrfs_cow_block+0x35e/0xa40 fs/btrfs/ctree.c:754
btrfs_search_slot+0xbdd/0x30d0 fs/btrfs/ctree.c:2116
btrfs_lookup_inode+0xdc/0x480 fs/btrfs/inode-item.c:411
__btrfs_update_delayed_inode+0x1e7/0xb90 fs/btrfs/delayed-inode.c:1030
btrfs_update_delayed_inode fs/btrfs/delayed-inode.c:1114 [inline]
__btrfs_commit_inode_delayed_items+0x2318/0x24a0 fs/btrfs/delayed-inode.c:1137
__btrfs_run_delayed_items+0x213/0x490 fs/btrfs/delayed-inode.c:1171
btrfs_commit_transaction+0x8a8/0x3740 fs/btrfs/transaction.c:2313
prepare_to_relocate+0x3c4/0x4c0 fs/btrfs/relocation.c:3586
relocate_block_group+0x16c/0xd40 fs/btrfs/relocation.c:3611
btrfs_relocate_block_group+0x77d/0xd90 fs/btrfs/relocation.c:4081
btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3377
__btrfs_balance+0x1b0f/0x26b0 fs/btrfs/volumes.c:4161
btrfs_balance+0xbdc/0x10c0 fs/btrfs/volumes.c:4538
btrfs_ioctl_balance+0x493/0x7c0 fs/btrfs/ioctl.c:3673
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl+0xf9/0x170 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff888042d1af00
which belongs to the cache kmalloc-64 of size 64
The buggy address is located 56 bytes inside of
freed 64-byte region [ffff888042d1af00, ffff888042d1af40)

The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x42d1a
anon flags: 0x4fff00000000000(node=1|zone=1|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 04fff00000000000 ffff88801ac418c0 0000000000000000 dead000000000001
raw: 0000000000000000 0000000000200020 00000001f5000000 0000000000000000
page dumped because: kasan: bad access detected
page_owner tracks the page as allocated
page last allocated via order 0, migratetype Unmovable, gfp_mask 0x52c40(GFP_NOFS|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP), pid 5055, tgid 5055 (dhcpcd-run-hook), ts 40377240074, free_ts 40376848335
set_page_owner include/linux/page_owner.h:32 [inline]
post_alloc_hook+0x1f3/0x230 mm/page_alloc.c:1541
prep_new_page mm/page_alloc.c:1549 [inline]
get_page_from_freelist+0x3649/0x3790 mm/page_alloc.c:3459
__alloc_pages_noprof+0x292/0x710 mm/page_alloc.c:4735
alloc_pages_mpol_noprof+0x3e8/0x680 mm/mempolicy.c:2265
alloc_slab_page+0x6a/0x140 mm/slub.c:2412
allocate_slab+0x5a/0x2f0 mm/slub.c:2578
new_slab mm/slub.c:2631 [inline]
___slab_alloc+0xcd1/0x14b0 mm/slub.c:3818
__slab_alloc+0x58/0xa0 mm/slub.c:3908
__slab_alloc_node mm/slub.c:3961 [inline]
slab_alloc_node mm/slub.c:4122 [inline]
__do_kmalloc_node mm/slub.c:4263 [inline]
__kmalloc_noprof+0x25a/0x400 mm/slub.c:4276
kmalloc_noprof include/linux/slab.h:882 [inline]
kzalloc_noprof include/linux/slab.h:1014 [inline]
tomoyo_encode2 security/tomoyo/realpath.c:45 [inline]
tomoyo_encode+0x26f/0x540 security/tomoyo/realpath.c:80
tomoyo_realpath_from_path+0x59e/0x5e0 security/tomoyo/realpath.c:283
tomoyo_get_realpath security/tomoyo/file.c:151 [inline]
tomoyo_check_open_permission+0x255/0x500 security/tomoyo/file.c:771
security_file_open+0x777/0x990 security/security.c:3109
do_dentry_open+0x369/0x1460 fs/open.c:945
vfs_open+0x3e/0x330 fs/open.c:1088
do_open fs/namei.c:3774 [inline]
path_openat+0x2c84/0x3590 fs/namei.c:3933
page last free pid 5055 tgid 5055 stack trace:
reset_page_owner include/linux/page_owner.h:25 [inline]
free_pages_prepare mm/page_alloc.c:1112 [inline]
free_unref_page+0xcfb/0xf20 mm/page_alloc.c:2642
free_pipe_info+0x300/0x390 fs/pipe.c:860
put_pipe_info fs/pipe.c:719 [inline]
pipe_release+0x245/0x320 fs/pipe.c:742
__fput+0x23f/0x880 fs/file_table.c:431
__do_sys_close fs/open.c:1567 [inline]
__se_sys_close fs/open.c:1552 [inline]
__x64_sys_close+0x7f/0x110 fs/open.c:1552
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f

Memory state around the buggy address:
ffff888042d1ae00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
ffff888042d1ae80: 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc fc
>ffff888042d1af00: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
^
ffff888042d1af80: 00 00 00 00 00 00 fc fc fc fc fc fc fc fc fc fc
ffff888042d1b000: 00 00 00 00 00 fc fc 00 00 00 00 00 fc fc 00 00
==================================================================

---
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